Didymodon tectorum

(Müller Hal.) K. Saito

J. Hattori Bot. Lab. 39: 516. 1975,.

Basionym: Barbula tectorum Müller Hal. Nuov. Giorn. Bot. Ital., n. s. 3: 101. 1896
Treatment appears in FNA Volume 27. Treatment on page 554. Mentioned on page 542, 544, 555.

Plants green to dark green, without a reddish cast. Stems to 2 cm, central strand present. Stem-leaves appressed to weakly spreading when dry, spreading but stiff and not keeled when moist, monomorphic, deltoid to deltoid-lanceolate, grooved adaxially along the costa, especially near leaf apex, 1–1.5 (–2) mm, base squared in shape, margins strongly recurved or revolute to near apex of leaf, entire, apex narrowly obtuse, not fragile, commonly ending in a mucro; costa short-excurrent as a several-celled blunt mucro, not strongly spurred, little widened toward apex, little tapering, sometimes rather thick and bulging adaxially, lacking a adaxial thin-walled pad of cells or this poorly developed, adaxial costal cells quadrate to shortrectangular, 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 shortrectangular, 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 roundedquadrate, walls weakly convex on both sides of lamina, distal leaf margins 1-stratose or occasionally 2-stratose in patches. Specialized asexual reproduction by axillary, multicellular gemmae. Seta 0.8–1 cm. Capsule 1.5–2.5 mm; peristome teeth 32, linear, twisted 1/2 to once, to 1300 µm. Spores 11–12 µm. Distal laminal KOH reaction negative or weakly red.


Habitat: Limestone shales, riverside, dry shaded rocks, granite cliffs and ledges, north-facing bluff
Elevation: low to high elevations (100-2200 m)

Distribution

V27 796-distribution-map.gif

Colo., Kans., Md., N.Mex., Asia (China), Asia (Japan)

Discussion

Although Didymodon brachyphyllus may occasionally lack the usual dense reddish cast in nature or even with KOH, D. tectorum is always green in nature (though weakly red-brown proximally) (R. H. Zander and R. Ochyra 2001). Didymodon luridus Hornschuch of Europe is similar but does not have the squared leaf base, is evenly narrowed to the mucro, and has leaf cells that are smooth or nearly so. The lanceolate leaves of D. vinealis distinguish it from this species though small plants rarely may have gemmae. One collection (New Mexico: E. B. Bartram 99, US) is similar in its stout costa to European material of D. cordatus Juratska. The cells on the adaxial surface of the costa are elongate in some European plants of D. cordatus but quadrate in others in the same collection.

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 tectorum"
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 +
Richard H. Zander +
(Müller Hal.) K. Saito +
weak +  and strong +
ovate +  and crescent--shaped +
papillose +  and smooth +
across the leaf +  and differentiated +
usually slightly wider +
squared +
differentiated +
Barbula tectorum +
obovoid +
cucullate +
stegocarpous +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
monoicous +, dioicous +  and sexual +
flat to bulging +
thin;thick +
1 (?) +  and 10 (?) +
hexagonal +
tomentose +  and bare +
short-excurrent +
tapering +
thick +  and widened +
quadrate +  and rectangular +
occasionally weakly dentate or crenulate +  and entire +
subquadrate;hexagonal or rounded-angular occasionally shortly rectangular or rhomboid +
Colo. +, Kans. +, Md. +, N.Mex. +, Asia (China) +  and Asia (Japan) +
low to high elevations (100-2200 m) +
differentiated +
multicellular +
occasional +
Limestone shales, riverside, dry shaded rocks, granite cliffs and ledges, north-facing bluff +
yellow +  and orange-red or red +
grooved +  and monomorphic +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
spreading +, appressed +  and weakly spreading +
deltoid;deltoid-lanceolate +
2-stratose +  and 1-stratose +
ovate +, keeled +  and curled +
reduced +
specialized +
dioicous +  and sexual +
roundedquadrate +  and quadrate +
several-celled +
short-conic;long-conic +
photosynthetic +
2 +  and 3 +
lateral +  and terminal +
lateral +  and terminal +
red +, orange +  and yellow +
oblong +  and linear or long-triangular +
1 (?) +  and 2 (?) +
J. Hattori Bot. Lab. +
straight +
yellowish;reddish-brown +
elongate +
0.8 cm8 mm <br />0.008 m <br /> (1 cm10 mm <br />0.01 m <br />) +
2 +  and 1 +
rounded-triangular +  and rounded-pentagonal +
0 cm0 mm <br />0 m <br /> (2 cm20 mm <br />0.02 m <br />) +
Barbula sect. Acutae +, Barbula subsect. Acutiformes +, Barbula sect. Asteriscium +, Barbula sect. Fallaces +, Barbula subsect. Fallaciformes +, Barbula sect. Graciles +, Barbula sect. Rubiginosae +, Barbula sect. Vineales +, Barbula subsect. Vinealiformes +, Dactylhymenium +, Didymodon sect. Asteriscium +, Didymodon sect. Fallaces +, Didymodon sect. Graciles +, Didymodon sect. Vineales +, Geheebia +, Husnotiella +  and Trichostomopsis +
Didymodon tectorum +
Didymodon +
species +
elliptic;cylindric +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
rudimentary +
not perforated +
red +  and yellow +
convex +  and quadrate +
stemless +  and perigoniate +