Didymodon australasiae
Didymodon johansenii
johansen's beard moss, johansen's didymodon moss
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 erect-appressed when dry, spreading and not keeled when moist, monomorphic, oblong-lanceolate, adaxially weakly concave across leaf, 0.7–1.1 mm (excluding the deciduous tip) to 2.5 mm whole, base scarcely differentiated in shape, margins recurved at mid leaf, entire, apex thickened, long-cylindric to clavate, seldom a long, filiform excurrency, usually soon deciduous, constricted in places, absent in mature leaves;
costa excurrent, excurrency absent in mature leaves, not much widened or tapering at mid leaf but swollen in excurrency, pad of cells absent, adaxial costal cells elongate at mid leaf but quadrate near apex, 2–4 cells wide at mid leaf, guide cells in 1 layer;
basal laminal cells differentiated medially, walls thin;
distal laminal cells 13–15 µm wide, 1:1, papillae absent, lumens often angular, walls thin to irregularly thickened, weakly convex on both sides, 1-stratose except in deciduous apex.
0.7–1 cm.
0.35–0.50 cm.
1–1.9 mm;
peristome teeth 32, linear, weakly twisted, to 600 µm, occasionally rudimentary.
0.75–1.00 mm;
peristome teeth 16, linear, cleft to near base, straight to weakly twisted, ca. 200 µm.
11–15 µm.
15–18 µm.
asexual reproduction by multicellular tubers on proximal rhizoids.
asexual reproduction by the deciduous leaf apex.
laminal KOH reaction variously negative or yellow- or orange- or red-brown.
laminal KOH reaction red.
Didymodon australasiae
Didymodon johansenii
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.)
Distinctive characters of Didymodon johansenii are the striate peristome teeth, deciduous, clavate leaf apex and large, trigonous laminal cells. Most collections of it lack the propaguliform apex in all but the most immature leaves, and the leaves are oblong-lanceolate. Some specimens (e.g., Northwest Territories: Scotter 22404, MICH), however, approach D. ridigulus var. icmadophilus in the green color, ovate leaf base, and apparently nondeciduous 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 distal laminal cells, which often have trigones. Didymodon nigrescens has fragile, clavate tips to its perichaetial leaves, but the crenulate distal leaf margins and very thin costa will distinguish it.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CalFlora
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
BC
