BFNA Title: Orthotrichum
Author: D. H. Vitt  
Date: October 8, 2003
Edit Level: R Brum+
Version: 2 Nov. 30, 2006

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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ORTHOTRICHUM - ORTHOTRICHACEAE

 

6.  Orthotrichum Hedwig, Spec. Musci.  162.  1801 * [Named for the straight, erect hairs found on the calyptra in many of the 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 leaf cells mostly rounded, almost isodiametric, usually 6--24(--30) µm, 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 120 (40 in the flora); worldwide, more common in temperate areas.

 

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

 

 

1.  Leaves ending in ± serrate, hyaline awn . . 8. Orthotrichum diaphanum

 

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

 

2.  Leaf margins erect, incurved, or involute; dioicous; leaves ovate or elliptic, with broadly obtuse or rounded apices; calyptrae papillose, not plicate or hairy.

 

3.  Leaf margins involute; distal leaf cells with 2--3 conical papillae per cell; peristome lacking; Newfoundland . . 13. Orthotrichum gymnostomum

 

3.  Leaf margins erect-incurved to incurved; distal leaf cells with 1 papilla per cell; peristome double; common throughout boreal and western regions . . 19. Orthotrichum obtusifolium

 

2.  Leaf margins plane, recurved, revolute, or thickened;  condition autoicous or if dioicous then leaves acuminate; leaves ± lanceolate or oblong, with narrowly obtuse, acute, or acuminate apices; calyptra smooth or 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 0.8--2 mm; distal leaf cells 7--11 µm wide; seta usually 2.5--6 mm; capsule long-exserted, ovate-cylindric when mature; peristome teeth 8, light-brown, finely papillose on the exterior, finely striate on the interior; stomates immersed, in the middle and proximal portion of the capsule . . 6. Orthotrichum consimile

 

5.  Plants usually less than 1.3 cm; distal leaf cells 9--14 µm wide; seta 1.5--3.5 mm; capsule barely exserted, oblong-cylindric when mature; peristome teeth 16, red, irregularly papillose-reticulate; stomates immersed above the middle of the capsule, never in the proximal portion . . 24. Orthotrichum pulchellum

 

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

 

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

 

7.  Endostome segments well-developed, usually present when capsule is old; exostome teeth recurved or reflexed; prostome never present; leaves sometimes flexuose when dry, always 1-stratose

 

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

 

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

 

9.  Exostome not fenestrate or cancellate, at most perforate at tips; Arctic south to California . . 28. Orthotrichum pylaisii

 

8.  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.

 

10.  Calyptra oblong-conic, naked; endostome segments hyaline, delicate, as wide as exostome teeth; capsule widest at mouth, ovate; leaves oblong-ovate, rounded-obtuse; plants never longer than 1 cm, largest at apex . . 10. Orthotrichum exiguum

 

10.  Calyptra short-conic, hairy; endostome segments yellowish, stout, not as wide as exostome teeth; capsule widest at middle or cylindric; leaves lanceolate, acute or acuminate; stems longer than 1 cm, of uniform thickness.

 

11.  Plants dioicous; exostome teeth acuminate; capsule long-cylindric and 8-ribbed . . 18. Orthotrichum lyellii

 

11.  Plants autoicous; exostome teeth acute or truncate; capsule of various types.

 

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

 

12.  Leaves acute or acuminate; peristome teeth acute, separate to base; not found in Appalachian Mts.

 

13.  Exostome teeth 16, endostome segments 16, usually not erose; New Mexico and Arizona . . 27. Orthotrichum pycnophyllum

 

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

 

14.  Capsule lightly 8-ribbed . . 33. Orthotrichum speciosum

 

14.  Capsule smooth.

 

15. Capsule cylindric, exserted; exostome teeth 8; endostome segments 8 . . 9. Orthotrichum elegans

 

15.  Capsule ovate, immersed; exostome teeth 16; endostome segments 16. . . 38. Orthotrichum striatum

 

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

 

16.  Leaves 2-stratose, margins plane; plants dark-green to black . . 5. Orthotrichum bolanderi

 

16.  Leaves 1-stratose, margins revolute; plants light- to olive-green.

 

17.  Peristome rudimentary, appearing absent . . 34. Orthotrichum spjutii

 

17.  Peristome present.

 

18.  Exostome teeth smooth; leaves smooth; calyptra naked; prostome large, extending 1/3 way up exostome; seasonally wet rocks . . 15. Orthotrichum holzingeri

 

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

 

19.  Capsule cylindric, fully exserted.

 

20.  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  . .  28. Orthotrichum pylaisii

 

20.  Exostome teeth usually 16, erect; capsule smooth or slightly plicate; exothecial cells not or scarcely differentiated; endostome rudimentary, usually absent in open capsules . . 17. Orthotrichum laevigatum

 

19.  Capsule usually oblong and emergent, if cylindric and exserted then strongly 8-ribbed.

 

21.  Exostome teeth erect; endostome absent . . 30. Orthotrichum rupestre

 

21.  Exostome teeth reflexed; endostome present.

 

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

 

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

 

23.  Exostome not fenestrate or cancellate, at most perforate at tips; Arctic south to California . . 28. Orthotrichum pylaisii

 

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

 

24.  Capsule oblong, ± 1/2 emergent; exostome teeth perforate only at tips, not cancellate; endostome segments usually not present when capsules are old and dry; leaves gradually narrowed to a long acuminate-cuspidate apex, which is ± colorless; rare, western states, saxicolous . . 23. Orthotrichum praemorsum

 

24.  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.

 

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

 

25.  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, which is less than 1.5 mm in length; endostome smooth; Great Lakes area, northeastern North America, and Alaska . . 32. Orthotrichum sordidum

 

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

 

26.  Leaves ± obtuse; margins coarsely dentate near apex; calyptra naked, distinctly plicate, papillose, peristome of 8, reflexed teeth; rocks or bases of trees near streams, sometimes submerged; west of continental divide. . 29. Orthotrichum rivulare

 

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

 

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

 

28.  Endostome segments 16, linear, papillose, as long as exostome. . 40. Orthotrichum underwoodii

 

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

 

29.  Capsule exserted, cylindrical, usually with 8 long and 8 short ribs; leaves 1-stratose . . 3. Orthotrichum anomalum

 

29.  Capsule immersed or emergent, rarely shortly exserted, ovate or oblong, usually with 8 or 16 ± uniform ribs; leaves 1- or 2-stratose.

 

30.  Capsule with 16 ribs, immersed to 1/3 emergent, ovate and constricted below mouth when dry; leaves ovate-lanceolate, acute, 1-stratose or rarely with 2-stratose streaks . . 7. Orthotrichum cupulatum

 

30.  Capsule with 8 ribs, ± emergent, oblong or oblong-ovate, sometimes constricted below mouth when dry; leaves lanceolate to ligulate, obtuse or blunt, 1- or 2-stratose.

 

31.  Exostome teeth finely papillose or finely reticulate-papillose, 16, yellowish, erect or spreading-recurved; leaf margins 1--5 cells thick, at least in some leaves thicker than lamina; capsule usually strongly constricted below mouth when old; eastern North America  . . 37. Orthotrichum strangulatum

 

31.  Exostome teeth ridged-striate, coarsely striate-reticulate, or coarsely papillose-striate, 8 splitting to 16, white to clear, incurved, spreading, or reflexed; leaf margins not thicker than lamina; capsule only moderately constricted below mouth when dry; western North America.

 

32.  Leaves 2-stratose or partially 2-stratose, green, lanceolate, obtuse, loosely-appressed, not incurved when dry; papillae small and conical; exostome teeth usually 8 . . 14. Orthotrichum hallii

 

32.  Leaves 1-stratose, usually thick and glaucous, ligulate, blunt, stiff, incurved when dry; papillae large, 2-3 forked; exostome teeth ± 16. . .  22. Orthotrichum pellucidum

 

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

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

 

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

 

34.  Leaf apex cuspidate and usually denticulate, margins incurved and forming channel at apex; southwestern U.S.A. . .4. Orthotrichum bartramii

 

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

 

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

 

36. Leaves acute, narrowly obtuse, or apiculate-crenulate, oblong-lanceolate to lanceolate; distal leaf cells less than 14 µm; calyptra conic-oblong . . 21. Orthotrichum pallens

 

36. Leaves apiculate, mucronate, or rounded-obtuse, ovate or narrowly ovate-lanceolate; distal leaf cells greater than 13 µm; calyptra oblong.

37.  Leaves ovate to ovate-oblong, rounded-obtuse, at least some leaves mucronate, carinate; western North America . . 12. Orthotrichum flowersii

 

37.  Leaves ovate-lanceolate to lanceolate, acute, most leaves apiculate, not carinate; throughout North America . . 25. Orthotrichum pumilum

 

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

 

38.  Leaves with 2- to 3-stratose margins; dry granite rocks . . 31. Orthotrichum shevockii

 

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

 

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

 

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

 

40.  Vaginula with numerous hairs . . 36. Orthotrichum stramineum

 

40.  Vaginula without hairs.

 

41.  Leaf tips incurved when dry; capsule cylindric to cylindric-elliptic, not constricted beneath mouth, but contracted along entire length; stomates in proximal 1/3 of capsule, completely covered by subsidiary cells; restricted to west coast  . . 39. Orthotrichum tenellum

 

41.  Leaf tips not incurved when dry; capsule oblong-cylindric, constricted beneath mouth, never contracted along entire length; stomates at middle of capsule; Rocky Mountains and eastward.

 

42.  Leaf cells greater than 14 µm, the lumina smooth and rounded; leaves apiculate or slenderly acute, ovate-lanceolate to oblong-lanceolate; subsidiary cells not completely covering stomates . . 39. Orthotrichum pumilum

 

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

 

43.  Capsule strongly constricted beneath mouth, brown; exothecial cells with thickened walls, in rows 6--8 cells wide; exostome teeth 8; subsidiary cells projecting horizontally over stomate . . 35. Orthotrichum stellatum

 

43. Capsule not constricted beneath mouth, yellow; exothecial cells with thickened walls in rows 4--6 cells wide; peristome teeth 16, rarely united into 8 pairs; subsidiary cells projecting upward over stomate . . 20. Orthotrichum ohioense

 

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 µm 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 µm.

 

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 the western portion of 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 µm 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 µm.

 

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 leaf cells, slightly twisted leaves, which are always sharply pointed, a calyptra with papillose hairs, the absence of a preperistome, and the papillose or papillose-reticulate exostome.  The endostome is always present in mature capsule and because of the enlarged crosswalls has a shiny appearance.  The capsule, as it is usually seen, is oblong and strangulate, although the shape depends on age, and in some specimens the capsule is short-cylindric and not much constricted under the mouth.

 

3.  Orthotrichum anomalum Hedwig, Spec. Musc. 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 µm 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 µm.

 

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 1-stratose leaves.  The most useful character in distinguishing this species from others is the exserted capsule with 8 long ribs alternating with 8 shorter ones.

 

4.  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 µm 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 µm.

 

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

 

The channeled, cuspidate apex of the mature leaves distinguishes this species 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

 

5.  Orthotrichum bolanderi Sullivant, Icon. Musc. Suppl. 64 Pl. 46.  1874

 

Plants 0.5--4 cm.  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 µm 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 µm.

 

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 leaves. It has leaves with a subsheathing base, ovoid cylindric capsules with a long wrinkled neck, and exostome teeth that are reflexed-recurved.  When dry the leaves are stiffly erect-appressed and when wet they lie flat on a microscope slide.

 

6.  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 contorted-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 µm 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 mature, 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 µm.

 

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.

 

7.  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 µm 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 µm.

 

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 broadly but sharply acute, ovate-lanceolate, and usually 1-stratose or occasionally partially 2-stratose;  (2)  papillae of the leaf cells usually large and forked, but if small and conical then the leaf is 1-stratose;  (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.

 

8.  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 µm 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 µm.

 

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 that lack 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.

 

9. 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 µm 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 µm. 

 

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 forming 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.

 

10.  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 µm 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 µm.

 

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

 

The distal leaf 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.

 

11.  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 µm wide, 1-stratose, with 1--2 small conical papillae per cell; basal laminal cells narrowly rectangular, grading to subquadrate at margin, nodose.  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, 1 row of cells, papillose-reticulate; exostome teeth 8 splitting to 16, erect to recurved when old, coarsely papillose above, becoming finely papillose to almost smooth near base.  Calyptra short-conic, plicate, with few, thick, white hairs.  Spores 20--27 µm.

 

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 this species.

 

12.  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 µm 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 µm.

 

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

 

This species is distinguished from O. pumilum and O. pallens by having blunt, carinate leaves that are ovate or ovate-oblong, and almost always have a small mucro.

 

13. 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 µm 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 µm.

 

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

 

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

 

14.  Orthotrichum hallii Sullivant & Lesquereux in W. S. Sullivant, Icones Musc. Suppl. 63.  Pl. 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 µm wide, 2-stratose, rarely with a few 1-stratose 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 µm.

 

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 so, 2-stratose in their distal portion, and oblong, 8-ribbed capsules that are emergent.  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 in all proportions.  The papillae are always small and conical.

 

15.  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 µm 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 µm.

 

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

 

This species is distinguished by having 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.

 

16.  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; margins revolute nearly to apex, often irregularly notched near apex; distal laminal cells 7--14 µm 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.  Calyptra conic-oblong, with papillose hairs 1--3 cells thick.  Spores 17--27 µm.

 

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.

 

17.  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 µm 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 16, erect, papillose-granulose, coarsely papillose or striate-papillose.  Calyptra conic-oblong, sparsely hairy, hairs finely papillose.  Spores 10--15 µm.

 

Usually on non-calcareous boulders in mesic, yet 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.

 

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

 

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

 

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 µm 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, distinctly 8-ribbed from 1/2 to entire length; stomates superficial; peristome double; endostome segments 16, large, coarsely papillose; exostome teeth 16, reflexed-recurved, densely papillose.