Didymodon norrisii

R. H. Zander

Bryologist 102: 112, figs. 1–11. 1999,.

Treatment appears in FNA Volume 27. Treatment on page 548. Mentioned on page 541, 547, 549.

Plants in nature redbrown, brick or rose red or occasionally blackened distally, redbrown to tan proximally. Stems 1–1.5 cm, central strand present. Stem-leaves appressed when dry, spreading and not keeled when moist, monomorphic; ovate to ovatelanceolate, adaxial surface broadly concave across leaf and sometimes narrowly channeled near apex, 1.2–1.5 mm; base weakly differentiated in shape, broadly ovate, sheathing at insertion; margins recurved in lower 2/3–3/4, minutely crenulate by projecting cell-walls; apex acute to short-acuminate, occasionally broken off; costa percurrent, strong, often weakly spurred, without an adaxial pad of cells or this weakly developed, adaxial cells quadrate from apex to near insertion, in 6-10 rows, guide cells in 2 layers; basal laminal cells not differentiated or of 2–5 rows of slightly larger cells, walls of basal-cells evenly thickened, quadrate to shortrectangular; distal laminal cells 9–13 mm wide, 1: 1 (–2), often transversely elongate near proximal leaf margins, papillae of 2–4 hemispherical salients per cell or essentially absent and cells appearing broadly mammillose, lumens roundedquadrate to ovate, walls evenly thickened and convex on both sides of lamina. Specialized asexual reproduction by fragile foliose stem tips. Seta 1.1–1.4 cm. Capsule 1.5–2 mm; peristome teeth apparently absent or rudimentary. Spores 10–13 µm. Distal laminal KOH reaction deep brick or rose red.


Phenology: Capsules mature May.
Habitat: Rock, outcrops, calcareous and volcanic boulders, fields, cliffs, runoff areas
Elevation: low to moderate elevations (200-1500 m)

Discussion

Didymodon norrisii is known only from four localities—California, one station each in Oregon and coastal British Columbia—and is quite distinctive. In addition to the characters given in the description, the leaves are reflexed above a very short-sheathing basal collar, the abaxial cells are quadrate in distal 4/5 of leaf, the costal transverse section is rounded-elliptical, the adaxial stereid band is absent, and there are 5–6 guide cells (4 in an abaxial layer and 1–2 in a second, adaxial layer). Sporophytes are uncommon, and the short-conic operculum is of cells in nearly straight rows.

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 norrisii"
quadrate +  and elongate +
0.3 cm3 mm <br />0.003 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
channeled +  and concave +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
of 1-2 rows +  and differentiated +
long-excurrent +  and short-excurrent +
Richard H. Zander +
R. H. Zander +
weak +  and strong +
ovate +  and crescent--shaped +
papillose +  and smooth +
of 2-5 rows +  and not differentiated +
usually slightly wider +
sheathing +
ovate;differentiated +
differentiated +
Pottiaceae tribe Barbuleae +
obovoid +
cucullate +
stegocarpous +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
monoicous +, dioicous +  and sexual +
flat to bulging +
thin;thick +
1 (?) +  and 10 (?) +
hexagonal +
larger +
tomentose +  and bare +
quadrate +  and rectangular +
occasionally weakly dentate or crenulate +  and entire +
subquadrate;hexagonal or rounded-angular occasionally shortly rectangular or rhomboid +
B.C. +, Calif. +  and Oreg. +
low to moderate elevations (200-1500 m) +
differentiated +
multicellular +
occasional +
Rock, outcrops, calcareous and volcanic boulders, fields, cliffs, runoff areas +
yellow +  and orange-red or red +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
concave;keeled;channeled;ovoid;lanceolate or lingulate +
ovate +, keeled +  and curled +
reduced +
specialized +
mammillose +
dioicous +  and sexual +
occasionally trigonous +  and weakly strongly convex +
dentate +  and entire +
crenulate +
short-conic;long-conic +
photosynthetic +
solid +  and simple +
roundedquadrate +  and ovate +
lateral +  and terminal +
lateral +  and terminal +
twisted +, cleft +  and perforated +
red +, orange +  and yellow +
oblong +  and linear or long-triangular +
Capsules mature May. +
1 (?) +  and 2 (?) +
straight +
hemispherical +
yellowish;reddish-brown +
elongate +
1.1 cm11 mm <br />0.011 m <br /> (1.4 cm14 mm <br />0.014 m <br />) +
2 +  and 1 +
rose red +, brick +  and deep +
ovate +  and ovatelanceolate +
rounded-triangular +  and rounded-pentagonal +
1 cm10 mm <br />0.01 m <br /> (1.5 cm15 mm <br />0.015 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 norrisii +
Didymodon +
species +
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 +
convex +  and quadrate +
stemless +  and perigoniate +