1897 | NORTH AMERICAN SPECIES OF AMBLYSTEGIUM 263 
Stereodon compactus Mitten, Jour. Linn. Soc. 8: 43. 
Amblystegium compactum Macoun & Kindberg, Cat. Can. Pl. 6: 1892. 
ExsiccaTl: Amblystegium compactum Austin, Musc. App. 372; Macoun, 
Can. Musc. 324 (Herb. Wis.). 
Hypnum serpens var. compactum Hookerin Drummond's Musc. Amer. 188. 
TyPeE in Herb. Hooker, Kew. 
Gametophyte bisexual, of medium size, usually in dense tufts 
Jrom 0.5 to 2.5™ deep, sometimes forming loosely woven mats, pale 
green above, becoming yellow or rust colored below with age: 
stems slender 2 to 3™ long, 120 to Igom in diameter, rarely 
reaching 220m, obscurely five angled, erect, ascending or occa- 
sionally almost prostrate, soft and flexible when moist, fragile 
when ary, Jasciculately branched, tomentose radiculose to near the 
apex; central strand small, 3 to 6m in diameter, of four to seven 
rows of cells, cells of ground tissue 13 to 32min diameter, cor- 
tex of one or two layers of cells 4.5 to 13.64, all tissues having 
thin walls ; branches slender, short, 0.4 to 1™ long, erect with tips 
generally inclined or curved, closely foliate; leaves lanceolate 
to ovate lanceolate, more or less long and narrowly decurrent, attain- 
ing greatest width in the basal fifth, usually near the line of 
insertion, 260 u wide by 780m long, varying in width from 180 
to 350m and in length from 550 to 1000p, in extremely large 
leaves reaching 500 wide by 1200p long, erect spreading 
crowded, not appressed when dry, straight or slightly falcate, 
gradually acuminate, acumen broad to tip, costate, costa gen- 
erally percurrent or nearly so,rarely ceasing just above the middle, 
Strong at base, sometimes thin and divided above or disappear- 
ing entirely for a short distance, one-fifth to one-sixth the leaf 
base at line of insertion, 30 to 50 wide; dentate or rarely 
almost entire at the base, teeth formed of a single or a double papilla 
over the transverse wall or by the protrusion of the adjoining corners 
of the marginal cells above, the teeth being of the ordinary 
form, but frequently recurved; leaf cells parenchymatous across 
the base, somewhat abruptly and regularly prosenchymatous 
above, those of the alar regions (excluding the decurrent wing) 
quadrate to short rectangular, 8.6 wide by 11.7 long, ranging 
from 7 to 12.54 wide and from 8.5 to 19m long, those near the 
