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juniper haircap moss, juniper polytrichum moss

swartz's polytrichum moss

Habit Plants small to medium to fairly robust, gray-green to bluish green to reddish brown with age, in loose tufts, often forming extensive patches. Plants often rather soft and flexuose, green to blackish when old.

(1–)4–5(–10) cm, simple, brownish tomentose only near the base.

2–9 cm, simple, erect, in proximal part moderately to densely brownish tomentose.


3–6(–8) mm, densely imbricate, ± erect and almost straight when dry, erect-spreading to widely spreading when moist;

sheath oblong-rectangular, yellowish, tapering to the blade;

blade slender, bluish green and nitid, rather flat, with sharply infolded margins;

marginal lamina 5–7 cells wide, 1-stratose, entire or minutely crenulate, membranous and transparent, enclosing the lamellae and overlapping towards the apex;

costa usually somewhat toothed distally, excurrent, forming a subulate, toothed awn, the awn reddish brown throughout or slightly decolorate at tip;

lamellae bluntly crenate in profile, 6–8 cells high, the marginal cells in cross-section ovate to pyriform, thick-walled, ending in a distinct knob, smooth or rarely faintly papillose, the marginal cells of lateral lamellae (enclosed by the overlapping margins) ovoid and less strongly thickened;

sheath cells 70–100 × 6–10 µm, narrowly rectangular (4–6:1), narrower toward the margin;

cells of the broad marginal lamina transversely elongate, very thick-walled.

3–8 mm, loosely imbricate, appressed to erect-spreading and flexuose when dry, patent to widely spreading and weakly recurved when moist;

sheath rectangular, scarcely narrowed to the blade;

blade lanceolate to linear-lanceolate, often caducous at the junction of sheath and blade, the apex subulate, weakly channeled;

marginal lamina 6–9 cells wide, distantly toothed to subentire;

costa excurrent as short brown entire to serrulate tip, smooth abaxially or with a few teeth near apex;

lamellae in profile entire to shallowly crenulate, 5–10 cells high, the marginal cells in section usually somewhat broadened, flat-topped or shallowly grooved, single or geminate, thin-walled, smooth, the marginal cells of lateral lamellae asymmetric;

median sheath cells 75–110 × 2–12 µm, linear;

cells of marginal lamina 9–15 µm, quadrate, thin- to firm-walled;

perichaetial leaves with long sheathing bases and short subulate blade.


(1–)3–5 cm, stout, yellowish to reddish brown.

2.5–5 cm, reddish brown.

Sexual condition


perigonial rosettes yellowish to reddish green;

perichaetial leaves longer than the foliage leaves, long-sheathing, the blade almost obsolete, ending in a slender yellowish or hyaline awn.


2.5–5 mm, rectangular, longer than wide (1.5–2:1), reddish brown to dark brown, glaucous when fresh, suberect, becoming horizontal when mature, sharply 4-angled and prismatic;

peristome 200–240 µm, divided to 0.6–0.8, the teeth 64, keeled at back.

2.5–3 cm, ± cubic, sharply 4–angled, suberect when mature, becoming horizontal when old;

peristome teeth 64, 160–210 µm, obtuse, the basal portion 60–75 µm.


whitish to light brown, covering the capsule.


6–10(–12) µm.

12–15 µm.

Polytrichum juniperinum

Polytrichum swartzii

Habitat Exposed, well-drained, mostly acid soils in old fields and open woods, in openings following forest fire, on trailside banks and road cuts, on thin shallow soil overlying rocks, blowdowns and open ridge tops near timberline, only rarely in moist or wet situations Very wet and regularly flooded situations, sedge meadows, wet tundra and lake shores (D. G. Long 1985)
Elevation low to high elevations
from FNA
AK; AL; AR; AZ; CA; CO; CT; DE; GA; IA; ID; IL; IN; KS; KY; MA; MD; ME; MI; MN; MO; MT; NC; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NL; NS; NT; NU; ON; PE; QC; YT; Mexico; Central America; c Asia; Australia; Pacific Islands (New Zealand); Atlantic Islands (Macaronesia); Greenland; n Asia; Europe; s South America; West Indies; Antarctica
[WildflowerSearch map]
from FNA
AK; LB; NT; NU; YT; Greenland; Europe (Scandinavia); n Asia; e Asia; Atlantic Islands (Iceland)

Polytrichum juniperinum occurs on a variety of substrates, but primarily in dryer situations than P. commune or P. strictum. It often forms extensive pure stands of a distinctive pale bluish green color from the reflection of light off the thin, membranous margins of the leaves. The narrow leaf blades are widely spreading and have short, reddish awns. Polytrichum juniperinum is common and generally distributed throughout continental North America. In the high Arctic, however, the species is rare and many older reports of it actually pertain to 5. P. hyperboreum (D. G. Long 1985).

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

Polytrichum swartzii is a northern species with distantly toothed to subentire leaves, differing chiefly by the rounded-quadrate, flat-topped (not retuse or grooved) and scarcely-thickened marginal cells of the lamellae. The capsules are shortly cubic. In Nunavut, it is known from Baffin and Devon islands.

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

Source FNA vol. 27, p. 138. FNA vol. 27, p. 137.
Parent taxa Polytrichaceae > Polytrichum Polytrichaceae > Polytrichum
Sibling taxa
P. commune, P. hyperboreum, P. jensenii, P. piliferum, P. strictum, P. swartzii
P. commune, P. hyperboreum, P. jensenii, P. juniperinum, P. piliferum, P. strictum
Synonyms P. alpestre, P. juniperinum var. alpestre, P. juniperinum var. waghornei P. commune var. swartzii, P. algidum, P. inconstans
Name authority Hedwig: Sp. Musc. Frond., 89, plate 18, figs. 6–10. (1801) C. J. Hartman: Handb. Skand. Fl. ed. 5, 361. (1849)
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