278 BOTANICAL GAZETTE [ocToBER 
ficient to enable one to distinguish it from its near relatives A. zrriguum and 
A. noterophiium. Its larger leaf cells in the basal half will assist in separat- 
ing it from the first, while the second generally has a much wider and gen- 
erally excurrent costa, and two layers of cells in the lamina at the base and 
along the costa for half its length or more. 
AMBLYSTEGIUM LESCURII (Sulliv.) Aust. Plate XT. fig. 9. 
Synon.: Hyfnum lescuréé Sullivant, Musc. and Hepat. of U.S. 79. 1856. 
Icon. Musc. 203. f/. 124. 1864.—Lesquereux & James, Man. Moss. of N. 
Amer. 376. 1884 
ExsiccaTi: AHypnum lescurit Sulliv. & Lesq., Musc. Bor. Amer. (Ist 
ed.) 350 (2d ed.) 529. 
Amblystegium lescurit Austin, Musc. App. 371. 1870. 
TYPE in herb. Sullivant, Harvard University. 
Gametophyte bisexual, of medium size, loosely cespitose, 
yellowish to dark green, ferruginous within the tufts with age: 
stems prostrate, generally defoliate in older parts, profusely 
branched, shick, rigid, 160 to 210 in diameter, 2 to 6™ long, 
obscurely angled; central strand small,6 to 10 in diameter, 
composed of five to ten rows of cells; cortex of three to five 
layers of small incrassate cells, 6.5 to 13 w in diameter, well dif- 
ferentiated from ground tissue, the cells of the latter abruptly 
larger, 18 to 26m in-diameter; branches erect with very few 
branchlets, 1 to 3°" long: leaves ovate to very broadly ovate, occa- 
sionally as broad as long, 360 wide by 750 u long, reaching in 
some instances 1500 long, concave, abruptly skort acuminate, 
bordered, border of two layers of linear vermicular incrassate cells, 
three to five cells wide, denticulate at apex, sometimes sparingly 
so to near the base, costate, costa thick, bi-convex in section, 40 
to 55 » wide, extending to the apex of the leaf, here becoming 
flattened and blending with the thickened border, when moist spread- 
ing in all directions, rarely subsecund, in the dry state the leaf 
tips more or less inflexed from the open-spreading bases ; leaf 
cells parenchymatous, walls thick in all parts of the leaf, in the 
alar region usually a few short oval cells, excluding these alar 
cells long hexagonal or rhomboidal, gu wide by 254 long, 
ranging in width from 6.5 to 13 # and in length from 15 to 37#% 
in the middle border region cells 5.6 « wide by 30.8 w long, Vaty 
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