BFNA Title: Mielichhoferiaceae
Author: J. A. Shaw
Date: March 23, 2009
Edit Level: R
Version: 1

Bryophyte Flora of North America, Provisional Publication
Missouri Botanical Garden

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XX. Mielichhoferiaceae Schimper

 

A. Jonathan Shaw

 

 

 

Plants acrocarpous, with sporophytes terminal though sometimes appearing lateral because of subfloral innovations, or cladocarpous with sporophytes lateral on short branches; tiny to robust, as scattered individuals or forming small to large colonies, green, reddish, whitish, or golden, often glossy when dry. Stems short to long, 0.3--10 cm, sometimes somewhat complanate, unbranched or irregularly forking when sterile, often bearing subfloral innovations when with gametangia; rhizoids sparse to abundant, variously colored, smooth to papillose, often bearing multicellular tubers. Leaves imbricate to slightly twisted when dry, erect to erect-spreading when wet, broadly lanceolate, ovate-lanceolate, elliptical, obovate, 0.3--2.5 cm, decurrent or not; margins plane or revolute, finely serrate to serrulate near the apex, rarely entire, apex bluntly acute to acute or shortly acuminate, costa ending well before the apex, subpercurrent or percurrent, rarely shortly excurrent, transverse section with stereid band single, usually well developed, occasionally reduced, generally with guide cells; distal medial laminal cells elongate-hexagonal, rhombic, or linear-rhomboidal, sometimes narrowly vermicular, with thin to thickened walls, proximal cells usually short- or long-rectangular, thin-walled, marginal cells undifferentiated, slightly narrower and longer than median cells [sometimes abruptly differentiated as a distinct border, rarely red]. Specialized asexual reproduction common, variously spherical to ovoid rhizoidal tubers or axillary filiform to buliform gemmae. Sexual condition dioicous, paroicous, autoicous, rarely synoicous, rarely variable within species (polyoicous); perigonia and perichaetia terminal or lateral, perichaetial leaves the same size as vegetative leaves, sometimes strongly differentiated, narrowly to linear-lanceolate, or smaller, with weaker costa, perigonia bud-like, perigonial leaves broadly ovate, concave and often brown to reddish basally, acute to long-acuminate distally, acumen erect to wide-spreading. Seta usually 1(2--5), variously colored, long, straight, bent to various degrees producing inclined to pendulous capsules. Capsule erect, or inclined to 180° from vertical, long-exserted, 1--5(--10) mm, narrowly cylindrical to broadly pyriform, neck well differentiated, sometimes as long or longer than the urn, stomata abundant in the neck, superficial to immersed, exothecial cells near mouth quadrate or short-rectangular, thick-walled, often reddish in 1--3 or more rows, median cells longer, short- to long-rectangular with straight or sinuose walls, rarely isodiametric, sometimes collenchymatous; annulus present, revoluble, or absent; operculum convex, short to tall-conic, sometimes shortly rostrate; peristome diplolepideous-alternate, rarely reduced to one layer or absent; peristomial formula 4:2:4--6, sometimes 4:2:8; exostome white, pale yellow to brown, rarely red, teeth triangular to lanceolate, rarely reduced or absent, trabeculate or not, pitted or rarely papillose below, coarsely or rarely finely papillose distally, endostome hyaline to yellow, segments narrow to wide, strongly to weakly or scarcely keeled, rarely absent or reduced to a rudimentary membrane, broadly to narrowly perforate or less commonly entire, basal membrane low to high, sometimes scarcely exceeding the capsule rim, cilia present or absent, 1--3, as long as the segments or shorter, nodulose or not. Calyptra fugacious, cucullate, smooth. Spores shed singly, 11--45 \um, smooth to papillose, pale yellow, tan or nearly hyaline, rarely darker.

 

Genera 4, species ca. 150 (3 genera, 36 species in the flora): worldwide, most speciose in the Northern Hemisphere.

 

The family Mielichhoferiaceae includes species that were traditionally classified in the Bryaceae, but are phylogenetically closer to the Mniaceae.  In addition to the three North American genera, the family probably includes Pseudopohlia of Mexico. The leaves are narrowly to broadly lanceolate (sometimes elliptic or, in tropical species of Epipterygium, obovate to spatulate), with elongate distal leaf cells.  The margins are generally serrate to serrulate; laminal cells along the margins are weakly or undifferentiated in Pohlia and Mielichhoferia, moderately differentiated in Epipterygium tozeri, and strongly differentiated and linear, forming a conspicuous border in some tropical species of Epipterygium.  The peristome is fundamentally diplolepideous and double with well-developed exostome and endostome but is variously reduced in many species.  It is absent in a few tropical species of Pohlia and Mielichhoferia. 

 

Among Epipterygium species, the North American E. tozeri is most similar to species of Pohlia, especially those of the Mniobryum group (the latter sometimes treated as a subgenus of Pohlia or as a separate genus). Tropical species of Epipterygium, including those of the Caribbean region and Mexico, may be strongly complanate with dimorphic leaves differentiated as larger lateral and ventral leaves and smaller dorsal leaves. Epipterygium grows on soil banks in humid, shaded lowland forest habitats.

 

Mielichhoferia is especially diverse in South America and is highly variable in peristome development ranging from double with well-developed exostome and endostome, single and endostomial, double but with the exostome short and barely exceeding the capsule rim, or double with the endostome reduced to an inconspicuous membrane adherent to the exostome teeth (two North American species).  Mielichhoferia species are gametophytically similar to small species of Pohlia, though they can be distinguished by a characteristic whitish color and very small size. The main features distinguishing the two genera are gametangia borne on short lateral shoots in Mielichhoferia and terminal in Pohlia.  The perichaetial leaves are as long or longer than vegetative leaves in Pohlia but are smaller, with more lax cells and shorter costa in Mielichhoferia. Mielichhoferia and Pohlia grow in similar habitats. 

 

The three genera of Mielichhoferiaceae were almost universally classified in the Bryaceae until C. J. Cox and T. A. J. Hedderson (2003) published their ground-breaking phylogenetic study in which they showed that these genera are more closely related to the Mniaceae than Bryaceae. Since that time, their conclusion has been repeatedly corroborated by additional data from all three genomic compartments; nuclear, chloroplast, and mitochondrial.  Phylogenetic resolution of precise relationships between genera in the Mielichhoferiaceae versus Mniaceace in the strict sense has, however, been more recalcitrant (C. J. Cox, pers. comm.). Molecular evidence from multiple loci suggests that the Mielichhoferiaceae may form early diverging lineages within the broader Mniaceae clade and the family may therefore be paraphyletic.  However, relationships are poorly supported and reciprocal monophylly for Mielichhoferiaceae and Mniaceae cannot presently be rejected. Very short branch lengths separating early diverging lineages of Mielichhoferiaceae and Mniaceae suggest that a rapid radiation early in the history of this clade may be the explanation for poor resolution of phylogenetic relationships among the lineages. 

 

SELECTED REFERENCES: Cox, C. J. and T. A. J. Hedderson. 2003. Phylogenetic relationships within the moss family Bryaceae based on chloroplast DNA evidence. J. Bryol. 25: 31--40. 

 

1.  Peristome appearing single and exostomial; exostome teeth long; endostome rudimentary and inconspicuous, adherent to the inside base of exostome teeth; perichaetia and perigonia on short lateral branches ..................................................................  1. Mielichhoferia, p. XX

1.  Peristome clearly double; endostome with well-developed segments from a low to high basal membrane or, if reduced, with at least a basal membrane free from the exostome teeth; perichaetia terminal, although sometimes appearing lateral because of subfloral innovations.

2.  Plants not complanate, without differentiation of dorsal and lateral leaves; leaves not bordered by linear cells although marginal cells sometimes slightly narrower than median cells, lanceolate to ovate-lanceolate ..................................  2. Pohlia, p. XX

2.  Plants slightly complanate, with 1--3 rows of dorsal leaves smaller than the lateral leaves; leaves bordered by 1--4 rows of ± differentiated linear, marginal cells, elliptic 3. Epipterygium, p. XX

 

 

1. Mielichhoferia Nees, Bryol. Germ. 2(2): 179. 1831 * [For Mathias Mielichhofer, 1772--1847, collector of the generitype specimen in the Salzburg Alps]

 

Plants small to medium size, usually forming ± compact turfs.  Stems short to long, 0.1--3 cm, unbranched or irregularly forking when sterile, bearing lateral gametangia when fertile. Leaves erect to erect-spreading, unaltered on drying, narrowly lanceolate to ovate-lanceolate, 0.4--1.5 mm, not decurrent; margins of vegetative leaves plane [rarely recurved], finely serrate to serrulate near the apex, rarely entire, acute or shortly acuminate, costa ending well before the apex to subpercurrent; distal medial laminal cells elongate-hexagonal, rhombic, or long-rhomboidal, with thin to thickened walls, proximal cells usually short- or long-rectangular, thin-walled, gradually differentiated, marginal cells undifferentiated. Specialized asexual reproduction rare, occasionally of bulbiform gemmae. Sexual condition dioicous, rarely autoicous or synoicous; perigonia and perichaetia on short lateral branches; perichaetial leaves typically smaller than vegetative leaves, with laxer cells, lanceolate to narrowly linear-lanceolate, with plane to slightly recurved margins; perigonia budlike, perigonial leaves broadly ovate, concave, brown to reddish proximally, shortly acute distally, acumen erect to erect-spreading. Seta single, variously colored, long, straight or bent to various degrees producing slightly inclined capsules. Capsule erect or inclined to ca. 30° from vertical, 1--4 mm, narrowly cylindrical to pyriform, neck well-differentiated, shorter than the urn, stomata abundant in the neck, superficial, exothecial cells near mouth quadrate or short-rectangular, thick-walled, often reddish, in 1--3 rows, medial cells longer, short- to long-rectangular with straight or slightly sinuose walls; annulus present and revoluble; operculum convex, short to tall-conic; peristome single or double, diplolepideous-alternate when both exostome and endostome present [rarely absent]; peristomial formula typically 4:2:4; exostome, when present, white to hyaline, teeth narrowly triangular to lanceolate, sometimes irregular, often reduced or absent, weakly or not trabeculate, papillose to nearly smooth, endostome hyaline, segments narrow, weakly or scarcely keeled, sometimes absent, broadly to narrowly perforate or entire, basal membrane low to high, sometimes scarcely exceeding the capsule rim, absent.

 

Mielichhoferia is characterized by perichaetia and perigonia borne on short lateral branches, perichaetial leaves that are often smaller and with cells that are more lax relative to those of the vegetative leaves, and frequent peristome reduction. The leafy stems themselves are much like those of a small Pohlia.

 

Species ca. 45 (3 in the flora); North America, South America, Europe, Africa, Pacific Islands (New Zealand), Australia.

 

Selected references. Shaw, A. J. and H. A. Crum.  1984.  Peristome homology in Mielichhoferia with a taxonomic account of the North American species.  J. Hattori Bot. Lab. 57: 363--381. Shaw, A. J. and P. E. Rooks.  1994. Systematics of Mielichhoferia Nees & Hornsch. (Bryaceae: Musci) I.  Morphological and genetic analyses of M. elongata and M. mielichhoferiana.  Bryologist 97: 1--12.   Shaw, A. J. 1994.  Systematics of Mielichhoferia (Bryaceae: Musci) II.  Morphological variation among disjunct populations of M. elongata and M. mielichhoferiana.  Bryologist 97: 47--55.

 

1.  Plants synoicous; peristome single; exostome absent, endostome of narrow, weakly keeled, smooth segments  ................................................................... 3. Mielichhoferia shevockii

1.  Plant dioicous; peristome double; exostome of 16 papillose teeth, endostome of a rudimentary membrane adherent to the inside of the exostome teeth.

2. Leaves dull dark green; distal medial leaf cells with firm to thickened walls .......................
................................................................................... 1. Mielichhoferia mielichhoferiana

2. Leaves pale whitish green; distal medial leaf cells lax and thin-walled ...............................
................................................................................................ 2. Mielichhoferia elongata

 

1. Mielichhoferia mielichhoferiana (Funck) Loeske, Stud. Vergleich. Morph. Phylog. Syst. Laubm.,  126. 1910

 

Weissia mielichhoferiana Funck, Crypt. Gew. Fichtelgeb. 24: 2. 1817 [1818]

 

Plants medium sized to robust, dull green. Leaves 0.6--1.3 mm, erect to ± spreading or commonly slightly secund, lanceolate; distal medial cells hexagonal to rhomboidal, 50--90 \um, moderately thick-walled. Specialized asexual reproduction absent or rarely present as axillary bulbiform gemmae. Sexual condition dioicous. Capsule erect or inclined to 20° from vertical; exostome teeth hyaline to whitish, narrowly acute- or bluntly triangular, papillose; endostome hyaline, segments absent, basal membrane rudimentary and adherent to the exostome teeth. Spores 15--22 \um, roughened.

 

Capsules mature summer (Jun--Aug). Rock crevices, soil banks, roadsides; low to high elevations; Greenland; B.C., Calif., Colo.; Eurasia.

 

Mielichhoferia mielichhoferiana is distinguished from M. elongata by darker green, more elongate-lanceolate, dull leaves that are commonly somewhat secund.  The leaf cells of M. mielichoferiana are smaller and narrower, hexagonal to rhombic, with thickened walls. The two species hybridize when they grow in mixed colonies but are usually readily distinguishable.  Recombinant plants that have genetic markers from both M. mielichhoferiana and M. elongata, presumably derived from hybrid sporophytes, have smaller, shorter, straighter leaves (not secund) than typical M. mielichhoferiana. They tend to have the dull, dark color of M. mielichhoferiana rather than the pale whitish aspect of M. elongata. Mielichhoferia mielichhoferiana is much less common than M. elongata in North America, and this is apparently so in Europe as well. One collection from the Canadian Northwest Territories had abundant axillary bulbiform gemmae with laminate leaf primordia, but gemmae have not been observed on plants from any other site.  

 

2. Mielichhoferia elongata (Hoppe & Hornschuch) Nees & Hornschuch, Bryologia Germanica 2(2): 186. 1831

 

Weissia elongata Hoppe & Hornschuch, Musci Exotici 2: 102. 1819

 

Plants slender to medium size, whitish pale-green. Leaves 0.5--1.1 mm, erect to ± spreading, lanceolate; distal medial cells rhomboidal, 50--100 \um, thin-walled. Specialized asexual reproduction absent. Sexual condition dioicous. Capsule erect or inclined to 20° from vertical, [peristome sometimes rudimentary] exostome teeth hyaline to whitish, narrowly acute- or bluntly triangular, papillose; endostome hyaline, segments absent, basal membrane rudimentary and adherent to the exostome teeth. Spores 15--22 \um, roughened.

 

Capsules mature spring (Apr--Jun). Rocks and soil, often on substrates naturally enriched with heavy metals; mine tailings; low to high elevations; Greenland; Alta., B.C., Nfld. and Labr., Nunavut; Alaska, Calif., Colo., Maine, Mich., Mont., N.Y., N.C., Tenn., Europe; Asia.

 

Mielichhoferia elongata grows in dense, compact turfs with a whitish or sometimes bluish color that makes this species easily recognizable. The leaf cells are thin-walled, giving the plants a softer texture than M. mielichhoferiana. The species might be mistaken for a Pohlia, but the turfs are usually more compact and the plants are smaller; when fertile the gametangial buds are lateral and the sporophytes are erect or nearly so. There is substantial variation in development of the exostome teeth but North American plants have relatively long, rather coarsely papillose segments. 

 

This species is one of the so-called copper mosses because it often grows on mineral enriched substrates, although not always with copper. Like other copper mosses, M. elongata has a broad and highly disjunctive geographic range but is nowhere common.  In North America, it is most frequent in the Rocky Mountains of Colorado, where it occurs on disused mine tailings, especially around the towns of Ouray and Silverton in San Juan County. Two morphologically cryptic lineages can be distinguished by genetic markers within M. elongata and both occur in Colorado.

 

3. Mielichhoferia shevockii (A. J. Shaw) A. J. Shaw, Bryologist XXX(YY): .

 

Schizymenium shevockii A. J. Shaw, Syst. Bot. 25: 190, figs. 1--9. 2000

 

Plants medium sized, dull green. Leaves 0.8--1.3 mm, erect to ± spreading, lanceolate; distal medial cells hexagonal to rhomboidal, 60--110 \um, moderately thick-walled. Specialized asexual reproduction absent. Sexual condition dioicous. Capsule erect or inclined to 30° from vertical; exostome absent; endostome hyaline to pale yellow, segments short, irregular, narrow, slightly keeled, not perforate, basal membrane scarcely exceeding the capsule rim. Spores 15--20 \um, finely roughened.

 

Capsules mature spring (Apr--Jun). Known from only three proximate sites, soil and rock; Calif.

 

The gametophytes of M. shevockii look much like those of genetically recombinant intermediates between M. elongata and M. mielichhoferiana derived from hybrid sporophytes, but can be readily distinguished by DNA markers.  The gametophytes of S. shevockii, like those intermediate between M. elongata and M. mielichhoferiana, have dull leaves that are a little more pale than is typical of pure M. mielichhoferiana, and are relatively small like those of M. elongata. Unlike those two species, M. shevockii is synoicous and has a single endostomial peristome.  The segments are nearly smooth.   In the original description of M. shevockii (as Schizymenium), the sexuality was incorrectly described as dioicous.

 

 

2. Pohlia Hedwig, Sp. Musc. Frond., 171. 1801 * [For Johann E. Pohl, 1782--1834, physician of Dresden]

 

Plants tiny to robust, occurring as scattered plants or as deep and sometimes extensive turfs. Stems short to long, 0.1--10 cm, unbranched or irregularly forking when sterile, often bearing subfloral innovations when with gametangia. Leaves erect to erect-spreading, rarely wide-spreading when wet, unaltered or sometimes slightly contorted on drying, narrowly lanceolate to ovate-lanceolate [rarely linear-lanceolate], 0.4--3 mm, decurrent or not; margins of vegetative leaves plane or rarely revolute, finely serrate to serrulate near the apex, rarely entire, acute or shortly acuminate, costa ending well before the apex, subpercurrent or percurrent, rarely shortly excurrent; distal medial laminal cells elongate-hexagonal, rhombic, or linear-rhomboidal, sometimes narrowly vermicular, with thin to thickened walls, proximal cells usually short- or long-rectangular, thin-walled, gradually differentiated, marginal cells undifferentiated or slightly narrower and longer than median cells. Specialized asexual reproduction common, variously as spherical to ovoid rhizoidal tubers or axillary filiform to bulbiform gemmae. Sexual condition dioicous, paroicous, rarely autoicous or synoicous, rarely variable within species (polyoicous); perigonia and perichaetia terminal, rarely the perigonia lateral (P. longibracteata); perichaetial leaves the same size as vegetative leaves or sometimes strongly differentiated, lanceolate to narrowly to linear-lanceolate, with recurved margins; perigonia bud-like, perigonial leaves broadly ovate, concave and often brown to reddish proximally, acute to long-acuminate distally, acumen erect to wide-spreading. Seta 1(2--5), variously colored, long, straight, bent to various degrees producing inclined to pendulous capsules. Capsule erect or inclined to 180° from vertical, 1--6[--10] mm, narrowly cylindrical to broadly pyriform or urceolate, neck well differentiated, sometimes as long or longer than the urn, stomata abundant in the neck, superficial to immersed, exothecial cells near mouth quadrate or short-rectangular, thick-walled, often reddish in 1--3 or more rows, medial cells longer, short- to long-rectangular with straight or sinuose walls; annulus present and revoluble or absent; operculum convex, short to tall-conic, sometimes shortly rostrate; peristome diplolepideous-alternate [rarely absent]; peristomial formula 4:2:4--6, rarely 4:2:8; exostome white, pale yellow to brown, sometimes dark reddish brown, teeth triangular to lanceolate, sometimes irregular [rarely reduced or absent], trabeculate or not, pitted or rarely papillose basally, coarsely or rarely finely papillose distally, endostome hyaline to yellow, segments narrow to wide, strongly to weakly or scarcely keeled, rarely reduced to rudimentary projections, broadly to narrowly perforate or less commonly entire, basal membrane low to high, sometimes scarcely exceeding the capsule rim, cilia present or absent, 1--3, as long as the segments or shorter, nodulose or not.

 

Species ca. 85 (32 species in the flora): North America, Central America, South America, Europe, Asia, Africa, Pacific Islands (New Zealand), Australia.

 

SELECTED REFERENCES. Ochi, H. 1959. A revision of the Bryaceae in Japan and the adjacent regions. Publ. Biol. Inst., Fac. Liberal Arts, Tottori University. Pp. 1--124. Shaw, A. J.  1981.  A taxonomic revision of the propaguliferous species of Pohlia Hedw. (Musci) in North America.  J. Hattori Bot. Lab. 50: 1--81. Shaw, A. J.  1982.  Pohlia in North and Central America and the West Indies.  Contr. Univ. Mich. Herb. 15: 217--295.

 

1. Plants with axillary gemmae.

2.. Gemmae with broadly laminate (leaf-like) leaf primordia

3.. Gemmae in clusters of 4--many per leaf axil, narrowly elongate to oblong-bulbiform or obconic

4.. Gemmae linear, extending beyond the leaves ......................  15.  Pohlia tundrae

4.. Gemmae oblong, obconic, or spheroidal.

5. Gemmae spheroidal to oblong, occasionally ovate ........  20.  Pohlia bulbifera

5. Gemmae obconic, distinctly narrowed to the base .....  19.  Pohlia andalusica

3.. Gemmae 1--2 per leaf axil, bulbiform.

6.. Gemmae ovate; leaf primordia small, stiffly triangular, mainly restricted to gemma apex or rarely 1--2 primordia occurring more proximally ..........  17. Pohlia filum

6.. Gemmae elongate-bulbiform; leaf primordia larger, flexuose, at the gemma apex and also commonly more proximally.

7. Plants dull, leaves slightly contorted when dry .....  16.  Pohlia rabunbaldensis

7. Plants shiny, leaves unaltered when dry.

8.. Leaves green or tinged with red, loosely erect to erect-spreading ..............
.........................................................................  14.  Pohlia drummondii

8.. Leaves pale whitish, stiffly erect ...........................  18. Pohlia beringiense

2.. Gemmae with peg-like leaf primordia.

9.. Plants shiny when dry.

10.  Gemmae linear-vermicular, with 1--2 elongate, erect leaf promordia
 .....................................................................................  23. Pohlia proligera

10.  Gemmae oblong, with 1--5 short, incurved leaf primordia 24.  Pohlia andrewsii

9. Plants dull when dry.

11.  Gemmae oblong, knobby in outline because of angular external cells, without leaf primordia .......................................................................  25.  Pohlia flexuosa

11.  Gemmae spheroidal, obconic, or linear, not knobby in outline, external cells rounded, with leaf primordia

12.. Gemmae spheroidal .....................................  22.  Pohlia camptotrachela

12.. Gemmae oblong or obconic to linear, clearly longer than wide.

13.  Gemmae oblong or obconic, with 2--5 conspicuous leaf primordia
                                                                           21. Pohlia annotina

13.. Gemmae narrowly linear, with 1(--2) inconspicuous leaf primordia   25.  Pohlia flexuosa

1.. Plants lacking axillary gemmae.

14.  Leaf margins recurved from base to apex.

15.. Leaves narrowly long-lanceolate, median leaf cells long- to linear-hexagonal, with thin, non-porose walls ....................................................  8.  Pohlia crudoides

15.. Leaves ovate-lanceolate, median leaf cells rhombic, with thickened ± porose walls ......................................................................................... 10. Pohlia cardotii

14.  Leaf margins plane (perichaetial leaves with ± recurved margins).

16.. Plants paroicous.

17.. Plants polysetous  ..................................................  6. Pohlia robertsonii

17.. Plants with one seta per inflorescence.

18.. Plants with lax, hexagonal, thin-walled median cells more than 10 \um wide ...............................................................  7.  Pohlia obtusifolia

18.. Plants with firm, hexagonal to rhomboidal, ± thick-walled cells less than 10 \um wide.

19.. Plants very shiny when dry, leaf cells linear-vermicular.

20.. Leaves broadly lanceolate to elliptic; endostome segments broadly perforate....................................... 5. Pohlia cruda

20.. Leaves long triangular-lanceolate; endostome segments narrowly or not all perforate, cilia absent  3. Pohlia longicollis

19.. Plants dull when dry, leaf cells short- to long-hexagonal.

21.. Neck of capsule shorter than the urn; endostome segments broadly perforate, cilia present.................. 1.  Pohlia nutans

21.. Neck of capsule as long or longer than the urn; endostome segments narrowly or not all perforate, cilia absent 2. Pohlia elongata

16.. Plants dioicous (very rarely autoicous).

22.. Capsules erect or nearly so, endostome segments narrow, scarcely keeled, hardly tapered, cilia absent  ..........................................  11. Pohlia erecta

22.. Capsules inclined 50--180° from vertical, endostome segments broader, keeled, tapered apically, cilia present or absent.

24.. Leaves long-decurrent, median leaf cells leaf cells rhombic to rhomboidal, less than 10 \um wide  .......................  9. Pohlia ludwigii

24.. Leaves not or scarcely decurrent, median leaf cells various but if leaves decurrent, median cells more than 12 \um wide.

25.. Capsules narrowly cylindrical, pendent 50--90° from vertical; endostome segments narrowly perforate, cilia absent ..................  
 .................................................................. 4. Pohlia bolanderi

25.. Capsules pyriform to urceolate, pendent 150--180° from vertical; endostome segments broadly perforate, cilia present.

26.. Annulus present; exothecial cells longer than wide.

27... Plants dull green, leaf cells shortly hexagonal ................
 ........................................................ 1. Pohlia nutans

27... Plants pale or shiny green, leaf cells long- to linear-rhomboidal.

28.. Plants very glossy green; leaves coarsely serrate at apex; median leaf cells 110--180 \um  13. Pohlia pacifica

28.. Plants pale green, not or slightly glossy; leaves serrulate at apex; median leaf cells 65--120 \um  ......................................... 12. Pohlia lescuriana

26.. Annulus absent; exothecial cells little or no longer than wide.

29... Median leaf cells laxly rhomboidal, 12 \um or more wide.

30.. Plants tiny (2--6 mm), reddish; stomates superficial or slight immersed; cells of perichaetial bracts narrower than those of vegetative leaves 30. Pohlia atropurpurea

30.. Plants small to robust (5--80 mm); yellow-green to whitish, rarely (when very robust) with some red pigmentation; stomates deeply immersed; perichaetial leaf cells broad and lax, like those of vegetative leaves

31... Plants pale whitish (sometimes tinged with red when very robust), 1--8 cm
............................ 32. Pohlia wahlenbergii

31.  Plants deep green, 0.5--1 cm high ...............
 .............................. 29. Pohlia melanodon

29... Median leaf cells linear-hexagonal to linear-rhomboidal, 6--10 \um wide.

32.. Plants medium size to robust; leaves wide-spreading; perigonial bracts long-acuminate, to 6 mm..........................   26. Pohlia longibracteata

32.. Plants slender; leaves erect to erect-spreading; perigonial bracts shorter, 1.5--3 mm.

33... Stomates deeply immersed.

34.. Stems cherry-red; leaves erect, glossy-green ....................   31. Pohlia vexans

34.. Stems green to pale orange or pink; leaves spreading, dull, often reddish
.........................  28. Pohlia columbica

33... Stomates superficial or slightly immersed.

35.  Stems elongate, to 1 cm; leaves erect, whitish; median cells of vegetative leaves linear, 6--9 \um wide
......................... 27. Pohlia brevinervis

35. Stems short, 2--6 mm, loosely spreading (except perichaetial leaves); median leaf cells of sterile plants and of proximal vegetative leaves broadly hexagonal, 10--12 \um wide
..................... 30. Pohlia atropurpurea

 

 

 

 

 

1.  Pohlia nutans (Hedwig) H. Lindberg, Musci Scand., 18. 1879

 

Webera nutans Hedwig, Sp. Musc. Frond., 168. 1801; Pohlia sphagnicola (Bruch & Schimper) Lindberg & Arnell

 

Plants small to robust, dull green or rarely reddish. Stems 0.5--3.5(--10) cm. Leaves to 2 mm, erect to ± spreading, lanceolate to ovate-lanceolate, acute; margins subentire or more commonly serrulate to serrate in the distal 1/3; costa subpercurrent, percurrent, or rarely shortly excurrent, broad; distal medial cells hexagonal to rhomboidal, 50--90 \um, moderately thick-walled. Specialized asexual reproduction absent. Sexual condition paroicous, rarely dioicous; perichaetial leaves somewhat differentiated, ± long-lanceolate, perigonial leaves ovate-lanceolate. Seta orange to orange-brown. Capsule inclined 80--100° from vertical, orange to orange-brown, slenderly pyriform, neck ca. 1/2  the urn length; exothecial cells elongate-rectangular, walls straight; stomata superficial; operculum conic; exostome teeth yellow to orange-brown, acute-triangular, pitted basally, coarsely papillose distally; endostome hyaline (to rarely orange-brown), basal membrane 1/2\x the exostome length, segments broadly keeled, broadly perforate, cilia short to long. Spores 16--22 \um, finely to distinctly roughened.

 

Capsules mature spring (Apr--Jun). A common species of soil banks, logs, tree bases and sometimes disturbed places; low to high elevations; Greenland; Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Nunavut, Ont., P.E.I., Que., Sask., Yukon; Ala., Alaska, Ariz., Ark., Calif., Colo., Conn., Del., D.C., Fla., Ga., Idaho, Ill, Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis., Wyo.; Mexico; Eurasia; Africa; Australia.

 

Pohlia nutans is the most common species of the genus in North America, as it is in Europe and elsewhere around the Northern Hemisphere.  In contrast to the treatment of A. J. Shaw (1982), P. sphagnicola is not separated here from P. nutans. The type of S. sphagnicola is European, so it is not included here in the synonomy of P. nutans.  Plants referable to P. sphagnicola, including North American collections, differ in being dioicous, and have entire leaves, slightly shorter leaf cells, and smaller spores. The habitat in Sphagnum hummocks is not diagnostic; at least 80% of plants growing in Sphagnum are P. nutans. Pohlia schimperi, a northern form with reddish leaves, also dioicous, is not recognized, as per Shaw (1982).  These rare dioicous forms, otherwise obviously close to P. nutans, are prime candidates for genetic analyses.  Conservatively, they are not recognized taxonomically, notwithstanding their evolutionary interest.

 

The peristome of P. nutans is as well developed as any in Pohlia, with long tapered, trabeculate exostome teeth and well-developed endostomes with broadly keeled, widely perforate segments and short to long cilia. The leaf cells are short-to elongate-hexagonal with thickened walls.  The only other North American species with relatively thick-walled leaf cells is P. elongata.  The cells of P. elongata are typically longer but there is extensive overlap in sizes. Plants without sporophytes have generally been named P. nutans although some such collections, from montane regions, may actually be P. elongata. Sporophytes of P. elongata have longer necks, as long as or longer than the urns, and reduced peristomes with endostome segments narrowly split along the keel and (usually) no cilia.

 

2. Pohlia elongata Hedwig, Sp. Musc. Frond., 171. 1801

 

Pohlia polymorpha Hoppe & Hornschuch ex Hornsuch; P. acuminata Hoppe & Hornschuch ex Hornschuch; P. elongata var. greenii (Brid.) A.J. Shaw

 

Plants small, dull green. Stems 0.5--2.5 cm. Leaves to 2 mm, erect to ± spreading, lanceolate to ovate-lanceolate, acute; margins subentire or more commonly serrulate to serrate in the distal 1/3; costa subpercurrent or percurrent; distal medial cells hexagonal to rhomboidal, 45--85 \um, moderately thick-walled. Specialized asexual reproduction absent. Sexual condition paroicous, autoicous, rarely dioicous; perichaetial leaves somewhat differentiated, ± long-lanceolate; perigonial leaves in dioicous plants shortly and broadly ovate. Seta orange to orange-brown. Capsule inclined 10--90° from vertical, stramineous, orange, or orange-brown, shortly to longly and slenderly pyriform, neck ca. 1/2--1\x the urn length; exothecial cells elongate-rectangular, walls straight; stomata superficial; operculum conic; exostome teeth yellow to brown, acute-triangular, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane barely exceeding the capsule rim or up to 1/3\x the exostome length, segments narrowly or not keeled, narrowly perforate to entire, cilia absent to rudimentary, rarely long. Spores 16--23 \um, distinctly roughened.

 

Capsules mature spring to summer (Apr--Jul). Humus-rich soil banks, along streams and paths, tree bases; moderate to high elevations; B.C., N.B., Nfld. and Labr., N.W.T., N.S., Ont., Que., Yukon; Ala., Alaska, Ariz., Calif., Colo., Ga., Iowa, Maine, Mich., Minn., Mont., N.H., N.Mex., N.Y., N.C., Ohio, Tenn., Utah, Vt., Va., Wash., Wis.; Mexico; Central America, South America; Eurasia; Africa; Pacific Islands; Australia.

Pohlia elongata is widespread in North America but not common anywhere.  Plants generally occur scattered or in small patches and regularly produce sporophytes from bisexual (paroicous) gametophytes. The capsule necks are typically longer than the urn and the endostome is reduced (see under P. nutans).  The endostomial segments vary from relatively broad and distinctly keeled with narrow perforations to narrowly linear, scarcely keeled, and not at all split along the keels.  A high elevation expression that has generally been collected from exposed sites, and often called P. polymorpha or P. acuminata, is characterized by small plants with relatively broad leaves and short, barrel-shaped sporophytes with short necks. Although not distinguished taxonomically here, these forms are worthy of additional study using experimental or genetic methods.  They seem to be more common in Europe than in North America.

 

3. Pohlia longicollis (Hedwig) H. Lindberg, Musci Scand., 18. 1879

 

Plants medium-size, shiny green to yellow-green. Stems 0.8--3.5 cm. Leaves 1.5--2.6 mm, erect to ± spreading, long-lanceolate, acute; margins serrulate to serrate in the distal 1/3; costa subpercurrent or percurrent; distal medial cells linear-rhomboidal, 80--140 \um, vermicular, thin-walled. Specialized asexual reproduction absent. Sexual condition paroicous; perichaetial leaves gradually differentiated, ± long-lanceolate. Seta orange to orange-brown. Capsule inclined 10--90° from vertical, stramineous to orange-brown, longly and slenderly pyriform, neck ca. 1/2--1\x the urn length; exothecial cells elongate-rectangular, walls straight; stomata superficial; operculum conic; exostome teeth yellow to brown, acute-triangular, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane 1/4--1/2\x the exostome length, segments narrowly keeled, narrowly perforate to entire, cilia absent to rudimentary. Spores 16--23 \um, distinctly roughened.

 

Capsules mature spring to summer (Apr--Jul). Humus-rich soil banks, along streams and paths; moderate to high elevations; Greenland; Alta., B.C., Nfld. and Labr., N.W.T., Ont., Yukon; Alaska, Mont., N.H., N.Y., N.C., Oreg., Pa., Tenn., Utah, Va., Wyo.; Mexico; Eurasia.

 

Pohlia longicollis is a handsome species characterized by relatively large, very shiny, long-lanceolate leaves.  The plants are bisexual (paroicous) and commonly form sporophytes although P. longicollis is relatively rare in North America. Sporophytes have long necks, like those of P. elongata, and like that species, the endostomial segments are narrowly or not at all perforate and cilia are absent or rudimentary. 

 

4. Pohlia bolanderi (Lesqereux) Brotherus in A. Engler & K. Prantl, Nat. Pfl. 1(3): 548. 1903

 

Bryum bolanderi Sullivant, Mem. Calif. Acad. Sci. 1: 22. 1868; Pohlia bolanderi var. seriata A. J. Shaw

 

Plants small to medium-size, somewhat shiny green or sometimes pale whitish; Stems 0.3--1.5 cm. Leaves 0.8--1.6 mm, erect to ± spreading, lanceolate to narrowly ovate-lanceolate, acute; margins serrulate to serrate in the distal 1/3; costa subpercurrent or percurrent; distal medial cells linear-rhomboidal, 55--100 \um, thin-walled. Specialized asexual reproduction absent. Sexual condition dioicous; perichaetial leaves slightly differentiated; perigonial leaves ovate, short-acuminate. Seta straw-colored to orange-brown. Capsule inclined 35--90° from vertical, straw-colored to orange-brown, slenderly pyriform, neck ca. 1/2--1\x the urn length; exothecial cells elongate-rectangular, walls straight; stomata superficial; operculum conic; exostome teeth yellow to yellow-brown, acute-triangular, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane 1/4--1/2\x the exostome length, segments narrowly keeled, narrowly perforate to entire, cilia absent to rudimentary. Spores 16--26 \um, distinctly roughened.

 

Capsules mature summer (Jun--Aug). Rather dry alpine soil or soil-filled rock crevices; low to high elevations; B.C.; Alaska, Calif., Colo., Nev., N.Mex., Oreg., Utah, Wash., Wyo.; Europe.

 

Pohlia bolanderi has glossy to whitish leaves.  Glossy forms might be confused with P. longicollis but P. bolanderi can be distinguished by its smaller size and dioicous inflorescences.  The leaves of P. bolanderi are not only smaller but are relatively broader than those of P. longicollis.  The var. seriata A. J. Shaw is characterized by whitish, ranked leaves.  It is not recognized here because of intermediate plants from western North America, although in their best development these plants are very distinctive.  They might be confused with Conostomum tetragonum.

 

5.  Pohlia cruda (Hedwig) H. Lindberg, Musci Scand., 18. 1879

 

Plants medium-size to robust, shiny green, whitish-green, sometimes with a bluish tinge. Stems 0.5--2.5 cm. Leaves 0.8--2 mm, erect to ± spreading, sometimes slightly complanate, lanceolate to elliptic, acute; margins serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells linear-rhomboidal, 70--140 \um, vermicular, thin-walled. Specialized asexual reproduction absent. Sexual condition paroicous, rarely dioicous; perichaetial leaves strongly differentiated, linear lanceolate, rarely weakly differentiated; perigonial leaves in dioicous plants linear- or long-lanceolate from an ovate base. Seta orange to orange-brown. Capsule inclined 10--135° from vertical, straw-colored to orange-brown, longly and slenderly pyriform, neck ca. 1/2\x  the urn length; exothecial cells elongate-rectangular, walls straight; stomata superficial; operculum conic; exostome teeth yellow-brown to red-brown, acute-triangular, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane 1/2\x the exostome length, segments broadly keeled, broadly perforate, cilia short to long. Spores 18--26 \um, ± coarsely papillose.

 

Capsules mature summer (Jun--Aug). Soil banks, crevices in rocks or under roots, tundra soil and paths; moderate to high elevations; Greenland; Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Nunavut, Ont., Que., Sask., Yukon; Alaska, Ariz., Calif., Colo., Idaho, Iowa, Maine, Md., Mass., Mich., Minn., Mont., Nebr., Nev., N.J., N.Mex., N.Y., N.C., Oreg., Pa., S.Dak., Tenn., Utah, Vt., Va., Wash., W.Va., Wyo.; Mexico; South America; Eurasia; Pacific Islands; Australia; Antarctic.

 

Pohlia cruda is distinguished by glossy, pale green to whitish or bluish leaves that are narrowly elliptic to lanceolate.  The cells are long and narrowly linear-vermicular. Perichaetial leaves are strongly differentiated, linear-lanceolate.  Sporophytes have necks about as long as the urn, with long-tapered exostome teeth, broadly keeled and perforate segments, and short to long cilia. Along with P. nutans, P. cruda is one of the most common North American species of the genus.  Unlike P. nutans, P. cruda is restricted to northern and montane sites where it grows in rock crevices and on soil banks.  The gametophytes can be unisexual (dioicous) or bisexual (paroicous), a pattern of variation worthy of additional study. 

 

6.  Pohlia robertsonii J. R. Shevock & A. J. Shaw, Bryologist 108: 177, fig. 1. 2005

 

Plants small to medium-size, dull green. Stems 0.5--1 cm. Leaves 1.3--1.6 mm, erect to ± spreading, lanceolate, acute; margins serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells irregularly hexagonal to rhomboidal, 70--120 \um,  thin- to firm-walled. Specialized asexual reproduction absent. Sexual condition paroicous, polysetous; perichaetial leaves scarcely differentiated. Seta orange-brown. Capsule inclined 10--45° from vertical, straw-colored to orange-brown, longly and slenderly pyriform, neck ca. 3/4--1\x the urn length; exothecial cells elongate-rectangular, walls slightly sinuose; stomata superficial; operculum high-conic; exostome teeth orange-yellow to brown, bluntly acute, pitted basally, coarsely papillose distally; endostome hyaline to yellow-brown, basal membrane low, barely exceeding the capsule rim, segments narrow, keeled at base, not or slightly perforate, cilia absent or rudimentary. Spores 16--20 \um, ± finely but distinctly roughened.

 

Capsules mature spring (Mar-Apr). Sandy or gravelly soil, bases of sandstone or volcanic rocks in open deciduous woodlands; low elevations; Calif.

 

Pohlia robertsonii is the only North American polysetous species of Pohlia.  The leaves are less dull in appearance than are those of P. elongata and P. nutans, but not notably shiny like those of P. longicollis or P. cruda. They are more like the moderately glossy leaves often seen in P. bolanderi.  The leaf cells have firm but not thickened walls, thinner-walled than in P. elongata and P. nutans, shorter and less vermicular than in P. longicollis or P. cruda.  Sporophytes are produced abundantly on the paroicous gametophytes.  The exostome teeth are rather irregular and poorly developed, not gradually tapered to narrow acute apices, and the endostome segments are narrow, scarcely keeled, and narrowly or not at all perforate.

 

7.  Pohlia obtusifolia (Villars ex Bridel) L. Koch, Leafl. West. Bot. 6: 20. 1950

 

Bryum obtusifolium Villars ex Bridel, Musc. Rec. 2(3): 52. 1803; P. cucullata (Schwägrichen) Bruch ex Hochstetter

 

Plants small to medium-size, dull pale green. Stems 0.3--0.8 cm. Leaves 0.7--1.4 mm, erect to ± spreading, broadly lanceolate, acute, subtly cucullate; margins serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells broadly rhombic, 30--70 \um,  thin-walled and lax. Specialized asexual reproduction absent. Sexual condition paroicous; perichaetial leaves scarcely differentiated. Seta orange-brown. Capsule inclined 160--180° from vertical, straw-colored to orange-brown, broadly pyriform, neck about 1/3\x urn length; exothecial cells elongate-rectangular, with straight walls; stomata superficial; operculum bluntly conic; exostome teeth yellow to brown, rather slender, bluntly acute, weakly pitted basally, coarsely papillose distally; endostome hyaline, basal membrane low, barely exceeding the capsule rim to 1/3\x the exostome length, segments narrow, delicate, weakly keeled, broadly perforate, cilia absent. Spores 17--25 \um, distinctly roughened.

 

Capsules mature summer (Jun--Aug). Soil, often in late snowmelt areas in alpine and subalpine zones; high elevations; Greenland; Alta., B.C., Nfld. and Labr., Nunavut, Ont., Que., Yukon; Alaska, Ariz., Calif., Colo., Maine, Mont., Nev., Tex., Vt., Wash., Wyo.; Eurasia.

 

Plants of Pohlia obtusifolia with sporophytes are generally small, but some sterile colonies in late snowmelt areas at high elevations form deeper cushions.  When sterile, the subtly cucullate leaves provide a clue to their identity; they are similar to those of P. drummondii but the stems tend to be less red than in that species, the leaf cells are broader and thinner walled, and axillary gemmae are absent.  The plants are paroicous (unlike P. drummondii, which is dioicous) and the capsules are barrel-shaped, with straight, rectangular walls (sinuose in P. drummondii and other gemmiferous species).  The peristome of P. obtusifolia is relatively reduced, with slenderly triangular exostome teeth, a low endostomial basal membrane, and narrow segments that are weakly keeled but broadly perforate.

 

8.  Pohlia crudoides (Sullivant & Lesqereux) Brotherus in A. Engler & K. Prantl, Nat. Pfl. 1(3): 548. 1903

 

Bryum crudoides Sullivant & Lesquereux, Proc. Am. Ac. Arts & Sc. 4: 278. 1859

 

Plants medium-size to robust, stiff, dull green. Stems 0.4--2.5 cm. Leaves 1--2.2 mm, erect to ± spreading, narrowly or rarely broadly lanceolate, acute; margins strongly revolute, serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells linear-hexagonal, 35--80 \um, thin-walled. Specialized asexual reproduction absent. Sexual condition dioicous; perichaetial leaves moderately differentiated, narrowly lanceolate; perigonial leaves shortly and broadly ovate. Seta orange-brown. Capsule inclined 30--90° from vertical, brown, ovoid-cylindrical, neck about 1/3\x  urn length; exothecial cells shortly to longly rectangular, with straight or weakly sinuose walls; stomata superficial; operculum conic; exostome teeth whitish to yellow, weakly tapered, bluntly acute, coarsely papillose throughout; endostome whitish to hyaline, basal membrane low, to 1/3\x the exostome length, segments narrow, scarcely keeled, narrowly or not perforate, papillose, cilia absent or rarely rudimentary. Spores 15--25 \um, finely roughened.

 

Capsules mature summer (Jun--Aug). Soil, generally in tundra, on banks and in depressions; low to high elevations; Greenland; Alta., B.C., N.W.T., Nunavut, Que., Yukon; Alaska; Eurasia.

 

Pohlia crudoides is a distinctive Arctic species characterized by cherry-red stems and relatively stiff, dark green leaves with strongly recurved margins.  The perichaetial leaves of most Pohlia species have recurved margins, but the only other North American species with strongly recurved vegetative leaf margins is P. cardotii. The latter has shorter, broader leaves with short-rhombic cells often with porose-thickened walls.  Pohlia crudoides has exostome teeth coarsely papillose from top to bottom, which give them a whitish appearance under a dissecting microscope.

 

9. Pohlia ludwigii (Sprengel ex Schwägrichen) Brotherus, Act. Soc. Sc. Fenn. 19: 27. 1892

 

Bryum ludwigii Schwägrichen, Spec. Musc. Frond., Suppl. 1(2): 95. 68. 1816

 

Plants medium-size to robust, dull green, sometimes tinged with red. Stems 0.8--3.5 cm. Leaves 1.2--2.4 mm, erect to ± spreading, lanceolate to broadly lanceolate, acute to bluntly acute; serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells rhombic to rhomboidal, 40--80 \um, firm to rather thin-walled. Specialized asexual reproduction absent. Sexual condition dioicous; perichaetial leaves scarcely differentiated in shape but with costa very strong at the base; perigonial leaves shortly and broadly ovate. Seta orange-brown. Capsule inclined 90--180° from vertical, brown to straw-colored, broadly pyriform, neck about 1/3\x urn length; exothecial cells shortly rectangular, with weakly to moderately sinuose walls; stomata superficial; operculum bluntly conic; exostome teeth yellow to brown, triangular-acute, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane to 1/2\x the exostome length, segments distinctly keeled, broadly perforate, papillose, cilia short to long. Spores 14--21 \um, finely roughened.

 

Capsules mature summer (Jun--Aug). Soil, often in late snowmelt areas in alpine and subalpine zones, in habitats similar to those of P. obtusifolia; high elevations; B.C., N.W.T., Ont., Que.; Alaska, Ariz., Colo., Idaho, Mont., Wash.; Eurasia.

 

Pohlia ludwigii is a rare alpine species characterized by strongly decurrent leaves, often slightly cucullate apically.  The older lower leaves generally have a pink to reddish tinge.  In late snowmelt areas P. ludwigii can form deep cushions when sterile.

 

10. Pohlia cardotii (Renauld in Renauld & Cardot) Brotherus in A. Engler & K. Prantl., Nat. Pfl. 1(3): 547. 1903

 

Webera cardotii Renauld in Renauld & Cardot, Rev. Bryol. 15: 71. 1888

 

Plants medium-size to robust, sometimes forming deep turfs, dull green, sometimes tinged with red. Stems 0.4--2.5 cm. Leaves 0.7--1.5 mm, erect to ± spreading, lanceolate to broadly lanceolate, acute; serrulate to serrate in the distal 1/3; costa subpercurrent, very broad; distal medial cells rhombic, 18--50 \um, thick-walled, ± porose. Specialized asexual reproduction absent. Sexual condition dioicous; perichaetial leaves weakly differentiated, elongate-lanceolate; perigonial leaves shortly and broadly ovate. Seta orange-brown. Capsule inclined 0--20° from vertical, brown to straw-colored, narrowly pyriform, neck about 1/3\x urn length; exothecial cells shortly rectangular, with sinuose walls; stomata superficial; operculum bluntly to acutely conic; exostome teeth yellow to brown, narrowly triangular-acute, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane scarcely exceeding the capsule rim, segments narrow but weakly keeled, distinctly perforate, cilia absent to rudimentary. Spores 14--19 \um, finely roughened.

 

Capsules mature summer (Jun--Aug). Soil in mesic alpine and subalpine zones; high elevations; B.C.; Alaska, Wash.; Europe.

 

A rare alpine species, P. cardotii is characterized by dull green, relatively broad leaves with a wide costa and recurved margins.  The sporophytes are erect, with irregular exostome teeth, a low endostomial basal membrane, and narrow, slightly keeled, broadly perforate segments.  This species sometimes forms deep turfs in moist alpine sites.

 

11. Pohlia erecta Lindberg, Bot. Not. 1882: 195. 1882

 

Pohlia defecta (Sanio) Andrews in Grout

 

Plants slender, rather glossy green, sometimes tinged with red. Stems 0.4--0.8 cm. Leaves 0.7--1.2 mm, erect to ± spreading, lanceolate to broadly lanceolate, acute; serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells rhomboidal, 35--60 \um, thin-walled. Specialized asexual reproduction absent. Sexual condition dioicous; perichaetial leaves weakly differentiated, elongate-lanceolate; perigonial leaves shortly and broadly ovate. Seta orange-brown. Capsule inclined 0--20° from vertical, brown to straw-colored, narrowly pyriform, neck ca. 1/3\x urn length; exothecial cells shortly rectangular, with sinuose walls; stomata superficial; operculum bluntly to acutely conic; exostome teeth yellow to light brown, narrowly triangular, blunt, often irregular, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane scarcely exceeding the capsule rim, segments rudimentary to elongate and weakly keeled, ± perforate, cilia absent. Spores 15--21 \um, finely roughened.

 

Capsules mature summer (Jun--Aug). Soil in mesic alpine and subalpine zones; high elevations; B.C., N.W.T.; Wash.; Europe.

 

Pohlia erecta is a very rare species with soft, sometimes reddish leaves having thin-walled cells.  The erect sporophyte has a highly reduced peristome with short, irregular exostome teeth and an endostome that consists of a low basal membrane and poorly developed to rudimentary segments. 

 

 

 

12. Pohlia lescuriana (Sullivant) Grout, Handlens. Microsc., 210. 1906

 

Bryum lescurianum Sullivant, Mem. Amer. Acad. Arts, n.s. 4: 171. 1849; Pohlia pulchella (Hedwig) Lindberg

 

Plants slender, pale whitish green. Stems 0.3--0.8 cm. Leaves 0.7--1.2 mm, erect to ± spreading, lanceolate, acute, serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells linear-rhomboidal, 65--110 \um, thin-walled. Specialized asexual reproduction occasionally present; rhizoidal tubers orange, orange-brown, or yellow. Sexual condition dioicous; perichaetial leaves weakly differentiated, lanceolate to linear-lanceolate; perigonial leaves ovate, acuminate. Seta orange-brown. Capsule inclined 95--180° from vertical, brown to straw-colored, shortly and rather broadly pyriform, neck about 1/3\x urn length; exothecial cells short-rectangular, with sinuose walls; stomata superficial; operculum low to high conic; exostome teeth light yellow-brown, triangular-acute, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane 1/2\x the exostome length, segments distinctly keeled, broadly perforate, cilia short to rudimentary. Spores 15--21 \um, finely roughened.

 

Capsules mature spring (Apr--Jun). On naturally or anthropogenically disturbed soils, upturned tree banks, path banks, in crevices of rocks, along streams; low elevations; N.B., Nfld. and Labr., N.S., P.E.I., Que.; Conn., Iowa, Maine, Md., Mass., Mich., Mont., N.H., N.J., N.Y., N.C., Pa., Tenn., Vt., Va., W.Va.; Europe.

 

Pohlia lescuriana is an inconspicuous woodland species in eastern North America.  It often grows in small sterile patches and can be recognized by the slender, pale green shoots.  The sporophytes, never common, are shortly pyriform to urceolate when dry.  Yellow to orange gemmae sometimes occur on the rhizoids.

 

13. Pohlia pacifica A. J. Shaw, Contr. Univ. Mich. Herb. 15: 268, fig. 25. 1982

 

Plants slender, glossy green. Stems 0.3--1.0 cm, simple. Leaves 0.9--1.8 mm, erect to ± spreading, lanceolate, acute; serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells linear-vermicular, 110--145 \um, thin-walled. Specialized asexual reproduction absent. Sexual condition dioicous; perichaetial leaves differentiated, linear-lanceolate, to 3.2 mm; perigonial leaves ovate, elongate-acuminate. Seta orange-brown. Capsule inclined 120--180° from vertical, brown to straw-colored, pyriform, neck about 1/3\x urn length; exothecial cells short-rectangular, with sinuose walls; stomata superficial; operculum convex-conic; exostome teeth yellow-brown, narrowly triangular-acute, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane 1/2\x the exostome length, segments distinctly keeled, broadly perforate, cilia short to rudimentary. Spores 15--21 \um, finely roughened.

 

Capsules mature spring (Apr-Jun). Acid clay or sandy soils in disturbed places, stream banks, ditches; low elevations; B.C., Calif., Oreg., Utah, Wash.

 

Pohlia pacifica is similar to P. lescurii, but is distinguished by glossy leaves and longer leaf cells.

 

14.  Pohlia drummondii (Müller Hal.) Andrews in Grout, Moss Fl. N. Am. 2: 196. 1935

 

Bryum drummondii Müller Hal., Bot. Zeit. 20: 328. 1862; Pohlia commutata Lindberg

 

Plants medium-size, dark-green to reddish-green. Stems 0.5--3.5 cm, red. Leaves 0.9--1.5 mm, ± spreading, lanceolate to ovate-lanceolate, acute; serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells rhombic to rhomboidal, 50--95 \um, thin-walled. Specialized asexual reproduction generally present when sterile; axillary gemmae arising singly in leaf axils, bulbiform, red (becoming ± black when dry), leaf primordia at gemma apex and lower, laminate.  Sexual condition dioicous; perichaetial leaves scarcely differentiated; perigonial leaves ovate, shortly acuminate. Seta orange-brown. Capsule inclined 95--180° from vertical, brown to straw-colored, pyriform, neck about 1/3\x urn length; exothecial cells short-rectangular, with sinuose walls; stomata superficial; operculum convex-conic; exostome teeth yellow-brown, narrowly triangular-acute, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane 1/2\x the exostome length, segments distinctly keeled, broadly perforate, cilia short to rudimentary. Spores 16--21 \um, finely roughened.

 

Capsules mature summer (Jun--Aug). Acid, relatively humus-rich soils, alpine tundra, stream banks, path banks; low to high elevations; Greenland; Alta., B.C., Nfld. and Labr., N.W.T., Nunavut, Ont., Que., Yukon; Alaska, Ariz., Calif., Colo., Idaho, Minn., Mont., Nev., N.H., N.Mex., Oreg., Utah, Vt., Wash., Wyo.; Europe.

 

Pohlia drummondii has red stems (when moist) with cherry red (when fresh) bulbiform gemmae in the leaf axils.  The gemmae look like small branches, with flexuose, laminate leaf primordia, and occur single or occasionally in pairs in 1--5 distal leaf axils.  The leaves pf P. drummondii are carinate and can be similar to those of P. obtusifolia, but are not cucullate (and the plants are dioicous).

 

15.  Pohlia tundrae A. J. Shaw, Bryologist 84: 65, fig. 1--10. 1981

 

Plants slender to medium-size, glossy, green to light green. Stems 0.5--2.5 cm. Leaves 0.9--1.5 mm, ± spreading, lanceolate to ovate-lanceolate, acute; serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells rhombic to rhomboidal, 45--95 \um, thin-walled. Specialized asexual reproduction generally present when sterile; axillary gemmae arising in clusters of 2--8 in leaf axils, narrowly branchlike to slender & flexible, yellow, pink, or green, leaf primordia at apex and lower, laminate.  Sexual condition dioicous; perichaetial leaves scarcely differentiated; perigonia leaves ovate, shortly acuminate. Seta orange-brown. Capsule inclined 95--180° from vertical, brown to straw-colored, pyriform, neck about 1/3\x urn length; exothecial cells short-rectangular, with sinuose walls; stomata superficial; operculum convex-conic; exostome teeth yellow-brown, narrowly triangular-acute, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane 1/2\x the exostome length, segments distinctly keeled, broadly perforate, cilia short to rudimentary. Spores 16--23 \um, finely roughened.

 

Capsules mature summer (Jun--Aug). Acid, relatively humus-rich soils, alpine tundra, stream banks, path banks, heavy metal mine tailings; low to high elevations; Alaska, Calif., Colo., Idaho, Nev., N.Mex., Oreg., Utah, Wash., Wyo.; Europe.

 

The gemmae of Pohlia tundrae are linear to oblong and extend widely from the upper leaf axils.  They develop in clusters, sometimes densely. The leaf primordia are broadly laminate and flexuose. Lax plants from shaded microsites have narrow pale to whitish gemmae, but plants from more exposed sites have thicker, sometimes reddish gemmae that can approach those of P. drummondii.  At high elevations in Yosemite National Park P. tundrae grows mixed with P. drummondii and the two appear to intergrade, but such intermediate plants have not been seen from elsewhere.  Occasional plants with very short gemmae can be confused with P. proligera, which typically has smaller, vermicular gemmae with peg-like apical leaf primordia.

 

16.  Pohlia rabunbaldensis A. J. Shaw, Bryologist 108: 180, fig. 2. 2005

 

Plants slender, dull, green to light green. Stems 0.5--1 cm. Leaves 0.9--1.2 mm, ± spreading, lanceolate to ovate-lanceolate, acute; serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells rhombic to rhomboidal, 45--95 \um, thin-walled. Specialized asexual reproduction generally present when sterile; axillary gemmae arising singly in leaf axils, narrowly bulbiform, orange to orange-red, leaf primordia at apex and lower, sometimes to base, laminate, flexuose.  Sexual condition unknown, presumed to be dioicous.

 

Capsules unknown. Acid, gravelly to sandy soil along trails; high elevations; Ga., N.C.

 

Pohlia rabunbaldensis has bulbiform gemmae occurring singly in a leaf axil, which are similar to those of P. drummondii, but the leaf primordia are even larger relative to the gemma body.  Plants of P. rabunbaldensis are slender, with dull leaves much like those of P. annotina, somewhat contorted when dry, distinct from the broader carinate somewhat shiny leaves of P. drummondii, which are unchanged on drying.

 

17. Pohlia filum (Schimper) Mårtenssen, Svensk. Vet-Ak. Arh. Natur. 14: 149. 1956

 

Bryum filum Schimper, 1876, Syn. Musc. Eur. (ed. 2), 1876.

 

Plants slender to medium-size, glossy, green to light green. Stems 0.5--4 cm. Leaves 0.6--1.2 mm, erect, imbricate to remote, lanceolate, acute; serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells rhombic to rhomboidal, 35--95 \um, thin-walled. Specialized asexual reproduction generally present when sterile; axillary gemmae 1(--2) in leaf axils, bulbiform, oblong or elliptic to subglobose, green to yellow, becoming black when old, leaf primordia at apex, small, laminate.  Sexual condition dioicous; perichaetial leaves scarcely differentiated; perigonia leaves ovate, shortly acuminate. Seta orange-brown. Capsule inclined 95--180° from vertical, brown to straw-colored, pyriform, neck about 1/3\x urn length; exothecial cells short-rectangular, with sinuose walls; stomata superficial; operculum convex-conic; exostome teeth yellow-brown, narrowly triangular-acute, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane 1/2\x the exostome length, segments distinctly keeled, broadly perforate, cilia short to rudimentary. Spores 16--23 \um, finely roughened.

 

Capsules mature summer (Jun--Aug). Gravely, organic-poor soils, glacial outwash, roadsides; low to high elevations; Greenland; Alta., B.C., N.W.T., Nunavut, P.E.I., Que., Sask.; Alaska, Oreg.; Europe.

 

Pohlia filum is an easily recognized species characterized by erect somewhat glossy leaves, and ovoid gemmae that normally arise singly in the leaf axils.  The gemmae have a few small, triangular, rather stiff leaf primordia at the apex, rarely with 1--2 primordia proximal on the gemma body.  The gemmae of P. drummondii are more elongate-cylindrical and branch-like, with larger, flexuose, often green leaf primordia at the apex and also frequently more proximally on the gemma body.

 

 

18. Pohlia beringiense A. J. Shaw, Contr. Univ. Mich. Herb. 15: 260. 1982

 

Plants slender, whitish green. Stems 0.5--2 cm. Leaves 0.9--1.5 mm, ± erect, lanceolate, acute; serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells linear-rhomboidal, vermicular, 60--100 \um, thin-walled. Specialized asexual reproduction generally present; axillary gemmae single in leaf axils, bulbiform, red (darker to black when dry), leaf primordia at apex and more proximally, stiffly laminate.  Sexual condition unknown, presumed to be dioicous.

 

Capsules unknown. Acid, gravelly or sandy soil disturbed soil, ditches; low to high elevations; Yukon; Alaska; Asia.

 

Pohlia beringiense has cherry-red stems with erect, whitish leaves and red bulbiform axillary gemmae.  The gemmae are much like those of P. drummondii, but are even more red, and contrast conspicuously with the whitish leaves.  The organic-poor substrates that P. beringiense on which occurs are quite different from the relatively humic soils on which P. drummondii occurs.

 

19.  Pohlia andalusica (Höhnel) Brotherus in A. Engler & K. Prantl,  Nat. Pfl. 1(3). 551. 1903

 

Webera andalusica Höhnel, Sitzungsber. Kaiserl. Akad. Wiss., Math.-Naturwiss. Cl., Abt. 1, 104: 326. 1895.

 

Plants slender to medium-size, ± glossy, green. Stems 0.3--3 cm, red. Leaves 0.8--1.1 mm, ± erect, lanceolate, acute; serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells rhombic to rhomboidal, 65--95 \um, thin-walled. Specialized asexual reproduction generally present when sterile; axillary gemmae arising in clusters of 2--8 in leaf axils, bulbiform, obconic to oblong, yellow, pink, or green, leaf primordia mostly at apex, occasionally more proximally, laminate. Sexual condition dioicous; perichaetial leaves scarcely differentiated; perigonia leaves ovate, shortly acuminate. Seta orange-brown. Capsule inclined 95--180° from vertical, brown to straw-colored, pyriform, neck about 1/3\x urn length; exothecial cells short-rectangular, with sinuose walls; stomata superficial; operculum convex-conic; exostome teeth yellow-brown, narrowly triangular-acute, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane 1/2\x the exostome length, segments distinctly keeled, broadly perforate, cilia short to rudimentary. Spores 16--21 \um, finely roughened.

 

Capsules mature summer (Jun--Aug). Acid, gravelly or sandy disturbed soil, path banks, stream banks; Alta., B.C., N.B., Nfld. and Labr., N.W.T., N.S., Ont., P.E.I., Que., Yukon; Alaska, Calif., Colo., Idaho, Maine, Mass., Mont., N.Y., Pa., Vt., Wash., Wyo.; Europe.

 

The gemmae of Pohlia andalusica occur in clusters of 2--6 in a few upper leaf axils and are reddish brown to green or sometimes reddish-yellow.  The gemmae are obconic in shape, with laminate leaf primordia at the apices.  This is one of the most common gemmiferous species in New England, but is much more rare in western North America.

 

20.  Pohlia bulbifera (Warnstorf) Warnstorf, Krypt. Fl. Brandenburg 2: 429. 1904

 

Webera bulbifera Warnstorf, Bot. Centrabl. 66: 230. 1896

 

Plants slender to medium-size, glossy, green. Stems 0.3--3 cm, green, orange or red. Leaves 0.9--1.4 mm, ± erect, lanceolate, acute; serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells rhombic to rhomboidal, 65--95 \um, thin-walled. Specialized asexual reproduction generally present when sterile; axillary gemmae arising in clusters of 2--6 in leaf axils, spheroidal to obovate, yellow, orange, or green, leaf primordia restricted to apex and forming a dome, laminate. Sexual condition dioicous; perichaetial leaves scarcely differentiated; perigonia leaves ovate, shortly acuminate. Seta orange-brown. Capsule inclined 95--180° from vertical, brown to straw-colored, pyriform, neck about 1/3\x urn length; exothecial cells short-rectangular, with sinuose walls; stomata superficial; operculum convex-conic; exostome teeth yellow-brown, narrowly triangular-acute, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane 1/2\x the exostome length, segments distinctly keeled, broadly perforate, cilia short to rudimentary. Spores 16--21 \um, finely roughened.

 

Capsules mature summer (Jun--Aug). Acid, gravelly or sandy disturbed soil, path banks, stream banks, also on peaty soil; Greenland; B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Ont., Que.; Alaska, Colo., Maine, Mass., Mich., N.H., N.Y., Vt., Wash., Wis.; Eurasia.

 

The gemmae of Pohlia bulbifera appear to be round to oblong because the 4--5 laminate leaf primordia are concave and form a dome over the gemma apex.  The leaves are wide-spreading so the gemmae, although small, can be seen clustered in the distal leaf axils. This species sometimes occurs on peaty soils in bogs but also occurs on gravelly soils in disturbed places.

 

21. Pohlia annotina (Hedwig) Lindberg, Musci Scand., 17. 1879

 

Bryum annotinum Hedwig, Sp. Musc. Fond., 183. 1801

 

Plants slender, dull, green. Stems 0.3--3 cm, green, green to orange-green. Leaves 0.6--1.1 mm, ± erect, lanceolate, acute; serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells rhombic to rhomboidal, 60--95 \um, thin-walled. Specialized asexual reproduction generally present when sterile; axillary gemmae arising in dense clusters in leaf axils, rarely few or single on older stems, oblong, obconic, ± elongate and vermicular, rarely oblong-bulbiform, hyaline to pale green, rarely reddish, leaf primordia 2--5, restricted to apex, peg-like or rarely ± laminate with age. Sexual condition dioicous; perichaetial leaves weakly differentiated, narrowly lanceolate; perigonia leaves ovate, shortly acuminate. Seta orange-brown. Capsule inclined 95--180° from vertical, brown to straw-colored, pyriform, neck about 1/3\x urn length; exothecial cells short-rectangular, with sinuose walls; stomata superficial; operculum convex-conic; exostome teeth yellow-brown, narrowly triangular-acute, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane 1/2\x the exostome length, segments distinctly keeled, broadly perforate, cilia short to rudimentary. Spores 16--21 \um, finely roughened.

 

Capsules mature summer (Jun--Aug). On acid, gravelly or sandy disturbed soil, path banks, stream banks; B.C., N.B., Nfld. and Labr., N.S., Ont., Que.; Alaska, Ark., Calif., Del., Ga., Idaho, Iowa, Maine, Md., Mass., Mich., Miss., Mo., Mont., N.H., N.J., N.Y., N.C., Ohio, Pa., S.C., Tenn., Vt., Va., Wash., Wis.; Europe.

 

Pohlia annotina is the most widespread and common gemmiferous species in eastern North America and along the Pacific coast.  The plants are slender and rather dull and the leaves are somewhat contorted when dry. The axillary gemmae are borne in clusters and are obconic to linear-obconic, with 2--5 apical, peg-like leaf primordia.

 

22.  Pohlia camptotrachela (Renauld & Cardot) Brotherus, in A. Engler & K. Prantl, Nat. Pfl. 1(3): 552. 1903

 

Webera camptotrachela Renauld & Cardot, Bot. Gaz. 13(8): 199. 1888

 

Plants slender, dull, green. Stems 0.3--2.5 cm, green, green to orange-green. Leaves 0.6--1.1 mm, ± erect, lanceolate, acute; serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells rhombic to rhomboidal, 60--95 \um, thin-walled. Specialized asexual reproduction generally present when sterile; axillary gemmae arising in dense clusters in leaf axils, globose to slightly elongate, yellow, green, or orange, leaf primordia 1--4, restricted to apex, peg-like. Sexual condition dioicous; perichaetial leaves weakly differentiated, narrowly lanceolate; perigonia leaves ovate, shortly acuminate. Seta orange-brown. Capsule inclined 95--180° from vertical, brown to straw-colored, pyriform, neck about 1/3\x urn length; exothecial cells short-rectangular, with sinuose walls; stomata superficial; operculum convex-conic; exostome teeth yellow-brown, narrowly triangular-acute, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane 1/2\x the exostome length, segments distinctly keeled, broadly perforate, cilia short to rudimentary. Spores 16--21 \um, finely roughened.

 

Capsules mature summer (Jun--Aug). On acid, gravelly or sandy disturbed soil, path banks, stream banks; B.C.; Calif., Colo., Mont., Nev., Wash., Wyo.; Europe.

 

The leafy stems of Pohlia camptotrachela are indistinguishable from those of P. annotina, but the gemmae are small, globose or subglobose, with 1--4 peg-like leaf primordial at the apex.  They are, in addition, translucent and may be yellow, green, or orange.

 

23. Pohlia proligera (Kindberg) Brotherus, in A. Engler & K. Prantl, Nat. Pfl. 1(3): 551. 1903

 

Webera proligera Kindberg, Forh. Vidensk.-Selsk. Kristiania 1888(6): 30. 1888

 

Plants medium-size, glossy, green. Stems 0.5--3.5 cm, green, green to orange-green. Leaves 0.6--1.6 mm, ± erect, lanceolate, acute; serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells rhombic to linear-rhomboidal, 60--105 \um, thin-walled. Specialized asexual reproduction generally present when sterile; axillary gemmae arising in dense felt-like clusters in leaf axils, oblong-linear to linear-vermicular, hyaline, white, or pale green, rarely pale orange, leaf primordia 1--2(--3), restricted to apex, peg-like. Sexual condition dioicous; perichaetial leaves weakly differentiated, narrowly lanceolate; perigonia leaves ovate, shortly acuminate. Seta orange-brown. Capsule inclined 95--180° from vertical, brown to straw-colored, pyriform, neck about 1/3\x urn length; exothecial cells short-rectangular, with sinuose walls; stomata superficial; operculum convex-conic; exostome teeth yellow-brown, narrowly triangular-acute, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane 1/2\x the exostome length, segments distinctly keeled, broadly perforate, cilia short to rudimentary. Spores 16--21 \um, finely roughened.

 

Capsules mature summer (Jun--Aug). Acid, sandy disturbed soil, path banks, stream banks; low to high elevations. Greenland; Alta., B.C., N.B., Nfld. and Labr., N.W.T., N.S., Nunavut, Ont., P.E.I., Que.; Alaska, Ariz., Calif., Colo., Idaho, Maine, Mich., Minn., Mont., N.Y., Oreg., S.Dak., Utah, Vt., Wash.; Europe.

 

Pohlia proligera is a relatively common species in boreal and high-montane habitats.  The leaves are glossy, with dense, felt-like clusters of whitish, pale green, or sometimes pale orange gemmae in their axils.  The gemmae are linear-vermicular with 1--2 peg-like apical leaf primordia.

 

24.  Pohlia andrewsii A. J. Shaw, Bryologist 84: 70. 1981

 

Plants medium-size, glossy, green. Stems 0.5--2.5 cm, green, green to orange-green. Leaves 0.6--1.6 mm, ± erect, lanceolate, acute; serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells rhombic to linear-rhomboidal, 60--105 \um, thin-walled. Specialized asexual reproduction generally present when sterile; axillary gemmae arising in dense clusters in leaf axils, isodiametric to oblong, green or more commonly orange to red, leaf primordia 1--2(--4), restricted to apex, peg-like, incurved over apex, becoming laminate with age. Sexual condition dioicous; perichaetial leaves weakly differentiated, narrowly lanceolate; perigonia leaves ovate, shortly acuminate. Seta orange-brown. Capsule inclined 95--180° from vertical, brown to straw-colored, pyriform, neck about 1/3\x urn length; exothecial cells short-rectangular, with sinuose walls; stomata superficial; operculum convex-conic; exostome teeth yellow-brown, narrowly triangular-acute, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane 1/2\x the exostome length, segments distinctly keeled, broadly perforate, cilia short to rudimentary. Spores 16--21 \um, finely roughened.

 

Capsules mature summer (Jun--Aug). On acid, sandy disturbed soil, path banks, stream banks; low to high elevations. Greenland; N.W.T., Yukon; Alaska; Europe.

 

The glossy leaves of Pohlia andrewsii are much like those of P. proligera but the axillary gemmae are oblong, typically orange to red, and have 2--5 short, primordia incurved over the gemma apex.

 

25.  Pohlia flexuosa Harvey, Icon. Pl. 1: plate 19, fig. 5. 1836

 

Plants slender, dull, green. Stems 0.5--1.5 cm, green, green to orange-green. Leaves 0.6--1.3 mm, ± erect, lanceolate, acute; serrulate to serrate in the distal 1/3; costa subpercurrent; distal medial cells rhombic to linear-rhomboidal, 60--105 \um, thin-walled. Specialized asexual reproduction generally present when sterile; axillary gemmae arising in dense clusters in leaf axils, dimorphic, isodiametric to oblong, brown, knobby in outline, without leaf primordia, or narrowly linear-vermicular, hyaline, with (0--)1--2 apical peg-like leaf primordia. Sexual condition dioicous; perichaetial leaves weakly differentiated, narrowly lanceolate; perigonia leaves ovate, shortly acuminate. Seta orange-brown. Capsule inclined 95--180° from vertical, brown to straw-colored, pyriform, neck about 1/3\x urn length; exothecial cells short-rectangular, with sinuose walls; stomata superficial; annulus revoluble; operculum convex-conic; exostome teeth yellow-brown, narrowly triangular-acute, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane 1/2\x the exostome length, segments distinctly keeled, broadly perforate, cilia short to rudimentary. Spores 16--21 \um, finely roughened.

 

Capsules unknown in North America. Acid, sandy disturbed soil, path banks, stream banks; low elevations; Calif.; Europe; Asia.

 

The slender, dull plants of Pohlia flexuosa, which have leaves somewhat contorted when dry, are like those of P. annotina and P. camptotrachela.  The gemmae are dimorphic, and are either hyaline to whitish and narrowly linear-vermicular, with 1--2 poorly differentiated leaf primordia, or small, blackish, oblong to globose, with angular cells.  This species is known from only one North American site but is common in parts of Asia including China, and also occurs in western Europe.

 

26. Pohlia longibracteata Brotherus in J. Röll, Bot. Centralbl. 44: 419. 1890

 

Plants medium-size to robust, very glossy, green to golden-green. Stems 0.5--2.5 cm. Leaves 2.0--3.5 mm, wide-spreading, narrowly long-lanceolate, narrowly acute; serrate in the distal 1/3; costa subpercurrent; distal medial cells linear-hexagonal, 80--160 \um, thin-walled. Specialized asexual reproduction absent. Sexual condition dioicous; perichaetial leaves ± strongly differentiated, lanceolate to linear-lanceolate; perigonia generally on short lateral branches; perigonial leaves ovate, very long-acuminate, to 6 mm. Seta orange-brown. Capsule inclined ± 180° from vertical, brown to straw-colored, shortly pyriform to urceolate, neck less than 1/3\x urn length; exothecial cells isodiametric, with straight to sinuose walls; stomata immersed; annulus undifferentiated; operculum low to high conic; exostome teeth light yellow-brown, triangular-acute, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane equal to or slightly greater than 1/2\x the exostome length, segments distinctly keeled, broadly perforate, cilia long, nodulose, or short. Spores 14--20 \um, finely roughened.

 

Capsules mature spring (May-Jul). On naturally or anthropogenically disturbed soils, upturned tree banks, path banks, in crevices of rocks; along streams; low elevations; B.C.; Alaska, Calif., Oreg., Wash.

 

The relatively long, narrow, wide-spreading leaves of Pohlia longibracteata are quite glossy, easing identification of sterile plants.  The perigonial bracts are very long-acuminate and spreading from the ovate base (providing the basis for the specific epithet).  Pohlia longibracteata occurs on soil in Pacific coastal forests, typically under redwood trees.

 

27. Pohlia brevinervis Lindberg & Arnell, Kongl. Svenska Vetenskapsakad. Handl. 23(10): 51. 1890.

 

Plants slender to very slender, somewhat glossy, whitish. Stems 0.3--1.5 cm. Leaves 0.6--1.4 mm, erect-spreading, lanceolate, acute; serrulate in the distal 1/3; costa subpercurrent; distal medial cells linear-rhomboidal, 60--110 \um, thin-walled. Specialized asexual reproduction absent. Sexual condition dioicous; perichaetial leaves weakly differentiated; perigonia leaves ovate, acuminate. Seta orange-brown. Capsule inclined ± 180° from vertical, brown to straw-colored, shortly pyriform to urceolate, neck less than 1/3\x urn length; exothecial cells isodiametric, somewhat collenchymatous, with sinuose walls; stomata superficial or slightly immersed; annulus undifferentiated; operculum low to high conic; exostome teeth dark to light brown or red-brown, triangular-acute, pitted basally, coarsely papillose distally; endostome light yellow, basal membrane equal to or slightly greater than 1/2\x the exostome length, segments distinctly keeled, broadly perforate, cilia long, nodulose. Spores 16--21 \um, finely roughened.

 

Capsules mature spring (Apr-Jun). Clay soils along streams, ditches, glacial outwash; Alta., Yukon; Alaska; Asia (Russia in eastern Siberia).

 

Pohlia brevinervis is a rare and poorly known species that seems to combine characters of P. vexans (erect, glossy leaves on sterile plants) and P. atropurpurea (dark, reddish brown exostome teeth and somewhat immersed stomates).  The leaves are distinctly more whitish than those of P. vexans.

 

28. Pohlia columbica (Kindberg) Andrews in A. J. Grout, Moss Fl. N. Am. 2: 202. 1935

 

Webera columbica Kindberg, Cat. Canad. Pl. 6: 115. 1892

 

Plants slender to medium-size, rather dull, green to reddish-green. Stems 0.4--1.5 cm. Leaves 1.2--2.5 mm, erect-spreading to spreading, narrowly lanceolate to lanceolate, acute; serrate in the distal 1/3; costa subpercurrent; distal medial cells linear-hexagonal, 85--150 \um, thin-walled. Specialized asexual reproduction absent. Sexual condition dioicous; perichaetial leaves ± differentiated, to 3 mm, lanceolate to linear-lanceolate; perigonia leaves ovate, elongate-acuminate, Seta orange-brown. Capsule inclined 145--180° from vertical, brown to straw-colored, shortly pyriform to urceolate, neck less than 1/3\x urn length; exothecial cells isodiametric, with sinuose walls, somewhat collenchymatous; stomata immersed; annulus undifferentiated; operculum low to high conic; exostome teeth yellow to yellow-brown, triangular-acute, pitted basally, coarsely papillose distally; endostome hyaline, basal membrane equal to or slightly greater than 1/2\x the exostome length, segments distinctly keeled, broadly perforate, cilia long, nodulose, or short. Spores 13--18 \um, finely roughened.

 

Capsules mature spring (May-Jul). Disturbed soils; along streams; low elevations; B.C.; Alaska, Wash.

 

Pohlia columbica is a very rare and poorly known species characterized by dull reddish plants, variably long-acuminate perigonial bracts, pale yellow-brown exostome teeth, and immersed stomates.

 

29. Pohlia melanodon (Bridel) A. J. Shaw, Bryologist 84: 506. 1982

 

Bryum melanodon Bridel, Bryol. Univ. 1: 845. 1827; B. carneum Withering; B. delicatulum Hedwig

 

Plants slender, soft and lax, dark green. Stems 0.3--1.0 cm. Leaves 0.7--1.3 mm, erect-spreading to spreading, lanceolate to ovate-lanceolate, acute or shortly acuminate; weakly serrulate in the distal 1/3; costa ending well before apex; distal medial cells laxly and broadly rhomboidal, 60--100 \um, thin-walled. Specialized asexual reproduction absent. Sexual condition dioicous; perichaetial leaves scarcely differentiated, lanceolate; perigonia leaves ovate, short-acuminate. Seta orange-brown. Capsule inclined ± 180° from vertical, brown to red-brown, sometimes straw-colored, shortly pyriform to urceolate, neck less than 1/3 urn length; exothecial cells isodiametric, with sinuose walls, somewhat collenchymatous; stomata immersed; annulus undifferentiated; operculum low to high conic; exostome teeth dark brown to red-brown, triangular-acute, pitted basally, coarsely papillose distally; endostome yellow to yellow-brown, basal membrane equal to or slightly greater than 1/2\x the exostome length, segments distinctly keeled, broadly perforate, cilia long, nodulose. Spores 13--18 \um, finely roughened.

 

Capsules mature spring (Apr-Jun). On naturally or anthropogenically disturbed clay or rarely sandy soils; path banks, along streams; low elevations; Ont.; Ark., Ill, Ind., Maine, Md., Mich., N.Y., N.C., Vt., Va., W.Va.; Europe.

 

Pohlia melanodon has soft, dark green, rather broad ovate-lanceolate leaves with lax, thin-walled cells.  It does not produce elongate sterile cushions as does P. wahlenbergii; even when sterile the plants have short stems and are rather densely leafy.  The species is more common in eastern North America than collection indicate; it is often sterile and for that reason rarely collected. 

 

30. Pohlia atropurpurea (Wahlenberg) H. Lindberg, Acta Soc. F. Fl. Fenn. 16: 14, figs. 1--7. 1899

 

Bryum pulchellum var. atropurpurea Wahlenberg, Fl. Lapp., 360. 1812

 

Plants very slender to tiny [[one reviewer says this are not comparable descriptive terms]], soft, green to reddish. Stems 0.2--0.4 cm. Leaves 0.6--1.2 mm, erect-spreading to spreading, lanceolate, acute; weakly serrulate in the distal 1/3; costa ending well before apex; distal medial cells broadly rhomboidal, narrower in perichaetial leaves, 65--110 \um, thin-walled. Specialized asexual reproduction absent. Sexual condition dioicous; perichaetial leaves scarcely differentiated, lanceolate; perigonia leaves ovate, short-acuminate. Seta orange-brown. Capsule inclined ± 180° from vertical, brown to red-brown, sometimes straw-colored, shortly pyriform to urceolate, neck less than 1/3 urn length; exothecial cells isodiametric, with sinuose, somewhat collenchymatous walls; stomata superficial; annulus undifferentiated; operculum low to high conic; exostome teeth dark brown to red-brown, triangular-acute, pitted basally, coarsely papillose distally; endostome yellow to yellow-brown, basal membrane about 1/2\x the exostome length, segments distinctly keeled, broadly perforate, cilia long, nodulose. Spores 15--21 \um, finely roughened.

 

Capsules mature spring (Apr-Jun). On naturally or anthropogenically disturbed clay or rarely sandy soils; path banks, along streams; low elevations; B.C., Man., Nfld. and Labr., Ont., Yukon; Alaska, Calif., Idaho, Iowa, Minn., N.Y., Wash.; Europe.

 

Pohlia atropurpurea has sporophytes similar to those of P. melanodon, with dark reddish brown exostome teeth, yellow endostomes, and immersed stomates.  This uncommon northern species is very small, generally consisting of unbranched gametophytes that do not form extensive cushions.  As in P. melanodon the leaf cells are lax and thin-walled.  Genetic relationships between this and P. melanodon need study; P. atropurpurea could be a northern form of that species.  Median cells of the perichaetial leaves are narrower than the broadly lax cells of proximal stem leaves.

 

31. Pohlia vexans (Limpricht) H. Lindberg, Acta Soc. F. Fl. Fenn. 16: 20. 1899

 

Mniobryum vexans Limpricht, Laubm. Deutsch. 2. 273. 1892

 

Plants slender, very glossy, green to reddish. Stems 0.5--1.5 cm. Leaves 0.6--1.3 mm, stiffly erect and ± imbricate to erect-spreading, lanceolate, acute; weakly serrulate in the distal 1/3; costa ending well before apex; distal medial cells broadly rhomboidal, 65--110 \um, thin-walled. Specialized asexual reproduction absent. Sexual condition dioicous; perichaetial leaves somewhat differentiated, lanceolate; perigonia leaves ovate, short- to ± long-acuminate. Seta orange-brown. Capsule inclined ± 180° from vertical, brown to red-brown, sometimes straw-colored, shortly pyriform to urceolate, neck less than 1/3 urn length; exothecial cells isodiametric, with sinuose walls; stomata immersed; annulus undifferentiated; operculum low to high conic; exostome teeth yellow to light brown, triangular-acute, pitted basally, coarsely papillose distally; endostome yellow to yellow-brown, basal membrane equal to or slightly greater than 1/2 the exostome length, segments distinctly keeled, broadly perforate, cilia long, nodulose. Spores 15--21 \um, finely roughened.

 

Capsules mature spring (Apr-Jun). On naturally or anthropogenically disturbed clay or rarely sandy soils; path banks, along streams; low to moderate elevations; Alta., B.C., Man., N.W.T.; Alaska, Mont., Wash.; Europe.

 

Pohlia vexans is a slender but handsome species characterized by abundant, elongate sterile shoots with erect, rather glossy leaves.  The exostome teeth are pale brown.  The species is fairly common on moist calcareous clays in cold continental regions of northwestern North America.

 

32. Pohlia wahlenbergii (F. Weber & D. Mohr) Andrews in A. J. Grout, Moss Fl. N. Am. 2. 203. 1935

 

Hypnum wahlenbergii, Bot. Taschenb. 280. 475. 1807; Mniobryum wahlenbergii (F. Weber & D. Mohr) Jennings; Pohlia albicans Lindberg

 

Plants slender to very robust, dull, whitish or sometimes in robust forms reddish. Stems 0.8--10 cm. Leaves 0.6--1.2 mm, laxly spreading to more stiffly erect, lanceolate to ovate-lanceolate, acute; weakly to strongly serrulate in the distal 1/3; costa ending well before apex; distal medial cells broadly and laxly hexagonal to rhomboidal, 65--110 \um, thin-walled. Specialized asexual reproduction absent. Sexual condition dioicous; perichaetial leaves weakly differentiated, lanceolate; perigonia leaves ovate, short-acuminate. Seta orange-brown. Capsule inclined ± 180° from vertical, brown to red-brown, sometimes straw-colored, shortly pyriform to urceolate, neck less than 1/3 urn length; exothecial cells isodiametric, with sinuose walls, somewhat collenchymatous; stomata immersed; annulus undifferentiated; operculum low to high conic; exostome teeth light brown to red-brown, triangular-acute, pitted basally, coarsely papillose distally; endostome hyaline to yellow, basal membrane equal to or slightly greater than 1/2 the exostome length, segments distinctly keeled, broadly perforate, cilia long, nodulose. Spores 15--21 \um, finely roughened.

 

Capsules mature spring (Apr--Jun). On naturally or anthropogenically disturbed clay or rarely sandy soils; path banks, along streams; low elevations; Greenland; Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Nunavut, Ont., P.E.I., Que., Yukon; Alaska, Ariz., Ark., Calif., Colo., Conn., D.C., Idaho, Ill, Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., S.Dak., Tenn., Utah, Vt., Va., Wash., W.Va., Wis., Wyo.; Mexico; Central America; South America; Eurasia; Antarctica.

 

Pohlia wahlenbergii is one of the most geographically widespread and common species of the genus.  The leaves are pale whitish, decurrent, and have lax thin-walled cells.  The species varies greatly in size, from very slender delicate plants in suboptimal habitats, to robust and forming deep cushions in cold high altitude and latitude sites.  Robust plants typically have red stems and sometimes reddish pigmentation to the leaves as well. Some authors refer robust expressions to the var. glaciale (or P. glaciale) but gradation in size and pigmentation is completely continuous, and different collectors draw the line between the typical variety and the var. glaciale at different points.

 

3. Epipterygium Lindberg, Öfvers. Förh. Kongl. Svenska Vetensk.-Akad. 19: 603. 1862 * [Greek epi, above, and pterigium, wing-like; alluding to small dorsal leaves]

 

Plants small to medium size, occurring in loose turfs or as scattered plants. Stems short to long, 0.1--1 cm, unbranched or irregularly forking when sterile, often bearing subfloral innovations when with gametangia. Leaves spreading, weakly [strongly] complanate, slightly [to very strongly] differentiated in 2--3 lateral and ventral rows of larger leaves and 1--2[--3] dorsal rows of smaller narrower leaves, 0.4--1.5[--2.5] mm, slightly decurrent; lateral and ventral leaves ovate-lanceolate to elliptic, ±  abruptly acute, dorsal leaves smaller and narrower, serrulate near the apex or entire, costa ending well before the apex; distal medial laminal cells broadly elongate-hexagonal to long-rhomboidal, with thin to firm walls, marginal cells weakly but distinctly [to strongly] differentiated from median cells. Specialized asexual reproduction absent. Sexual condition dioicous; perigonia and perichaetia terminal; perichaetial leaves somewhat differentiated, lanceolate; perigonia bud-like, perigonial leaves ovate, short- to ± long-acuminate. Seta 1, stramineous to pale orange, bent near the apex thus producing pendulous capsules. Capsule inclined 160--180° from vertical, 1--3 mm, narrowly cylindric to short-pyriform or urceolate, neck differentiated but short, stomata abundant in the neck, superficial, median exothecial cells strongly collenchymatous, near mouth quadrate or short-rectangular; annulus present and revoluble; peristome diplolepideous-alternate; peristomial formula 4:2:6--8; exostome pale yellow to brown or red-brown, teeth triangular, trabeculate, pitted basally, coarsely or finely papillose distally, endostome hyaline to yellow, segments wide, strongly keeled, broadly perforate, basal membrane high, cilia 1--3, as long as the segments or shorter, nodulose or not.

 

Species ca. 12 (1 in the flora); North America, Central America, South America, Europe, Asia, Pacific Islands (New Zealand).

 

Epipterygium is a small genus of tropical and temperate mosses similar in morphology to Pohlia, generally distinguished by more or less complanate foliation in which 2--3 rows of larger lateral leaves are differentiated in size and shape from 1--3 rows of smaller, narrower dorsal leaves.  The degree of leaf dimorphism reaches an extreme in E. wrightii of the Caribbean region, but the only North American species, E. tozeri, is almost uniformly foliate and scarcely complanate.  This species is especially similar to Pohlia, and phylogenetic analyses corroborate a close relationship between the two genera.

 

SELECTED REFERENCES  Shaw, A. J. 1984.  Quantitative taxonomic study of morphology in Epipterygium.  Bryologist 87: 132--142.

             

1. Epipterygium tozeri (Greville) Lindberg, Öfvers. Förh. Kongl. Svenska Vetensk.-Akad. 21: 576. 1865.

 

Bryum tozeri Greville, Scott. Crypt. Fl. 5: 285. 1827

 

Leaves loosely foliate and ± complanate, weakly differentiated in 1--3 dorsal rows and 2--3 lateral andventral rows, lateral and ventral leaves ovate-lanceolate to elliptic, ±  abruptly acute, dorsal leaves smaller and narrower, weakly serrulate in distal 1/3; costa ending well before apex; distal medial cells broadly rhomboidal, 65--110 \um, 12--20 \um wide, thin-walled. Seta orange-brown. Capsule with exostome teeth yellow to light brown, triangular-acute, endostome yellow to yellow-brown, basal membrane equal to or slightly greater than 1/2\x the exostome length, segments distinctly keeled, broadly perforate, cilia long, nodulose. Spores 16--20 \um, finely roughened.

 

Capsules mature spring (Apr-Jun). On naturally or anthropogenically disturbed clay or more humus-rich soil, wet, shaded banks along trails and streams; upturned tree bases;  low elevations; B.C., Calif., Oreg., Wash.; Europe; Asia.

 

Epipterygium tozeri is a characteristic species of soil banks in redwood forests of the Pacific coast.  The soft pale bluish color is distinctive when plants are growing in well-developed turfs.  Plants of E. tozeri can be distinguished from any Pohlia by the (sometimes subtle) complanate foliation with smaller dorsal than lateral and ventral leaves, broad, nearly elliptic leaves, weak costa ending about 2/3 up the leaf, and by marginal leaf cells differentiated from the median; longer, narrower, and more thick-walled. 

 

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