BFNA Title: Eurhynchiastrum
Author: M. S. Ignatov 
Date: October 6, 2009
Edit Level: R
Version: 2

Bryophyte Flora of North America, Provisional Publication
Missouri Botanical Garden
BFNA Web site: http://www.mobot.org/plantscience/BFNA/bfnamenu.htm

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XX. Eurhynchiastrum Ignatov & Huttunen, Arctoa 11: 260. 2002 [2003]  *  [Eurhynchium, and Latin -astrum, incomplete resemblance]

Michael S. Ignatov

 

Plants small to medium-sized, in loose to dense tufts, green or yellowish to brownish, glossy. Stems prostrate to arching, with central strand, loosely to densely terete-foliate, rather irregularly densely branched, branches obtuse by smaller, more crowded and more obtuse leaves at their tips; axillary hairs 3--4-celled; juvenile branch leaves acute. Stem leaves loosely to closely imbricate or somewhat spaced, erect to erecto-patent, broadly ovate-triangular to ovate-lanceolate, broadest at 1/10 of leaf length or below, gradually tapered to apex or broadly acuminate, sometimes blunt at apex, rounded to base, narrowly decurrent, slightly concave, smooth or in large plants plicate, margins plane or recurved near base, serrulate to subentire; costa strong, reaching 0.6--0.85 the leaf length, ending in a spine; juxtacostal basal cells slightly shorter, but not clearly differentiated from cells above, cells above decurrency broader, isodiametric, relatively thin-walled, forming a small, more or less distinct subquadrate group and often surrounded by small subquadrate cells forming a more or less extensive, but indistinctly delimited group; mid laminal cells linear, smooth. Branch leaves smaller and narrower than stem leaves, blunt, smooth or, in large plants, plicate, costa to 0.6--0.9 the leaf length, cells just before apex short, nearly isodiametric or irregular in shape. Sexual condition phyllodioicous or dioicous; perichaetial leaves reflexed, gradually acuminate from a sheathing base, entire or occasionally serrulate, costa weak and short, reaching to about half of basal part of leaf. Seta red-brown, smooth or rarely very slightly rough at places. Capsule red-brown, inclined to horizontal, oblong, slightly curved dorsally, annulus separating by fragments; operculum rostrate; peristome perfect. Calyptra naked. Spores 12--17 /um, slightly papillose.

 

Species 1 (1 in the flora): North America, Central America, Eurasia, Africa, Atlantic Islands; widespread throughout temperate, boreal, Arctic and alpine regions.

 

Eurhynchiastrum was segregated from the polyphyletic Eurhynchium (M. S. Ignatov and S. Huttunen 2002), where it was placed by most authors. Other authors, e.g. G. De Notaris (1867), H. Robinson (1987), and K. D. McFarland (2004), accepted its placement in Rhynchostegium. North American species of Rhynchostegium differ from Eurhynchiastrum in their robust habit and lack of an abaxial spine at end of costa. In the present concept, Eurhynchium is strictly a Palearctic genus.

 

SELECTED REFERENCE  Grout, A. J. 1898. A revision of the North American Eurhynchia. Bull. Torrey Bot. Club 25: 221--256.

 

1. Eurhynchiastrum pulchellum (Hedwig) Ignatov & Huttunen, Arctoa 11: 262. 2002 [2003]

 

Hypnum pulchellum Hedwig, Sp. Musc. Frond., 265, plate 68: figs. 1--4. 1801; Eurhynchium pulchellum (Hedwig) Jennings; E. strigosum (Hedwig) Jennings; Eurhynchium strigosum var. scabrisetum Grout; Rhynchostegium pulchellum (Hedwig) H. Robinson

 

Stems 2--5(--13) cm, branches to 3--8(--17) mm. Stem leaves 0.5--1.3(--2.6) x 0.2--0.9(--1.8) mm; basal cells near costa 7--10 /um wide; cells just proximal to decurrency 12--20 x 10--15 /um; mid-leaf cells 30--75(--100) x 4.5--6 /um. Branch leaves 0.4--1.3(--1.6) x 0.2--0.5(--1.1) mm. Seta 1--1.8 cm. Capsule 1.5 mm.

 

Varieties 2 (2 in the flora). North America. Mexico; Central America; Eurasia; n, e Africa; Atlantic Islands; Pacific Islands.

 

Eurhynchiastrum pulchellum is easy to recognize by the characteristically blunt branch leaves. The most common phenotype for plants on soil and tree trunk bases in forests is light green plants with rigid erect leaves. In xeric and Arctic environments leaves (of both stems and branches) become strongly appressed, with shoots julaceous, and these plants are often brownish and quite fragile. They have been segregated as var. praecox (temperate areas, branch leaves 0.5--0.8 mm, alar cells as in typical variety) and var. diversifolium (Arctic-alpine, branch leaves 0.5--0.6 mm, alar cells very numerous) but these grade to typical phenotypes and thus do not merit taxonomic recognition despite a sometimes distinctive appearance. The seta is almost always smooth in this species, but some few collections, described as Eurhynchium strigosum var. scabrisetum Grout, from New Jersey, New York and Massachusetts have roughened setae, although the mammillae are very low, appearing as a shallowly wavy outline, mostly at mid seta. In various parts of North America plants of more robust stature occur. They were described at the level of variety (var. robusta, var. barnesii), of even species (Eurhynchium fallax, E. substrigosum, E. taylorae). Many so-named collections in herbaria are, however, only slightly larger than the average phenotype of E. pulchellum, but some are conspicuous in their large size. Some populations in eastern North America, commonly referred to var. robusta, have longer branches and longer stem leaves, but their branch leaves are only slightly longer and rather narrow. At the same time, in Idaho, Montana, British Columbia, and neighboring regions plants in some populations have longer, broader, and strongly plicate branch leaves resulting in very robust appearance; but stem leaves are not always larger in these phenotypes. Plants with broadly triangular branch leaves up to 1 mm have been reported from California and Colorado as Eurhynchium striatum (D. H. Norris and J. R. Shevock 2004; W. A. Weber and R. C. Wittmann 2007). Among the taxa of large Eurhynchium pulchellum, H. A. Crum et al. (1965) accepted only var. barnesii, as the largest one in all dimensions, and this treatment is followed here.

 

1. Stem leaves 0.5--1.3 mm long; branch leaves 0.2--1.1 x 0.2--0.5(--0.6) mm, not or slightly plicate . . . 1a. Eurhynchiastrum pulchellum var. pulchellum

1. Stem leaves 1.2--2.6; branch leaves 1--1.9 x 0.4--0.8(--1) mm, strongly plicate . . . 1b. Eurhynchiastrum pulchellum var. barnesii

 

1a. Eurhynchiastrum pulchellum (Hedwig) Ignatov & Huttunen var. pulchellum

 

Eurhynchiastrum pulchellum var. diversifolium (Schimper) Ochyra & Żarnowiec; E. pulchellum var. praecox (Hedwig) Ochyra & Żarnowiec; Eurhynchium fallax (Renauld & Cardot) Grout, E. substrigosum Kindberg; E. pulchellum var. robustum (Roll) Jennings

 

Stems 2--10 cm. Stem leaves 0.5--1.3 x 0.4--0.9 mm. Branch leaves 0.2--1.1 x 0.2--0.5(--0.6) mm, not or slightly plicate.

 

Soil in forests, rocks, decaying logs and stumps, tree bases, in a broad range of environmental conditions from shady rock vertical surfaces and wet slopes of forested ravines to open ground in xeric steppe areas, and among other mosses in tundra, granite, limestone; 0--3200 m; Greenland; Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Nunavut, Ont., Que., Sask., Yukon; Ala., Alaska, Ariz., Ark., Calif., Colo., Conn., Del., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis., Wyo. Mexico; Central America; Eurasia; n and e Africa.

 

Sporophytes of E. pulchellum var. pulchellum are rare, confined probably to forest environments. There are no collections from a few states and provinces, but the var. pulchellum apparently occurs throughout the flora area with probably the only exception being Florida; it also appears to be rare in Georgia.

 

1b. Eurhynchiastrum pulchellum var. barnesii (Renauld & Cardot) Ignatov, xxxxxxx. 2008

 

Eurhynchium strigosum var. barnesii Renauld & Cardot, Revue Bryologique 15: 72. 1888; E. pulchellum var. barnesii (Renauld & Cardot) H. A. Crum, W. C. Steere & L. E. Anderson; E. taylorae R. S. Williams

 

Stems 6--13 cm. Stem leaves 1.2--2.6 x 0.6--1.8 mm. Branch leaves 1--1.9 x 0.4--0.8(--1) mm, often broadly obtuse, strongly plicate.

 

Soil, rocks, and decaying logs; probably middle elevations; ca. 500 m; Alta., B.C.; Alaska, Calif., Colo., Idaho, Mont., Wash.

 

Eurhynchiastrum pulchellum var. barnesii seems to be a relatively rare and endemic plant, probably deserving the status of species. Its separation from the large expressions of var. pulchellum needs additional attention.

 

OTHER REFERENCES:

Crum, H. A., W. C. Steere, and L. E. Anderson 1965 [1966]. A list of the mosses of North America. Bryologist 68: 377--432.

 

De Notaris, G. 1867. Cronaca della briologia italiana. Comment. Soc. Crittog. Ital. 2: 269--312.