168 JUNGERMANNIACEAE 
late, bright yellowish-green ; elaters 2 75-325 t! х 9-10 p, obtuse, 
2- (3-) spiral. 
Exsicc. Hep. Bor.-Am. 9r. 
Hep. Am. 30. 
Common on trunks and branches of trees and more rarely on 
rocks throughout the Pacific Coast from California to Alaska; as 
far east as Idaho (Leiberg); Mexico (Jide Gottsche). 
Mill Valley (1215), Olema (1216, 1217); Duncan's Mills 
(1180), Cazadero (1 181), Sonoma Co.; Mendocino (563, 564), 
Navarro (Miss Edith S. Byxbee), Ukiah (776) ; Mission Hills, San 
Francisco (Ог. Kellogg); Lake Pilarcitos, San Mateo Co. (W. C. 
Blasdale) ; Santa Cruz Mts. (Underwood). Collected in California 
also by the botanists of Beechey's expedition (in herb. Taylor), Бу. 
Dr. Bolander and others, 
The original specimens were collected by Menzies on the wes- 
tern coast of North America, exact locality unknown. Linden- 
berg's specimen of “ Jungermannia navicularis n. sp." is preserved 
in the Naturhistorisches Museum at Vienna. We are indebted to 
Prof. Dr. G. von Beck for the privilege of seeing a portion of this. 
type. The European plants referred by some authors to Porella 
navicularis probably all belong with P. platyphylla or P. laevigata. 
This species in a fertile condition can always be very easily distin- 
guished from any simulating form of 2 platyphylla by the broadly 
obovate perianth, scarcely narrowed at the mouth, and by the twice 
larger diameter of the spores. When sterile, if more obvious 
characters fail, the numerous, small, thick-walled cells filling the 
inferior basal wing of the dorsal lobe are of importance ; these are 
Д-И the diameter of the cells in the middle of the lobe while in 
P. platyphylla the cells are nearly of a uniform size throughout the 
lobe or slightly smaller at the basal margin. 
In two cases, we have observed a peculiar modification of Por- 
ella navicularis due, we believe, to the influence of an epiphytic 
fungus, The leaves were here bilobed rather than bipartite, the 
union of the lobes resembling that of Lejeunia or Radula. The 
ventral lobes were shortened so that their longer axis was nearly 
parallel to that of the dorsal lobe and were conspicuously inflated 
as in most of the Zejeuniae. The underleaves were also shortened 
and often ventricose. In fact, when, as sometimes happened, а 
