732 RICCIACE^. 



thickened at the apex, with delicate whitish obliquely ovate appressed scales; 

 rootlets wanting beneath above the middle ; fruiting plant unkuowu. — Dried 

 up pools and ditches, Canada to Mo., and southward. An analogous form has 

 been developed by Lindberg from K. nataus. 



9. R. tenuis, Aust. Thallus thin, olive or yellowish-green, shining, the 

 2-4 divisions roundish-obovate, 2-4" long, flat, with sinuate margins, green 

 beneath with a slender costa and few rootlets ; capsule very delicate, closely 

 adherent to the substance of the thallus, minutely apiculate ; spores round or 

 short-oval, conspicuously depressed at one end when dry. — AVet ground in 

 open woods, Closter and Lawrence, N. J. {Austin), and Mo. {Hall). 



§ 3. EICCIELLA. Thallus linear ^ d ichotomous, Jtoating or rarely terrestrial i 

 capsule protuberant from the lower surface. 



10. R. fluitans, L. Thallus often in extended patches, tliin, green, ra- 

 diately expanding, the often imbricate divisions | - H" wide, parallel-nerved, 

 flat, without rootlets, cavernous only toward the slightly dilated very obtuse 

 or subtruncate apex ; capsules present only in some terrestrial forms, very 

 prominent below, rupturing beneath the apex. — Very variable. Tlie most not 

 able form is var. Scllivanti, Aust., with divisions about |" wide, channelle;!, 

 cavernous throughout, the margins crisped-crenulate, and rootlets numerous 

 on the costa tumid with abundant capsules, which are tipped with a long 

 funnel-mouthed point ; spores obscurely angled, reticulate and margined. 

 (R. Sullivanti, ^1ms/.)_ — In ponds or ditches or growing in wet places upon 

 the ground ; the variety often in cultivated fields. (Eu.) 



§ 4. RICCIOCARPUS. Thallus ohcordate, floating or rarely terrestrial ; cap- 

 sules not fjrotruding, at length exposed by a cleft in the central groove. 



11. R. natans, L. (PI. 22.) Divisions obcordate or cuneate, broadly 

 emarginate, 3-6" long, purplish, very narrowly channelled, with numerous 

 uniform air-cavities beneath the epidermis, rooting toward the base and at 

 length with dark purple scales beneath the apex ; capsules in 1 or 2 rows 

 beneath the groove; spores black, angular, strongly papillose. — Canada to 

 the Gulf. (Eu.) 



2. SPH^ROCARPUS, Micheli. (PI. 22.) 



Thallus lobed, without costa or epidermis. Involucres sessile, obconic o* 

 pyriform, perforated at the apex, continuous with the thallus at base. Caiyp- 

 tra closely investing the single globose indehiscent capsule, crowned with a 

 deciduous point. Spores globose, muriculate, remaining united in a coccus. 

 Antheridia borne in follicular bodies on the surface of a separate thallus. — 

 An anomalous genus, perhaps more closely related to the Jungermanniaceee. 

 (Name from crcpaTpos, a sphere, and KUfyirSs, fruit.) 



1. S. terrestris, Smith. Thallus orbicular, 3-6" broad, covered by 

 the clustered inflated involucres, which are nearly 1" long, 3-4 times the 

 length of the capsule ; coccus 102 - 127/i wide, indistinctly lobed. (S. Michelii 

 Bellardi.) —In cultivated fields, mostly southern. (Eu.) 



