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peel en ical 
1897 } NORTH AMERICAN SPECIES OF AMBLYSTEGIUM 251 
ranging in length from 15 to 28m and in width from 4 to 10.5p,; 
perichetial leaves elong:te lanceolate from a broadly ovate base, 
abruptly contracted above into a narrow acumen which varies in 
length from one half the body of the leaf to its full length, den- 
ticulate especially at the base of the acumen, ecostate or with 
very narrow thin costa in the lower third. 
Sporophyte small, .75 to 1.5™ long: seta reddish-brown, 90 
to 120m in diameter, cortex of one or two layers of cells 4 to 10m 
in diameter, central strand composed of twelve to twenty-five 
rows of cells 15 to 30m in diameter, capsule symmetric or slightly 
asymmetric, suberect to almost horizontal, ovate or cylindrical, 
not contracted below mouth when dry, incurved, dark dull brown ; 
exothecium cells parenchymatous, oblong rectangular, 21.5 wide 
by 34 long, varying from 13 to 26m wide and from 17 to 43# long, 
lateral walls 3 to 6m thick, three rows of cells below the mouth 
hexagonal isodiametric or transversely elongated (17); stomata 
few, six to ten, scattered, 28.54 wide by 31long; teeth of peri- 
stome yellow with narrow hyaline border striz, on the back trans- 
verse in the lower three-fourths, above this oblique or longi- 
tudinal, giving place finally to rows of long papilla; endostome 
light yellow, membrane occupying more than half its entire 
height ; segments strongly carinate, opened slightly along the 
keel between the articulations, finely papillose, not equaling the 
teeth, cilia one or two, generally shorter than the segments, 
Sometimes not more than one-third their length; operculum 
apiculate from a convex or conic base, usually as broad as the 
capsule; annulus of one or two rows of cells: spores pale, finely 
tuberculate, 8.5 to 1 5“ in diameter: calyptra usually shorter 
than capsule, split little more than half its length. 
Has.: On bowlders in moist woods or on shaded moist lime- 
Stone cliffs. Type locality Austria. 
Europe, Asia, North America: New England, New Bruns- 
Wick, Ontario, Ohio, along the great lakes, and Rocky mountains. 
Not abundant. 
A small plant, very generally confused with A. sprucet and A. subtile by 
American collectors and writers. From the former it may usually be readily 
