525 
basal angles slightly smaller, all with evident trigones; ventral 
lobes ovate, linguiform or ovate-oblong, usually much narrowed 
toward the obtuse or subacute apex, suberect or patent, scarcely 
connate with the dorsal, commonly about % as wide as the un- 
derleaves, length 24 the width of the dorsal, somewhat concave 
ventrally, margins plane or slightly recurved, a little decurrent, 
very rarely dentate above, more or less strongly spurred at the 
base, especially at the outer angle, the spur entire or dentate, 
rarely subciliate; underleaves approximate, ovate-linguiform, 
rounded-obtuse, the margins recurved, long-decurrent, entire or 
most rarely subdentate, the wings sometimes crisped: dioicous: 
g spikes 1-2 mm. long; ? branch somewhat elongated, bearing 
3-8 leaves (or ‘“bracts’’) (usually 2 pairs) nearly similar to the 
cauline ; inmost bracts a little larger, the lobes subacute, entire, 
repand-dentate, or sparingly denticulate, bracteole ovate, subentire 
or denticulate ; perianth large, somewhat goblet-shaped or broadly 
obovate, undulate-concave ventrally, here and there inflated, 
scarcely narrowed or lobed at the wide truncate dentate mouth, 
the oral margins plane or slightly deflexed at the sides. 
Exsicc. Can. Hep. +4 (as Porella Bolanderi var.). 
Under shelving rocks and on moist shaded cliffs, rarely on tree- 
trunks. Washington: Kitchelos Lake (Roell, June 12, 1888) ; 
Olympia (Henderson, 1892, no. 2594). British Columbia (Ma- 
coun) : Cascades, Yale (May 1875, also at Yale, May 17, 1889, 
no. 61); Mt. Benson, Vancouver Island, June 8, 1887; near 
Victoria (May 12, 1893, no. 7,and May 30, 1893, no. 63). Ore- 
gon (Pringle, 1881, no. 502, in part). California (Howe): Mill 
Valley (no. 1168) and Mt. Tamalpais (no. 1171), Marin Co. ; 
near Cazadero (no. 1170), Sonoma Co.; Ukiah (no. 759) and 
Navarro (Miss Edith S. Byxbee), Mendocino io. % Blue Lake 
(no. 994) and Deer Creek (nos. 1068 and 1073), Humboldt Co. ; 
Hay Fork (no. 1109), Trinity Co. 
Type from Kitchelos Lake, Washington (Roell, June 12, 1888) 
—in Herb. Stephani, Leipsic. Type duplicate in Herb. Under- 
wood, . 
Porella Roellii is closely related to the forms of the European 
P. laevigata with obtuse dorsal lobes and subentire ventral lobes 
and underleaves, as represented, for example, in Carrington and 
Pearson’s no. 275 Hep. Brit. Exsicc., from Scotland. This is — 
