Didymodon revolutus

(Cardot) R. S. Williams

Bryologist 16: 25. 1922,.

Basionym: Husnotiella revoluta Cardot Rev. Bryol. 36: 71. 1909
Synonyms: Husnotiella revoluta var. palmeri (Cardot) Thériot
Treatment appears in FNA Volume 27. Treatment on page 548. Mentioned on page 539, 542, 543, 547, 549, 554, 567.

Plants usually green to blackish green. Stems to 0.6 cm, central strand present. Stem-leaves appressed, imbricated, incurved when dry, widely spreading and not keeled when moist, monomorphic, ovate to elliptical, broadly concave adaxially across leaf, usually 0.4–1 (–2) mm, base scarcely differentiated in shape, margins usually recurved to revolute to near apex but sometimes plane, entire, apex obtuse to rounded, often strongly cucullate, not fragile; costa percurrent or ending a 2–6 cells below the apex, slightly broader at mid leaf, usually strongly spurred, little tapering, with a low adaxial pad of cells, adaxial costal cells quadrate, (4–) 6–8 cells wide at mid leaf, guide cells in 1 layer; basal laminal cells differentiated somewhat medially or across leaf, walls weakly thickened or thin, rectangular, not perforated; distal laminal cells 7–10 wide, 1: 1, papillae absent or low, simple or 1 multiplex, rather flat papilla per lumen, lumens oval to roundedquadrate, walls convex on both sides of lamina, 1-stratose or occasionally 2-stratose in patches. Specialized asexual reproduction rare, by unicellular gemmae in masses in leaf-axils. Seta 0.4–0.9 cm. Capsule 0.7–1.5 mm; peristome teeth absent to rudimentary, irregularly ligulate, to 65 µm. Spores 9–11 µm. Distal laminal KOH reaction light-brown to medium orangebrown.


Phenology: Capsule maturity not determined.
Habitat: Seep, sandstone outcrop, cliffs, associated with prairie grasses
Elevation: low to moderate elevations (100-1500 m)

Distribution

V27 785-distribution-map.gif

Ariz., Calif., Mo., N.Mex., Okla., Tex., Mexico, Central America, South America, Asia (Yemen)

Discussion

Distinctive characters of Didymodon revolutus 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 rudimentary or absent peristome. Like Didymodon perobtusus and Bryoerythrophyllum calcareum, D. revolutus has unicellular gemmae occasionally present in the leaf axils; the similar D. brachyphyllus has multicellular gemmae, has ovate to short-lanceolate leaves that lack hydroids in the costa, and have laminal cell lumens that are quadrate or angled. In an Arizona collection (E. B. Bartram 1688, Musci Acroc. Bor.-Amer. Eur. 642, NY), D. brachyphyllus and D. revolutus were mixed, though easily separated by the above characters.

Selected References

None.

Lower Taxa

None.

"um" is not declared as a valid unit of measurement for this property."um" is not declared as a valid unit of measurement for this property.

... more about "Didymodon revolutus"
quadrate +  and elongate +
0.3 cm3 mm <br />0.003 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
channeled +, concave +  and long-triangular +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
of 1-2 rows +  and differentiated +
long-excurrent +  and short-excurrent +
not fragile +
Cucullate (?) +, Obtuse (?) +  and Rounded (?) +
Richard H. Zander +
(Cardot) R. S. Williams +
weak +  and strong +
ovate +  and crescent--shaped +
papillose +  and smooth +
across leaf +  and differentiated +
usually slightly wider +
differentiated +
differentiated +
Husnotiella revoluta +
obovoid +
cucullate +
stegocarpous +
0.07 cm0.7 mm <br />7.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
monoicous +, dioicous +  and sexual +
flat to bulging +
thin;thick +
1 (?) +  and 10 (?) +
hexagonal +
tomentose +  and bare +
ending a 2-6 cells +  and percurrent +
tapering +
broader +
quadrate +  and rectangular +
occasionally weakly dentate or crenulate +  and entire +
subquadrate;hexagonal or rounded-angular occasionally shortly rectangular or rhomboid +
Ariz. +, Calif. +, Mo. +, N.Mex. +, Okla. +, Tex. +, Mexico +, Central America +, South America +  and Asia (Yemen) +
low to moderate elevations (100-1500 m) +
differentiated +
Seep, sandstone outcrop, cliffs, associated with prairie grasses +
yellow +  and orange-red or red +
0.1 cm1 mm <br />0.001 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
spreading +  and incurved +
concave;ovate;elliptical +
ovate +, keeled +  and curled +
reduced +
specialized +
dioicous +  and sexual +
oval +  and roundedquadrate +
short-conic;long-conic +
photosynthetic +
lateral +  and terminal +
lateral +  and terminal +
red +, orange +  and yellow +
oblong +  and linear or long-triangular +
Capsule maturity not determined. +
1 (?) +  and 2 (?) +
straight +
yellowish;reddish-brown +
elongate +
0.4 cm4 mm <br />0.004 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
2 +  and 1 +
light-brown +  and medium orangebrown +
rounded-triangular +  and rounded-pentagonal +
0 cm0 mm <br />0 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
Husnotiella revoluta var. palmeri +
Didymodon revolutus +
Didymodon +
species +
elliptic;cylindric +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
rudimentary +
2-stratose +, 1-stratose +  and not perforated +
red +  and yellow +
specialized +
convex +  and rectangular +
thin +  and thickened +
stemless +  and perigoniate +
usually green;blackish green +