Pogonatum pensilvanicum
Pogonatum
Pennsylvania pogonatum moss
pogonatum moss
0.2–0.6 cm.
simple or branched by subfloral innovations.
2–4 mm, when dry loosely sheathing at the base, the blade narrow, curved and often hooked at the tips, erect-spreading and almost straight when moist;
sheath oblong to oblong-ovate, in leaves near the base of the shoot abruptly contracted to the blade, in distal leaves more gradually tapering, not hyaline-margined, with a narrow strip of incrassate cells at the shoulders;
blade narrowly lanceolate to linear, slenderly acuminate, ending in a short point;
marginal lamina ± plane, variable in width, 1-stratose, irregularly notched-dentate or at times almost entire;
costa smooth or weakly toothed abaxially near the tip;
lamellae 11–16, entire in profile, 4–8 cells high, the marginal cells larger and rounded in section, single or in pairs, smooth;
sheath cells short-rectangular;
cells of lamina 10–12 µm, subquadrate to irregular.
with a sheathing base merging gradually or ± abruptly contracted to the blade, the sheath entire (toothed in P. contortum), with or without incrassate hinge-cells at the shoulders, not hyaline-margined (except in P. urnigerum);
margins serrate, toothed, or entire, without a differentiated border of elongated cells;
adaxial lamellae numerous and compact, occupying the full width of the blade, or somewhat fewer with an evident marginal lamina, marginal cells not differentiated, or strongly differentiated, thick-walled and coarsely papillose.
1–3.5 cm, reddish.
smooth.
dioicous;
male plants similar to females in appearance, or bud-like and inconspicuous.
2.5–4 mm, erect or nearly so, sometimes indistinctly angled;
exothecium scabrous, the cells short-rectangular, thick-walled;
operculum obliquely rostrate;
peristome 190–220 µm, divided to 0.8.
ovoid to short-cylindric, ± regular to somewhat asymmetric, terete, sometimes with 4 or more indistinct angles or ridges;
hypophysis not differentiated, tapering;
stomata none;
exothecium mammillose to scabrous, the exothecial cells mamillate or with a single papillate projection of the outer wall;
operculum rostrate from a convex base;
epiphragm persistent, attached to the peristome teeth;
peristome deeply reddish pigmented (at least in the median line), the teeth 32, compound, with median sinus narrow or almost obliterated.
with a densely matted felt of hairs, covering most or all of the capsule.
9–12 µm.
finely papillose.
Pogonatum pensilvanicum
Pogonatum
Pogonatum pensilvanicum is widespread in eastern North America. It differs from P. brachyphyllum by the more slender, membranous leaves with irregularly dentate margins and fewer lamellae. The marginal cells of the lamellae are typically in pairs, and they may “bulge out and proliferate, giving rise to masses of what apparently are gemmae” (G. E. Nichols 1937). The calyptra is dirty white and stands out in contrast to the bright emerald-green protonema. When taken up, the texture of the protonemal mat is firm and often quite rubbery. Specimens with more regularly dentate leaf margins are sometimes distinguished as var. torreyanum (Bridel) Paris. Pogonatum pensilvanicum has been reported from South America.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Species 52 (5 in the flora).
North American species of Pogonatum vary greatly in size and habit from tall, laxly tufted plants to protonema mosses with individual plants scattered and only a few millimeters high. Pogonatum contortum of the Pacific Northwest, with leaves strongly crisped and contorted when dry, is the most “typical” of the genus as a whole. Pogonatum brachyphyllum and P. pensilvanicum are protonema-mosses, the gametophyte consisting of a persistent felted mat of protonema and leafy plants small and scattered. The other two species are distinctly polytrichoid in habit, with the margins of the lamellae thick-walled and coarsely papillose. Pogonatum dentatum is an arctic-montane species, whereas P. urnigerum has a somewhat more southerly distribution and occurs as well in the Himalayas and New Guinea. The sporophytes of our species are more uniform, with a scabrous exothecium, deeply pigmented peristome with compound peristome teeth, and no stomata. The exothecial “papillae” are projections of the cell wall, unlike the wart-like cuticular papillae often seen on the leaf surfaces of many Polytrichaceae.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Plants to 0.6 cm, scattered over a green, persistent protonema | → 2 |
1. Plants 3-8(-12) cm, in loose pure tufts or growing among other bryophytes | → 3 |
2. Lamellae 25-40, compact, the leaf appearing thick and fleshy; leaf margins entire. | P. brachyphyllum |
2. Lamellae 11-16, the leaf membranous; leaf margins irregularly notched. | P. pensilvanicum |
3. Leaves toothed from the apex nearly to the base; marginal cells of lamellae not differentiated, smooth | P. contortum |
3. Leaves toothed above the shoulders, the margins of the sheath entire; marginal cells of lamellae thick-walled and coarsely papillose | → 4 |
4. Leaf margins with multicellular, hooked teeth; leaf sheath not hyaline-margined; marginal cells of lamellae ± rectangular, flat-topped, the lumen quadrate; peristome divided nearly to the base. | P. dentatum |
4. Leaf margins with mostly 1-cellular teeth; leaf sheath hyaline-margined; marginal cells of lamellae rounded to transversely elliptical, the lumen pentagonal; peristome divided to ca. 0.6. | P. urnigerum |
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