Bryum incrassatolimbatum Card., a Mexican Species New to the U.S.A.

Abstract

A specimen of Bryum incrassatolimbatum Card. was discovered among some collections from Oklahoma, U.S.A. It is otherwise known only from the type locality in west-central Mexico. While examining some unidentified specimens in the University of Michigan herbarium (MICH), I recently encountered an unusual Bryum collection from Oklahoma. After eliminating known Anglo-American species of Bryum, I sent the specimen to Dr. H. Ochi, who suggested the name Bryum incrassatolimbatum Card. Having examined an isotype from the New York Botanical Garden (NY), I can confirm that the present specimen should be referred to that species, for which this is the first record for North America north of Mexico. Bryum incrassatolimbatum is one of a few North American Brya that can be readily identified in the sterile condition. A description, illustration, and discussion of diagnostic features should aid in the detection of additional specimens. Bryum incrassatolimbatum Card., Rev. Bryol. 36: 114, 1909. (FIG. 1-7) Plants rather robust, forming deep tufts, red-brown to brown, ? encrusted with lime below. Stems 3-15(-20) mm high, simple or rarely forked, in transverse section with a poorly developed central strand surrounded by large, thin-walled cells and 1-2 rows of smaller, thickened, peripheral cells; rhizoids few, mostly restricted to the base, orange to orange-brown, finely but densely papillose. Leaves erect to erect-spreading, strongly keeled and + twisted when dry, spreading to erect-spreading and + concave when moist, 1.2-2.3 mm long, 0.6-1.2 mm wide, broadly lanceolate to ovate, sometimes broadest above the midleaf, broadly acute to rounded at the apex, ? longly decurrent by 2-5 rows of rectangular cells, the decurrencies up to /4 the length of the lamina, often bistratose in part; margins plane, multistratose to bistratose except at the apex, entire; costae broad, ending 1-4 cells below the apex, sometimes at the apex, in transverse section with a layer of enlarged superficial cells (sometimes bistratose on the ventral surface-Fig. 5) and welldeveloped stereids interior to these, guide cells lacking. Upper leaf cells extremely thinwalled, broadly rhombic to rectangular, 40-90(-110) Am long, 12-28 Am wide, ? abruptly linear at the margin, scarcely longer than wide at the apex, rectangular near the base, sometimes ? quadrate across the insertion. Dioicous; perigonia inconspicuous, terminal on unbranched stems; outer perigonial bracts broadly acute from an ovate, concave base, erect and ? twisted from an erect base. Perichaetia and sporophytes unknown. U.S.A. OKLAHOMA. CHEROKEE CO.: along Terapin Creek near Hwy. 82, Redfearn 24839 (MICH, SMS). MEXICO. JALISCO: Etzatlhin, C. G. Pringle 15-217 (NY-iostype), Barnes & Land 252 (NY). Bryum incrassatolimbatum can be recognized in the sterile condition by a combination of these unusually distinctive features: elongate stems with evenly distributed, ovate 007-2745/81/365-367$0.45/0 This content downloaded from 157.55.39.208 on Fri, 14 Oct 2016 04:20:57 UTC All use subject to http://about.jstor.org/terms 366 BRYOLOGIST [Volume 84