684 (84) HEPATIC^, (liverworts.) 



2. R. Beyrichiana, Hampe. Frond oblong-linear, thickened and bi- 

 fid at the apex, narrowly channelled above, dark purple beneath ; the margins 

 entire, ascending. — Tennessee. 



3. R. bifurca, Hoffm. Frond suborbicuiar, pale-green; its divisions 

 wedge-shaped, 2-lobed at the apex ; lobes spreading, dotted, broadly channelled 

 above, purplish beneath, the thickened margins ascending. — " North America." 

 (G.L.Sr N. Syn. Hepat. p. 600.) (Eu.) 



* * Frond with large air-cavities : terrestrial or aquatic. 



4. R. natans, L. Frond inversely heart-shaped, channelled above (3" - 

 5" broad), clothed beneath M'ith long pendent rootlets in the fonn of linear-lan- 

 ceolate, serrate, purple fringes ; capsules in two rows, lengthwise of the frond. 



— Floating on the surface of stagnant water. (Tab. VI.) (Eu.) 



5. R. fluitaus, L. Frond radiately expanding (1' or more in diameter) ; 

 divisions naiTowly linear, repeatedly forking, nearly membranaceous ; at the 

 apex thickened, emarginate and cavernous ; capsule protuberant from the lower 

 surface of the frond. — Floating on stagnant water. (Eu.) 



6. R;, lutescens, Schwein. Frond light-green, orbicular, 1' - 1^' in di- 

 ameter ; the divisions 6-8, linear, 2-3 times forking, channelled above, obcor- 

 date at the exti-emity, thickened, with whitish obliquely-ovate and appressed 

 scales beneath. — On the ground, margins of ponds, &c. — Fruit unknown. — 

 {Sulliv. in Mem. Amer. Acad. n. ser. 4, p. 176, t. 4.) 



7. R. crystallina, L. Frond orbicular, 4" - 6" in diameter ; its di- 

 visions obcordate or Hnear-bifid, the margins subcrenate, the surface broken up 

 by deep pits, communicating -nith the air-cavities. — Damp ground. — Fruits 

 abundantly. (R. velutina. Hook. Ic. PI. t. 149, is founded on sterile fronds of 

 No. 6, and fertile fronds of No. 7.) (Eu.) 



2. SPHJEROCARPUS, Mich. Round-headed Liverwort. 



(Tab. VI.) 



Involucre sessile upon and continuous with the frond, obtusely conical or 

 pyriform, perforated at the apex, 1-fi-uited. Capsule globose, closely invested 

 by the calypti'a. Spores round, mmiculate. (Antheridia in folliculose bodies 

 on the surface of separate fronds. Wilson.) (Name composed of a-cj^alpos, a, 

 sphere, and Kapms, fruit.) 



1. S. Michelii, Bellardi. Frond orbicular, 3" -6" in diameter, lobed, 

 entirely concealed by the numerous aggregated inflated involucres, which are 

 about I" long, and 4-5 times larger than the capsules. (S. ten-estris of authors.) 



— Cultivated fields. South Carolina, Curt/s, iJai-eweL (Tab. VI.) (Eu.) 



Suborder H. ANTHOCEROTE^. 



Terrestrial, frondose annuals, vrith the fruit protruded from tlie upper 

 surface of the frond. Perianth none. Capsule pod-like, mostly 1-2- 

 valved. Columella filiform. Elaters none or imperfect. 



