A PHYLOGRAMMATIC EVOLUTIONARY ANALYSIS OF THE

MOSS GENUS DIDYMODON IN NORTH AMERICA NORTH OF MEXICO
Richard H. Zander
Res Botanica
February 19, 2003

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Originally published in Bulletin of the Buffalo Society of Natural Sciences 36: 81–115. 1998.

 

A PHYLOGRAMMATIC EVOLUTIONARY ANALYSIS OF THE

MOSS GENUS DIDYMODON IN NORTH AMERICA NORTH OF MEXICO

 

Richard H. Zander

Division of Botany, Buffalo Museum of Science, 1020 Humboldt Parkway,

Buffalo, New York 14211

 

Abstract: A key is presented for the 22 known species of Didymodon (Musci) in North America north of Mexico, with taxonomic commentaries for each. A phylogram combining PCA ordination and a cladogram shows evident morphological convergence between five pairs of species. Six species are interpreted as surviving ancestors. Phylogenetic analysis is an assumption-laden and belief-oriented attempt at reconstructing a past unique conditional chain of events. Through misapplication of the theory of statistical relevance, the fine structure of trees of maximum synapomorphy is generally artificial and antiparsimonious; also, trees of maximum likelihood are often not probabilistic estimations. Cladistic analysis, however, may be useful under certain conditions in devising general classifications and in phylo­grammatic analysis.

 

The moss genus Didymodon as expanded by Saito (1975) has proven large and complex in North America (e.g., studies by Zander 1978a, 1981, 1994). Work on the genus Didymodon for the bryophyte volume of the Flora of North America (FNA Editorial Committee 1993) is sufficiently advanced that an annotated key to the 22 known species might be profitably presented in advance of FNA final publication four or five years from now. A phyletic evolutionary study addresses apparent morphological convergence, while the statistical assumptions and methods used for obtaining modern detailed classifications are reviewed.

 

Many species of the genus are common and often difficult to distinguish. The present study updates the above-cited previous work. The key below should aid considerably the floristic and ecological studies by other botanists that have been given impetus by the FNA project. Descriptions and details of geographic ranges, habitats and sporo­phyte maturation dates will be given in that work.

 

TAXONOMY

 

DIDYMODON Hedw., Sp. Musc. 104, 1801.

Sections of the genus previously recognized for North America north of Mexico are: Didymodon Hedw. sect. Didymodon, type: Didymodon rigidulus Hedw.; Didymodon sect. Asteriscium (C. Müll.) Zand., type: Didymodon umbrosus (C. Müll.) Zand.; Didymodon sect. Fallaces (De Not.) Zand., type: Didymodon fallax (Hedw.) Zand.; and Didymodon sect. Vineales (Steere) Zand., type: Didymodon vinealis (Brid.) Zand. Sectional synonyms and descriptions were given and species were assigned to the sections by Zander (1978a, 1993). Many species, however, remain problematic in assignment to sections.

 

There are about 122 species of Didymodon worldwide (Zander 1993), growing on a variety of substrates, mostly soil and rock. It is a large genus widely diversified in temperate and montane areas worldwide.

 

The genus Didymodon is distinguished from a similarly widely distributed relative Barbula Hedw., with which it is often confused, by its usually lanceolate to long-lanceolate leaves, axillary hairs with one or more brown basal cells, basal laminal cells less strongly differentiated from the upper, ventral costal cells usually quadrate (six species have elongate ventral costal cells), laminal papillae absent or simple or only occasionally multiplex, gemmae composed of only 1–10 cells, and peristome teeth seldom long and twisted (see also Saito 1975).

 

KEY TO DIDYMODON IN NORTH AMERICA NORTH OF MEXICO

 

1. Leaf apices caducous or very fragile.

2. Leaf apices not swollen, usually evenly narrowing.

3. Cells of leaf apex smooth...... 1. Didymodon rigidulus (var. icmadophilus)

3. Cells of leaf apex weakly conic-mamillose.......... 14. Didymodon sinuosus

2. Leaf apices apically swollen as a propagulum.

4. Upper laminal cells 13–15 mm wide................... 3. Didymodon johansenii

4. Upper laminal cells 8–10 mm wide............. 2. Didymodon anserinocapitatus

1. Leaf apices intact or only occasionally broken.

5. Plants in nature red- to black-brown, leaves not keeled, not highly recurved, margins finely crenulate by bulging cell walls, usually plane above midleaf, costa thin, 2–3 cells wide above midleaf, laminal papillae absent or low, massive and lens-shaped.

6. Leaves dimorphic: cochleariform, epapillose leaves present on fragile branchlets or portions of some stems................................ 9. Didymodon subandreaeoides

6. Leaves monomorphic.

7. Plants often fruiting, leaf apices acute, propagula absent 7. Didymodon nigrescens

7. Plants sterile, leaf apices obtuse, clusters of unicellular propagula in the leaf axils.................................... 8. Didymodon perobtusus

5. Plants without the above exact combination of characters, usually green, orange or red, sometimes keeled or highly recurved, margins usually entire or dentate, often recurved above midleaf, costa usually broad, of 2–4 or more cells wide above midleaf, laminal papillae seldom absent or massive and lens-shape.

8. Costa with elongate superficial ventral cells.

9. Leaf base auriculate or weakly winged at insertion, apex often whip-like, very long-acuminate...................................... 18. Didymodon leskeoides

9. Leaf base gradually or quickly narrowed to the insertion, not flaring, apex obtuse to acuminate.

10. Leaves ovate to long-elliptical, apex often obtuse, costa often ending before the apex........................... 21. Didymodon tophaceus

10. Leaves short- to long-lanceolate, apex always acute, costa subpercurrent to short-excurrent.

11. Plants with axillary gemmae, leaves mostly 0.9–1.1 mm long, catenulate when dry........................................... 17. Didymodon michiganensis

11. Plants lacking gemmae in leaf axils, leaves usually 1.2–5.0 mm long, appressed-incurved to weakly spreading when dry.

12. Leaves when moist spreading to weakly recurved, usually lying flat, costa usually distinctly widened at base.

13. Leaves 0.8–1.7(–2.5) mm, acuminate, upper cell walls little thickened or irregularly thickened and lumens angular, trigones absent or weakly developed................. 15. Didymodon fallax

13. Leaves usually 2.0(–3.5) mm, upper cell walls irregularly thickened and trigonous, trigones as large as the lumens or nearly so...................................... 20. Didymodon giganteus

12. Leaves when moist strongly recurved and keeled, lying on their sides, costa little widened at base.

14. Stems to 2.5 cm, leaves usually 0.8–2.0 mm long 16. Didymodon ferrugineus

14. Stems usually more than 3 cm, leaves mostly 2.0–2.5 mm long 19. Didymodon maximus

8. Costa with quadrate or occasionally short-rectangular superficial ventral cells, or, if elongate, then upper laminal cells bistratose.

15. Leaves ventrally with a narrow medial channel about the width of the costa at least at leaf apex, apex mostly apiculate by one or more conical cells, costa usually percurrent, margins usually recurved, often to near the apex, laminal color reaction to KOH usually brick-red, occasionally orange.

16. Entire leaf strongly both reflexed backwards and strongly keeled when moist, papillae when present simple, stem central strand usually absent 22. Didymodon asperifolius

16. Entire leaf spreading to weakly reflexed backwards and weakly keeled when moist, papillae when present bifid to multiplex, stem central strand present.

17. Leaves deltoid to short-lanceolate, to 1.5 or rarely to 2.0 mm long, margins recurved or revolute to near apex, propagula sometimes present.

18. Costa often with an apical conical cell, costa gradually narrowing distally, ventral surface nearly flat and not forming a wide pad of cells (but costa occasionally thickened and bulging ventrally), guide cells in 1 layer, leaf margins recurved to tightly revolute, gemmae often present in leaf axils

......................................... 12. Didymodon brachyphyllus

18. Costa usually lacking an apical conical cell, costa wider at midleaf than below, with bulging ventral surface forming a long-elliptical unistratose pad of cells, guide cells in 2(–3)  layers, leaf margins loosely revolute, tubers occasional on basal rhizoids .................................. 13. Didymodon nevadensis

17. Leaves short- to long-lanceolate or long-triangular, to 4.0 mm long, margins recurved near base or up to lower 2/3 of leaf, propagula rare.

19. Leaves long-ovate to broadly lanceolate, apex blunt to broadly acute, upper marginal cells bistratose marginally, throughout or or occasionally in patches, laminal color reaction to KOH deep yellow or orange-brown to red-brown  ................ 11. Didymodon nicholsonii

19. Leaves triangular to narrowly lanceolate, apex narrowly acute, upper marginal cells unistratose or occasionally bistratose in patches, laminal color reaction to KOH deep red to red-brown ............................................. 10. Didymodon vinealis

15. Leaves ventrally very widely channeled medially or merely slightly concave across leaf, apex seldom apiculate by a conical cell, costa percurrent or excurrent as a multicellular, stout mucro, margins plane to recurved below midleaf, laminal color reaction to KOH usually negative, yellow or orange, seldom brick-red.

20. Axillary gemmae present.

21. Propagula all multicellular, leaf apex acute 1. Didymodon rigidulus (var. rigidulus)

21. Propagula mostly unicellular, leaf apex broadly obtuse.

22. Costa narrow, usually 2 cells wide at midleaf, not strongly spurred ................................... 8. Didymodon perobtusus

22. Costa broad, 4–6 cells wide at midleaf and often strongly spurred by rows of lateral cells ending abruptly in the lamina 6. Didymodon revolutus

20. Axillary gemmae absent.

23. Upper lamina unistratose or occasionally bistratose in small patches.

24. Plants flagellate, leaves strongly appressed when dry, linear-lanceolate, costa long-excurrent

.......................... 1. Didymodon rigidulus (var. ditrichoides)

24. Plants not flagellate, leaves appressed-incurved to weakly twisted and weakly spreading when dry, short- to long-lanceolate, costa short- to long-excurrent.

25. Leaf base rectangular and gradually widened, costa short-excurrent, unbroken, basal leaf cells short-rectangular 1. Didymodon rigidulus (var. gracilis)

25. Leaf base ovate and often abruptly widened, costa long-excurrent, often fragile, basal leaf cells quadrate 1. Didymodon rigidulus (var. icmadophilus)

23. Upper lamina bistratose totally or just along margins.

25. Upper lamina entirely bistratose 1. Didymodon rigidulus (var. subulatus)

25. Upper lamina bistratose along margins.

26. Basal laminal cells with firm, weakly to strongly thickened walls, differentiated usually only medially.

27. Leaves long-ligulate to lanceolate 1. D. rigidulus (var. rigidulus)

27. Leaves short-ovate........................... 6. D. revolutus

26. Basal laminal cells thin-walled and usually somewhat inflated,  often bulging-rectangular, differentiated across leaf base.

28. Leaves long-lanceolate, usually smooth or weakly papillose, marginal basal cells narrowly rectangular in 2–4 rows, ventral superficial cells of costa usually elongate, stem with hyalodermis............................. 5. Didymodon umbrosus

28. Leaves short-lanceolate, smooth to strongly papillose, marginal basal cells not or weakly differentiated from the medial, ventral superficial cells of costa quadrate, stem lacking hyalodermis or this weakly differentiated.. 4. D. australasiae

 

1. Didymodon rigidulus Hedw., Sp. Musc. 104. 1801.

 

Barbula acuta var. bescherellei (Sauerb. ex Jaeg. & Sauerb.) Crum; Barbula bescherellei Sauerb. in Jaeg.; Barbula rigidula (Hedw.) Mild.; Barbula valida (Limpr.) Möll.; Barbula waghornei Kindb.; Didymodon fuscoviridis Card.; Didymodon mexicanus Besch.; Didymodon rigidulus subsp. validus (Limpr.) Loeske; Didymodon rigidulus var. validus (Limpr.) R. Düll; Tortula rigidula (Hedw.) Lindb.; Tricho­stomum rigidulum (Hedw.) Turn.

 

The species s. lat., as emended by Zander (1981) is polymorphic, with several varieties distinguished by fairly good correlations of combinations of characters. Speci­mens of intermediate morphology that are not clearly assignable to any one variety may be identified as D. rigidulus s. lat. Although some authors use the presence of axillary gemmae as diagnostic of the typical variety, the other varieties, notably var. gracilis, may occasionally have such. These gemmae are also found in other species, especially those of the D. vinealis complex, which may likewise have a bistratose upper lamina, e.g., D. vinealis itself may have bistratose upper laminal cells, and should be carefully distinguished. From D. vinealis, this species may be distinguished by the combination of long-triangular or oblong-lanceolate leaf shape, usual presence of many gemmae in the leaf axils and the commonly yellow-green color in nature (sometimes blackish green, rarely reddish below) and yellow or yellow-orange color in KOH.

 

KEY TO VARIETIES OF DIDYMODON RIGIDULUS

 

1. Upper lamina entirely bistratose...1b. Didymodon rigidulus var. subulatus

1. Upper lamina unistratose or bistratose only at the extreme leaf apex or on the margins.

2. Leaves oblong-lanceolate to long-triangular; costa usually short-excurrent and blunt; apex and upper margins generally bistratose; gemmae often present .............

1a. Didymodon rigidulus var. rigidulus

2. Leaves lanceolate; costa percurrent to long-excurrent, usually sharp; upper margins unistratose or less commonly bistratose in patches; gemmae usually absent.

3. Plants flagellate, leaves strongly appressed when dry, linear-lanceolate, costa long-excurrent................... 1c. Didymodon rigidulus var. ditrichoides

3. Plants thickly leaves, leaves appressed to spreading when dry, short-lanceolate to long-lanceolate; costa percurrent to long-excurrent.

4. Leaves short- to long-lanceolate; base evenly broadened, square or rectangular; costa percurrent to long-excurrent as a rigid subula; upper cells generally papillose, oval or rounded-quadrate; basal cells short-rect­angular; gemmae occasionally present........... 1d. Didymodon rigidulus var. gracilis

4. Leaves long-lanceolate; base abruptly broadened, ovate; costa long-excurrent as a straight or flexuose, often fragile subula; upper cells usually smooth, lumens usually angular, basal cells usually quadrate; gemmae very rare 1e. Didymodon rigidulus var. icmadophilus

 

1a. Didymodon rigidulus Hedw. var. rigidulus

 

Didymodon rigidulus var. rigidulus is relatively uniform in eastern North America, with slightly spreading, oblong-lanceolate to long-triangular leaves with thickened upper margins, percurrent or short-excurrent costa, thick-walled cells, gemmae usually present, and the peristome straight or only weakly twisted (var. gracilis and var. icmadophilus sometimes have long peristomes which are somewhat twisted). When the upper margins are not bistratose or are only slightly so, it can be difficult to identify, especially as it may occasionally have the costal groove of D. vinealis. It intergrades in the West with the other varieties, and propagula are less common. The typical variety, with distinctive oblong-lanceolate leaf shape and propagula, is rare in the Arctic.

 

1b. Didymodon rigidulus var. subulatus (Thér. & Bartr.) Zand., Cryptogamie, Bryol. Lichénol. 2: 395. 1981.

 

Didymodon mexicanus var. subulatus Thér. & Bartr. ex Bartr., Bryologist 29: 1. 1926.

 

This variety is similar to var. icmadophilus in leaf shape and most other characters, and intergrades occur. It may be regarded as a somewhat distinctive geographical variant.

 

1c. Didymodon rigidulus var. ditrichoides (Broth.) Zand., Phytologia 41: 20. 1978.

 

Barbula ditrichoides Broth., Sitzungsb. Akad. Wiss. Wien Math. Nat. Kl. 133: 566. 1924; Didymodon acutus var. ditrichoides (Broth.) Zand.

 

The var. ditrichoides is a highly reduced, flagellate form of the var. icmadophilus but has a distinctive appearance. It is disjunct from montane China (Chen 1941). The olive coloration and general appearance is similar to that of D. leskeoides but the plant is somewhat smaller and the alar auricles are lacking.

 

1d. Didymodon rigidulus var. gracilis (Hook. & Grev.) Zand., Cryptogamie, Bryol. Lichénol. 2: 393. 1981.

 

Tortula gracilis Hook. & Grev., Edinburgh J. Sci. 1:300. 1824; Barbula acuta (Brid.) Brid.; Didymodon acutus (Brid.) Saito; Tortula acuta Brid.

 

The var. gracilis may sometimes have gemmae and the upper lamina is sometimes bistratose in patches, but it differs from var. rigidulus most clearly its the short- to long-lanceolate leaves. The upper laminal cells are commonly papillose, and their lumens are oval or rounded-quadrate. Because of intergradation, some collections must be assigned to this variety only on the basis of a majority of the characters given in the key. Problems involving synonymy of heterotypic type specimens that cannot be confidently assigned to any infraspecific taxon are discussed by Zander (1981). Although leaves in this variety are short in dry habitats—in the lower range for the species, which commonly causes the stems to appear filiform—leaf length in collections from moist environments may be in the upper range.

 

1e. Didymodon rigidulus var. icmadophilus (C. Müll.) Zand., Cryptogamie, Bryol. Lichénol. 2: 394. 1981.

 

Barbula icmadophila C. Müll., Syn. Musc. 1: 614. 1849; Barbula acuta subsp. icmadophila (C. Müll.) Amann; Barbula acuta var. icmadophila (C. Müll.) Crum; Barbula acuta ssp. icmadophila (C. Müll.) Podp.; Barbula gracilis ssp. icmadophila (C. Müll.) Amann; Barbula grailis var. icmadophila (C. Müll.) Moenk.; Didymodon acutus var. icmadophilus (C. Müll.) Zand.; Didymodon icmadophilus C. Müll.) Saito as “icmadophyllus”; Tortula icmadophila (C. Müll.) Lindb.

 

This taxon is similar to var. gracilis in general aspect but the leaf apices are usually hairlike, the upper laminal cells are usually smooth and their lumens usually angular. Var. icmadophilus is common on the North American Plains, where it may occur in association with D. fallax. The var. icmadophilus is dark green, sometimes with a blue-black cast, and has boat-shaped, elon­gate, erect leaves that are only slightly incurved when dry, laminal cells smooth and costa excurrent and often flexuose. Didymodon fallax has light green to reddish green color and triangular leaves that are often incurved or even catenulate when dry, costa percurrent and leaves papillose.

 

2. Didymodon anserinocapitatus (X.-j. Li) Zand., Bull. Buffalo Soc. Nat. Sci. 32: 162. 1993.

 

Barbula anserinocapitata X.-j. Li, Acta Bot. Yunnan. 3: 103, 1981.

 

This rare Asian species is known from only two sites in the New World: Colorado (Freemont Co., 4.5 km up lower portion of Phantom Canyon, 1500–2200 m elev., red-sandstone cliff, Weber, Herman & Feddema, 1 June 1971, herb. no. B-37528, COLO), and New Mexico (San Miguel Co., Pecos, along Pecos River, 2100 m elev., Richards & Drouet 456, 21 Oct. 1939, DUKE). It differs from D. johansenii mainly by the smaller upper laminal cells and the double layer of guide cells, with the appearance of a robust D. rigidulus var. icmadophilus, which differs, however, by leaf apices never swollen though sometimes fragile. Details were reported by Zander and Weber (1997).

 

3. Didymodon johansenii (Williams) Crum, Canad. Field-Nat. 83: 157. 1969.

 

Barbula johansenii Williams, Rep. Canad. Arctic Exped. 1913–18, Bot. 4E: 4. 1921.

 

Distinctive characters of this Arctic species are the striate peristome teeth, deciduous, clavate leaf apex and large, trigonous laminal cells. Most collections of D. johansenii have truncate leaves, with the propaguliform apex fallen in all but the most immature leaves; the leaves are oblong-lanceolate. Some specimens (e.g., Northwest Territories, Scotter 22404, MICH) of this species, however, approach D. ridigulus var. icmadophilus in the green color, ovate leaf base, not much widened or tapering and apparently non-deciduous leaf apices. These collections can be rightly placed by the presence of claviform apices in at least some leaves (especially those near an inflorescence) and the large upper laminal cells, which often have trigones. Didymodon nigrescens has fragile, clavate tips to its perichaetial leaves, but the crenulate upper leaf margins and very thin costa will distinguish it.

 

4. Didymodon australasiae (Hook. & Grev.) Zand., Phytologia 41: 21. 1978.

 

Tortula australasiae Hook. & Grev., Edinburgh J. Sci. 1: 301. 1824; Didymodon diaphanobasis Card.; Didymodon diaphanobasis var. angustifolius Thér. in Bartr.; Didymodon torquescens Card.; Husnotiella torquescens (Card.) Bartr.; Tricho­stomopsis australasiae (Hook & Grev.) Robins.; Tricho­stomopsis brevifolia Bartr.; Tricho­stomopsis crispifolia Card.; Tricho­stomopsis diaphanobasis (Card.) Grout; Tricho­stomopsis fayae Grout

 

In Didymodon, hydroids are found only in the costae of D. australasiae, D. umbrosus, D. revolutus and D. vinealis. The ventral stereid band usually absent in well developed specimens of the first three species, and is often absent in the fourth. Intergrades exist between D. australasiae and D. umbrosus, but the extreme forms are common and quite distinctive.

 

5. Didymodon umbrosus (C. Müll.) Zand., Phytologia 41: 22. 1978.

 

Barbula umbrosa C. Müll., Linnaea 42: 340. 1879; Didymodon australasiae var. umbrosus (C. Müll.) Zand.; Tricho­stomopsis crispifolia Card.; Tricho­stomopsis umbrosa (C. Müll.) Robins.

 

This species is one of a number of mundivagant taxa the distribution of which is associated with human activities (e.g., Eckel 1986). The transversely slit basal cells are distinctive in many specimens though also found in taxa of the Dicranaceae (Zander & Cleef 1982).

 

6. Didymodon revolutus (Card.) Williams, Bryologist 16: 25. 1922.

 

Husnotiella revoluta Card., Rev. Bryol. 36:71. 1909; Husnotiella revoluta var. palmeri (Card.) Thér.

 

Distinctive characters in combination are: arid habitat, ovate leaves with often revolute margins, subpercurrent, strongly spurred costa (with one or more lateral costal cells wending into the lamina), one layer of guide cells, and a rudimentary or absent peristome. Like D. perobtusus and Bryoerythrophyllum calcareum (Thér.) Zand., D. revolutus has unicellular gemmae occasionally present in the leaf axils.

 

7. Didymodon nigrescens (Mitt.) Saito, J. Hattori Bot. Lab. 39: 510. 1975.

 

Barbula nigrescens Mitt., J. Linn. Soc. Bot. Suppl. 1: 36. 1859; Barbula rufofusca Lawt. & Herm.

 

The specimens cited from the Firth River Basin by Steere (1978), det. R. Zander, are actually D. subandreaeoides. The distinguishing characters of D. nigrescens are the blackish coloration when dry (red in KOH), thin costa, and upper laminal margins minutely crenulate by the small, bulging marginal cells. This and the following two species appear to be closely related. Didymodon asperifolius is similar but may be distinguished by its longer leaves, straight or reflexed to strongly recurved when wet, upper margins recurved, upper laminal cells larger, 10–13 mm wide, epapillose or papillae simple, and costa usually comparatively wide.

 

8. Didymodon perobtusus Broth., Rev. Bryol. n. ser. 2: 1. 1929.

 

Barbula perobtusa (Broth.) Chen.

 

Didymodon perobtusus has several characters in common with D. revolutus (Card.) Williams of the southwestern U.S.A. and Mexico, including leaf and laminal papillae shape and unicellular gemmae borne in dense axillary clusters; however, D. revolutus differs by the strongly recurved to revolute margins, leaf cells with thin, light yellow walls, and gemmiferous plants uncommon. Both North American collections seen were from stations in which D. subandreaeoides is also present, growing in separate or occasionally confluent cushions. The taxonomic position of D. perobtusus is not clear. It is placed near D. subandreaeoides because of dark, reddish color, and similarity of areolation and laminal papillae. It may, however, turn out to be related to D. tophaceus, with which it has a certain resemblance.

 

9. Didymodon subandreaeoides (Kindb.) Zand., Phytologia 41: 23. 1978.

 

Barbula subandreaeoides Kindb., Rev. Bryol. 32: 36. 1909; Barbula andreaeoides Kindb.

 

The distribution of D. subandreaeoides is through inland mountain ranges from the North Slope of Alaska south along the Cordillera into Colorado. It is commonly associated with Molendoa sendtneriana (BSG) Limpr. with which it is often mixed in collections, and which apparently has a similar distribution in northwestern North America. The fragile, cochleariform-leaved branchlets may possibly figure in asexual reproduction. Andreaea rothii Web. & Mohr lacking sporophytes may be confused with D. subandreaeoides, but may be distinguished by the former's autoicous inflorescence, its ecostate, oblong perichaetial leaves, leaves monomorphic, cauline leaves plane, cells with bulging but epapillose bright orange walls, bistratose along the upper margins, middle lamellae often evident between basal cells, and costa not sharply distinguished from laminal cells above midleaf.

 

10. Didymodon vinealis (Brid.) Zand., Phytologia 41: 25. 1978.

 

Barbula vinealis Brid., Bryol. Univ. 1: 830. 1827; Barbula bakeri Card. & Thér.; Barbula circinnulata C. Müll. & Kindb; Barbula cylindrica (Tayl.) Schimp. in Boul.; Barbula fallax var. vinealis (Brid.) Hüb.; Barbula flexifolia Hampe; Barbula horridifolia C. Müll. & Kindb.; Barbula laterita Kindb.; Barbula pseudorigidula C. Müll. & Kindb.;