HEPATIC AE 431 



the involucre, oblong, spheroidal, flattish, or ovoid-cylindrical, 

 slightly pedicellate, dehiscing in a 2-valved manner from the apex 

 halfway down by a suture, or rupturing irregularly. Columella 

 linear. Elaters wanting. Spores produced in Ifours. Monoicous. 

 Antheridia globular, immersed in the frond, which is orbicular, 

 laciniate, tender, undulate-crisped on the margin, with gemmae as 

 in Anthoceros. 



1. HT valvata, Sulliv. [ Valvate'] : Involucre horizontal, elon- 

 gated, tapering-deflexed ; capsule elongated-cylindrical, somewhat 

 curved, with a dark-colored suture ; spores light yellowish-brown. 

 Moist grounds. 



SUBORDER IV. RICCIA V CEAE. 



Frondose'annuals, mostly floating ; the fructification of both kinds immersed in the 

 frond ; involucre, perianth, and elaters, all wanting ; capsule bursting irregularly. 



59O. RIC'CIA. Mich. Floating Liverwort. 



[Dedicated to Pietro Francesco Ricci,& Florentine Botanist.] 



Fruit immersed in the lobed or cleft frond. Calyptra adherent to 



the sessile globose capsule, crowned with the persistent style. 



Spores angular. Monoicous, or dioicous. 



j- TERRESTRIAL : Frond witfiout air-cavities. 



1. R. uj a 11 i , L. [ Glaucous] : Frond somewhat stellate-lobed ; 

 divisions linear-obovate, emarginate-lobed, channelled, dotted, glau- 

 cous, membranous along the margin. Moist grounds. 



f t FLOATING (in still waters') : Frond with large air-cavities. 



2. R. fliiitaiis, L. [Floating] : Frond pale or yellowish-green, 

 radiately expanding from a centre ; divisions narrowly linear, re- 

 peatedly forking, nearly membranaceous, the apex thickened, 

 emarginate and cavernous. Ditches, &c. 



CLASS V. 



THAL'LOPHYTES.* 



VEGETABLES composed of parenchyma alone, of congeries of cells, 

 or of seperate cells, often vaguely combined in a thallus, never 

 exhibiting a marked distinction into root, stem, and foliage, or into 

 axis and leaves; fructification of the simplest kinds, the spores 

 often termed sporules and sporidia. 



ORDER CXXV. LICHENES. 



PERENNIAL plants, often spreading over the surface of the earth, or of rocks, or 

 trees, in the form of a lobed and foliaceous, or hard and crustaceous, or leprous 



*The Chester County Plants of this obscure Class have been investigated with 

 singular diligence and success, by my ingenious friend EZRA MICHENER, M. D. to 

 whose kindness I am indebted for the following account of them ; the Lichens 

 being arranged in conformity with the excellent work of EDWARD TUCKERMAN, A. M. 



