708 JUNGERMANNIACE^E. (SCALE-MOSSES.) 



spicate leaves. (Radula, a scraper or spatula, in allusion to the form of the 

 perianth.) 



* Lower lobe subquadrate, barely incumbent on the stem. 



1. B. COmplanata, Dumort. Creeping, widely subpinnately branch- 

 ing ; leaves imbricate, spreading, rounded, the lower lobe obtuse or acute ; 

 monoecious ; perianth obconic, compressed, the mouth entire, truncate ; anthe- 

 ridia in the bases of 2 - 3 pairs of strongly imbricate tumid leaves. On rocks 

 and roots of trees ; common. (Eu.) 



2. R. obconica, Sulliv. (PL 24.) Smaller, indeterminately branched ; 

 leaves somewhat remote, round-obovate, convex; monoecious; perianth cla- 

 vate-obconic, obliquely truncate ; antheridia axillary on short lateral branches 

 rising near the terminal involucre. On trees in cedar swamps, N. J. to Ohio. 



* * Lower lobe small, rounded, more or less transversely adnate. 



3. R. t6nax, Lindb. Stems brownish-green, rigid, tenacious; leaves 

 remote, scarcely decurrent, obliquely elliptic-ovate, opaque, the cells round 

 and strongly chlorophyllose ; dioecious; the antheridial spike lateral below 

 the keel of a leaf, long, linear, somewhat obtuse. (R. pallens, Sulliv. ; not 

 Gottsche.) On rotten trunks, in the Catskill Mts., and southward, especially 

 in the mountains. 



5. P OREL LA, Dill. (PI. 24.) 



Leaves large, incubous, complicate-bilobed ; lower lobe ligulate, suberect ; 

 underleaves similar, decurrent at base, the apex entire. Dioecious. Fruit on 

 a short lateral branch. Involucral leaves usually 4, 2-lobed, the margin ciliate 

 or denticulate ; perianth somewhat oval, compressed, bilabiate, incised or entire. 

 Calyptra globose, persistent. Capsule globose, reddish, short-stalked. Elaters 

 very numerous, 2-3-spiral, free. Spores large, rough. Antheridia solitary in 

 the saccate bases of leaves, crowded in short spikes. (Name a diminutive of 

 porus, an opening.) 



# Leaves more or less remote ; stems bipinnate. 



1. P. pinnata, L. Stems irregularly pinnate, fastigiate at the ends, 

 leaves scarcely incubous, ovate-oblong, the rounded apex sometimes slightly 

 decurved ; lower lobe minute, flat, oblong, obtuse, as long but not half as wide 

 as the flat, entire, ovate-rectangular, scarcely decurrent underleaves. (Mado- 

 theca Porella, Nees.) On rocks and trees subject to inundation; common. 

 (Eu.) 



* # Leaves mostly closely imbricate ; stems mostly simply pinnate (or bipinnate 



in n. 2). 



2. P. platyph^lla, Lindb. (PI. 24.) Yellowish or fuscous-green; 

 stems irregularly pinnate, often fastigiate at the ends ; leaves obliquely ovate, 

 more or less concave at base and the rounded upper margin curved upward 

 and undulate, mostly entire ; lower lobe obliquely ovate, the margin strongly 

 recurved, with an acute tooth at base ; underleaves semicircular, with strongly 

 reflexed margins. (Madotheca platyphylla, Dumort.) On rocks and trees; 

 common eastward. (Eu.) 



3. P. Thtlja, Lindb. Fuscous-green or blackish, somewhat regularly 

 pinnate ; leaves convex, closely appressed, obliquely round-ovate, the rounded 



