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Polytrichum strictum

This is the only common species of the Polytrichaceae that occurs in bogs and poor fens. Less frequent in swamps and paludified woodlands is P. commune. It is larger, has recurved leaves when moist, no stem tomentum, and the lamellae are not covered by the lamina. Polytichum juniperinum, a species of mineral soils, is similar to P. strictum in leaf morphology, but lacks abundant whitish stem tomentum. The apical cells of the lamellae are u-shaped in transverse section of the leaf. The complex leaf structure is unique to this group of mosses. Macrofossil material often decomposes rapidly, but isolated leaf sheaths sometimes are observed still attached to short portions of the stem.

Clockwise from top left: plant, x-section of leaf, whole leaf

Habit	Erect, unbranched, plants with a bluish-green hue, occurring gregariously or in loose mats.
Stems	covered with whitish tomentum of rhizoids.
Leaves	erect when dry, spreading when moist, lanceolate from a hyaline, unistratose, expanded, sheathing base, acuminate, ending in a short, reddish, toothed awn; upper portion of leaves consisting of an expanded costa, from which numerous, vertical, green, lamellae arise that are encased in the inrolled leaf lamina.
Leaf Cells	upper cells irregularly quadrate to isodiametric, smooth, cells of sheath hyaline, long-rectangular, smooth. Apical cells of lamellae rounded in transverse section of leaf, smooth.
Alar Cells	not differentiated.
Habitat	This species occurs intermixed with Sphagnum on high hummocks in oligotrophic habitats. The individual shoots are elevated 1 cm or so above the Sphagnum canopy. Also this species is one of the first bryophyte species to colonize disturbed bare peat surfaces, especially after fire where it forms large continuous mats.
Common Associates	Most commonly associated with Sphagnum fuscum, but also with other hummock forming species of Sphagnum; hummocks may also contain Pohlia nutans and Leiomylia anomala.

pH Meter