Polytrichastrum sexangulare

(Bridel) G. L. Smith

Mem. New York Bot. Gard. 21(3): 37. 1971,.

Basionym: Polytrichum sexangulare Bridel J. Bot. (Schrader) 1800(1): 285. 1801
Treatment appears in FNA Volume 27. Treatment on page 128. Mentioned on page 125, 126, 129.

Plants small to medium, rather wiry, dark green to reddish-brown with age. Stems 1–3 (–6) cm, simple, erect or decumbent, the cortical cells thin or thick-walled. Leaves 3–6 mm, loosely to densely imbricate, erect-incurved at the tips and appressed to the stem when dry, erect-spreading when moist, obtusely cucullate, often secund; sheath broadly elliptic, hyaline-margined, gradually tapering or abruptly contracted to the blade; blade lanceolate to ligulate, almost tubular when dry; costa percurrent or slightly excurrent, cucullate at the apex, rarely bluntly mucronate; marginal lamina 2–6 cells wide, entire to obscurely denticulate, slightly broader and inflexed in the distal part of blade, covering the lamellae; lamellae 5–8 (–11) cells high, minutely crenulate in profile, the marginal cells in section larger than those beneath, narrowly ovate to pyriform, smooth or very rarely indistinctly papillose; median sheath cells elongate-rectangular, (18–) 24–40 × 8–10 (–18) µm; cells of marginal lamina 11–15 µm, quadrate to short rectangular, ± equally thick-walled; perichaetial leaves slightly longer than the foliage leaves. Seta 1.5–3 cm, rather stout, straight or arcuate with age. Capsule 2–3 mm, short-cylindric to ovoid to globose, bluntly (4–) 5–6-angled to terete, erect to horizontal to nodding; hypophysis small, scarcely delimited, stomata large and scattered on the proximal 1/3 of the urn; exothecium smooth, the cells variable in shape, trigonal to hexagonal, with a diffuse thin spot; peristome pale 220–300 µm high, divided to 0.3–0.5, the teeth 50–64, slender, of uniform size, or short triangular, the alternate teeth smaller. Spores 16–18 µm.

Distribution

V27 153-distribution-map.gif

Cool temperate and boreal Northern Hemisphere

Discussion

Varieties 2 (2 in the flora).

There has been a long-standing confusion of the names Polytrichum septentrionale, Polytrichastrum norwegicum, and Polytrichastrum sexangulare dating from the earliest days of bryology, and still met with in older collections in herbaria. Hedwig’s Polytrichastrum norwegicum was briefly in vogue as a name for this species, but the type of Polytrichastrum norwegicum is a form of Polytrichastrum alpinum (Gary L. Smith 1971).

Selected References

None.

Key

1 Stem cortical cells thin-walled; seta straight; capsule short-cylindric to ovoid to subglobose, (4-)5-6-angled; peristome teeth 50-64, slender, of uniform size Polytrichastrum sexangulare var. sexangulare
1 Stem cortical cells thick-walled; seta rather thick and curved; capsule subglobose, terete; peristome teeth 32, attenuate, of unequal size. Polytrichastrum sexangulare var. vulcanicum

"um" is not declared as a valid unit of measurement for this property."broader" is not a number. "wide" is not a number.

prominent +
Gary L. Smith Merrill +
(Bridel) G. L. Smith +
toothed +
differentiated +
Polytrichum sexangulare +
distinct +
tubular +  and lanceolate +
broadened +
thick-walled +
not pitted +  and papillose +
monoicous +, dioicous +, sexual +  and vegetative +
sparsely ciliate;smooth +
cucullate +
erect;horizontal +
short-cylindric +  and ovoid +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
excurrent +  and percurrent +
prolonged +
mucronate +  and cucullate +
undifferentiated +
Cool temperate and boreal Northern Hemisphere +
scabrous +, mammillose +  and smooth +
cylindric +  and tapering +
photosynthetic +
5 +  and 8 +
serrate +, crenulate +  and serrulate +
0.3 cm3 mm <br />0.003 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
membranous +
1(-3)-stratose +
papillose +  and smooth +
crenulate +  and serrulate +
shape +  and size +
polygamous +, dioicous +  and sexual +
narrowly ovate;pyriform +
sharply toothed +  and entire +
interwoven +
toothlike +
Mem. New York Bot. Gard. +
underground +
undifferentiated +
arcuate +  and straight +
1.5 cm15 mm <br />0.015 m <br /> (3 cm30 mm <br />0.03 m <br />) +
hyaline-margined +
elongate-rectangular +
tapering +
differentiated +
larger +  and minute +
secund +  and simple +
erect-spreading +, decumbent +  and erect +
cucullate +
1 cm10 mm <br />0.01 m <br /> (3 cm30 mm <br />0.03 m <br />) +
Polytrichastrum sexangulare +
Polytrichastrum +
species +
unjointed +
triangular +
smaller +  and slender +
dark green +  and reddish-brown +
small +  and medium +