PORELLA. L. Sp. PI. 2:1106. 1753. 



By Wm. C. Barbour. 



One of the first hepatics to be found by one who is beginning the study 

 of the group is a dull brownish-green mass, usually growing at or near the 

 foot of a tree, on the bark. It was the first hepatic species to be identified by 

 the present writer, and in the packets sent to him for identification by 

 Chapter members and readers of the Bryologist, it figures prominently and 

 often. This species is Porella platyphylla. Like Frullania the leaves are 

 incubous and deeply bilobed, the lower lobe (lobule) being smaller than the 

 upper. In Northeastern America there are five genera whose leaves answer 

 to this general description, viz. : Frullania, Jubula, Lejeunea, Radula and 

 Porella. Of these, Frullania and Lejeunea can be readily distinguished 

 from Porella by their smaller size. Again, the lobule in Porella is ligulate, 

 while in Frullania and Jubula it is usually inflated, in Lejeunea it is simply 

 incurved, and in Radula it is subquadrate or nearly rotund. 



The plants are large, dark-green to yel- 

 lowish-brown, mostly 2-3 pinnate; root 

 hairs few, these at base of the underleaves. 

 Lobes very deeply two-parted, the dorsal 

 large, orbicular-ovate, and in most species 

 entire. Ventral lobes are much smaller, 

 sometimes nearly separate from the dorsal, 

 varying in different species from ovate or 

 oblong to lanceolate. Underleaves large, 

 entire or dentate, sometimes long decur- 

 rent at the sides. The male inflorescence 

 is in the form of spherical antheridia in the 

 axils of densely imbricate leaves, which 

 form short spikes or branches having some- 

 what the appearance of "a pine cone. They 

 are very readily recognized with the naked 

 eye, and are noticeably abundant in some 

 species, as, for example, P. navicularis. 



The perianth is oval to obovate, flat- 

 tened dorso-ventrally at the mouth, which 

 is ciliate, dentate or sometimes nearly 

 Fig. I. A. Porella platyphylla ^^^ire. 

 (L.) Lindb. Plant X i^- 



The following key to the species is taken from Dr. M. A. Howe's Mono- 

 graph, "The North American Species of the Genus Porella." Bull. Torr. 

 Club. 24: 517, 1897, by the kind permission of the author. 



