Hypnum subimponens
Hypnum revolutum
curly claw-moss, hypnum moss
revolute hypnum moss
leaves circinate-secund, ovate-lanceolate, gradually tapering to insertion, gradually narrowed to apex, 1.5–2.8 × 0.4–0.6 mm;
base not decurrent;
margins plane, sinuate proximally, serrate toward apex;
apex narrowly acuminate;
costa double, short, indistinct, less than 1/3 leaf length;
alar region slightly differentiated, of 3 or 4 cells at extreme basal angles;
basal laminal cells shorter, broader than medial cells, not strongly pigmented, walls pitted;
medial cells 50–80(–90) × 3–4 µm. Sexual condition dioicous;
inner perichaetial leaves lanceolate, weakly or not plicate, margins slightly toothed or entire near apex.
leaves straight to falcate-secund, ovate or broadly ovate-oblong, gradually narrowed to apex, 0.5–1.8 × 0.4–0.6 mm;
base not decurrent, not auriculate;
margins revolute from base to near apex, entire at apex;
apex narrowly acuminate;
costa distinct to rarely ecostate;
alar cells subquadrate, not pigmented, region not well defined, not excavate, 8–15 cells in marginal row, forming clearly defined angles, 2 or 3 larger, hyaline, rectangular cells in decurrent portion;
basal laminal cells wider than medial cells, sometimes yellowish, walls porose, pitted;
medial cells 25–40 × 4–5 µm, walls not pitted.
similar, slightly smaller.
red-brown, 2.5–3 cm.
yellowish to reddish when mature, 1–2 cm.
dioicous;
inner perichaetial leaves oblong-lanceolate, plicate, margins almost entire distally, apex short, costa indistinct.
erect to suberect, light brown, cylindric, 3–5 mm;
annulus 1–3-seriate;
operculum conic or rostellate;
endostome cilia unknown.
inclined to horizontal, dull yellowish to brown, oblong-cylindric, 2–3 mm;
annulus 2 (or 3)-seriate;
operculum conic;
endostome cilia 2 or 3.
Hypnum subimponens
Hypnum revolutum
Specimens of Hypnum subimponens from Arctic regions are problematic; in fact, any specimens from horizontal surfaces can be difficult to place accurately. Sporophytes, produced in spring, are frequent only on vertical surfaces and then often abundant. Unlike similar species in western North America, H. subimponens produces cylindric, erect capsules (slightly curved below the mouth when mature). Hypnum lindbergii has falcate-secund leaves, while those in H. subimponens are circinate-secund to strongly hamate. Key traits of the stem leaves separate H. subimponens from H. hamulosum, and the former is usually more than twice the size of the latter. See also discussions of 3. H. callichroum, 11. H. holmenii, and 16. H. plicatulum. Plants of H. subimponens have branches 0.5–1 mm wide; the alar cells are slightly bulging, hyaline, and thin-walled.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Varieties 2 (2 in the flora).
Hypnum revolutum is circumpolar in the Northern Hemisphere but bipolar in distribution. The species occurs at sea level in the northern portion of its range but is most frequent at higher elevations. Strongly revolute leaf margins are found in the genus only in H. revolutum, and the areolation in combination with the alar cell differentiation usually make this species readily recognizable. Creeping plants tend to be pinnate, sometimes closely and regularly; suberect plants tend to be more loosely and irregularly branched. The longest branches are the ones most distant from the stem apex. Plants of H. revolutum have outer stem cell walls often thin and collapsed inward; the stem leaves are concave. The antheridial and archegonial plants are alike.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Plants medium-sized; leaves plicate; margins strongly revolute to near apex. | var. revolutum |
1. Plants relatively small; leaves not plicate; margins plane or sometimes revolute basally. | var. ravaudii |
BC
CalFlora
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
