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bog haircap moss, hummock haircap, narrow-leaf haircap, polytrichum moss, slender haircap

arctic haircap moss, polytrichum moss

Habit Plants slender, green to whitish green, dark brownish with age, in deep, compact tufts. Plants small to fairly robust, green to attractive chestnut brown with age.
Stems

6–12(–20) cm, simple, densely matted with wooly whitish to light-brownish tomentum.

2–6(–10) cm, simple or more commonly fasciculately branched, whitish tomentose only at base.

Leaves

2–5(–6) mm, erect to closely appressed when dry, erect-spreading when moist;

sheath oblong-rectangular, brownish, ± abruptly contracted to the blade;

blade narrowly lanceolate, acuminate, flat, with sharply infolded margins;

marginal lamina 6–7 cells wide, 1-stratose, entire to finely crenulate above, membranous and transparent, abruptly infolded and enclosing the lamellae and overlapping towards the apex;

costa toothed abaxially towards the apex, short-excurrent as a short, reddish brown awn;

lamellae bluntly crenate in profile, 5–8 cells high, the marginal cells in section pyriform, thick-walled, ending in a thickened knob, end cells of lateral lamellae ovoid and scarcely thickened at the apex;

sheath cells 45–80 × 7–10 µm, elongate-rectangular (5–7:1), narrower toward the margin;

cells of the marginal lamina transversely elongate, shorter and obliquely oriented towards the margins, very thick-walled and colorless.

3–6 mm, crowded in distal half stem, erect and closely appressed when dry, erect-spreading when moist;

sheath rectangular, abruptly contracted to the blade;

blade linear-lanceolate, rather flat, with sharply infolded margins, channeled at the apex and tapering to the bicolored awn;

marginal lamina 7–9 cells wide, 1-stratose, entire, membranous, infolded and overlapping, completely enclosing the lamellae;

costa excurrent with low blunt teeth abaxially near apex, the awn coarsely spinulose at the base, brown in the basal 1/3 to 1/2, hyaline distally;

lamellae 5–9 cells high, the marginal cells in section ovoid, somewhat larger than cells below, thin-walled or very slightly thickened at apex;

median sheath cells 45–90 × 12–15 µm, narrowly rectangular, thin-walled;

cells of marginal lamina 10–15 × 24–45 µm, thick-walled, obliquely oriented and shorter toward the margin and thin-walled.

Seta

2–4 cm, yellowish to reddish brown.

rather short for plant size, 1.2–3 cm, reddish.

Sexual condition

dioicous;

perichaetial leaves somewhat longer than the stem leaves, ending in a slender awn.

dioicous;

perichaetial leaves elongate, with hyaline lamina and long, tapering awn.

Capsule

2–3 mm, short-rectangular to almost cubic (1–1.5:1), brownish, sharply 4-angled and prismatic, suberect, becoming horizontal when ripe;

peristome 200–230 µm, divided to 0.8, the teeth 64, obtuse.

2.3–3 mm, ovoid-rectangular (1.2–2:1), somewhat broader at base, sharply 4(–5)-angled, erect, becoming inclined to horizontal when mature;

peristome 150–230 µm, divided to 0.6, the teeth pale brownish, acute.

Calyptra

dirty white to light brown, enclosing the capsule.

Spores

7–9(–15) µm.

15–17 µm.

Polytrichum strictum

Polytrichum hyperboreum

Habitat Sphagnum bogs, wet heaths and tundra, muskeg, sedge meadows, moist alpine tundra, also on local elevations and on rotten stumps in wet spruce forests Open sandy or stony ground, ridges, moraines, and open tundra, and in deep masses on stream banks and margins of lakes and ravines
Elevation low to high elevations low to moderate elevations (0-1500 m) (low to moderate elevations (0-4900 ft))
Distribution
from FNA
AK; CA; CO; CT; GA; IA; IL; IN; MA; MD; ME; MI; MN; MT; NC; NH; NJ; NY; OH; OR; PA; RI; UT; VT; WA; WI; WV; WY; AB; BC; MB; NB; NL; NS; NT; NU; ON; PE; QC; SK; YT; South America; e Asia (Russia, Japan); Atlantic Islands (Faroes, Iceland); Greenland; n Asia; n Europe (Scandinavia, Svalbard); Antarctica
[WildflowerSearch map]
from FNA
AK; LB; NT; NU; QC; YT; Greenland; n Europe (Scandinavia); n Asia (Russia)
Discussion

Polytrichum strictum is widespread in the boreal regions of the Holarctic, and is one of the commonest low arctic representatives of the family (D. G. Long 1985), with survivals southward in relict bogs, for example in northern Indiana, northern Illinois, and northwestern Iowa, also in alpine situations in the eastern mountains to the Carolinas and Georgia. In Nunavut, it is known from Baffin, Bathurst, and Devon islands. Its characteristic habitat is on hummocks in Sphagnum bogs, in deep masses tightly bound together by dirty-white, wooly tomentum, with short, stiffly erect leaves, and cubical capsules, a clear correlation between a distinctive morphology, distribution, and ecology.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Polytrichum hyperboreum is a handsome species, widespread in arctic America. Sporophytes are commonly produced. In Nunavut, it is known from Baffin, Ellesmere, and Melville islands. The most distinctive characters are the branching habit, channeled leaf apex, and the distinctive bicolored awn, which is coarsely and thickly spinulose at the base, brownish below and hyaline in the distal 1/2. In P. juniperinum, P. strictum, and P. piliferum the awns are ± evenly roughened throughout to almost smooth. It differs from these species also in the rather thin-walled, ovoid marginal cells of the lamellae, and the broad marginal laminae overlapping and completely enclosing the lamellae.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 27, p. 139. FNA vol. 27, p. 138.
Parent taxa Polytrichaceae > Polytrichum Polytrichaceae > Polytrichum
Sibling taxa
P. commune, P. hyperboreum, P. jensenii, P. juniperinum, P. piliferum, P. swartzii
P. commune, P. jensenii, P. juniperinum, P. piliferum, P. strictum, P. swartzii
Synonyms P. affine, P. juniperinum var. affine, P. juniperinum var. gracilius P. piliferum var. hyperboreum
Name authority Bridel: J. Bot. (Schrader) 1800(1): 286. (1801) R. Brown: Chlor. Melvill., 36. (1823)
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