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Habit Plants usually blackish green. Plants green to dark green, usually with a reddish cast.
Stem(s)

leaves spreading-incurved and twisted to incurved-appressed when dry, spreading to spreading-recurved and not keeled when moist, monomorphic, short-lanceolate or sometimes short-ovate to long-elliptic, broadly concave adaxially across leaf, usually 1–2.5 mm, base scarcely differentiated in shape to ovate, margins usually recurved at mid leaf, entire, apex broadly acute or occasionally narrowly so, not fragile;

costa percurrent or ending a few cells below the apex, broader at mid leaf, occasionally weakly spurred, with a low adaxial pad of cells, adaxial costal cells quadrate, 4–6 cells wide at mid leaf, guide cells in 1–2 layers;

basal laminal cells differentiated medially or across leaf, quadrate to short-rectangular, walls very thin and not perforated;

distal laminal cells 7–12 wide, 1:1 or occasionally transversely elongate below, papillae usually distinct, low or simple to 2-fid, occasionally absent, lumens oval to rounded-quadrate, walls thin to evenly thickened, convex on both sides of lamina, 2-stratose in one or more rows along margins.

leaves appressed to weakly spreading when dry, spreading but stiff and not keeled when moist, monomorphic, ovate to ovate-lanceolate, grooved adaxially along the costa, often cucullate near leaf apex, 0.7–1 mm, base scarcely differentiated to ovate in shape, margins weakly recurved to near apex of leaf, entire, apex broadly acute or blunt, not fragile, often ending in 1–3 celled apiculus;

costa ending shortly before the apex or percurrent, seldom weakly excurrent, often weakly spurred, little widened towards apex, little tapering, sometimes rather thick and bulging adaxially, lacking an adaxial thin-walled pad of cells or this poorly developed, adaxial costal cells quadrate to short-rectangular, 4(–6) cells wide at mid leaf, guide cells in 1(–2) layers;

basal laminal cells differentiated medially or across the leaf, walls mostly thin, quadrate to short-rectangular, not perforated;

distal laminal cells 7–10 µm wide, 1:1, nearly smooth or papillae simple or 2-fid, 2–3 per lumen, lumens quadrate or rounded-quadrate, walls somewhat thickened, weakly convex on both sides of lamina, distal leaf margins 1-stratose or occasionally 2-stratose in patches.

Seta

0.7–1 cm.

0.8–1 cm.

Capsule

1–1.9 mm;

peristome teeth 32, linear, weakly twisted, to 600 µm, occasionally rudimentary.

1.5–2.5 mm;

peristome teeth rudimentary or 32, linear, twisted 1/2, 200–250 µm, delicate and commonly coming off with the operculum.

Spores

11–15 µm.

10–13 µm.

Specialized

asexual reproduction by multicellular tubers on proximal rhizoids.

asexual reproduction by axillary, multicellular gemmae.

Distal

laminal KOH reaction variously negative or yellow- or orange- or red-brown.

laminal KOH reaction yellow- or red-brown.

Didymodon australasiae

Didymodon brachyphyllus

Phenology Capsules mature winter–spring. Capsules mature spring–fall.
Habitat Soil, gypsum, acid rock, ledges, sandstone, silt Soil, limestone, lava, mortar, steppe, road banks, near spring, streamside, arid grassland, soil over lava, sandstone cliffs
Elevation moderate to high elevations (300-2000 m) (moderate to high elevations (1000-6600 ft)) low to high elevations (80-2300 m) (low to high elevations (300-7500 ft))
Distribution
from FNA
AZ; CA; CO; NM; NV; OR; TX; Mexico; Central America; South America; Europe; n Africa; s Africa; Pacific Islands (New Zealand); Australia
from FNA
AK; AZ; CA; CO; ID; MT; NM; OR; UT; WA; BC; Mexico; Greenland; Atlantic Islands (Iceland); Antarctica
Discussion

In North American Didymodon, hydroids are found in the costae of D. anserinocapitatus, D. australasiae, D. nevadensis, D. norrisii, D. umbrosus, D. revolutus, and D. vinealis, and in these species the adaxial stereid band is usually absent in well developed specimens. Intergrades exist between D. australasiae and D. umbrosus, but the extreme forms are common and quite distinctive.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

A largely arid land species, Didymodon brachyphyllus, has an ovate leaf shape, margins only moderately recurved, and costa ending before the apex, which may terminate in a small conical cell or apiculus. Propagula are not always produced. Although the KOH reaction is commonly red, it may be yellow but not negative, as in D. tectorum. Didymodon luridus Sprengel (see R. H. Zander 1978e) does not occur in the flora area, though reported from there by many authors (often as D. trifarius, see Zander 1981). It differs in the triangular leaves and the smooth, more homogeneous and smaller distal laminal cells, 6–9 µm. American collections identified as this species are commonly actually D. brachyphyllus, D. nicholsonii, D. tophaceus, or D. vinealis. Small forms of D. nicholsonii have the leaf shape of D. brachyphyllus but the lamina is 2-stratose. Sterile Grimmia species are similar, but a small hyaline apex is commonly found on at least some Grimmia leaves. Small forms of D. vinealis may be confused with D. brachyphyllus but the latter never has lanceolate leaves, and its perichaetial leaves are also short and rather deltoid. Didymodon tectorum is similar but has larger leaves, usually green in nature, broadly rectangular leaf base, and an excurrent costa. Didymodon revolutus is similar but has unicellular gemmae. The exsiccat N. Amer. Musci Perf. 404, distributed by A. J. Grout as Husnotiella torquescens, is D. brachyphyllus with operculate sporophytes having rudimentary peristomes.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 27, p. 547. FNA vol. 27, p. 554.
Parent taxa Pottiaceae > subfam. Barbuloideae > Didymodon Pottiaceae > subfam. Barbuloideae > Didymodon
Sibling taxa
D. anserinocapitatus, D. asperifolius, D. bistratosus, D. brachyphyllus, D. eckeliae, D. fallax, D. ferrugineus, D. giganteus, D. johansenii, D. leskeoides, D. maschalogena, D. maximus, D. murrayae, D. nevadensis, D. nicholsonii, D. nigrescens, D. norrisii, D. perobtusus, D. revolutus, D. rigidulus, D. subandreaeoides, D. tectorum, D. tophaceus, D. umbrosus, D. vinealis
D. anserinocapitatus, D. asperifolius, D. australasiae, D. bistratosus, D. eckeliae, D. fallax, D. ferrugineus, D. giganteus, D. johansenii, D. leskeoides, D. maschalogena, D. maximus, D. murrayae, D. nevadensis, D. nicholsonii, D. nigrescens, D. norrisii, D. perobtusus, D. revolutus, D. rigidulus, D. subandreaeoides, D. tectorum, D. tophaceus, D. umbrosus, D. vinealis
Synonyms Tortula australasiae, D. diaphanobasis, Husnotiella torquescens, Trichostomopsis australasiae, Trichostomopsis brevifolia, Trichostomopsis diaphanobasis, Trichostomopsis fayae Barbula brachyphylla, Barbula olivacea, D. reedii, D. vinealis var. brachyphyllus
Name authority (Hooker & Greville) R. H. Zander: Phytologia 41: 21. (1978) (Sullivant) R. H. Zander: Phytologia 41: 24. (1978)
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