Trichostomum arcticum

Kaalaas

Bot. Not. 1900: 257. 1900,.

Synonyms: Didymodon arcticus (Kaalaas) Brotherus Trichostomum cuspidatissimum Cardot & Thériot
Treatment appears in FNA Volume 27. Treatment on page 492. Mentioned on page 489.

Stem triangular in section. Leaves flattened, narrowly lanceolate, distal margins plane, minutely crenulate, not bordered; apex narrowly acute, plane or keeled; basal-cells differentiated across leaf base as a W, commonly running up margins, distinctly enlarged submarginally submarginally just proximal to the lowest point the quadrate medial cells extend in the leaf; distal laminal cells pluripapillose with low papillae; mucro narrowly conic, of 6–9 cells. Not fruiting in the flora area.


Habitat: Gravel, fen, mire, calcareous bog, sedge meadow, low-center polygon, tundra, wet or occasionally dry areas, often associated with snow melt runnels
Elevation: moderate elevations (400-700 m)

Distribution

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Greenland, B.C., Nfld. and Labr. (Labr.), N.W.T., Nunavut, Ont., Que., Yukon, Alaska, n Eurasia

Discussion

The triangular stem cross section with a strong central strand will easily distinguish Trichostomum arcticum from the disconcertingly similar Tortella tortuosa var. arctica. Additionally, the former has leaves usually strongly recurved when wet and the basal cells extend upwards both juxtacostally and marginally, while the latter has leaves weakly recurved when wet and basal cells extending upwards only towards the leaf margins. Trichostomum arcticum also has a distinctive area of enlarged basal cells submarginally just below the lowest point to which the quadrate distal cells extend in the leaf, and its laminal papillae are more coarse. Most species of the genus have leaf margins to some extent minutely crenulate by projecting laminal cells and their papillae, but this feature seems distinctively pronounced in T. arcticum, which is found generally worldwide across the arctic.

Selected References

None.

Lower Taxa

None.
... more about "Trichostomum arcticum"
elongate +  and quadrate +
0.25 cm2.5 mm <br />0.0025 m <br /> - 0.5 cm5 mm <br />0.005 m <br /> +
channeled +  and flat +
0.15 cm1.5 mm <br />0.0015 m <br /> - 0.25 cm2.5 mm <br />0.0025 m <br /> +
of 1-2 rows +  and differentiated +
long-excurrent +  and short-excurrent +
keeled +, plane +  and acute +
Richard H. Zander +
Kaalaas +
all +  and walled +
crescentlike +
rectangular +
papillose +  and smooth +
usually slightly wider +
differentiated;elliptic;rectangular +
Undefined subfam. Trichostomaceae +
obovoid +
papillose +
cucullate +
cleistocarpous +  and stegocarpous +
monoicous +, dioicous +  and sexual +
flat to bulging +
6 +  and 9 +
elongate-rhomboid +  and elongate +
thicker +
tomentose +  and bare +
ovate +, reniform +  and semicircular +
roundedquadrate +
incurved +  and erect +
crenulate +  and plane +
Greenland +, B.C. +, Nfld. and Labr. - Labr. +, N.W.T. +, Nunavut +, Ont. +, Que. +, Yukon +, Alaska +  and n Eurasia +
moderate elevations - 400-700 m +
differentiated +
multicellular +
Gravel, fen, mire, calcareous bog, sedge meadow, low-center polygon, tundra, wet or occasionally dry areas, often associated with snow melt runnels +
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 +
reflexed +  and incurved +
lanceolate +  and flattened +
reduced +
dentate +  and entire +
6um;12um +
long-conic;rostrate +
photosynthetic +
compound +, simple +, hollow +  and solid +
2 +  and 6 +
lateral +  and terminal +
lateral +  and terminal +
twisted +, perforate +  and ligulate +
red +, orange +  and yellow +
2-3-fid +, cleft +  and entire +
straight +
elongate +
0.4 cm4 mm <br />0.004 m <br /> - 1.5 cm15 mm <br />0.015 m <br /> +
2 +  and 1 +
yellow +, orange +  and yellowish orange +
4 cm40 mm <br />0.04 m <br /> - 10 cm100 mm <br />0.1 m <br /> +
triangular +
0 cm0 mm <br />0 m <br /> - 3 cm30 mm <br />0.03 m <br /> +
autoicous +, dioicous +, sexual +  and asexual +
Didymodon arcticus +  and Trichostomum cuspidatissimum +
Trichostomum arcticum +
Trichostomum +
species +
elliptic;ovate;cylindric +
0.1 cm1 mm <br />0.001 m <br /> - 0.3 cm3 mm <br />0.003 m <br /> +
orange +  and yellow +
stemless +  and perigoniate +
brown;light-brown +
occasionally smaller than the perichaetiate +