BFNA Title: Leskea
Author: P. L. Redfearn, Jr.
Date: December 20, 2003
Edit Level: R
Version: 1

Bryophyte Flora of North America, Provisional Publication
Missouri Botanical Garden
BFNA Provisional Publication


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Leskea - Leskeaceae

xxx.LESKEA Hedwig, Species Muscorum, 1801. 211 * [for Gottfried Leske of Leipzig]


Paul L. Redfearn, Jr.


Plants small, in pale green, dark-green or brownish mats. Stems sparsely radiculose, freely to subpinnately branched. Branches horizontal to ascending, straight to somewhat curved at tips. Paraphyllia few, linear-lanceolate. Leaves of stems and branches similar, erect or somewhat recurved when dry, erect spreading when moist, somewhat asymmetric, oblong-ovate or ovate-lanceolate, plicate on one side, 2-plicate or plane; margins plane or recurved proximally, entire, serrulate to subserrulate distally; costa subpercurrent or ending before apex, often flexuose-curved distally; distal laminal cells 4--11 m, irregularly quadrate-hexagonal, thick-walled, obscure, unipapillose on abaxial or both surfaces; proximal laminal cells somewhat longer than distal cells, proximal marginal cells subquadrate. Sexual condition autoicous; perichaetial leaves elongate, erect, pale-brown, acuminate. Seta 4--12 mm, yellow, pale-brown, orange-brown to reddish. Capule symmetric to distinctly curved, cylindric to oblong-cylindric; operculum bluntly conic; stomata present; annulus narrow or absent; exostome teeth incurved when dry, linear-lanceolate, whitish or yellow, densely papillose throughout or, more often, cross-striolate near the base; endostome erect wet or dry, pale, papillose, consisting of a low basal membrane, segments long linear, somewhat keeled, perforate (sometimes rudimentary), cilia none or rudimentary. Calyptra smooth, naked. Spores 9--18 μm, smooth to very finely papillose.


Species 24 (4 in the flora): North America, Central America, South America, Europe, Africa, Asia.

Plants of this genus occur in terrestrial habitats in temperate, subtropical and tropical regions.


SELECTED REFERENCES: Anderson, L., H. A. Crum and W. R. Buck. 1990. List of the mosses of North America north of Mexico, Bryologist 93: 448--449. Crosby, M. R., R. E. Magill, B. Allen and S. He. 1999. A Checklist of Mosses. p. 143. Missouri Botanical Garden, St. Louis. Crum, H. and L. E. Anderson. Mosses of Eastern North America. 2 vols. Pp. 840--847. New York. Ireland, R. R. 1982. Moss flora of the Maritime Provinces. Ottawa, National Museums of Canada. Pp. 438--439. Seppelt, R. D. and G. A. Laursen. 2003. Leskea polycarpa Hedw., new to the moss flora of Alaska. Evansia 19: 148--152. Vitt, D. H. 1982. Bryopsida. In: S. P. Parker, Ed.-In-chief, Synopsis and Classification of Living Organisms. New York. P. 324.


1. Branch leaves 0.2--0.5 mm; distal laminal cells 4--7 μm . . . . .1. Leskea australis

1. Branch leaves 0.4--0.8 mm; distal laminal cells 6--11 μm.

2. Stem leaves clearly different from branch leaves, longer than broad, obliquely acuminate and subsecund at the tips; branches usually somewhat curved at tip; capsules subcylindric, distinctly curved. . . . . . . . . . . . . . . . . . . 4. Leskea polycarpa

2. Stem and branch leaves similar, leaves not much longer than broad, not oblique or subsecund at tips; branches not distinctly curved at tip; capsules oblong, straight, or slightly curved.

3. Stem and branch leaves loosely foliate, rounded to rounded-obtuse at apex, not plicate to occasionally slightly plicate, margins not recurved; endostome segments less than half as long as exostome teeth; operculum rounded conic, blunt at apex. . . . . . 3. Leskea obscura

3. Stem and branch leaves, tightly foliate, acute to sometimes bluntly pointed, not rounded at apex, 2-plicate, margins irregularly recurved in proximal half, especially when dry; endostome segments about as long as the exostome teeth; operculum rounded-conic, pointed . . . . . . . 2. Leskea gracilescens



1. Leskea australis Sharp in A. J. Grout, Moss Fl. No. America. 3(4): 193. 1934


Leskea microcarpa Sullivant, 1856 not Bridel, 1812, nor Mitten, 1869


Plants in rigid, dark -green or brown mats. Branches ascending, terete and somewhat tapering, tightly foliate, not curved at tips. Stem leaves 0.4--0.7 mm, more slenderly acuminate than branch leaves. Branch leaves crowded, erect, not or only slightly 2-plicate when dry, erect-spreading when moist, 0.2--0.5 mm, ovate-lanceolate, gradually acuminate to an acute, apex often blunt; margins plane, entire to subserrulate distally; costa subpercurent, slightly roughened on back, especially in proximal part of leaf; distal cells 4--7 μm, bulging-papillose abaxially. Seta 4--9 mm, yellow-brown. Capsules straight, cylindric, yellow-brown, 1.2--1.8 mm; annulus of 1--2 rows of cells; exostome teeth whitish; endostome segments irregular, segments very short and irregular. Spores 9--13 μm, very finely papillose.


Capsules mature throughout year. Lower trunks and bases of hardwood trees and bald cypress, logs, low woods along rivers, streams, sloughs, swamps; 5--350 m; Ala., Ark., Del., Fla., Ga., La., Miss., Mo., N.C., Tenn., Tex.


This slender species is common on the Coastal Plain of the southeastern United States. Rigid, dark-green or brownish mats with ascending, terete, and somewhat tapering branches and small leaves make this species easy to recognize.


2. Leskea gracilescens Hedwig. Spec. Musc. 222, 1851


Plants in dark-green or brownish-green mats. Branches spreading, rather rigid, tightly foliate, erect not curved at tips. Stem leaves similar to branch leaves, 0.6--0.8 mm. Branch leaves, tightly foliate, usually rigid and erect to somewhat incurved-erect when dry, erect-spreading when moist, 0.4--0.5 mm, ovate to ovate-lanceolate, acute or sometimes bluntly pointed, 2-plicate at base; margins irregularly revolute in proximal half or beyond especially when dry, entire to subserrulate distally; costa ending near apex; distal laminal cells 7--11 μm, obscurely bulging-papillose on both surfaces, more noticeable so abaxially. Seta 5--8 mm, yellow-brown, becoming orange brown or reddish with age. Capsule straight, oblong-cylindric to sometimes curved before dehiscence; 1.5--2.2 mm; annulus of 1--2 rows of cells; operculum rounded-conic, pointed, exostome teeth 0.2--0.4 mm, pale, yellowish to brownish yellow; endostome segments nearly as long as exostome teeth. Spores 12--14 μm, very finely papillose.


Capsules mature throughout year. Bases and trunks of hardwood trees, red cedar, soil around tree bases, on logs, shingle roofs, rocks; 10--900 m; Man., Ont., Que.; Ark., Ala., Conn., D.C., Del., Fla., Ind., Ill., Tenn., Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Nebr., N.J., N.Y., N.C., N.Dak., Ohio, Okla., Pa., S.Dak., Tenn., Tex., Vt., Va., W.Va., Wis.


Leskea gracilescens is the most common Leskea in North America. While it occurs throughout the United States and Canada from North Dakota to Ontario south to the Coastal Plain, it is most common in the mid West where its colonies are often quite large and dense. In the western part of its range, plants with blunt leaves are difficult to distinguish from Leskea obscura. However, these blunt-leaved forms will have some leaves with plications and revolute margins. If mature capsules with intact peristomes are present, L. gracilescens is easily distinguished from L. obscura by an endostome and exostome of nearly equal in length and an operculum that is more pointed than the operculum of L. obscura.


3. Leskea obscura Hedwig. Sp. Musc., p. 223, 1801


Leskea cardoti Kindberg;.L. obtusa Renauld



Plants in loose dark green or brownish mats. Branches spreading, loosely foliate, not curved at tips. Stem leaves 0.9--1.2 mm, rounded-obtuse to sometimes acute or short-acuminate, occasionally very slightly plicate. Branch leaves remote, loosely foliate and slightly incurved when dry, spreading when moist, 0.4--0.8 mm, concave, not plicate, elliptic or broadly oblong-ovate, rounded-obtuse at apex, shortly decurrent, margins erect, entire to subserrulate distally; costa ending 8--10 cells before the apex; distal laminal cells 6--9 μm, indistinctly bulging-papillose abaxially. Seta 5--12 mm, yellow to orange-brown. Capsule straight, oblong-cylindric, yellow-brown, 1.5--2.25 mm; annulus of 2--3 rows of cells; operculum rounded-conic, blunt at apex; exostome teeth 0.2--0.3 mm, yellow; endostome segments less than 1/3 as long as exostome teeth. Spores 11-18 μm, very finely papillose.


Capsules mature Mar.--Nov. Bases and lower trunks of hardwood trees, bald cypress, pines, and logs, especially in floodplains, occasionally on rocks; 20--400 m; Alta.; Man., Ont., Que.; Ala., Conn., Del., D.C., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Md., Mass., Mich., Minn., Miss., Mo., Nebr., N. J., N.C., Ohio, Okla., Pa., S.C., Tenn., Tex., Va., W.Va., Wis.


Leskea obscura is more common in eastern North America. Smooth, concave, branch blunt, rounded-obtuse leaves with erect margins, exostome teeth longer than endostome segments, and an operculum that is distinctly bluntly pointed separate this species from L. gracilescens.


4. Leskea polycarpa {{J.}} Hedwig. Sp. Musc. 225, 1801.


Leskea arenicola Best; L. polycarpa var. paludosa (Hedwig) Schimper


Plants in soft or fairly rigid, generally loose, pale-green or brownish mats. Branches spreading, usually somewhat curved at the tips. Stem leaves clearly differentiated, 0.8--1.2 mm, distinctly longer than broad, somewhat obliquely acuminate and subsecund at the tips. Branch leaves remote to crowded, loosely erect, usually somewhat oblique and subsecund at tips, smooth or slightly plicate, 0.5--0.8 mm, ovate-lanceolate, apex blunt or acute; margins plane to somewhat recurved proximally, entire to subserrulate distally; costa ending near apex; distal laminal cells 7--9 μm, papillose abaxially. Seta 7--12 mm, orange-brown to red. Capsule 2--3 mm, subcylindric, somewhat curved, brown to yellow-brown; operculum short to occasionally rather high-conic; annulus composed of 2(--3) rows of cells; exostome teeth yellowish to brownish yellow; endostome segments somewhat shorter than exostome teeth. Spores 9--13 μm, very finely papillose or nearly smooth.


Capsules mature Mar.--Nov. Bases and lower trunks of hardwood and coniferous trees, soil around bases of trees, logs, occasionally on rocks, mostly in low areas near streams and creeks, occasionally on roofs; 10--1100 m; Alta., B.C., Man., N.B., Nfld., N.S., Ont., Que., Sask.; Ala., Alaska, Calif., Colo., Conn., Del., D.C., Ga., Idaho, Ill., Ind., Ind., Iowa, La., Maine, Md., Mass., Mich., Minn., Mo., Mont., N.C. (?), Nebr., N.H., N.J., N.Y., N.Dak, Ohio, Oreg., Pa., S.Dak., Tenn., Tex., Vt., Va., Wash., W.Va., Wis.; Europe; Asia; Africa.


Leskea polycarpa is distinguished by branches typically curved at the tips, clearly differentiated stem leaves that are distinctly longer than wide and somewhat oblique and subsecund at tips, and capsules that are subcylindric and curved.


EXCLUDED SPECIES Leskea angustata Taylor is cited for the flora area by L. E. Anderson et al. (1990). However, no voucher specimens or other literature citations of Leskea angustata for the area have been seen. It is consequently excluded from this treatment.