Didymodon rigidulus var. rigidulus

Synonyms: Barbula waghornei Kindberg Didymodon fuscoviridis Cardot
Treatment appears in FNA Volume 27. Treatment on page 544. Mentioned on page 543, 545.

Stem-leaves appressed to weakly spreading when dry, spreading when moist, oblong-lanceolate, ellipticlanceolate or long-triangular, base not or weakly broadened, oval; costa usually short-excurrent and blunt; proximal cells shortrectangular or quadrate; distal laminal cells smooth to weakly papillose, quadrate, with quadrate lumens, distal lamina 2-stratose at apex or along margins; gemmae often present in distal leaf-axils. Peristome teeth short and straight to very weakly twisted.


Phenology: Capsules mature May–Sep.
Habitat: Calcareous rock, boulders, cliff faces, soil, outcrops, sinks, ledges, tufa
Elevation: low to moderate elevations (60-500 m)

Distribution

V27 776-distribution-map.gif

Greenland, Alta., B.C., N.B., Nfld. and Labr. (Nfld.), N.W.T., N.S., Nunavut, Ont., Que., Yukon, Alaska, Ariz., Colo., Fla., Ill., Iowa, Kans., Mass., Mich., Mo., N.Mex., N.Y., N.Dak., Oreg., Pa., S.Dak., Tex., Va., Wis., Wyo., Mexico, South America, Europe, n Africa

Discussion

Variety rigidulus is relatively uniform in eastern North America, with slightly spreading, oblong-lanceolate to long-triangular leaves with thickened distal margins, percurrent or short-excurrent costa, thick-walled cells, gemmae usually present, and the peristome straight or only weakly twisted. When the distal margins are not 2-stratose or only slightly so, it can be difficult to identify, especially as it may occasionally have the costal groove of D. vinealis, and large specimens may similarly have guide cells in two layers. It intergrades in the West with the other varieties, and propagula are commonly absent. The typical variety, with distinctive oblong-lanceolate leaf shape and propagula, is rare in the Arctic, and though generally hygrophilic may be found on merely moist substates in southern states. From D. vinealis in the narrow sense, this variety may be distinguished by the combination of stiff, long-triangular or oblong-lanceolate leaves, usual presence of many gemmae in the leaf axils and the commonly yellow-green color in water (sometimes blackish green, rarely reddish below) and yellow or yellow-orange color in KOH. Commonly misidentified as this variety is the western D. tectorum, which also has axillary gemmae, but differs by the costa narrowly excurrent from a blunt leaf apex, and a rectangular (not elliptical) leaf base.

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.

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 +
Acute (?) +  and Subulate (?) +
Richard H. Zander +
Hedwig +
weak +  and strong +
ovate +  and crescent--shaped +
papillose +  and smooth +
usually slightly wider +
differentiated +
broadened +
Pottiaceae tribe Barbuleae +
obovoid +
cucullate +
stegocarpous +
0.1 cm1 mm <br />0.001 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
monoicous +, dioicous +  and sexual +
flat to bulging +
thin;thick +
1 (?) +  and 10 (?) +
hexagonal +
differentiated +
tomentose +  and bare +
short-excurrent +
widened +
quadrate +  and rectangular +
smooth +  and weakly papillose +
occasionally weakly dentate or crenulate +  and entire +
subquadrate;hexagonal or rounded-angular occasionally shortly rectangular or rhomboid +
Greenland +, Alta. +, B.C. +, N.B. +, Nfld. and Labr. (Nfld.) +, N.W.T. +, N.S. +, Nunavut +, Ont. +, Que. +, Yukon +, Alaska +, Ariz. +, Colo. +, Fla. +, Ill. +, Iowa +, Kans. +, Mass. +, Mich. +, Mo. +, N.Mex. +, N.Y. +, N.Dak. +, Oreg. +, Pa. +, S.Dak. +, Tex. +, Va. +, Wis. +, Wyo. +, Mexico +, South America +, Europe +  and n Africa +
low to moderate elevations (60-500 m) +
differentiated +
multicellular +
occasional +
Ovate (?) +  and Elliptic (?) +
Calcareous rock, boulders, cliff faces, soil, outcrops, sinks, ledges, tufa +
yellow +  and orange-red or red +
long-ligulate +  and monomorphic +
0.17 cm1.7 mm <br />0.0017 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.17 cm1.7 mm <br />0.0017 m <br />) +
not +, spreading +, appressed-incurved +  and weakly spreading +
channeled;ovatelanceolate;keeled +
ovate +, keeled +  and curled +
reduced +
specialized +
dioicous +  and sexual +
quadrate +
short-conic;long-conic +
photosynthetic +
lateral +  and terminal +
lateral +  and terminal +
red-orange +  and yellow +
0-740 um +  and rudimentary +
0-740 um +  and occasionally absent +
0-740 um-triangular +  and long-triangular +
Capsules mature May–Sep. +
1 (?) +  and 2 (?) +
Sp. Musc. Frond., +
straight +
yellowish;reddish-brown +
elongate +
0.7 cm7 mm <br />0.007 m <br /> (1.7 cm17 mm <br />0.017 m <br />) +
2 +  and 1 +
yellow +, red-orange +, red +  and laminal +
spreading;appressed;weakly spreading +
long-triangular +  and oblong-lanceolate +
rounded-triangular +  and rounded-pentagonal +
0 cm0 mm <br />0 m <br /> (2 cm20 mm <br />0.02 m <br />) +
Barbula waghornei +  and Didymodon fuscoviridis +
Didymodon rigidulus var. rigidulus +
Didymodon rigidulus +
variety +
elliptic;cylindric +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
rudimentary +
red +  and yellow +
specialized +
thin +  and evenly thickened +
stemless +  and perigoniate +