Coscinodon yukonensis

Hastings

Bryologist 102: 278, figs., 42–51, 53–54. 1999,.

Treatment appears in FNA Volume 27. Treatment on page 260. Mentioned on page 259.

Plants 7–10 mm, dark-brown green. Leaves broadly ovatelanceolate, 0.9-1.2 × 0.4 mm, margins plane, apex plane, awn 0.2–1 mm, lamina non-plicate; basal juxtacostal laminal cells rectangular to long-rectangular, 27–51 × 8–12 µm, thin to thick-walled; basal marginal laminal cells oblate to quadrate, 5–12 × 9–12 µm, evenly thick-walled; medial laminal cells 1-stratose; distal laminal cells 1-stratose. Sexual condition dioicous. Seta 0.3–0.5 mm. Capsule immersed, cupulate; peristome present, scalloped, xerocastique.


Habitat: Siliceous or granite-slate outcrops
Elevation: moderate to high elevations (1500-1700 m)

Discussion

Coscinodon yukonensis is known only from northwestern North America. The specimens were all originally identified as C. cribrosus, which it resembles in its immersed capsules and superficially cribrose peristome teeth. However, C. yukonensis is separated by its xerocastique peristome (i.e., opens when dry) and non-plicate, plane margined, 1-stratose leaves. Additionally, unlike those of C. cribrosus, the peristome teeth are not perforated; rather, the ornamentation has been “scalloped out” down to the cell walls on either side of the teeth. Thus, while superficially appearing perforated, the cell walls are intact. Its leaves resemble those of C. calyptratus but are much smaller, more broadly ovate, and never revolute. Additionally, it has an immersed capsule and the peristome teeth are scalloped, not solid as in C. calyptratus. The basal marginal laminal cells are oblate to quadrate, unlike those of any other Coscinodon in North America.

Selected References

None.

Lower Taxa

None.
... more about "Coscinodon yukonensis"
deciduous +  and persistent +
differentiated +
Roxanne I. Hastings +
Hastings +
not papillose +
toothed +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
sinuous +  and straight to sometimes +
sinuose-nodulose;quadrate;elongate +
rectangular +
divided +
undifferentiated +
plicate +  and smooth +
not papillose +
cucullate +  and campanulate +
sulcate +  and smooth +
striate +  and smooth +
excurrent;percurrent;excurrent +
subpercurrent +
reniform +, elliptical +  and terete +
usually not markedly larger +
2-stratose +  and 1-stratose +
dioicous +  and sexual +
B.C. +, Yukon +  and Alaska. +
moderate to high elevations (1500-1700 m) +
reproduction +  and asexual +
dioicous +, autoicous +  and sexual +
Siliceous or granite-slate outcrops +
papillose +, mammillose +  and smooth +
Thin (?) +, 8um (?) +  and 12um (?) +
specialized +
dioicous +, autoicous +  and sexual +
0.9mm;1.2mm +
ovatelanceolate +
0.4 cm4 mm <br />0.004 m <br /> (?) +
1;multistratose +
recurved +  and incurved +
thick-walled +  and sinuose +
thick-walled +  and sinuose +
conic;rostrate +
not +  and differentiated +
straight +
sigmoid +  and arcuate +
papillose +  and smooth +
short to long +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
ornamented +  and smooth +
globose +
Coscinodon yukonensis +
Coscinodon +
species +
straight +