Flora of North America species comparison

The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Hypnum subimponens

Hypnum hamulosum

curly claw-moss, hypnum moss

hypnum moss
Habit Plants medium-sized, not in tufts, pale yellow-green to golden green. Plants small, in tufts, yellowish.
Stem(s)

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 strongly hamate and falcate-secund, ovate-lanceolate, gradually tapering to insertion, gradually narrowed to apex, 1.3–1.5 × 0.4–0.5 mm;

base sometimes weakly decurrent;

margins plane, usually entire, weakly toothed toward apex;

apex narrowly acuminate;

costa double, short or sometimes to 1/2 leaf length;

alar region rarely differentiated except at margin and near insertion, with 2 or 3 slightly larger, thin-walled cells;

basal laminal cells shorter, broader than medial cells, unpigmented, walls not pitted;

medial cells 40–60(–70) × 3–4 µm. Sexual condition phyllodioicous;

inner perichaetial leaves ovate-lanceolate, margins toothed distally, apex attenuate.
Seta

red-brown, 2.5–3 cm.

reddish, 1–2 cm.
Capsule

erect to suberect, light brown, cylindric, 3–5 mm;

annulus 1–3-seriate;

operculum conic or rostellate;

endostome cilia unknown.

inclined to horizontal, brown, long-cylindric, 1.5–1.8 mm;

annulus 2- or 3-seriate;

operculum conic;

endostome cilia 1 or 2.

Hypnum subimponens

Hypnum hamulosum
Phenology Capsules mature May–Jun. Capsules mature Jul–Aug.
Habitat Epiphytic on living trees, cliffs, vertical rock faces, decaying logs, terrestrial Calcareous rock, in crevices, tundra, mountains
Elevation low to moderate elevations (0-1500 m) (low to moderate elevations (0-4900 ft)) elevation unknown
Distribution
from FNA
AK; CA; ID; MT; OR; WA; BC; NT; NU; YT; e Asia
[WildflowerSearch map]
from FNA
AK; CO; AB; BC; NT; NU; YT; Greenland; Europe; Asia
Discussion

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.)

Hypnum hamulosum resembles the related species H. callichroum, H. holmenii, and H. plicatulum, especially the last two, but is distinguished by its strongly hamate stem leaves that generally do not taper to the base or have differentiated alar cells. Because branch leaves are not diagnostic, tundra forms can be impossible to name with confidence; these often possess only branch leaves, as the main stem is not present. Many reports of H. hamulosum from North America are based on such specimens. Plants of H. hamulosum have scarce pseudoparaphyllia. The capsules are infrequent, with opercula 0.5 mm and smooth endostome cilia.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 28, p. 548. FNA vol. 28, p. 541.
Parent taxa Hypnaceae > Hypnum Hypnaceae > Hypnum
Sibling taxa
H. andoi, H. bambergeri, H. callichroum, H. circinale, H. cupressiforme, H. curvifolium, H. dieckei, H. fauriei, H. fujiyamae, H. hamulosum, H. holmenii, H. imponens, H. jutlandicum, H. lindbergii, H. pallescens, H. plicatulum, H. pratense, H. procerrimum, H. recurvatum, H. revolutum, H. vaucheri
H. andoi, H. bambergeri, H. callichroum, H. circinale, H. cupressiforme, H. curvifolium, H. dieckei, H. fauriei, H. fujiyamae, H. holmenii, H. imponens, H. jutlandicum, H. lindbergii, H. pallescens, H. plicatulum, H. pratense, H. procerrimum, H. recurvatum, H. revolutum, H. subimponens, H. vaucheri
Synonyms Stereodon subimponens Stereodon hamulosus
Name authority Lesquereux: Trans. Amer. Philos. Soc. n. s. 13: 14. (1865) Schimper: in P. Bruch and W. P. Schimper, Bryol. Europ. 6: 96, plate 590. (1854)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



Type/paste one or more Latin names into the boxes above; matching taxa will show up below the box as you type. You can use the up/down arrow keys to move through the list.

(If the plant you're looking for doesn't show up in the auto-complete list, that means it either isn't described in Flora of North America yet, or it's listed under a synonym. And please note that Flora of North America is still missing several plant families, including Fabaceae, Apiaceae, Boraginaceae, and Polemoniaceae.)

Choose a data source: Flora of North America

The species comparison tool is brought to you by:
Northwest Wildflowers