BFNA Title: Orthotrichum
Author: D. H. Vitt
 Date: August 12, 2009
Edit Level: R
Version: 2

Bryophyte Flora of North America, Provisional Publication
Missouri Botanical Garden

BFNA Web site: http://www.mobot.org/plantscience/BFNA/bfnamenu.htm

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Aug. 12, 2009 Second version

 

ORTHOTRICHUM - ORTHOTRICHACEAE

 

6.  Orthotrichum Hedwig, Spec. Musc. Frond., 162.  1801 * [For straight, erect hairs of calyptra in many species]

                                                                                                                                       Dale H. Vitt

 

Plants 1--5(--13) cm.  Stem leaves imbricate, usually erect-appressed and straight when dry, spreading to wide-spreading when moist, 0.6--6.5 mm; ovate, lanceolate, or linear-lanceolate, obtuse, acute to rounded-acute, acuminate or sometimes obtuse, rarely channeled, rarely acuminate or piliferous; margins reflexed to revolute, rarely plane or involute, entire or denticulate near apex; costa strong, usually ending near apex; distal laminal cells mostly rounded, almost isodiametric, usually 6--24(--30) \um, with 1--3 papillae per cell, papillae conical or forked; basal leaf cells elongate-linear, thick-walled and nodose or rectangular, thin-walled, and smooth near base; marginal leaf cells shorter.  Specialized asexual reproduction by brood-bodies, sometimes present on leaves, 3--14 cells long.  Perichaetial leaves similar to stem leaves or sometimes slightly differentiated.  Sexual condition goniautoicous or cladautoicous, rarely dioicous.  Seta to 15 mm, twisted to left.  Capsule immersed, emergent or exserted, varying from globose to cylindric, 0.7--3 mm, more or less gradually constricted to seta, smooth or with 8 or 16 ribs and sometimes constricted below mouth when dry; stomates superficial or immersed in central or proximal parts of capsules; peristome double or more rarely single or absent; exostome teeth 0, 8, or 16, papillose or striate, reflexed, recurved, or erect; endostome segments 0, 8, or 16. Calyptra large, mitrate, conic-oblong to short-conic, more or less hairy or naked, plicate or more rarely smooth, not split at base.  Spores isomorphic.

 

Species 125 (47 in the flora); worldwide, more common in temperate areas.

 

SELECTED REFERENCES:  Lewinsky, J.  1993.  Monographic studies on Orthotrichum (Musci).  Bryobrothera 2: 1--59.  Vitt, D. H.  1973.  A Revision of the Genus Orthotrichum in North America, North of Mexico.  Bryophytorum Bibliotheca 1: 1--108.

 

(For Key to species, see end of treatment.)

 

 

1.  Orthotrichum affine Bridel, Musc. Rec. 2(2): 22. 1801 

 

Plants to 3 cm.  Stem leaves erect-appressed and straight when dry, ligulate, elongate- to ovate-lanceolate, 2--4 mm, acuminate, sharply acute, obtuse, or rounded, sometimes broadly apiculate; margins recurved-revolute to just below apex, entire; distal laminal cells 9--13 \um wide, 1-stratose with 2--3 low, forked papillae per cell; basal laminal cells long-rectangular to elongate, nodose.  Sexual condition goniautoicous.  Seta 1--2.2 mm.  Capsule 1/2 emergent to shortly exserted; urn oblong-cylindric when mature, narrowly-cylindric and constricted along entire length when old and dry, 1.6--2.5 mm, strongly 8-ribbed 2/3 entire length of capsule; stomates superficial; peristome double; endostome segments 8, rarely 16, 2 cells wide at base, reticulate-papillose; exostome teeth 8, erect when mature, reflexed-recurved when old, coarsely and obscurely papillose or sometimes papillose-reticulate.  Calyptra conic-oblong, with a few papillose hairs.  Spores 15--18 \um.

 

Deciduous trees, rarely on shaded rocks, shaded forests near stream beds and in canyons, usually in mountainous areas; 0--3000 m; Alta., B.C.; Calif., Colo., Idaho, Mont., Oreg., Utah, Wash; Europe; Asia; n Africa.

 

Orthotrichum affine, a species confined to western North America, is best recognized by the following combination of characters: superficial stomates; cylindric, strongly ribbed, almost exserted capsules; a well-developed, but not stout endostome; and a calyptra that is only sparsely hairy.

 

2.  Orthotrichum alpestre Hornschuch ex Bruch, Schimper & W. Gümbel, Bryol. Eur. 3 (fasc. 2/3) Orthotrichum Suppl. 1: 1. 1849

 

Orthotrichum alpestre var. majus Lesquereux & James; O. alpestre var. watsonii (James) Grout; O. occidentale James; O. watsonii James

 

Plants 0.5--2.3 cm.  Stem leaves loosely erect-appressed and ± loosely twisted when dry; elongate- to ovate-lanceolate, 2--3.5 mm, sharply acute, sometimes acuminate, cuspidate or apiculate; margins revolute to below apex, entire; distal laminal cells 9--14 \um wide, 1-stratose, with 2--3 large, conical or forked papillae per cell; basal laminal cells long-rectangular to rectangular, sometimes nodose at insertion.  Sexual condition goniautoicous.  Seta less than 1.4 mm.  Capsule 1/2--3/4 emergent, sometimes almost exserted; urn oblong-ovate when mature, oblong to short-cylindric when old and dry, less than 1.4 mm, strongly 8-ribbed 2/3 to the entire length; stomates immersed, just below middle of the capsule, ± 1/2 covered by well-differentiated subsidiary cells; peristome double; endostome segments 8 or 16, of 1 or 2 rows of cells, smooth or finely roughened; exostome teeth 8, reflexed, densely and evenly papillose.  Calyptra oblong, ± hairy, hairs with large, distinct papillae.  Spores 10--15 \um.

 

Rocks and trees, at the bases of trees and in moist crevices of large boulders, especially common in moist, pine and deciduous forests; 2100--3000 m; Greenland; Alta., B.C., Nfld., Ont., Yukon; Ariz., Calif., Colo., Idaho, Mich., Mont., Nev., N.Mex., Oreg., S.Dak., Utah, Wash., Wyo.; Europe; Asia; Pacific Islands (New Zealand).

 

Orthotrichum alpestre is distinguished by the highly papillose distal laminal cells, slightly twisted, sharply pointed leaves, a calyptra with papillose hairs, the absence of a preperistome, and the papillose or papillose-reticulate exostome.  The endostome is always present in mature capsules and, because of enlarged crosswalls, has a shiny appearance.  The capsule is usually oblong and strangulate, although the shape depends on age. In some specimens the capsule is short-cylindric and not much constricted under the mouth.

 

3.  Orthotrichum anodon Lara, Garilleti & Mazimpaka in Grarilleti, Lara, & Mazimpaka, Bryologist 109: 188.  2006

 

Plants to 5 mm.  Stem leaves erect and slightly flexuose when dry, broadly ligulate to ovate-ligulate, 2--2.5 mm, obtuse; margins recurved to near apex, entire; distal laminal cells 10--16 \um wide, 1-stratose, smooth or with 1--2 low papillae; basal laminal cells shortly rectangular, not nodose.  Sexual condition goniautoicous.  Seta ± 0.5 mm.  Capsule immersed to shortly emergent, urn shortly cylindric to elliptic when dry, 1.4--1.6 mm, smooth and constricted at mouth by 8 short ribs; stomates immersed in neck and proximal third of urn, completely covered by strongly differentiated subsidiary cells; peristome single; endostome of 16 hyaline and fragile, finely papillose segments; exostome none.  Calyptra conic, smooth, hairy.  Spores 17--21 \um.

 

Quercus trunks; low elevations; known from one locality in Los Angeles Co., Calif.

 

The small plants, ligulate, blunt leaves, immersed stomates, lack of an exostome, and capsule characters, unique among North American Orthotricha, distinguish Orthotrichum anodon.  The puckered capsule mouth is reminiscent of that of several species of Ulota including U. obtusiuscula and U. coarctata.

 

4.  Orthotrichum anomalum Hedwig, Spec. Musc. Frond., 162. 1801

 

Orthotrichum anomalum var. americanum Macoun & Kindberg; O. canadense Bruch & Schimper; O. consimile ssp. anomaloides Kindberg

 

Plants to .5 mm.  Stem leaves stiff, erect-appressed when dry, elongate-lanceolate, lanceolate, or narrowly ovate-lanceolate, 2--3.8 mm, acute, bluntly acute, or narrowly obtuse; margins recurved-revolute to near apex, smooth; distal laminal cells 9--14 \um wide, 1-stratose, with 1--3 small, conical papillae; basal laminal cells long-rectangular to rectangular, sometimes slightly nodose.  Sexual condition goniautoicous.  Seta 1--3 mm.  Capsule exserted; urn oblong-cylindric to cylindric, 1.8--2.4 mm, usually 16-ribbed with 8 long ribs extending 1/2--2/3 length of capsule and alternating short 8 ribs; stomates immersed in middle and proximal portion of capsule; peristome usually single; endostome rarely present; exostome teeth 16, rarely united into 8 pairs, finely horizontally-striate below, vertically-striate above.  Calyptra oblong-conic, with few to many papillose hairs.  Spores 11--15 \um.

 

Rocks, especially limestone, rarely at the base of trees or on dead branches;common on the dryer rock faces in canyon areas; 0--3000 m; Greenland; Alta., B.C., Man., N.B., Nfld., N.W.T., N.S. Ont. Que., Sask., Yukon; Alaska, Ariz., Colo., Conn., Idaho, Ill., Ind., Iowa, Maine, Mich., Minn., Mont., N.Mex., N.Y., N.Dak., Ohio, Pa., R.I., S.C., S.Dak., Tenn., Utah, Vt., Va., Wash., Wisc., Wyo.; Mexico (Nuevo León, San Luis Potosí); West Indies (Haiti); Europe; Asia; n Africa.

 

Orthotrichum anomalum has exserted capsules that are slightly constricted beneath the mouth, and unistratose leaves.  The most useful character in distinguishing this species from others is the exserted capsule with 8 long ribs alternating with 8 shorter ones.

 

5.  Orthotrichum bartramii Williams, Bryologist 28: 76.  1925

 

Plants to 10 mm.  Stem leaves erect-appressed when dry, oblong to oblong-lanceolate, 2--3 mm, bluntly cuspidate or sometimes irregularly obtuse or acute; margins recurved to broadly revolute, incurved and serrate at apex; distal laminal cells 8--13 \um wide, 1-stratose, with two, small conical papillae; basal laminal cells narrowly rectangular, grading to quadrate at margin, non-nodose.  Sexual condition goniautoicous or cladautoicous.  Seta less than 1 mm.  Capsule ± emergent or rarely immersed; urn oblong to oblong-cylindric when old, 1.3--2 mm, 8-ribbed entire length; stomates immersed in proximal 1/2 of capsule, 1/2 to completely covered by subsidiary cells; peristome double; endostome segments 8, composed of 1--2 rows of cells, papillose, sometimes coarsely so; exostome teeth 8, reflexed, densely and evenly papillose.  Calyptra oblong-conic, hairy, hairs papillose, deeply plicate.  Spores 14--24 \um.

 

Bark of Quercus or Populus tremuloides; ± 3000 m; Ariz.; Mexico; Central America (Guatemala).

 

The channeled, cuspidate apex of the mature leaves distinguishes Orthotrichum bartramii  from all other species with immersed stomates.  The sporophytic characters strongly resemble those of O. tenellum; however, the latter species has non-channeled, incurved leaf tips

 

6.  Orthotrichum bolanderi Sullivant, Icon. Musc. Suppl., 64, plate 46.  1874

 

Plants 0.5--4 cm, dark-green to black.  Stem leaves stiffly erect-appressed, rarely incurved when dry, lanceolate, 2--3.5 mm, narrowly obtuse to acute; margins plane, entire; distal laminal cells 7--11 \um wide, 2-stratose, each cell with 2--4 conical, sometimes large papillae; basal laminal cells elongate, with ± wavy walls, smooth.  Sexual condition goniautoicous.  Seta ± 1 mm.  Capsule emergent; urn ovate-oblong when mature, ovate-cylindric when old, 1.4--2 mm, lightly 8-ribbed in distal 1/3 of capsule; stomates superficial; peristome double; endostome segments 8, 2 rows of cells, papillose; exostome teeth 8, reflexed-recurved, papillose to coarsely papillose-striate.  Calyptra oblong-conic, with papillose hairs.  Spores 17--23 \um.

 

Rocks, especially sandstone; 100--2000 m; Calif., Wash.; Mexico; Central America (Guatemala).

 

Orthotrichum bolanderi is the only species with superficial stomates that has 2-stratose distal laminal cells. It has leaves with subsheathing bases, ovoid cylindric capsules with long wrinkled necks, and reflexed-recurved exostome teeth.  When dry, the leaves are stiffly erect-appressed and they lie flat on a microscope slide when wet.

 

7.  Orthotrichum consimile Mitten, J. Linn. Soc. Bot. 8: 24.  1864

 

Orthotrichum columbicum Mitten; O. hendersonii Renault & Cardot; O.  pulchellum var. columbicum (Mitten) Grout; O. pulchellum var. leucodon Venturi; O. pulchellum var. longipes Lesquereux & James; O. pulchellum var. productipes Renault & Cardot; O. pulchellum ssp. ulotaeforme (Renault & Cardot) Kindberg; O. ulotaeforme Renault & Cardot

 

Plants 8--20 mm.  Stem leaves erect and loosely flexuose to crisped-flexuose when dry, linear-lanceolate, 2--3.2 mm, acuminate (sometimes bluntly so) or acute; margins recurved to near apex, sometimes reflexed above, entire; distal laminal cells 7--11 \um wide, 1-stratose, smooth or bluntly papillose; basal laminal cells linear-elongate to long-rectangular, non-nodose.  Sexual condition goniautoicous.  Seta (1.5--)2.5--6 mm.  Capsule exserted to long-exserted; urn ovate-oblong when young, elliptic-cylindric when old, 2.5--6 mm, 8-ribbed entire length; stomates numerous, immersed, in neck, proximal, and middle portion of capsule 1/3--2/3 covered by strongly differentiated subsidiary cells; peristome double; endostome segments usually 16, rarely 8 (sometimes 8 long and 8 short), of 1 row of cells, smooth or finely roughened; exostome teeth 8, erect when mature, reflexed when old, very finely and densely papillose on outside, finely striate on inner surface.  Calyptra oblong-conic to short-conic, naked or rarely sparsely hairy.  Spores 12--14 \um.

 

Tree trunks and branches in coniferous forests, sometimes found on boulders in shaded habitats; low elevations; B.C.; Alaska, Calif., Idaho, Oreg., Wash.;  Europe.

 

Orthotrichum consimile is distinguished from superficially similar species of Ulota by its glabrous calyptra, immersed stomates, and undifferentiated basal leaf cells.  From O. pulchellum, it differs by having stomates confined to the proximal portion of the capsule and an exostome of 8 yellowish teeth that are finely papillose on the outer surface and finely striate on the inner.  Also, O. consimile is much larger and has capsules that are long-exserted and constricted beneath the mouth when old and dry.

 

8.  Orthotrichum cupulatum Bridel, Musc. Rec. 2(2): 25. (May 9) 1801

 

Orthotrichum leiodon Kindberg; O. utahense Lesquereux

 

Plants to 12 mm.  Stem leaves erect-appressed when dry, ovate-lanceolate to oblong-lanceolate, 2.5--4 mm, acute or rarely narrowly obtuse; margins recurved or revolute to near the apex, entire; distal laminal cells 8--12 \um wide, 1-stratose, or occasionally areas with 2-stratose, densely pluri-papillose with 2--3 large, forked papillae or papillae sometimes small and conical; basal laminal cells long- to short-rectangular, non-nodose.  Sexual condition goniautoicous.  Seta 0.5--1 mm.  Capsule immersed to 1/2 emergent when dry; urn ovate-pyriform to sometimes short-oblong, 1.2--1.6 mm, ± 0.8 mm wide, 16-ribbed; stomates immersed, in 1 or 2 rows in the middle of the capsule; peristome single, rarely double; endostome segments rarely present, 8, 1 row of cells wide, smooth; exostome teeth 16, erect, becoming spreading-reflexed with age, usually not present when the capsule is old, papillose-striate or papillose-reticulate.  Calyptra oblong to oblong-conic, with papillose hairs.  Spores 9--16 \um.

 

Faces of calcareous cliffs and large boulders in coniferous forests, most common in the dryer areas of Ponderosa Pine forests and on the dryer cliff faces in canyons; 100--3000 m; B.C.; Ariz., Calif., Colo., Idaho, Mont., Nev., Oreg., S.Dak. Texas, Utah, Wash., Wyo.; Mexico (Nuevo León). Europe; Asia; n Africa.

           

Orthotrichum cupulatum is extremely variable but can be distinguished by the following combination of characters most of which are usually evident:  (1)  leaves ovate-lanceolate, broadly but sharply acute, and usually unistratose or occasionally partially 2-stratose;  (2)  papillae of the leaf cells usually large and forked, but if small and conical then the leaf is unistratose;  (3)  margin of leaf never thicker than lamina; (4)  peristome teeth always 16, erect or spreading, and yellow-brown; and (5) capsule 16-ribbed, sometimes with 8 short and 8 long ribs.

 

9.  Orthotrichum diaphanum Bridel, Musc. Rec. 2(2): 29.  1801

 

Orthotrichum garretii Grout & Flowers

 

Plants 2--7 mm.  Stem leaves loosely-erect when dry, ovate-lanceolate to oblong, 1.8--3 mm, gradually acute to a ± serrate, hyaline awn; margins revolute nearly to base of awn; distal laminal cells 14--24 \um wide, 1-stratose, smooth or with 1-2 small, conical papillae; basal laminal cells broadly rectangular, non nodose.  Sexual condition autoicous.  Seta less than 1 mm.  Capsule immersed to emergent; urn oblong to oblong-cylindric, 1.2--1.8 mm, wrinkled or moderately 8-ribbed when dry; stomates immersed, numerous, at middle of capsule; peristome double; endostome segments 16, of 1 or 2 rows of cells, densely papillose; exostome teeth 16, reflexed when old and dry, longitudinally-striate or coarsely and densely papillose.  Calyptra conic-oblong, naked or with a few, smooth hairs.  Spores 13--20 \um.

 

Bases and trunks of trees less than 2 m, in dry, usually exposed areas, rarely on rock; 100--1000 m; B.C.; Alaska, Ariz., Ark., Calif., Colo., Kans., La., Mo., Neb., Ohio, Okla, N.Mex. S.Dak., Tenn., Texas, Utah; South America (Uruguay) ; Europe; n Asia; Africa (Algeria); Atlantic Islands (Canary Islands).

 

Orthotrichum diaphanum is distinguished by the hyaline awn of the distal stem leaves.  Gametophytically, O. diaphanum is most closely related to O. pumilum, with which it shares the following attributes:  large chlorophyllose leaf cells lacking large papillae, presence of numerous gemmae, and ovate-lanceolate leaves. Orthotrichum pumilum has apiculate leaf apices that often are similar to those found on the young plants of O. diaphanum.

 

10. Orthotrichum elegans Hooker & Greville, Edin. Jour. of Sc. 1 (1): 122.  1824

 

Orthotrichum psilothecium Macoun & Kindberg; O. speciosum ssp. elegans (Hooker & Greville) Lindberg; O. speciosum var. elegans (Hooker & Greville) Warnstorf; O. speciosum var. roellii Venturi

 

Plants 5--22 mm.  Stem leaves stiffly flexuose when dry, wide-spreading when moist, lanceolate to narrowly lanceolate, 2.3--3 mm, broadly acuminate to acute, margins strongly revolute nearly to apex, entire; distal laminal cells 8--10 \um wide, 1-stratose, with small conical papillae; basal laminal cells elongate, nodose.  Sexual condition autoicous.  Seta 1--2 mm.  Capsule smooth, erect, emergent to sometimes shortly exserted; urn small and narrow, narrowly cylindric to fusiform-cylindric, 1.3--2 mm, smooth; stomates superficial; peristome double; endostome segments 8, 2 rows of cells, coarsely papillose; exostome teeth 8, recurved, coarsely papillose.  Calyptra conic-oblong, sparsely hairy.  Spores 13--26 \um. 

 

Deciduous trees, especially Populus species; occasionally conifers;  200--1000 m;  Alta., B.C., Man., N.B., Nfld., N.W.T., N.S., Ont., P.E.I., Que., Sask.; Alaska, Maine, Mass., Mich., Minn., Mo., N.H., N.J., N.Y., Ohio, Pa., R.I., Vt., Wis.; Europe; Asia.

 

The small plants of Orthotrichum elegans in a rather compact tuft are quite different from the larger, loosely tufted plants of O. speciosum.  Orthotrichum elegans also has fusiform-cylindric, totally smooth, and emergent to shortly exserted capsules while O. speciosum has long-cylindric, generally lightly 8-ribbed, fully exserted capsules.  Orthotrichum striatum has 16 exostome teeth and endostome segments.

 

11.  Orthotrichum euryphyllum Venturi, Bot. Centralbl. 44:  418.  1890.

 

Orthotrichum epapillosum E. Lawton & F. J. Hermann

 

Plants to 3 cm, in dense, dark red-brown to black tufts.  Stem leaves appressed and erect with reflexed apices when dry, oblong-lanceolate to ovate-lanceolate, 2.5--4 mm, obtuse and cucullate at apex, margins recurved-revolute to near apex, entire or sometimes irregularly serrulate near apex; distal laminal cells to 20 \um wide, 1-stratose, smooth or with 1--2 low papillae; basal laminal cells short-rectangular with somewhat nodose walls.  Sexual condition goniautoicous.  Seta to 1.5 mm.  Capsule immersed, urn oblong to oblong-ovate, 1.5--2 mm long, strongly 8-ribbed the entire length; stomates immersed in proximal part of capsule, completely covered by subsidiary cells; peristome double; endostome segments (8--)16, well-developed, persistent, finely papillose; exostome teeth 8 splitting to 16, erect until old, then loosely reflexed, densely papillose-striate.  Calyptra 16-plicate with long beak, naked.  Spores to 15 \um.

 

Calcareous springs in Artemisia scrub; 0--500 m; Calif., Oreg., Wash.

 

Orthotrichum euryphyllum has compact, red-brown plants, cucullate, entire leaf apices, and distal laminal cells approaching 20 \um in width.  In comparison, O. rivulare has loose, blackish plants; flat, dentate leaf apices, and small distal laminal cells rarely wider than 13 \um.

 

12.  Orthotrichum exiguum Sullivant in A. Gray, Man. Bot. No. U. States ed. 2: 633.  1858

 

Plants 3--10 mm.  Stem leaves erect-appressed when dry, lanceolate-oblong to oblong, 0.7--1.3 mm, rounded-obtuse to abruptly tapering to a broadly acute apex; margins reflexed to broadly recurved, entire; distal laminal cells 7--13 \um wide, 1-stratose, with conical or c-shaped papillae; basal laminal cells irregularly rounded.  Sexual condition goniautoicous.  Seta less than 5 mm.  Capsule immersed or slightly emergent, urn ovate-oblong, less than 1 mm, distinctly 8-ribbed to the base when dry; peristome double; endostome segments 8, as wide as exostome teeth, granulate-papillose; exostome teeth 16, spreading or reflexed when dry, papillose to cross-striolate below, papillose to vertically or reticulately striolate above.  Calyptra short-conic, naked or with a few hairs near tip.  Spores 17--20 \um.

 

Base of trees or on tree trunks; 10--200 m; Ga., N.C., S.C., Tenn., Va.; e Asia.

 

The distal laminal cells with bulging walls and c-shaped papillae, delicate, hyaline endostome, clavate stems, papillose, quadrate basal cells, differentiated perichaetial leaves, and capsules that are widest at the mouth, with 16, reflexed exostome teeth, separate this species from all others.

 

13.  Orthotrichum fenestratum Cardot & Thériot, Proc. Wash. Ac. Sc. 4: 310. 16.  1902

 

Plants to 12 mm.  Stem leaves erect-appressed when dry, ovate-lanceolate to narrowly lanceolate, 2.2--3.2 mm, acute and often cuspidate-apiculate; margins narrowly revolute to below apex, entire; distal laminal cells 9--15 \um wide, 1-stratose, with 1--2 small conical papillae per cell; basal laminal cells narrowly rectangular, grading to subquadrate at margin, nodose, thick-walled.  Sexual condition goniautoicous.  Seta ± 2 mm.  Capsule exserted; urn ovate when moist, ovate-oblong when dry, 1--1.8 mm, smooth to moderately 8-ribbed; stomates superficial; peristome single, rarely double; endostome segments 8, narrow, consisting of 1 row of cells, papillose-reticulate; exostome teeth 8 splitting to 16, erect to recurved when old, coarsely papillose distally, becoming finely papillose to almost smooth near base, fenestrate and cancellate.  Calyptra short-conic, plicate, with few, thick, white hairs.  Spores 20--27 \um.

 

Collected only once, by J. M. Macoun, who did not record the substrate; probably near sea level; Alaska.  Endemic to Alaska.

 

The exostome teeth that are cancellate to the base, and fenestrate and perforate only in the distal portion, and the ovate capsule, distinguish Orthotrichum fenestratum.

 

14.  Orthotrichum flowersii Vitt, Bryologist 74: 159.  1971

 

Plants to 5 mm.  Stem leaves stiffly-erect and loosely-appressed when dry, ovate-oblong to oblong-ligulate, 2--2.8 mm, rounded or obtuse, often mucronate, carinate, subcucullate; margins revolute, entire or rough  by means of projecting papillae near apex; distal laminal cells 13--19 \um wide, 1-stratose, with ± 2, small, conical papillae; basal laminal cells rectangular to short-rectangular, non-nodose.  Sexual condition autoicous.  Seta ± 0.5 mm.  Capsule immersed or shortly emergent; urn ovate-oblong to oblong when mature, 1--1.4 mm, strongly 8-ribbed 1/2 to 3/4 the length of the capsule, stomates immersed, in 1 or 2 rows at middle of the capsule, guard cells barely to 1/2 covered by subsidiary cells which have inner walls ± thickened; peristome double; endostome segments 8, usually of 1 row of cells, finely roughened; exostome teeth 8, reflexed, densely papillose or papillose-striate above.  Calyptra oblong, naked or with a few hairs.  Spores 10--17 \um.

 

Base of tree trunks and trunks of deciduous trees in xeric and exposed habitats;  500--2000 m; Calif., Idaho, Nev., Utah; Europe.

 

Orthotrichum flowersii is distinguished from O. pumilum and O. pallens by blunt, carinate leaves that are ovate or ovate-oblong, almost always with a small mucro.

 

15. Orthotrichum gymnostomum Bridel, Bryol. Univ. 1: 782.  1827

 

Nyholmiella gymnostoma (Bridel) Holmen & E. Warncke

 

Plants 4--12 mm.  Stem leaves imbricate, erect-appressed when dry, ovate to ovate-oblong, concave, 2--2.8 mm; rounded to obtuse; margins involute, entire; distal laminal cells 7--12 \um wide, 1-stratose, with 2--3 conical papillae; basal laminal cells elongate-rectangular, non-nodose.  Sexual condition dioicous.  Seta ± 0.5 mm.  Capsule immersed; urn oblong, 1.8 mm; moderately 8-ribbed when dry; stomates superficial, in one row at distal end of capsule; peristome none.  Calyptra obscurely plicate, naked, papillose.  Spores 18--20 \um.

 

Bark of deciduous trees; 0--200 m; Nfld.; Europe; Asia (Japan).

 

Orthotrichum gymnostomum differs from the similar O. obtusifolium by leaves with involute margins, laminal cells with 2--3 papillae, and immersed capsules with no peristome, while O. obtusifolium has leaves with erect margins, 1-papillose cells, and emergent capsules  with a double peristome. Orthotrichum gymnostomum is rare in North America, restricted to the coastal areas of Newfoundland.

 

16.  Orthotrichum hallii Sullivant & Lesquereux in W. S. Sullivant, Icones Musc. Suppl., 63,  plate 45.  1874

 

Plants to 2.5 cm.  Stem leaves loosely erect-appressed when dry, elongate-lanceolate to lanceolate, 1.7--3.5 mm, ± narrowly obtuse, rarely bluntly acute; margins revolute below, recurved to almost plane near apex, entire; distal laminal cells 7--13 \um wide, 2-stratose, rarely with a few unistratose areas, papillae always small, conical, 1--3 per cell; basal laminal cells rectangular to short-rectangular, grading to quadrate at margins, non-nodose.  Sexual condition goniautoicous.  Seta 0.5--1 mm.  Capsule immersed when moist, about 1/2 emergent when dry, urn oblong, short-oblong, or oblong-ovate, 1--1.8 mm, strongly 8-ribbed 1/2 to entire length, rarely with 8 very short intermediate ribs; stomates immersed; peristome double; endostome segments 8, of 1 row of cells, finely longitudinally-striate; exostome teeth 8, sometimes irregularly split to 16, incurved until old, then spreading or rarely reflexed, coarsely striate-reticulate, or striate-papillose.  Calyptra oblong, sparsely hairy, hairs papillose.  Spores 10--17 \um.

 

Rocks, usually limestone or calcareous sandstone, sometimes granite, quartzite, or basalt, rarely on trunks of deciduous trees, open pine forest, spruce-fir forests or deciduous scrub oak-maple forests, especially common on vertical canyon walls and shaded cliff faces; 200--3,000 m; B.C.; Ariz., Calif., Colo., Idaho, Mont., Nev., N.Mex., S.Dak., Utah, Wyo.  Restricted to western North America.

 

Orthotrichum hallii is distinguished by having leaves that are completely, or nearly 2-stratose in their distal portion, and emergent, oblong, 8-ribbed capsules.  The peristome teeth vary from ridged-striate to papillose-striate. The proximal portions of the teeth are often coarsely papillose with the distal portions having striae mixed with papillae. The papillae are always small and conical.

 

17.  Orthotrichum holzingeri Renault & Cardot in J. M. Holzinger, Contr. U.S. Nat. Herb. 3: 270.  1895

 

Plants to 3 cm.  Stem leaves erect, loosely-appressed when dry, oblong-lanceolate to ovate-lanceolate, 1.8--3 mm, broadly acute to obtuse; margins narrowly recurved-revolute to near apex, entire; distal laminal cells 7--12 \um wide, 1-stratose, smooth; basal laminal cells rectangular, not nodose in small leaves, long-rectangular and sometimes nodose in larger leaves.  Sexual condition goniautoicous, perigonia numerous.  Seta 2--3 mm.  Capsule fully exserted; urn cylindric, 1.5--2.2 mm, slightly to distinctly 8-plicate for 1/2 length; stomates superficial; peristome single; endostome segments absent; exostome teeth 16, erect to spreading-reflexed when old and dry, smooth.  Calyptra short-conic, naked.  Spores 13--18 \um.

 

Seasonally wet rocks in small streams of dry montane forests; 1000--2000 m; Calif., Idaho, Oreg., Wash., Wyo. 

 

Orthotrichum holzingeri is distinguished by smooth leaf cells, smooth exostome, naked calyptra, and exserted, lightly-ribbed capsules.  It is a distinct species, endemic to a small region in western North America, and is most closely related to O. laevigatum.

 

18.  Orthotrichum keeverae H. A. Crum & L. E. Anderson, J. Elisha Mitchell Sc. Soc. 72: 281.  1956 

 

Plants 0.5--2 mm.  Stem leaves rigid, erect-appressed when dry, oblong-lanceolate from ovate base to narrowly lanceolate, 2.2--4 mm, slenderly acute, tip contracted to a large, cuspidate point; margins revolute nearly to apex, often irregularly notched near apex; distal laminal cells 7--14 \um wide, 1-stratose, with small, conical papillae, basal laminal cells linear-elongate, nodose.  Sexual condition goniautoicous.  Seta ± 1 mm.  Capsule about 1/2 emergent when dry; urn cylindric, 1.5--2 mm, distinctly 8-ribbed entire length when mature; stomates superficial; peristome double, endostome segments 16, almost as wide as exostome teeth, densely papillose; exostome teeth 16, recurved when dry, densely papillose, often united at base.  Calyptra conic-oblong, with papillose hairs 1--3 cells thick.  Spores 17--27 \um.

 

Trunks and branches of live and dead Quercus montana; ± 1500--2000 m; N.C., Va.  Endemic.

 

Orthotrichum keeverae is the only species in southeastern North America with 16, recurved, exostome teeth, a stout endostome, and cuspidate leaf apices.  The exostome teeth are truncate and partially fused at the base forming a basal membrane.

 

19.  Orthotrichum kellmanii Norris, Shevock & Goffinet, Bryologist 107: 210.  2004

 

Plants to 10 mm.  Stem leaves erect-appressed when dry, ovate-ligulate to ovate-oblong, grading to lanceolate or ovate lanceolate on reproductive stems; 1.4--2.5 mm, obtuse, acute to broadly acuminate near perichaetia; margins recurved to near apex, entire; distal laminal cells 10--12 \um wide, uniformly 2-stratose, with low, simple papillae; basal laminal cells quadrate to short rectangular; non-nodose.  Sexual condition goniautoicous.  Seta ±1 mm.  Capsule immersed; urn ovate-oblong, ± 1.5 mm, 8-ribbed entire length; stomates immersed in proximal half of capsule, mostly covered by subsidiary cells; peristome double; endostome segments 8, delicate and smooth, fragile; exostome teeth 8, blunt, cribose and splitting to 16, densely and coarsely papillose, erect to spreading when dry.  Calyptra short-conic, with sparse, papillose hairs.  Spores 8--12 \um.

 

Dry sandstone boulders in dense chaparral; Calif.

 

Only two species of Orthotrichum have immersed stomates and uniformly bistratose distal laminal cells.  Orthotrichum hallii is a species of calcareous rocks found sporadically throughout the west, while O. kellmanii occurs on sandstone boulders only at a few sites in central California.  Orthotrichum kellmanii is unique in the genus because it has prostrate stems that give rise to ascending vegetative and reproductive stems, the latter with differentiated leaves when compared to vegetative stems.

 

20.  Orthotrichum laevigatum Zetterstedt, Oefv. Svensk. Vet. Ak. Foerh. 19: 363.  (May 14) 1862

 

Orthotrichum hainesiae Austin; O. kingianum Lesquereux; O. laevigatum var. kingianum (Lesquereux) Grout; O. lonchothecium Macoun & Kindberg; O. macounii Austin; O. macounii var. lonchothecium (Macoun & Kindberg) Grout; O. raui Austin; O. roellii Venturi; O. roellii ssp. schlotthaueri (Venturi) Kindberg; O. roellii ssp. stenocarpum (Venturi) Kindberg; O. schlotthaueri Venturi; O. speciosum var. brevicaule Lesquereux; O. speciosum var. hainesiae (Austin) Paris; O. speciosum ssp. laevigatum (J. E. Zetterstedt) J. J. Amann; O. speciosum var. polyanthum Lesquereux; O. speciosum var. polycarpum Lesquereux & James; O. speciosum var. raui (Austin) Lesquereux & James

 

Plants 0.5--4.3 cm, usually ± 2 cm.  Stem leaves erect-appressed, slightly secund and stiff when dry, oblong-lanceolate to lanceolate to ovate-lanceolate, 2--4.3 mm, obtuse, bluntly acute, or gradually acuminate to narrowly acute; margins revolute from base to near apex, entire; distal laminal cells 8--12 \um wide, 1-stratose, densely papillose with low, 1--3 conical or low-forked papillae; basal laminal cells rectangular to elongate, grading to elliptic-quadrate, nodose.  Sexual condition goniautoicous.  Seta 1.5--4 mm.  Capsule fully exserted; urn cylindric, 1.4--2.6 mm, smooth or sometimes slightly plicate in distal portion; stomates superficial; endostome segments 8, 1 row of cells, caducous and inconspicuous; exostome teeth usually16, erect, papillose-granulose, coarsely papillose or striate-papillose.  Calyptra conic-oblong, sparsely hairy, hairs finely papillose.  Spores 10--15 \um.

 

Usually on non-calcareous boulders in mesic, open coniferous forests; rarely at the base of deciduous trees; 500--3,000; Alta., B.C., Man., N.W.T., Sask., Yukon; Alaska, Ariz., Calif., Colo., Idaho, Mont., Nev., Oreg., S.D., Utah, Wash., Wyo.; Europe; Asia (Japan).

 

Orthotrichum laevigatum is a part of a complex group of intergrading taxa that generally are characterized by an exserted, cylindric capsule with 16 erect or reflexed exostome teeth and a poorly developed endostome.  Gametophytically, robust plants have stiff, erect leaves and large, blunt papillae.  This complex is treated here as three species.  These are O. holzingeri, a distinct, highly specialized species of seasonally wet rocks with smooth exostome teeth, smooth leaf cells, smooth calyptra, and lightly ribbed capsule as distinguishing features; O. pylaisii, distinguished by lightly 8-ribbed capsule and reflexed-recurved exostome teeth; and O. laevigatum, distinguished by smooth capsule; erect, papillose exostome teeth.

 

21.  Orthotrichum lescurii Austin, Musci Appalach., 163. 1870

 

Plants to 10 mm.  Stem leaves erect, stiffly appressed when dry, narrowly lanceolate to lanceolate, 2--2.5 mm, acute, margins entire, revolute to just below apex; distal laminal cells 8--12 \um wide, 1-stratose; with 1--3 small, conic papillae; basal laminal cells quadrate to rectangular, non-nodose.  Sexual condition goniautoicous.  Seta 0.5--0.7 mm.  Capsule immersed; urn ovate-globose, constricted beneath mouth when dry, 1.1--1.8 mm, distinctly 8-ribbed; stomates immersed in proximal half of capsule, almost completely covered by subsidiary cells; peristome single; endostome segments absent; exostome teeth 8, incurved-erect to spreading-recurved when dry, densely and evenly papillose.  Calyptra oblong-conic, covered with erect, papillose hairs.  Spores 12--16 \um.

 

Calcareous rocks, 0--1500 m; Ont.; Conn., Ga., Ind., Maine, Mass., Md., Mich., Minn., Mo., N.J, N.Y, Va., Ver., W.Va.

 

Orthotrichum lescurii is sparsely distributed across eastern North America. It is distinguished from other Orthotricha that occur on calcareous rocks in eastern and middle North America by strongly revolute leaf margins and immersed, ovate, and strongly 8-ribbed, strangulate capsules.  Orthotrichum strangulatum has multistratose leaf margins, O. parvulum has plane, unistratose margins, and O. anomalum has exserted capsules.

 

22.  Orthotrichum lyellii Hooker & Taylor, Musc. Brit., 76, plate 22.  1818

 

Dorcadion lyellii (Hooker & Taylor) Lindberg; Orthotrichum lyellii var. howei Renault & Cardot; O. lyellii var. papillosum (Hampe) Lesquereux & James; O. lyellii var. pringlei (Müll. Hal.) Macoun & Kindberg; O. lyellii ssp. strictum Venturi; O. lyellioides Kindberg; O. menziesii Mitten; O. papillosum Hampe; O. papillosum ssp. strictum (Venturi) Kindberg; O. pringlei Müll. Hal.

 

Plants to 13 cm.  Stem leaves erect-spreading to loosely-erect, ± contorted when dry, lanceolate to linear-lanceolate, 2.5--6.5 mm, narrowly acute to acuminate; margins plane, entire; distal laminal cells 7--14 \um wide, 1-stratose, with conical papillae; basal laminal cells narrowly-elongate, ± nodose. Sexual condition dioicous. Seta 0.8--2.7 mm.  Capsule immersed, emergent, or rarely exserted; urn oblong-cylindric to long-cylindric, 1.7--3 mm, strongly 8-ribbed from 1/2 to entire length; stomates superficial; peristome double; endostome segments 16, large, of two rows of cells, coarsely papillose; exostome teeth 16, reflexed-recurved, densely papillose.  Calyptra conic-oblong, very hairy.  Spores 18--35 \um. 

 

Usually on trees, many times covering entire tree trunks to 10 m, rarely on boulders; 10--1000 m; B.C.; Alaska, Calif., Idaho, Oreg. Wash.; Mexico (Baja California); Europe; n Africa.

 

Orthotrichum lyellii is easily distinguished from all other species of Orthotrichum by its dioicous sexual condition, the male plants being slightly smaller and having numerous and conspicuous perigonia.  In addition, the 16 slenderly acuminate, whitish exostome teeth and 16 endostome segments are characteristic.  Sterile plants usually have abundant laminal brood bodies.

 

23.  Orthotrichum norrisii Lara, Medina & Garilleti in Medina, Lara, Mazimpaka, & Garilleti, Bryologist 111: 670.  2008

 

Plants to 15 mm.   Stem leaves erect-appressed when dry, narrowly lanceolate to lanceolate-ligulate from ovate base, 1.3--3 mm, narrowly obtuse, acute to notched and channeled; margins recurved becoming incurved or plane at apex; entire; distal laminal cells 10--16 \um wide, 1-stratose, with 2--3 simple papillae; basal laminal cells shortly rectangular to polygonal, thin-walled to occasionally thick-walled and nodose.  Sexual condition goniautoicous.  Seta 0.5--1 mm.  Capsule emergent, urn cylindric when dry, 1.5--2 mm, lightly 8-ribbed the entire length; stomates immersed, in proximal third of capsule, partially to completely covered by subsidiary cells; peristome double; endostome of 8 smooth to faintly papillose, well-developed segments; exostome of 8 teeth, well-developed, finely papillose, reflexed teeth.  Calyptra oblong-conic, hairy toward distal end.  Spores 14--18 \um.

 

Epiphytic in Mediterranean climate woodlands and chaparral; Calif.

 

Orthotrichum norrisii is somewhat similar to O. tenellum, both with a well-developed peristome of 8 reflexed exostome teeth and 8 long-lasting endostome segments.  Also, both species occur on tree trunks in Mediterranean climate California.  Orthotrichum norrisii differs in having some leaves with irregular, channeled apicies (versus mostly obtuse in O. tenellum) and lightly ribbed capsules (compared to thick, broad ribs in O. tenellum).

 

24.  Orthotrichum obtusifolium Bridel, Musc. Rec. 2(2): 23.  1801

 

Nyholmiella obtusifolia (Bridel) Holmen & E. Warncke; Orthotrichum inflexum Müll. Hal.

 

Plants 3--14 mm.  Stem leaves erect-appressed when dry, ovate to ovate-lanceolate, concave, 1.4--2 mm, obtuse; margins erect-incurved, entire; distal laminal cells 13--18(--20) \um wide, 1-stratose, unipapillose on both surfaces; basal laminal cells ± rectangular.  Sexual condition dioicous.  Seta ± 0.5 mm.  Capsule ± 1/2 emergent; urn oblong-cylindric, 1.6--2 mm, strongly 8-ribbed to base; stomates superficial at or above middle of capsule; peristome double; endostome segments 8, composed of 2 rows of cells; exostome teeth 8, reflexed, evenly papillose, sometimes irregularly striate above.  Calyptra short-conic, naked, papillose.  Spores 20--25 \um.

 

Deciduous trees in open areas; in the Northeast, common on the trunks of Populus; in the West, sporadic on trunks of Juniperus, base of scrub-oaks in dry cut-over areas, and trunks of Populus balsamifera in river bottoms; in the southern boreal forest found commonly on aspen trunks;  a pronounced xerophyte growing only in pioneer situations; 10--2000 m;  Alta., B.C., Man., N.B., Nfld., N.W.T., N.S., Ont., P.E.I., Sask., Que., Yukon; Alaska, Ariz., Calif., Colo., Idaho, Iowa, Maine, Md., Mich., Minn., Mont., Neb., N.H.,  N.Mex. N.Y., N.C., N.Dak., Oreg., Pa., S.Dak., Utah, Vt., Wash., Wis., Wyo.; Europe; Asia.

 

Species that might be confused with Orthotrichum obtusifolium are O. flowersii, O. exiguum, and O. gymnostomum.  None of these species has distal laminal cells with one papilla per cell as does O. obtusifolium.  In addition, O. flowersii and O. exiguum have reflexed to revolute leaf margins and both are autoicous. Orthotrichum gymnostomum has distinctly involute leaf margins and, like O. obtusifolium, is dioicous.

 

25.  Orthotrichum ohioense Sullivant & Lesquereux in C. F. Austin, Musci Appal., 30, n. 169.  1870

 

Orthotrichum citrinum Sullivant & Lesquereux; O. ohioense var. citrinum (Sullivant & Lesquereux) Lesquereux & James

 

Plants 0.4--1.4 cm.  Stem leaves loosely-erect when dry, narrowly lanceolate to oblong-lanceolate, 1.4--2.9 mm; obtuse to bluntly acute; margins strongly revolute to just before the apex, entire; distal laminal cells 8--10 \um wide, 1-stratose, with low papillae; basal laminal cells subquadrate to short-rectangular with rounded corners, non-nodose.  Sexual condition goniautoicous.  Seta less than 1 mm.  Capsule emergent; urn oblong to ovate, 1--1.5 mm, 8-ribbed to almost base; stomates immersed; peristome double; endostome segments 8, of 1 row of cells, smooth, often not present; exostome teeth 8, later splitting to 16, reflexed, finely and densely papillose.  Calyptra oblong, naked or slightly hairy.  Spores 15--19 \um.

 

Deciduous trees in mesic hardwood forests especially along streams; 100--1000 m; N.B., N.S., Ont., Que.; Ala., Ark., Conn., Del., D.C., Fla., Ga., Ill., Ind., Ky., Maine, Md., Mass., Mich., Mo., Miss., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., S.C., Tenn., Vt., Va., W.Va.

 

Orthotrichum ohioense is distinguished by 16 exostome teeth, 8 rudimentary endostome segments, lightly 8-ribbed ovate capsule, leaves that are lanceolate and bluntly acute at apex, and cells less than 10 \um.  Orthotrichum stellatum has 8 paired exostome teeth, 8 well-developed endostome segments, and constricted, strongly 8-ribbed capsules.

 

26.  Orthotrichum pallens Bridel, Bryol. Univ. 1: 788.  1827

Orthotrichum immersum Bridel,; O. pallens var. immersum (Bridel) Müll. Hal.

 

Plants 3--10 mm.  Stem leaves loosely erect-appressed and slightly incurved when dry, oblong-lanceolate to broadly lanceolate, 1.6--3 mm, narrowly obtuse, broadly acute to broadly apiculate; margins recurved to near apex, entire; distal laminal cells 9--14 \um wide, 1-stratose, with 2(3) low, conical papillae; basal laminal cells rectangular, non-nodose.  Sexual condition cladautoicous.  Seta 0.5--1.5 mm.  Capsule emergent to barely exserted; urn oblong to oblong-cylindric, 1--2.5 mm, strongly 8-ribbed, becoming narrowly-cylindric and contracted along entire length when old; stomates immersed; peristome double; endostome segments 16, 1--2 rows of cells, smooth or finely papillose; exostome teeth 8, erect until old, then reflexed, evenly and densely papillose to papillae-striate.  Calyptra conic-oblong, naked or sparsely hairy.  Spores 10--20 \um.

 

Varieties 9 (3 in the flora):  North America, Mexico, Europe.

 

Orthotrichum pallens is distinguished by having immersed stomates that are scarcely covered by thin-walled subsidiary cells.  The peristome is double with a well-developed endostome of 16 (or 8) segments that remains intact until the capsule is quite old.  Gametophytically, the species is distinguished by having narrowly obtuse, oblong-lanceolate leaves, and an autoicous sexual condition.

 

1.  Leaf margins crenulate at the apex . . 26a. Orthotrichum pallens var. crenulatum

1.  Leaves entire.

2.  Endostome segments 8; calyptra sparsely hairy; Arizona . . 26b. Orthotrichum pallens var. johnseniae

2.  Endostome segments 16; calyptra naked; sporadic throughout North America. . 26c. Orthotrichum pallens var. pallens

 

26a.  Orthotrichum pallens var. crenulatum Vitt, Bryologist 74: 161. 1971

 

Stem leaves oblong to oblong-lanceolate, rounded-obtuse, often broadly apiculate; margins usually crenulate at apex.  Seta ± 0.5 mm; urn oblong when mature, becoming strangulate when old, 1--1.6 mm, strongly 8-ribbed nearly to base; endostome segments 8, shorter than exostome; exostome teeth 8, reflexed, papillose-striate.  Calyptra naked.  Spores 10--14 \um.

 

Tree trunks, especially near their base, dry, exposed areas; 500--1500 m; Nev., Utah.

 

The endemic variety Orthotrichum palens var. crenulatum is characterized by oblong to oblong-lanceolate leaves with apiculate, broadly obtuse apices.  The margins in almost all leaves are crenulate near the apex and the seta is short (less than 0.6 mm).  The exostome is papillose-striate as opposed to papillose.  There are 8 endostome segments and the capsule is strangulate when old.

 

26b.  Orthotrichum pallens var. johnseniae Vitt, Bryologist 74: 162.  1971

 

Stem leaves broadly lanceolate to lanceolate, narrowly obtuse or bluntly acute; margins entire.  Seta 0.5--1 mm; urn oblong-cylindric, gradually contracted to seta through long neck, constricted below mouth, 1.5--2 mm; endostome segments 8, of 1 row of cells, smooth; exostome teeth 8, recurved-reflexed, finely papillose.  Calyptra sparsely hairy, the hairs smooth.  Spores 13--20 \um.

 

Basaltic boulders in spruce-popular forests; 3000 m; Ariz. 

 

Orthotrichum pallens var. johnseniae is also endemic to the West and is distinguished by its hairy calyptra.  It has 8 endostome segments and capsules that are shorter and moderately constricted under the mouth.  The stomates are barely covered with subsidiary cells, which usually have their interior walls thickened, and the exostome teeth tend to be somewhat recurved instead of reflexed.

 

26c.  Orthotrichum pallens Bridel var. pallens

 

Stem leaves oblong-lanceolate to lanceolate, narrowly obtuse to broadly acute, margins entire.  Seta 0.5--1.5 mm; urn oblong-cylindric, becoming strangulate when old, 1.3--2.5 mm, endostome segments 16, long; exostome with 8, reflexed, densely papillose.  Calyptra naked.  Spores 10--17 \um.

 

Tree trunks and branches and dry, calcareous or granitic rocks along streams; 300--3000 m; Alta., B.C., Man., Nfld., Nun., Ont., Que., Yukon; Ariz., Calif., Colo., Mich., Minn., Mont., Nev., S.Dak., Utah; Mexico (Nuevo León); Europe.

 

Orthotrichum pallens var. pallens has entire leaves, 16 endostome segments, and a naked calyptra.

 

27.  Orthotrichum parvulum Mitten, J. Proc. Linn. Soc. Bot. 8: 25. 1865.

 

Plants to 10 mm.  Stem leaves erect, stiffly appressed when dry, oblong-lanceolate to lanceolate, 2--3.5 mm, bluntly acute to obtuse; margins entire, plane or weakly recurved; distal laminal cells 10--15 \um wide, 1-stratose; with 1--2 low, conic papillae; basal laminal cells quadrate to rectangular, non-nodose.  Sexual condition goniautoicous.  Seta 0.5--0.8 mm.  Capsule immersed; urn oblong, constricted beneath mouth when dry, 1.2--1.9 mm, distinctly 8-ribbed; stomates immersed in distal half, almost completely covered by subsidiary cells; peristome single or rarely with fugacous endostome; endostome segments 8 when present, thin, short, hyaline; exostome teeth 16, incurved-erect to spreading-recurved when dry, coarsely papillose to reticulate-papillose.  Calyptra oblong-conic, covered with erect papillose hairs.  Spores 12--19 \um.

 

Calcareous rocks; 90--130 m; Ark., Ill., Ind., Iowa, Kan., Ky., Minn., Mo., Wis.

 

Orthotrichum parvulum is most frequent in the interior highlands of Missouri and Arkansas. It differs from O. strangulatum (with 2--7 stratose leaf margins) and O. lescurii (with revolute, uni-stratose leaf margins) in having plane leaf margins and completely unistratose distal laminal cells.

 

28.  Orthotrichum pellucidum Lindberg, Oefv. K. Svensk. Vet. Ak. Foerh. 23: 549.  1867

 

Orthotrichum cupulatum var. jamesianum (James) Lawton; O. jamesianum James;

 

Plants to 2.5 cm.  Stem leaves stiff, closely erect-appressed, incurved when dry, oblong-lanceolate or lanceolate, 2--2.7 mm, blunt or obtuse; margins recurved below, reflexed in distal portion, entire; distal laminal cells 6--11 \um wide, 1-stratose, papillae always large, conical or forked; basal laminal cells short-rectangular to quadrate, grading to subquadrate at margin.  Sexual condition goniautoicous.  Seta 1--1.5 mm.  Capsule 1/2 emergent to shortly  exserted; urn oblong to short-oblong when old and dry, oblong-ovate to ovate when mature, 1.2--1.9 mm, strongly 8-ribbed entire length, rarely 16-ribbed with 8 short intermediate ribs; stomates immersed in middle and proximal portion, ± completely covered by protruding subsidiary cells; peristome single; endostome segments none; exostome teeth usually 16 when mature, irregularly split, often absent when capsule is old, papillose-striate to coarsely reticulate-papillose.  Calyptra oblong, covered with papillose, whitish hairs.  Spores 10--15 \um.

 

Calcareous, more rarely siliceous boulders and cliff faces in xeric areas, often found growing in direct sunlight; 500--3000 m; Greenland; Alta., B.C., Man., N.W.T., Nun., Yukon; Alaska, Ariz., Calif., Colo., Idaho, Mont., Nev., N.Mex., Oreg., S.Dak., Utah, Wyo.; n Europe.

 

Orthotrichum pellucidum is distinguished by the blunt, lanceolate-oblong leaves that always have a glaucous appearance because of the large forked papillae of the distal laminal cells.  When the plants are fertile, which is usually the case, the shortly exserted, oblong-ovate, eight-ribbed capsule should identify this species.

 

29.  Orthotrichum praemorsum Venturi in J. Roell, Bot. Centralbl. 44: 418.  1890

 

Orthotrichum affine ssp. praemorsum (Venturi) Kindberg; O. arcticum var. praemorsum (Venturi) Wijk & Margadant; O. microblephare var. praemorsum (Venturi) Grout

 

Plants 1--2.5 cm.  Stem leaves erect-appressed when dry, ovate-lanceolate to narrowly lanceolate, 2.5--4.5 mm, gradually narrowed to acuminate-cuspidate apex; margins recurved-revolute to near apex, entire; distal laminal cells 9--13 \um wide, 1-stratose, with 1--3 low, forked papillae; basal laminal cells elongate-rectangular, nodose.  Sexual condition goniautoicous.  Seta 0.5--1.1 mm.  Capsule 1/2 emergent when dry, barely emergent when moist; urn ovate-oblong when mature, oblong to oblong-cylindric and constricted beneath mouth when old and dry, 1.6--2.4 mm, strongly 8-ribbed 1/2 to 2/3 the length; stomates superficial; peristome double; endostome segments 16, large, coarsely papillose; exostome teeth 8, reflexed-recurved, finely papillose, sometimes papillose-striate below.  Calyptra short-conic, hairy, hairs with small papillae.  Spores 12--18 \um.

 

Rocks, rarely lava, dry montane areas; middle elevations; Calif., Nev., Wyo., Wash.  Restricted to w North America.

 

Orthotrichum praemorsum is rare, having been collected only a few times. It is distinguished from other species by strongly-ribbed, emergent capsule, and by the cuspidate, shortly hyaline-tipped leaves.

 

30.  Orthotrichum pulchellum Brunton in J. E. Smith, Engl. Bot. 25: (Sept. 1) 1807

 

Orthotrichum pulchellum var. groutii E. Lawton

 

Plants to 1.6 cm.  Stem leaves loosely-twisted and crisped-flexuose when dry, narrowly lanceolate to linear-lanceolate, 1.6--3.2 mm, sharply acute; margins recurved to near apex, entire; distal laminal cells 8--14 \um wide, 1-stratose, with small, conical papillae; basal laminal cells rectangular, non-nodose.  Sexual condition goniautoicous.  Seta (0.8--)1--3(--3.5) mm.  Capsule exserted or sometimes 1/2 emergent; urn oblong-cylindric, 0.9--2.1 mm, strongly 8-ribbed entire length, stomates immersed in middle and distal portion of capsule, 1/2 to completely covered by strongly differentiated subsidiary cells; peristome double; endostome segments 16, of 1 row of cells, finely roughened; exostome teeth 16, rarely united into 8 pairs, erect when mature, later reflexed, densely papillose.  Calyptra oblong-conic to conic, naked.  Spores 12--24 \um.

 

Tree trunks, branches, and twigs of deciduous and coniferous trees; 0--1000 m: B.C.; Alaska, Calif., Idaho, Oreg., Wash.  Restricted to western North America.

 

Orthotrichum pulchellum is distinguished from all species of Ulota by glabrous calyptra and immersed stomates, and from O. consimile by 16, reddish exostome teeth that are papillose-reticulate with slender, high papillae, and by stomates that are always located at or beyond the middle of the capsule. Also, O. pulchellum plants are rarely longer than 1 cm and capsules are usually just barely exserted and oblong-cylindric.

 

31.  Orthotrichum pumilum Swartz, Monthly Rev. London 34: 538.  (June 1) 1801

 

Orthotrichum affine var. fallax (Bridel) Hampe; O. brachytrichum Lesquereux & James; O. fallax Bridel; O. fallax var. truncatulum Austin; O. pumilum var. americanum Venturi; O. pumilum var. fallax (Bridel) J. Kickx f.; O. pumilum var. fallax (Bridel) Bertsch; O. schimperi Hammar; O. schimperi var. truncatulum (Austin) Paris; O. tenellum var. pumilum (Swartz) Boulin

 

Plants to 5 mm.  Stem leaves loosely-erect when dry, ovate-lanceolate to lanceolate, 1.8--2.8 mm, sharply to slenderly acute, most leaves ending in 1--2 celled apiculus, rarely obtuse; margins revolute nearly to apex, entire; distal laminal cells 14--20 \um wide, 1-stratose, smooth or with 1--2 small, conical papillae; basal laminal cells rectangular, grading to quadrate at margin, non-nodose.  Sexual condition autoicous.  Seta less than 0.5 mm.  Capsule immersed to 3/4 emergent; urn oblong to oblong-cylindric, 1.2--1.5 mm, strongly 8-ribbed; stomates immersed, at middle of capsule, 1/2 or less covered by subsidiary cells; peristome double; endostome segments 8, of 1--2 rows of cells, smooth; exostome teeth 8, rarely splitting to 16, reflexed, finely and evenly papillose.  Calyptra oblong, sparsely hairy or rarely naked.  Spores 14--21 \um.

 

Trunks, lower branches, and bases of deciduous trees, rarely on coniferous trees or in crevices of rocks; common in open, hardwood forests and on trees along roadsides; 10--1000 m; Alta., Man., Ont., Sask.; Ariz., Calif., Colo., D.C., Idaho, Ill., Iowa, Kans., Md., Mass., Mich., Minn., Mis., Mo., Mont., Neb., N.H., N.J., N.Mex., N.Y., N.Dak., Ohio, Okla., Pa., S.C., S.Dak., Tenn., Texas, Utah, Vt., Va., Wash., W.Va., Wisc.; Europe; n Africa.

 

Orthotrichum pumilum can usually be distinguished by its strongly ribbed capsules, reflexed peristome teeth, apiculate leaves with cells larger than 14 \um, and papillae that are very small or absent.  In eastern North America this taxon is uniform and non-variable, but in the west it is much more variable.  Many western specimens have capsules that are oblong-cylindric, often strangulate, over 1/2 emergent, and gradually contracted to the seta.

 

32.  Orthotrichum pusillum Mitten, J. Linn. Soc. Bot. 8: 25. (June 30) 1864

 

Orthotrichum psilocarpum Sullivant

 

Plants 2--4 mm.  Stem leaves loosely-appressed when dry, ovate-lanceolate to oblong-lanceolate, 1--2.2 mm, narrowly obtuse to broadly acute, sometimes with small apiculus; margins revolute nearly to apex, entire except for denticulate apex on some leaves; distal laminal cells 9--14 \um wide, 1-stratose, with 2--4 small, conical papillae; basal laminal cells, broadly rectangular, non-nodose.  Sexual condition autoicous.  Seta less than 1 mm.  Capsule immersed to 1/2 emergent; urn oblong to ovate-oblong, 0.8--1.4 mm, wrinkled to lightly 8-plicate; stomates immersed, at middle or distal portion of capsule; peristome single; endostome segments usually absent or if present 8, rudimentary, smooth; exostome teeth 16, erect or recurved.  Calyptra oblong, smooth.  Spores 13--20 \um.

 

Trunks of deciduous trees in open, dry woods and along roadsides, rarely on Juniperus associated with habitation along streams; 10--1000 m;  Ala., Ark., Conn., D.C., Fla., Ga., Ill., Ind., Kans., Ky., La., Md., Mass., Mich., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., S.C. Tenn., Texas, Va., W.Va.

 

Orthotrichum pusillum is distinguished by its smooth, oblong capsule, which is sharply contracted to the seta, 16 peristome teeth, which are erect or recurved when old, some leaves of each plant having 1--4 small denticulations at the apex, and distal laminal cells 9--14 \um in width.  The leaf cells are smaller than those of O. pumilum and in longitudinal rows, but they are larger, with thinner walls, than those of O. ohioense.  To help identify sterile material: O.  pusillum has denticulate leaf apex that may be narrowly obtuse or acute, and  leaf cells 9--14 \um with thin walls; O. pumilum has an apiculate leaf apex that is normally acute and entire, and leaf cells 14--20 \um, with thin walls; and O. ohioense has an obtuse leaf apex, which is never apiculate or denticulate, and leaf cells 8--10 \um, with thick walls.

 

33.  Orthotrichum pycnophyllum Müll. Hal., Syn. 1: 709.  1849

 

Orthotrichum lozanoi Cardot; O. lozanoi var. lutescens Cardot; O. pycnophyllum var. lutescens (Cardot) Grout; O. recurvans Müll. Hal.

 

Plants 0.8--4 cm.  Stem leaves loosely erect-spreading when dry, lanceolate, 2.5--4 mm, gradually acuminate to long-acuminate-cuspidate; margins revolute to just below apex, often wavy and slightly notched near apex; distal laminal cells 7--13 \um wide, 1-stratose, with 1--2 conical papillae per cell; basal laminal cells elongate, nodose.  Sexual condition goniautoicous.  Seta 1--1.5 mm.  Capsule immersed to fully exserted, generally 1/2--1/4 emergent, urn oblong-ovate to cylindric, 1.5--2 mm, smooth to lightly 8-ribbed; stomates superficial; peristome double; endostome segments 16, 2 cells wide, coarsely papillose, usually not erose; exostome teeth 16, recurved, obscurely and densely papillose.  Calyptra conic-oblong, moderately hairy, with dark beak.  Spores 17--29 \um.

 

Branches and trunks of trees; 500--2000 m; Ariz., N.Mex., Texas; Mexico. 

 

Orthotrichum pycnophyllum is restricted to southwestern North America, being found only south of 35° N latitude in the southwestern United States and Mexico. The distinguishing features are the 16 exostome teeth that are not united at the base to form a membrane as in O. keeverae, 16 endostome segments, and a lightly ribbed capsule that is usually 3/4 emergent.

 

34.  Orthotrichum pylaisii Bridel, Brol. Univ. 1: 722.  1826

 

Orthotrichum arcticum Schimper; O. arcticum ssp. blyttii (Schimper) Kindberg; O. arcticum var. groenlandicum (Berggren) Moenkemeyer; O. blyttii Schimper; O. blyttii ssp. arcticum (Schimper) Macoun; O. blyttii ssp. microblephare (Schimper) Macoun; O. blyttii var. arcticum (Schimper) I. Hagen; O. blyttii var. groenlandicum (Berggren) C. E. O. Jensen; O. blyttii var. microblephare (Schimper) C. E. O. Jensen; O. groenlandicum Berggren; O. idaohense Cardot & Thériot; O. pylaisii ssp. arcticum (Schimper) Kindberg; O. pylaisii ssp. groenlandicum (Berggren) Kindberg; O. pylaisii ssp. microblephare (Schimper) Kindberg; O. rhabdophorum Venturi

 

Plants to 3 cm.  Stem leaves erect-appressed when dry, ovate-lanceolate to lanceolate, 2--3 mm, broadly acute to narrowly obtuse, often bluntly acuminate; margins revolute, entire; distal laminal cells 9--16 \um wide, 1-stratose, with 1--4 forked papillae; basal laminal cells rectangular-elongate, ± nodose, thick-walled.  Sexual condition goniautoicous.  Seta 2--3 mm.  Capsule emergent or exserted; urn oblong to cylindric, 1.2--2.5 mm, moderately 8-ribbed ± 1/2 length; stomates superficial; peristome double or single; endostome segments 8, about 1/2 as long as exostome, narrow, of 1 row of cells, smooth or finely papillose, often absent; exostome teeth 16, sometimes united into 8 pairs, 4--6 cells wide, densely papillose.  Calyptra oblong to oblong-conic, sparsely hairy.  Spores 16--27 \um.

 

Usually on rocks near the ocean or in alpine or arctic zones, rarely on trees such as Salix or Alnus, bone and frequently in or near bird rookeries, in western North America found on granitic boulders in coniferous forests; 100--3000 m; Greenland; B.C., Alta., Man., Nfld., N.W.T. Nun., Que., Yukon; Alaska, Calif., Idaho, Mont., Wash., Wyo.; n Europe; n Asia.

 

Orthotrichum pylaisii is distinguished by ribbed capsules with reflexed exostome teeth and a rudimentary endostome, along with superficial stomates and large, ovate-lanceolate leaves.  The capsule is almost always exserted in North America; in Europe, however, it is sometimes only emergent.

 

35.  Orthotrichum rivulare Turner, Musc. Hib., 96.  1804

 

Plants 1--5 cm; in loose, dark green to blackish tufts.  Stem leaves erect and loosely appressed when dry; oblong-lingulate, oblong-lanceolate, or ovate-lanceolate, 2.8--5 mm, broadly rounded to obtuse, flat; margins strongly revolute to just below apex, usually irregularly dentate at apex; distal laminal cells 10--13 \um wide, 1-stratose, with 1--3 small, conical papillae; basal laminal cells rectangular to short-rectangular, smooth.  Sexual condition goniautoicous.  Seta 1--1.5 mm.  Capsule immersed when moist, barely to 3/4 emergent when dry; urn oblong to oblong-ovate, 1.5--2.5 mm, strongly 8-ribbed entire length; stomates immersed; peristome double; endostome segments 16, usually 1 cell wide, finely papillose; exostome teeth 8, sometimes splitting to 16, erect until old, then loosely reflexed, irregularly papillose, papillae tending to be confluent forming longitudinal striae.  Calyptra 16-plicate with long beak, naked.  Spores 10--17 \um.

 

Exposed tree roots, bases of trees along streams, also commonly on siliceous boulders at the edges of streams and rivers, occasionally on rocks that are frequently inundated, rarely in aquatic habitats; 0--1000 m; Alta., B.C.; Calif., Idaho, Nev., Oreg., Wash., Wyo.; Europe.

 

Orthotrichum rivulare is distinguished from all others in the genus by the following combination of characters:  (1) leaves often obtuse, the margins dentate near the apex, (2) calyptra plicate, the projecting edges papillose, otherwise smooth and naked, (3) 16 endostome teeth, and (4) stomates completely covered by the overarching subsidiary cells.  From O. euryphyllum, the flat, dentate apex is a key differentiating feature.

 

36.  Orthotrichum rupestre Schwaegrichen, Spec. Musc. Frond. Suppl. 1(2): 27. 53. 1816

 

Dorcadion rupestre (Schwaegrichen) Lindberg; Orthotrichum bullatum Müll. Hal.; O. californicum Venturi; O. douglasii Duby; O. macfaddenae R. S. Williams; O. rupestre var. globosum (Lesquereux) Grout; O. rupestre var. macfaddenae (R. S. Williams) Grout; O. texanum Sullivant & Lesquereux; O. texanum var. globosum Lesquereux

 

Plants 1--12.5 cm, usually longer than 3 cm.  Stem leaves erect-appressed when dry, narrowly lanceolate to ovate-lanceolate, 2--4.5 mm, sharply to slenderly acute; margins recurved to narrowly revolute to near apex, entire; distal laminal cells 6--13 \um wide, 1-stratose, with 1--2 small, conical or low, forked papillae per cell; basal laminal cells elongate, thick-walled and nodose to rectangular and thin-walled.  Sexual condition goniautoicous.  Seta less than 1.8 mm. Capsule immersed, emergent or slightly exserted, usually ± 1/3 emergent; urn globose ovate, ovate-oblong, or short-oblong, 1.3--1.8 mm, lightly or distinctly 8-ribbed for 1/2--2/3 the length; stomates superficial; peristome single, rarely double; endostome segments lacking or rarely 8 and rudimentary; smooth or roughened; exostome teeth 16, erect or sometimes spreading-recurved when old; smooth, scattered-papillose to coarsely papillose-granulate.  Calyptra oblong, hairy or rarely naked, hairs finely papillose.  Spores 13--21 \um.

 

Non-calcareous boulders and cliff faces in mesic areas of pine, spruce-fir or aspen forests, usually at higher elevations, rarely found in sterile condition at the base of trees, frequently collected in subalpine shaded situations; 100--3000 m; Greenland; Alta., B.C., N.W.T., Nun., Ont., Yukon; Alaska, Ariz., Calif., Colo., Idaho, Mont., Nev., N.Mex., Oreg., S.Dak., Utah, Wash., Wyo.; South America ; Europe; Asia; n and e Africa; Asia (Japan); Atlantic Islands (Canary Islands); Pacific Islands (New Zealand); Australia.

 

In typical form, O. rupestre is characterized as follows: plants much branched in loose tufts, leaves lanceolate, apex narrowly and bluntly acute, basal cells elongate, thick-walled, and nodose, yellowish in older leaves, capsule oblong, emergent, 8-ribbed 1/2 the length when old and dry, smooth or slightly 8-ribbed when mature, exostome of 16 erect teeth, coarsely papillose, and calyptra with abundant spinulose, papillose hairs, some of which extend over the beak.

 

37.  Orthotrichum shawii Wilson in Schimper, Musci Nov. Eur. Bryol. Eur. Suppl. 1-2 Mon 1.1. 1864

 

Plants to 4 cm.  Stem leaves erect-appressed when dry, lanceolate, 2.7--3.6 mm, shortly acuminate to acute, margins broadly recurved, plane at apex, smooth; distal laminal cells 9--15 um wide, 1-stratose, with 2--4 thick, well-developed, blunt, simple or forked papillae; basal laminal cells long-rectangular, with thick and nodose walls.  Sexual condition goniautoicous.  Seta less than 0.4 mm.  Capsule immersed to emergent; urn ovate to cylindric-ovate, 1.6-1.8 mm, usually smooth or lightly 8-ribbed when dry; stomates superficial in middle and distal portion of capsule, peristome usually single; endostome rarely present, of 8 very short hyaline segments; exostome teeth 16, irregularly divided and recurved, coarsely papillose to papillose-striate.  Calyptra oblong-conic, with long, yellowish, papillose hairs.  Spores 14--17(--20) mm.

 

Apparently on tree trunks; Calif.; Europe.

 

 

Orthotrichum shawii is similar to O. rupestre, differing in an exostome of 16 short, recurved teeth and nearly smooth capsules compared to O. rupestre with erect or spreading exostome teeth and variable capsule ribbing. This species was collected once without locality, by Bolander in the 1860’s, but is probably not uncommon in California.

 

 

38.  Orthotrichum shevockii Lewinsky-Haapasaari & D. H. Norris, Bryologist 101: 435.  1998

 

Plants less than 1.5 cm.  Stem leaves rigid, erect to spreading when moist, ligulate- to elliptic-lanceolate, less than 5. mm, obtuse to rounded-acute; margins recurved from near apex to just above base, entire; distal laminal cells 13--16 \um wide, 1-stratose, strongly papillose, papillae high, simple to forked; basal laminal cells short-rectangular, pellucid and thin-walled with corner thickenings.  Sexual condition goniautoicous.  Seta less than 0.5 mm.  Capsule immersed; urn short-cylindric to oblong-ovate, 1--2 mm, strongly 8-ribbed entire length; stomates immersed, 2/3 to completely covered by well-developed subsidiary cells; peristome double; endostome segments 8 well-developed, occasionally 16, 1 cell wide, smooth or roughened; exostome teeth 8 ± 16, reflexed, papillose to papillose-reticulate near apex.  Calyptra oblong-conic, hairy, hairs papillose.  Spores 15--18 \um.

 

Dry granitic rocks; 1100--1600 m; Calif.  Endemic.

 

Orthotrichum shevockii is known only from the southern Sierra Mountains of California. It is distinguished by small, blackish tufts, obtuse to bluntly acute leaf apicies, strongly pluripapillose distal laminal cells, bistratose (or more) leaf margins, completely immersed, strongly 8-ribbed capsules, with immersed stomates, reflexed exostome teeth, well-developed endostome, and papillose calyptra hairs.

 

39.  Orthotrichum sordidum Sullivant & Lesquereux in C. F. Austin, Musci Appal., 30. n. 168.  1870

 

Orthotrichum affine var. sordidum (Sullivant & Lesquereux ) Grout; O. affine ssp. subrivale Kindberg; O. cancellatum Cardot & Thériot

 

Plants 0.5--3 cm.  Stem leaves loosely erect-appressed and often slightly contorted when dry, narrowly lanceolate to oblong-lanceolate, 2--3.6 mm, sharply acute or bluntly acuminate; margins revolute to near apex, entire; distal laminal cells 7--14 \um wide, 1-stratose, with 2--3 conical papillae per cell; basal laminal cells elongate-rectangular, nodose, thin-walled.  Sexual condition goniautoicous.  Seta 0.5--1.6 mm.  Capsule usually 1/2--2/3 emergent, sometimes immersed or fully exserted, tapering to seta through a long, shriveled neck, which is less than 1.5 mm in length; urn oblong to oblong-cylindric, 0.8--1.5 mm, strongly 8-ribbed 1/2--2/3 length; stomates superficial; peristome double; endostome segments 8, 1--2 rows of cells, smooth or finely verrucose; exostome teeth 8, reflexed, reticulately papillose to obscurely papillose.  Calyptra oblong-conic, sparsely hairy, hairs smooth or with small papillae.  Spores 19--29 \um.

 

In the Great Lakes region usually trunks of both deciduous and coniferous trees, rarely boulders in hardwood forests, in the Arctic usually on small trees; 0--1000 m; Man., N.B., Nfld., N.W.T., N.S., Ont., P.E.I., Que.; Alaska, Maine, Mass., Mich., Minn., N.H., N.J., N.Y., Pa., Vt., Wis.; n Asia.

 

Orthotrichum sordidum species is distinguished by having oblong capsules with exostome teeth perforate almost to the base and cancellate in the distal portions.

 

40.  Orthotrichum speciosum Nees in J. W. Sturm, Deutschl. fl. 2(3) (fasc. 17): 5.  1819

 

Orthotrichum killiasii Müll. Hal.; O. speciosum ssp. killiasii (Müll. Hal.) Kindberg; O. speciosum var. killiasii (Müll. Hal.) Venturi

 

Plants 0.8--5 cm, robust.  Stem leaves loosely erect, usually slightly contorted or curved, lanceolate to narrowly lanceolate, 3--4 mm, acuminate to narrowly acute, margins revolute nearly to apex, entire; distal laminal cells 7--13 \um wide, 1-stratose, 1--3, conic or forked papillae; basal laminal cells elongate, with nodose or wavy walls.  Sexual condition goniautoicous.  Seta 1--3 mm.  Capsule exserted to rarely emergent; urn cylindric to ovate-cylindric when mature, 1.5--2.4 mm, lightly ribbed ± 1/2 length of capsule; stomates superficial; peristome double; endostome segments 8, 2 rows of cells, coarsely papillose; exostome teeth 8, recurved, coarsely papillose.  Calyptra conic-oblong, with finely papillose hairs.  Spores 13--26 \um. 

 

Coniferous and decidious trees, rocks; 10--2000 m; Greenland; Alta., B.C., Man., N.B., Nfld., N.W.T., N.S., Nun., P.E.I., Que., Sask. Yukon; Alaska, Calif., Colo., Idaho, Mich., Minn., Mont., Nev., N.H., N.Y., Oreg., Utah, Wash., Wyo.; Europe, n Africa; n Asia.

 

Orthotrichum speciosum is mainly western and Arctic in distribution.  The ribbed capsule, large size, and more slender leaf apices distinguish it.  Orthotrichum elegans has smooth capsules.

 

41.  Orthotrichum spjutii Norris &Vitt, Nova Hedw. 56: 259. 1993 

 

Plants to 3.5 cm.  Stem leaves erect-spreading to spreading when moist, loosely erect-appressed to erect-curved when dry, 2--4 mm, broadly lanceolate, ovate-lanceolate, or ovate-ligulate, bluntly acute to obtuse; margins strongly revolute from just before apex to near base, papillose-crenulate; distal laminal cells 10--15 \um wide, 1-stratose, irregularly rounded to isodiametric, with obvious corner thickenings, strongly papillose, papillae forked and densely arranged; basal laminal cells long-rectangular to elongate, pellucid, smooth, lateral walls somewhat irregularly thickened, shorter, narrower, somewhat papillose along the margins.  Sexual condition goniautoicous.  Seta 1--1.5 mm.  Capsule emergent, often rather shortly so; urn oblong to shortly-cylindric, erect, nearly smooth to lightly 8-ribbed sometimes becoming deeply 8-ribbed and constricted with flaring mouth when old and dry; stomates superficial; peristome superficially absent, of about 16, very short, blunt, papillose teeth 1--3 cells high.  Calyptra ovoid-campanulate, mitrate, plicate, hairy; hairs with spiculose papillae throughout.  Spores 8--11 \um, finely papillose.

 

Shaded forests near stream beds, canyons, usually in mountainous areas, deciduous trees, rarely on shaded rocks; 2600 m; Calif.  Endemic.

 

Orthotrichum spjutii is confined to California, and is best recognized by the following combination of characters:  large multifid distal leaf cell papillae, strongly revolute leaf margins, emergent, oblong capsules with peristome reduced to 1--2 cells and seemingly absent, and small spores.

 

42.  Orthotrichum stellatum Bridel, Bryol. Univ. 1: 274.  1826

 

Orthotrichum braunii Bruch, Schimper & W. Gümbel

 

Plants 3--8 mm.  Stem leaves loosely-erect when dry, lanceolate to oblong-lanceolate, 1.8--2.2 mm, narrowly obtuse to bluntly acute; margins recurved to just below the apex, entire; distal laminal cells 8--13 \um wide, smooth or with small, conic papillae; basal laminal cells rectangular, becoming nodose toward the costa.  Sexual condition goniautoicous.  Seta 0.4--1 mm.  Capsules emergent; urn oblong-cylindric and strangulate when dry, 0.4--1 mm, dark-brown ribs; stomates immersed; peristome double; endostome segments 8, of 1--2 rows of cells, smooth; exostome teeth 8, reflexed finely and evenly papillose.  Calyptra oblong, naked or sparsely hairy.  Spores 13--18 \um.

 

Hardwood tree trunks in moist forests, often associated with O. ohioense in mesic, shaded situations along streams; 10--1000 m; Nfld, N.B., N.S. Ont.; Ark., Del., Ga., Ill., Ind., Iowa, Ky., Maine, Md., Mass., Mich., Mo, N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Ver., Va., W.Va.

 

Orthotrichum stellatum is distinguished by strongly ribbed, strangulate capsules with a well-developed endostome of 8 segments.  Orthotrichum ohioense has weakly ribbed capsules that are not constricted beneath the mouth and an endostome which is lacking or rudimentary.  From O. pumilum, the narrowly lanceolate leaves and small leaf cells with unevenly incrassate walls differentiate O. stellatum.

 

43.  Orthotrichum stramineum Bridel, Bryol. Univ., 789.  1827 

 

Orthotrichum strangulatum var. stellatum (Bridel) E. Britton

 

Plants 0.5--1 cm.   Stem leaves erect-appressed or slightly flexuose when dry, lanceolate, 1.8--2.4 mm, acute; margin recurved to just below apex, entire; distal laminal cells 8--12 \um wide, 1-stratose, smooth or small, conic papillae; basal laminal cells rectangular, smooth, rather thin.  Sexual condition goniautoicous.  Seta 0.7--1.5 mm.  Capsules emergent, elliptic-cylindric and strangulate, urn 0.8--1.5 mm, strongly 8-ribbed; stomates immersed, 1/2 to completely covered by well-developed subsidiary cells; peristome double, endostome segments 8 or 16, 1--2 rows of cells wide, smooth on outside or finely sriate; exostome teeth 8, reflexed to revolute when old and dry, finely and evenly papillose.  Calyptra oblong, with few smooth or papillose hairs, rarely naked.  Spores 10--15 \um.

 

Trees; 10--500 m; Nfld.; Europe; Asia

 

Orthotrichum stramineum is distinguished by rather long, elliptic (fat), strongly ribbed capsules that are strangulate as useful field characters.  The hairy vaginula and the shape of the capsule will separate O. stramineum from O. stellatum.

 

44.  Orthotrichum strangulatum Palisot de Beauvois, Prodr., 81. 1805 

 

Orthotrichum calcareum Austin; O. lescurii ssp. porteri (Sullivant & Lesquereux) Kindberg; O. missouricum Grout; O. nudum var. strangulatum (Palisot de Beauvois) Baehni; O. peckii Sullivant & Lesquereux; O. porteri Sullivant & Lesquereux; O. strangulatum var. typicum Venturi; O. strangulatum var. missouricum Grout

 

Plants 4--10 mm.  Stem leaves erect, stiff when dry, ovate- to oblong-lanceolate, 2--2.7 mm, acute to ± narrowly obtuse; margins thickened to near apex, entire; distal laminal cells 7--12 \um wide, 1-stratose (or occasionally with 2-stratose streaks) except at margins, there 2- to 3(--7)-stratose, with 2--3 conic, sometimes forked papillae; basal laminal cells quadrate to rectangular, non-nodose.  Sexual condition goniautoicous.  Seta 0.8 mm or less in length. Capsules immersed to 1/2 emergent; urn oblong-ovate to oblong, 1.1--1.8 mm, distinctly 8-ribbed and constricted beneath mouth when dry; stomates immersed in distal half of capsule, nearly completely covered by subsidiary cells; peristome single (or rarely double); endostome segments none (or rarely 8 fragile, short segments); exostome teeth 16, incurved-erect to spreading-recurved, granulose or reticulate-papillose.  Calyptra oblong-conic, covered with erect papillose hairs.  Spores 12--16 \um.

 

Found exclusively on dry, exposed, calcareous or dolomitic bluffs and rock faces; 150-700 m elev; Man., Ont., Que.; Ala., Ark., Ill., Ind., Iowa, Kans., Ky., Maine, Md., Minn., Mo., N.J., N.Y., N. C., Ohio, Okla., Pa., S.C., S.D., Tenn., Vt., Va., W.Va.

 

The Orthotrichum strangulatum complex contains three species, all endemic to eastern and middle North America.  These three species all occur as blackish, dense tufts on dry calcareous rocks, and have similar sporophytes with immersed, oblong, deeply 8-ribbed, capsules that are strongly constricted under the mouth when dry. Although often described as one polymorphic species; here plants with multi-stratose leaf margins are recognized as O. strangulatum, those with unistratose, plane margins as O. parvulum, and those with unistratose, revolute margins as O. lescurii.

 

45.  Orthotrichum striatum Hedwig, Spec. Musc. Frond., 163.  1801

 

Dorcadion striatum (Hedwig) Lindberg; Weissia striata (Hedwig) P. Gaertner, B. Meyer & Schreber

 

Plants 1--6 cm, robust.  Stem leaves loosely-erect, flexuose when dry, lanceolate, 3--4 mm, narrowly acute to acuminate, appearing revolute to near apex, margins entire; distal laminal cells 7--9 \um wide, 1-stratose, with simple papillae; basal laminal cells elongate, nodose.  Sexual condition goniautoicous.  Seta 0.8--1.2 mm.  Capsule immersed; urn broadly-oblong to narrowly-ovate, 1.5--2.3 mm, smooth; stomates superficial; peristome double; endostome segments 16, in 2 rows of cells, densely papillose; exostome teeth 16, recurved, densely papillose.  Calyptra broadly oblong, moderately hairy.  Spores 17--31 \um.

 

Deciduous trees, usually Acer and Alnus trunks in moist woods, less commonly on conifers; 10--1000 m; B.C.; Alaska, Calif., Idaho, Wash., Oreg; Europe; n Africa Asia (India in Kashmir).

 

Orthotrichum striatum is distinguished from its closest relatives, O. pycnophyllum, O. speciosum, and O. lyellii, by its ovate, smooth capsule, which is immersed even when dry.  The exostome consists of 16, recurved teeth, and the endostome consists of 16 erose segments.  In the area of the flora, Orthotrichum striatum is restricted to the Pacific Northwest. 

 

46.  Orthotrichum tenellum Bridel, Bryol. Univ. 1: 786.  1827

 

Orthotrichum coulteri Mitten; O. cylindrocarpum Lesquereux; O. tenellum var. coulteri (Mitten) Grout; O. tenellum var. cylindrocarpum (Lesquereux) L. F. Koch

 

Plants 3--10 mm.  Stem leaves stiffly erect-appressed, tips incurved when dry, spreading to wide spreading in distal portions of branches, ranging from ligulate to lanceolate-oblong, 1.3--2.6 mm, polymorphic, obtuse to broadly acute, rarely ending in short, hyaline cell, apiculate, or serrulate, concave; margins revolute to below apex or sometimes broadly reflexed in distal 1/2 of leaf, entire; distal laminal cells 8--13 \um wide, 1-stratose, with 2--3 conical papillae per cell; basal laminal cells broadly rectangular, non-nodose.  Sexual condition usually cladautoicous, rarely goniautoicous.  Seta less than 2 mm.  Capsule 2/3 emergent to shortly-exserted; urn cylindric to cylindric-elliptic when mature, 1.3--2 mm, strongly 8-ribbed entire length; stomates immersed in proximal 1/3 of capsule, ± completely covered by projecting subsidiary cells; peristome double; endostome segments 8, rarely 16, finely papillose, exostome teeth 8, rarely split to 16 when old, erect when mature, reflexed when old.  Calyptra conic-oblong, naked or sparsely hairy, the hairs sometimes papillose by projecting walls.  Spores 11--18 \um.

 

Trunks of deciduous trees in dry, open areas, rarely on rocks; restricted to lower elevations; 100--2000 m; B.C.; Calif., Nev., Wash.; Europe, n Africa; Atlantic Islands (Azores, Canary Islands).

 

Orthotrichum tenellum is the only western species with deeply immersed stomates, blunt leaves, and oblong-cylindric capsules.  Its small size distinguishes it from other Californian species found on trees.

 

47.  Orthotrichum underwoodii F. Lara, R. Garilleti & V. Mazimpaka, Bryologist 104: 268.  2001

 

Plants to 1 cm.  Stem leaves erect when dry, slightly flexuose to erect when moist, lanceolate, 2--3.2(--3.5) mm, with acute apex; margins entire or papillose-crenulate; distal laminal cells (7--)11--14(--16) \um wide; 1-stratose, basal laminal cells rectangular to almost quadrate, rarely nodose.  Sexual condition goniautoicous or cladautoicous.  Seta 0.4--0.6 mm.  Capsule 2/3 emergent to shortly-exserted; urn cylindric, 8 narrow ribs entire length; stomates immersed; peristome double; endostome segments 16, filiforme, exostome teeth 16, erect when mature, reflexed when old.  Calyptra conic-oblong, slightly plicate, with scattered short, thin hairs.  Spores 16--18(--19) \um.

 

Trees; elevation unknown; Calif.  Endemic.

 

Orthotrichum underwoodii is known only from type material from the Santa Clara Mountains of Santa Clara Co., California. Orthotrichum underwoodii has 8--16 lightly ribbed cylindric capsules with an erect exostome of 16 teeth and endostome of 16, long and linear segments.  In peristome features, it is similar to O. diaphanum, but that species has hair points.  Perhaps O. underwoodii could be confused with O. tenellum, but the latter species has much more strongly ribbed capsules, reflexed exostome, endostome of 8, well-developed but short segments, and blunt, very stiff leaves with incurved tips.

 

For Key, see below

 

 

 

 

1.  Leaves gradually acute and ending in hyaline awn . . 9. Orthotrichum diaphanum

 

1.  Leaves obtuse, acute, acuminate, or cuspidate, not ending in hyaline awn.

 

2.  Leaf margins erect-incurved, or involute; leaves ovate or elliptic, concave with broadly obtuse or rounded apices; laminal brood-bodies abundant; dioicous; calyptrae papillose, neither plicate nor hairy.

 

3.  Leaf margins involute; distal laminal cells with 2--3 conical papillae per cell; peristome lacking; Newfoundland . . 15. Orthotrichum gymnostomum

 

3.  Leaf margins erect-incurved to incurved; distal laminal cells with 1 papilla per cell; peristome double; common throughout boreal and western regions . .24. Orthotrichum obtusifolium

 

2.  Leaf margins plane, recurved, revolute, or thickened; leaves ± lanceolate or oblong, plane to keeled, with narrowly obtuse, acute, or acuminate apices; laminal brood bodies absent, few, or abundant; autoicous, if dioicous then leaves acuminate; calyptrae smooth, rarely papillose, plicate, hairy or naked.

 

4.  Leaves crisped-flexuose when dry; capsule cylindric or elliptic-cylindric, fully exserted; stomates immersed; Pacific Northwest and Alaska.

 

5.  Plants 8--20 cm; distal laminal cells 7--11 \um wide; seta usually 2.5--6 mm; capsule long-exserted, elliptic-cylindric when mature; peristome teeth 8, light-brown, finely papillose on the exterior, finely striate on the interior; stomates in the middle and proximal portion of the capsule . . 7. Orthotrichum consimile

 

5.  Plants usually less than 1.3 cm; distal laminal cells 9--14 \um wide; seta 1.5--3.5 mm; capsule barely exserted, oblong-cylindric when mature; peristome teeth 16, red, irregularly papillose-reticulate; stomates above the middle of the capsule, never in the proximal portion . . 30. Orthotrichum pulchellum

 

4.  Leaves erect-appressed when dry; capsules various; stomates superficial or immersed; throughout North America.

 

6.  Leaves with abundant laminal gemmae; restricted to California and Oregon . . 22. Orthotrichum lyellii

 

6.  Leaves without or with few laminal gemmae; variously distributed in North America.

 

7.  Stomates superficial; basal leaf cells elongate, ± nodose, thick-walled.

 

8.  Endostome segments well-developed, usually present when capsule is old; exostome teeth usually recurved or reflexed; prostome absent; leaves sometimes flexuose when dry, 1-stratose

 

9.  Exostome teeth reflexed; endostome segments 8, narrow, consisting of a single row of cells; capsule 8-ribbed at least 1/2 length of capsule.

 

10.  Capsule ovate to ovate-oblong, fully exserted; exostome teeth 16.

 

11.  Exostome fenestrate and cancellate; endemic to St. Paul's Island, Alaska . . 13. Orthotrichum fenestratum

 

11.  Exostome not fenestrate or cancellate, at most perforate at tips; Arctic south to California . . 34. Orthotrichum pylaisii (in part)

 

10.  Capsule oblong to cylindric, emergent to slightly exserted; exostome teeth 8.

 

12.  Capsule oblong, ± 1/2 emergent; exostome teeth perforate only at tips, not cancellate; endostome segments usually absent when capsules are old and dry; leaves gradually narrowed to a long acuminate-cuspidate, ± colorless apex; rare, western states, saxicolous . . 29. Orthotrichum praemorsum

 

12.  Capsule long-cylindric to oblong, 1/2 emergent to exserted; exostome teeth deeply perforate and cancellate, each tooth appearing as split into 4 vertical rows; endostome segments usually present when capsules are old and dry; leaves acute; common, throughout northern North America, corticolous.

 

13.  Capsule long-cylindric to cylindric, greater than 1.5 mm, ribbed entire length, over 1/2 emergent; tapering gradually to seta; endostome papillose; western North America . . 1. Orthotrichum affine

 

13.  Capsule oblong to oblong-cylindric, less than 1.5 mm, ribbed for ± 1/2 length of capsule, ± emergent; tapering to seta through a long, shriveled neck; endostome smooth; Great Lakes area, northeastern North America, and Alaska . . 39 Orthotrichum sordidum

 

9.  Exostome teeth recurved; endostome segments 8 or 16, large, stout, and thick, consisting of 2 rows of cells; capsule smooth or weakly 8-ribbed no more than 1/2 length of capsule or if strongly 8-ribbed, then dioicous.

 

14.  Calyptra naked; endostome segments hyaline, delicate, as wide as exostome teeth; capsule widest at mouth, ovate; leaves lanceolate-oblong to oblong, rounded-obtuse; stems less than 1 cm, largest at apex . . 12. Orthotrichum exiguum

 

14.  Calyptra hairy; endostome segments yellowish, stout, narrower than exostome teeth; capsule widest at middle or cylindric; leaves lanceolate, acute or acuminate; stems longer than 1 cm, of uniform thickness.

 

15.  Dioicous; exostome teeth acuminate; capsule oblong-cylindric, 8-ribbed . . 22. Orthotrichum lyellii

 

15.  Autoicous; exostome teeth acute or truncate; capsule of various types.

 

16.  Leaves slenderly acute, tip contracted to large, cuspidate point; peristome teeth truncate, often united at base to form basal ring, endemic to Appalachian Mts. . . 18. Orthotrichum keeverae

 

16.  Leaves acute or acuminate; peristome teeth acute, separate to base; absent in Appalachian Mts.

 

17.  Exostome teeth 16, endostome segments 16, usually not erose; New Mexico and Arizona . . 33. Orthotrichum pycnophyllum

 

17.  Exostome teeth 8, or if 16 endostome erose; endostome segments 8 to 16; temperate and boreal regions southward to California and Missouri.

 

18.  Capsule lightly 8-ribbed . . 40. Orthotrichum speciosum

 

18.  Capsule smooth.

 

19. Capsule cylindric, exserted; exostome teeth 8; endostome segments 8 . . 10. Orthotrichum elegans

 

19.  Capsule ovate, immersed; exostome teeth 16; endostome segments 16 . . 45. Orthotrichum striatum

 

8.  Endostome segments usually absent, occasionally rudimentary; exostome teeth erect, sometimes reflexed when old and dry; prostome usually present; leaves stiff, erect-appressed when dry, rarely 2-stratose.

 

20.  Distal laminal cells 2-stratose, margins plane; plants dark-green to black . . 6. Orthotrichum bolanderi

 

20.  Distal laminal cells 1-stratose, margins revolute; plants light- to olive-green.

 

21.  Peristome rudimentary, appearing absent . . 41. Orthotrichum spjutii

 

21.  Peristome present, evident.

 

22.  Exostome teeth smooth; leaves smooth; calyptra naked; prostome large, extending 1/3 way up exostome; seasonally wet rocks . . 17. Orthotrichum holzingeri

 

22.  Exostome teeth papillose; leaves papillose; calyptra hairy; prostome small or absent; dry rocks.

 

23.  Capsule cylindric, fully exserted.

 

24.  Exostome teeth usually 16, erect; capsule smooth or slightly plicate; exothecial cells homogeneous; endostome rudimentary, usually absent in open capsules . . 20. Orthotrichum laevigatum

 

24.  Exostome teeth usually 8, reflexed-recurved; capsule lightly 8-ribbed, exothecial cells differentiated for 1/2 length of capsule; endostome usually present in at least some capsules . .  34. Orthotrichum pylaisii (in part)

 

23.  Capsule usually oblong and emergent.

 

25. Exostome teeth erect to spreading; mostly on rocks, sometimes on trees . . 36. Orthotrichum rupestre

 

25.  Exostome teeth recurved; on trees . . 37. Orthotrichum shawii

 

7.  Stomates immersed; basal leaf cells rectangular, not nodose, thin-walled.

 

26.  Leaves ± obtuse; margins coarsely dentate or cucullate at apex; calyptra naked, distinctly plicate, papillose, peristome of 8, reflexed teeth; on seasonally wet rocks or bases of trees near streams, sometimes submerged; west of continental divide.

 

27.  Plants in tight, red-brown to black tufts; leaf apices cucullate, entire to sometimes irregularly serrulate; costa sinuose, often forked near apex; distal laminal cells to 20 \um wide . . 11. Orthotrichum euryphyllum

 

27.  Plants in loose, dark-green to blackish-green tufts; leaf apices flat, often dentate; costa straight; distal laminal cells to 13 \um wide . . 35.  Orthotrichum rivulare

 

26.  Leaves ± acute or narrowly obtuse; margins entire or denticulate near apex; calyptra naked or hairy, not distinctly plicate, smooth; peristome various; on trunks of trees or dry rock faces; variously distributed.

 

28.  Capsules with 8 short ribs constricting capsule at mouth when dry; exostome lacking; known only from California . . 3. Orthotrichum anodon

 

28.  Capsules smooth or with 8 or 16 ribs constricting capsule below mouth; exostome of 8 or 16 variably developed teeth; throughout North America.

 

29.  Distal laminal cells uniformly 2-stratose. 

 

30.  Plants with all stems erect; leaves similar on vegetative and fertile stems; scattered throughout western North America . . 16. Orthotrichum hallii (in part)

 

30.  Plants with creeping primary stems from which erect vegetative and fertile stems arise; leaves of vegetative axes differentiated from those of fertile axes; rare, restricted to California  19. Orthotrichum kellmanii

 

29.  Distal laminal cells mostly 1-stratose, occasionally 2-stratose in streaks, or with 2- to multistratose margins.

 

31.  Exostome teeth erect or spreading, striate, reticulate, densely papillose or papillose-striate; capsule with 8 or 16 ribs.

 

32.  Endostome segments 16, linear, papillose, as long as exostome. . 47. Orthotrichum underwoodii

 

32.  Endostome segments absent, or 8 and short, not well-developed.

 

33.  Capsule exserted, cylindrical, usually with 8 long and 8 short ribs; distal laminal cells 1-stratose . . 4. Orthotrichum anomalum

 

33.  Capsule immersed or emergent, rarely shortly exserted, ovate or oblong, usually with 8 or 16 ± uniform ribs; distal laminal cells 1- or partially 2-stratose.

 

34.  Capsule with 16 ribs, ovate and constricted below mouth when dry; leaves ovate-lanceolate, acute; distal laminal cells 1-stratose, rarely 2-stratose in streaks . . 8. Orthotrichum cupulatum

 

34.  Capsule with 8 ribs, oblong or oblong-ovate, sometimes constricted below mouth when dry; leaves lanceolate to ligulate, obtuse or blunt; distal laminal cells 1- or 2-stratose.

 

35.  Distal laminal cells of either laminae or margins 2--7-stratose

 

36.  Cells of leaf margins and of distal leaf lamina mostly to completely 2-stratose . . 16. Orthotrichum hallii (in part)

 

36.  Cells of leaf margins 2--7 stratose, laminal cells 1-stratose, occasionally with a few 2-stratose streaks . . 44. Orthotrichum strangulatum

 

35.  Distal laminal cells 1-stratose.

 

37.  Leaves appearing thick and glaucous; papillae 1--2, large, 2--3, forked; western North America . . 28. Orthotrichum pellucidum

 

37.  Leaves blackish green, dull; papillae 1--3, small, conic; eastern and interior North America.

 

38.  Leaves oblong-lanceolate, margins plane or nearly so; capsules oblong; exostome teeth reticulate-papillose. . 27. Orthotrichum parvulum

 

38.  Leaves narrowly lanceolate, margins revolute; capsules ovate; exostome teeth finely papillose. . 21. Orthotrichum lescurii

 

31.  Exostome teeth reflexed or recurved, finely papillose, rarely striate at tips; capsule smooth or 8-ribbed.

 

39.  Capsule smooth (wrinkled and lightly 8-plicate when old) when dry; exostome teeth 16, erect to recurved; endostome absent . . 32. Orthotrichum pusillum

 

39.  Capsule 8-ribbed when dry; exostome teeth 8, or 8 splitting to 16, reflexed; endostome usually present

 

40.  Leaf apex cuspidate, usually denticulate, margins incurved and forming channel at apex; southwestern U.S.A . . .5. Orthotrichum bartramii

 

40.  Leaf apex obtuse, acute, or apiculate, margins not forming channel at apex; throughout North America.

 

41. Stomates scarcely to 1/2 covered by non-projecting subsidiary cells, inner walls not much thickened; calyptra usually naked, sometimes with a few hairs, oblong to conic-oblong.

 

42. Leaves acute, narrowly obtuse, or apiculate-crenulate, oblong-lanceolate to lanceolate; distal laminal cells less than 14 \um; calyptra conic-oblong . . 26. Orthotrichum pallens

 

42. Leaves apiculate, mucronate, or rounded-obtuse, ovate or narrowly ovate-lanceolate; distal laminal cells greater than 13 \um; calyptra oblong.

 

43.  Leaves ovate to ovate-oblong, rounded-obtuse, at least some leaves mucronate, carinate; western North America . . 14. Orthotrichum flowersii

 

43.  Leaves ovate-lanceolate to lanceolate, acute, most leaves apiculate, not carinate; throughout North America . . 31. Orthotrichum pumilum

 

41.  Stomates 1/2 to completely covered by projecting subsidiary cells, inner walls thickened; calyptra usually with a few to many hairs, oblong.

 

44.  Leaves with 2- to 3-stratose margins; dry granite rocks . . 38. Orthotrichum shevockii

 

44.  Leaves with 1-stratose margins; trees and mesic rocks.

 

45. Exostome teeth striate-reticulate in distal portion; calyptra with strongly papillose hairs; leaf cells with regular, long-forked papillae; leaves slightly twisted when dry; capsule strangulate when dry. . . 2.  Orthotrichum alpestre

 

45.  Exostome teeth papillose; calyptra hairs smooth or papillae formed by projecting cell walls; leaf cells smooth or with low, conical papillae, never forked; leaves stiff, erect-appressed when dry; capsule variously constricted beneath mouth when dry.

 

46.  Vaginula with numerous hairs.

 

47.  Capsules with thin, delicate ribs when dry; California . . 23. Orthotrichum norrisii

 

47.  Capsules with thick, broad ribs when dry; Newfoundland . . 43. Orthotrichum stramineum

 

46.  Vaginula without hairs.

 

48.  Leaf tips incurved when dry; capsule cylindric to cylindric-elliptic,  contracted along entire length, not constricted beneath mouth; stomates in proximal 1/3 of capsule, completely covered by subsidiary cells; restricted to west coast  . . 46. Orthotrichum tenellum

 

48.  Leaf tips not incurved when dry; capsule oblong-cylindric, sometimes constricted beneath mouth, never contracted along entire length; stomates at middle of capsule, completely covered by subsidiary cells or not; Rocky Mountains and eastward.

 

49.  Leaf cells greater than 14 \um, lumina smooth and rounded; leaves apiculate or slenderly acute, ovate-lanceolate to oblong-lanceolate; subsidiary cells not completely covering stomates . . 31. Orthotrichum pumilum

 

49.  Leaf cells less than 14 \um, lumina irregular due to uneven wall thickenings; leaves broadly acute to obtuse, lanceolate; subsidiary cells completely covering stomates.

 

50. Capsule not constricted beneath mouth, yellow, with thin, delicate ribs; exostome teeth 16, rarely united into 8 pairs; subsidiary cells projecting upward over stomate . . 25. Orthotrichum ohioense

 

50.  Capsule strongly constricted beneath mouth, brown, with thick, broad ribs; exostome teeth 8; subsidiary cells projecting horizontally over stomate . . 42. Orthotrichum stellatum