BFNA Title: Leucolepis
Author: S. G. Newmaster & Terry T. McIntosh
Date: July 31, 2009
Edit Level: R
Version: 1

Bryophyte Flora of North America, Provisional Publication
Missouri Botanical Garden

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XXX.  LEUCOLEPIS Lindberg, Not. Sällsk. Fauna Flora Fenn. Förh. 9: 80. 1868 * [Greek leuco, white, and lepis, scaly, alluding to hyaline, scale-like stem leaves]


                                                                                                                    S. G. Newmaster
Terry T. McIntosh


Plants to 3--8 cm, in loose tufts or carpets, dark green. Stems 1.5(--2) cm, reddish brown to black, dendroid, branches clustered distally, spreading and recurved; rhizoids brown, numerous and matted proximally. Stem and branch leaves differentiated, slightly crisped when dry, spreading when wet, decurrent; margins plane, serrate, teeth single, large, of one cell, 1-stratose; costa single, percurrent, broader proximally, toothed on abaxial surface distally. Specialized asexual reproduction absent. Sexual condition dioicous. Perigonial leaves short and broad, forming rosette around antheridia. Perichaetial leaves lanceolate, reddish, hyaline. Seta usually single, rarely 2(--3), red-brown, 4--5 cm, somewhat flexuose, smooth. Capsule pendulous, yellow-brown to dark brown, cylindric, 6--8 mm; stomata confined to neck, cryptoporous; annulus differentiated in 3 rows of cells; operculum hemispherical; exostome brownish yellow, papillose; endostome yellow-brown, papillose, basal membrane porose, cilia 2--3. Spores 28--30 \um, papillose, yellow-green.


Species 1: western North America.


Leucolepis is a monotypic genus distinguished by its dendroid habit and differentiated stem leaves. Morphological (T. Koponen 1968) and cytological (R. J. Lowry 1948; Steere et al. 1954) research support the split of Leucolepis from Mnium. The chromosome number of Leucolepis is n = 5, whereas Mnium is n = 6, 7, and 12.


SELECTED REFERENCES:  Lowry, R. J. 1948. A cytotaxonomic study of the genus Mnium. Mem. Torrey Bot. Club 20: 1--42. Koponen, T. 1968. Generic revision of Mniaceae Mitt. (Bryophyta). Ann. Bot. Fenn. 5: 117--51. Koponen, T., 1974. A guide to the Mniaceae in Canada. Lindbergia 2: 160--184. Steere, W. C, L. E. Anderson and V. S. Bryan. 1954.  Chromosome studies in Californian mosses. Mem. Torrey Bot. Club 20:  1--75.


1. Leucolepis acanthoneura (Schwägrichen) Lindberg, Not. Sällsk. Fauna Flora Fenn. Förh. 9: 81. 1868


Hypnum acanthoneuron Schwägrichen, Sp. Musc. Frond., Suppl. 4, 2(1): 258b. 1829; Leucolepis menziesii (Hooker) Steere in L. F. Koch; Mnium menziesii (Hooker) Müller Hal.


Stem leaves differentiated; proximal and medial stem leaves distant, closely appressed to stem, elongate-lanceolate, long-acuminate, 2.5--4 × 0.8--1.2 mm, whitish hyaline, reddish brown proximally; distal stem leaves subtending branches, ovate-lanceolate, long-acuminate, 2.5--3 × 1--1.5 mm, mostly chlorophyllose with hyaline apex and acumen. Branch leaves ovate-lanceolate, acute, 1.5--2 × 0.8(--2) mm; laminal cells of branch leaves short-rhombic, sometimes isodiametric, thick-walled, sometimes weakly collenchymatous, marginal and apical cells elongate, forming a weak border.


Capsules mature spring. Common on moist soil, boulders, rotten logs, tree trunks, shaded habitats along streams, in lowlands and forests; 0--1000 m; B.C., Alaska, Calif., Idaho, Oreg., Wash.


The distinctive dendroid growth form and the recurved branches of Leucolepis acanthoneura gives this species a palm tree or umbrella-like appearance; it is sometimes called umbrella moss. Male plants have a distinctive rosette of perigonial leaves. The epithet “acanthoneura” alludes to spiny teeth on the abaxial surface of the costa. This species may be found as an epiphyte, particularly on broadleaf trees, extending up the trunk in moist coastal forests. Climacium dendroides is distinguished by rhizome-like stem, erect capsules, and shiny, broad, cordate stem leaves.