BFNA Title: Pseudocampylium
XX. Pseudocampylium Vanderpoorten & Hedenäs, J. Bryol. 31: 131. 2009 * [Greek pseudes, false, and genus Campylium]
Plants slender in soft, loose, light green to yellowish mats. Stems creeping, freely and irregularly branched; central strand of small, thin-walled cells present; rhizoids smooth; axillary hairs with a single, elongate, rectangular to long-rectangular, of 1 brown basal cell and up to 4 elongate hyaline distal cells; paraphyllia sparse, narrowly lanceolate to ovate-lanceolate. Stem leaves wide-spreading to squarrose wet or dry, cordate-ovate, long-acuminate, narrowed to base, decurrent, concave at basal angles; margin plane or slightly recurved in alar region, entire or nearly so; costa ending at mid-leaf to reaching 3/4 of leaf length; alar cells few, differentiated, somewhat inflated, hyaline, the widest 14--25 \um in width. Sexual condition autoicous. Perichaetial leaves erect, lanceolate. Capsule horizontal, curved, 1.5--2 mm, when dry constricted below mouth; operculum conical; annulus of 2--3 rows of separating cells; exostome yellow-brown, cross-striolate basally, papillose and dentate distally, trabeculate at back; endostome cilia nodose. Spores finely roughened.
Species: 1 (1
in the flora): widespread, but
nowhere frequent: North America; Central America;
Pseudocampylium radicale, the only species in Pseudocampylium, has been shifted variously among Campylium, Leptodictyum and, most recently, Amblystegium. Its slender habit is reminiscent of Amblystegium serpens, while its wide-spreading to squarrose leaves recall Campylium, and its fairly long laminal cells are somewhat similar to those of Leptodictyum. Molecular evidence shows that P. radicale is unrelated to these genera and is nested within a clade including similarly slender species with a weak or even absent costa, including Pseudoamblystegium subtile and Serpoleskea confervoides, but also a morphologically heterogeneous assemblage of genera including Anacamptodon and Hygrohypnum. All these taxa have fairly narrow ecological ranges, and it seems that habitat specialization has triggered an array of contrasting morphologies among taxa that do, however, share a common ancestor.
SELECTED REFERENCES Hedenäs, L. 1997. A partial revision of Campylium (Musci). Bryologist 100: 65--88. Vanderpoorten, A. and L. Hedenäs. 2009. New combinations in the Amblystegieceae. J. Bryol. 31: 129--132.
1. Pseudocampylium radicale (P. Beauvois) Vanderpoorten & Hedenäs, J. Bryol. 31: 131. 2009
Hypnum radicale P. Beauvois, (Prodr. Aethéogam., 68. 1805; Amblystegium saxatile Schimper; Campylium radicale (P. Beauvois) Grout
Stem leaves 0.5--0.7 x 0.8--1.6 mm; median leaf cells 30--60 x 5—9 \um, 4--8:1. Seta elongate, 2--4.5 cm, smooth. Spores 9--18 \um.
The morphology of Pseudocampylium radicale is may be misleading, since the taxon shares with Campylium in the broad sense spreading to squarrose stem leaves. Specimens with non-squarrose leaves also bear much resemblance with Hygroamblystegium varium subsp. varium var. humile, which occurs in similar habitats. Pseudocampylium radicale may, however, be distinguished from the latter by the decurrency of its stem leaves.
Humus and litter in mineral-rich and eutrophic wet meadows and swamps, often under a fairly dense grass and sedge vegetation; 0--3000 m; Alta., B.C., Labr., N.B., N.S., Ont., Man., Que., Sask., N.W.T., Yukon; Ala., Calif., Colo., Conn., Del., Fla., Ga., Idaho, Ill., Ind., Kans., Ky., La., Maine, Md., Mich., Minn., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Oreg., Pa., R.I., S.C., Tenn., Va., Vt., Wash., W.Va.; Mexico; Central America; Europe.