Polytrichastrum formosum

(Hedwig) G. L. Smith

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

Basionym: Polytrichum formosum Hedwig Sp. Musc. Frond., 92, plate 19, fig. 1a. 1801
Synonyms: Polytrichum attenuatum Menzies
Treatment appears in FNA Volume 27. Treatment on page 130. Mentioned on page 125, 131, 132.

Plants medium and slender to large and robust, green to dark olive green to blackish, in loose tufts. Stems (2–) 3–8 (–20) cm, mostly unbranched. Leaves 6–8 (–12) mm, erect to erect-spreading when dry, spreading to subsquarrose and broadly recurved when moist; sheath ovate to elliptic, yellowish, hyaline-margined, gradually tapering or abruptly contracted to the blade, the cells at the shoulders forming a differentiated hinge; blade lanceolate to linear; costa prominent abaxially and toothed near the tip; excurrent as a short, toothed point; marginal lamina erect, (2–) 3–5 (–10) cells wide, plane or erect, sharply toothed from apex nearly to the sheath; lamellae (3–) 4–5 (–7) cells high, margins ± entire to finely serrulate in profile, the marginal cells in section rounded to narrowly elliptic and somewhat taller than the cells beneath, the cell-walls not or moderately thickened; median cells of sheath 8–12 µm wide, narrowly rectangular, 5–7 (–10):1; cells of marginal lamina subquadrate, 10–15 µm. Sexual condition dioicous or polygamous; perichaetial leaves similar to the foliage leaves, or somewhat longer, with a longer sheath. Seta 3–6 cm, yellowish to reddish-brown. Capsule 4–7 mm, rather slender or short-rectangular, acutely 4 (–6) -angled, inclined to almost horizontal, pale yellowish-brown to brownish; hypophysis cylindric, indistinctly delimited or set off by a shallow groove; exothecium smooth or the cells weakly convex, quadrate to hexagonal, without a central thin spot; peristome 600 µm, divided to 0.6, the teeth 64 and highly regular in form or fewer and somewhat irregular, pale to brownish; epiphragm absent marginal teeth. Spores 12–16 µm.

Distribution

V27 157-distribution-map.gif

Widespread, temperate to cool temperate latitudes in the Northern Hemisphere

Discussion

Varieties 3 (2 in the flora).

European treatments often assert a similarity between Polytrichastrum formosum and Polytrichum commune, which cannot be said of the North American expression of the species. The habitat and ecology of the European plants are also distinct: A. J. E. Smith (2004) described P. formosum in Britain as a common and weedy species of heaths, moorland, woods, outcrops, and old walls.

Selected References

None.

Key

1 Plants often robust, 5-10(-20) cm; leaves subsquarrose and broadly spreading- recurved when moist; lamellae 5-7 cells high, entire, the marginal cells in section rounded, moderately thick-walled; capsule short rectangular; hypophysis delimited by a shallow groove; peristome teeth 64, regular in form; dioicous Polytrichastrum formosum var. formosum
1 Plants rather slender, 3-6(-10) cm; leaves spreading when moist; lamellae (3-)4-6 cells high, the marginal cells narrowly elliptic, not or only slightly thickened; capsule slender; hypophysis not sharply delimited; peristome teeth 50-64, somewhat irregular in size and shape; monoicous (polyga- mous) Polytrichastrum formosum var. densifolium

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

... more about "Polytrichastrum formosum"
prominent +
Gary L. Smith Merrill +
(Hedwig) G. L. Smith +
toothed +
differentiated +
Polytrichum formosum +
distinct +
lanceolate +  and linear +
broadened +
not pitted +  and papillose +
polygamous +, dioicous +  and sexual +
sparsely ciliate;smooth +
cucullate +
pale yellowish-brown +  and brownish +
horizontal;inclined to almost +
4(-6)-angled +  and short-rectangular +
0.4 cm4 mm <br />0.004 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
prolonged +
toothed +
undifferentiated +
Widespread +  and temperate to cool temperate latitudes in the Northern Hemisphere +
scabrous +, mammillose +  and smooth +
differentiated +
photosynthetic +
4 +  and 5 +
serrate +, crenulate +  and serrulate +
0.8 cm8 mm <br />0.008 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
0.6 cm6 mm <br />0.006 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
membranous +
1(-3)-stratose +
less entire;finely serrulate +
papillose +  and smooth +
crenulate +  and serrulate +
shape +  and size +
somewhat taller +
polygamous +, dioicous +  and sexual +
sharply toothed +  and entire +
interwoven +
600 cm6,000 mm <br />6 m <br /> (?) +
toothed +
toothlike +
Mem. New York Bot. Gard. +
underground +
undifferentiated +
rounded +  and narrowly elliptic +
yellowish +  and reddish-brown +
3 cm30 mm <br />0.03 m <br /> (6 cm60 mm <br />0.06 m <br />) +
hyaline-margined +
rectangular +
tapering;ovate;elliptic +
differentiated +
larger +  and minute +
3 cm30 mm <br />0.03 m <br /> (8 cm80 mm <br />0.08 m <br />) +
Polytrichum attenuatum +
Polytrichastrum formosum +
Polytrichastrum +
species +
pale +  and brownish +
unjointed +
not keeled +
green +  and dark olive green +
slender +  and large +