518 
imbricate, horizontal, commonly deflexed or convolute in drying, 
oblong or ovate, rounded-obtuse, 1-2.5. mm. x .65—-1.7 mm., mar- 
gins plane or the inferior slightly inflexed, entire, cells mostly 
with inconspicuous trigones; ventral lobes minute, closely ap- 
pressed to the stem or to the dorsal lobes, very nearly or wholly 
discrete, lingulate-oblong or subfalcate, flat, with plane margins or 
slightly concave ventrally, obtuse, entire, not decurrent, .25-.68 
mm. x .I—.27 mm., length usually equaling 1-2? the width 
of the dorsal lobe ; underleaves subquadrate or short-oblong, dis- 
tant, appressed, scarcely decurrent, equaling stem in width or oc- 
casionally twice as broad, margins plane, entire, apex rounded or 
rarely repand-emarginate: dioicous: perianth obovate-pyriform, 
4-5 times the length of the bracts, slightly crenulate at mouth ; 
lobes of bracts entire or subrepand-crenulate ; bracteole oblong, 
entire ; spores 30-42 yp, papillate; elaters 2-(3-4-) spiral, 170- 
—240 BXQ-14 p. 
Exsicc. Drumm. Musc. Am. (Southern States) 167, 168 
(both as Jungermannia platyphylla). 
Musc. Allegh. 264. 
Hep. Bor-Am. 92, 92°, 93 (as Madotheca involuta), 94 (as 
Madotheca Sullivantii). é 
Hep. Am. 9, 115 (as Porella involuta), 175. 
Can. Hep. 85. 
On banks of shaded streams and on rocks and logs subject to 
overflow. Common in eastern North America from Nova Scotia 
to Louisiana. Owen Sound, Ontario (Macoun); Indiana (Under- 
wood) ; Illinois (Schneck) ; Missouri (Demetrio) ; Arkansas (Co- 
ville) ; Cuba (Wright). 
Type from Pennsylvania—in the Dillenian Herbarium at Ox- 
ford, England. 
Usually collected in a sterile condition. Jungermama distans 
Schwein. is a form with rather remote leaves, found especially in 
the Southern States. Madotheca involuta Hampe differs from the 
typical form only in unimportant and wholly inconstant charac- 
ters. The leaves are a little more imbricate, their inferior mar- 
gins sometimes more inflexed ; in drying, the leaves are closely 
wrapped about the stem or decurved and the branches often sub- 
circinate. It produces sporogonia more freely than the type and — 
evidently grows in somewhat drier situations. What is apparently 
