Leucodon andrewsianus comb. et stat. nov.

Abstract

The eastern North American endemic moss Leucodon andrewsianus (Crum & Anderson) Reese & Anderson (basionym: Leucodon brachypus var. andrewsianus Crum & Anderson) is recognized at the rank of species. Although perichaetia are present rarely in this moss, it is not known to produce perigonia or sporophytes; it evidently reproduces and disperses by caducous branchlets. A key is provided for the three species of Leucodon known to occur in North America, north of Mexico. Leucodon C. E Schwaigrichen is a genus of dioicous pleurocarpous mosses with wide distribution around the world. Two species and one variety were attributed to North America north of Mexico by Anderson et al. (1990): Leucodon brachypus Bridel, L. brachypus var. andrewsianus Crum & Anderson, and L. julaceus (Hedwig) Sullivant. On the basis of new information discovered during a review of the genus for the Flora of North America project, we here recognize L. brachypus var. andrewsianus at the rank of species. Nomenclature for mosses mentioned in this article is mostly based on Anderson et al. (1990). LEUCODON ANDREWSIANUS (Crum & Anderson) Reese & Anderson comb. et stat. nov. Leucodon brachypus Bridel var. andrewsianus Crum & Anderson, THE BRYOLOGIST 75: 101. 1972. TYPE: U.S.A. NEW JERSEY. Palisades, on red cedars, C. E Austin, Musci Appalachiani 260, sub nom. Leucodon julaceus forma stolonifera, nom. nud., (holotype MICH!; isotypes CANM!, DUKE!, MO!, NY!). Plants mostly medium sized, rarely robust, dull to somewhat glossy. Primary stems rhizome-like, usually inconspicuous, bearing often crowded ascending branches. Branches mostly elongate and curved, rarely straight, simple or branched, commonly with conspicuous clusters of short fragile branchlets in upper leaf axils and at tips. Branch leaves erect-appressed, plicate, concave, rarely secund, mostly 1.41.9 mm long, lanceolate-acuminate, ecostate, commonly with the terminal cell hyaline and narrowly elongate (mostly 34-60 jxm long) on young leaves, and with the distal end of the terminal cell often curved or even uncinate. Leaf cells thick-walled, somewhat elongate in the interior of the lamina, mostly more or less isodiametric in the marginal rows at midleaf and in the basal angles, rarely somewhat papillose-roughened abaxially near leaf tip. Perichaetia rarely present, axillary, gemmiform; perigonia and sporophytes unknown. Habitat.--On logs, tree trunks, and rocks in forests; sea level to 2,100 m. Leucodon andrewsianus occurs at or near sea level in the northern part of its range, but only in the mountains in the southern part. Ra ge.---CANADA. NEW BRUNSWICK. Albert Co., Ireland 11637 CANM, DUKE, NY. NEWFOUNDLAND. Ca 10 km N of Deer Lake community, Belland 3983 CANM, MICH, MO, TENN. NOVA SCOTIA. Cape Breton Island, Victoria Co., Schofield 6017 CANM, DUKE, MICH. ONTARIO. Bruce Co., Colpoy Bay, Crum 11476 LAF. PRINCE EDWARD ISLAND. Macoun 6211 DUKE. QUEBEC. Rimouski Co., Lepage 1202 DUKE. U.S.A. ARIZONA. Coconino Co., Mack's Crossing, Haring & Haskell 22762 MO. CONNECTICUT. East Haven, J.B.H. s.n., 12 Nov 1883 NY. ILLINOIS. Dr. Vasey, sin. loc. NY. MAINE. Penobscot Co., Hermann 19213 DUKE. MASSACHUSETrS. Amesbury, Huntington s.n., 31 Jan 1902 DUKE. MICHIGAN. Alger Co., Steere 590 FH. NEW HAMPSHIRE. Plymouth, Grout s.n., 7 Mar 1898, DUKE, FH, NY. NEW JERSEY. The type material of Leucodon andrewsianus. NEW YORK. Essex Co., Smith et al. 38743 FH. NORTH CAROLINA. Jackson Co., Soco Gap, Anderson 25283 DUKE. PENNSYLVANIA. Centre Co., State College, Roberts s.n., 11-22-24 DUKE, TENN. TENNESSEE. Sevier Co., Sharp 35122 MICH, NY, TENN. VERMONT. Newfane, Grout, N. Amer. Musci Pleurocarpi 81 CANM, DUKE, FH, MO, NY. VIRGINIA. Giles Co., Mountain Lake, Blomquist 3407 DUKE, FH. WEST VIRGINIA. Fairmont, Roberts s.n., 4/16/36 MO. WISCONSIN. Lander s.n., 7/16/32, sin. loc. NY. DIFFERENTIATION OF LEUCODON ANDREWSIANUS FROM