



RICCIACE^. 731 



* * Thallus with white scales beneath (dark purple in n. 4), the margin naked. 



2. H. sorocarpa, Bisch. Thallus 3- 8" in diameter, pale green becom- 

 ing whitish, finely reticulate, subradiately or dichotomously divided, the ob- 

 lorig-linear segments subacute, deeply sulcate, with a few inconspicuous scales 

 toward the apex not extending beyond the margin ; margins erect when dry ; 

 spores issuing through chinks early appearing along the groove above. 

 Thin rocky soil and cultivated fields, Closter, N. J. (Austin), western N. Y. 

 ( Clinton), and 111. (Hall). (Eu.) 



3. R. lamellbsa, Raddi. Thallus pale green, elegantly reticulated, sub- 

 radiately divided, the divisions obovate or obcordate, bifid or 2-lobed, 2 - 5" 

 long, channelled at the apex, with membranous ascending margins, and fur- 

 nished beneath with transverse scales which extend considerably beyond the 

 margin; spores much as in n. 2. Thin rocky soil, Closter, N. J. (Austin). 



4. R. nigr^lla, DC. Thallus dichotomously divided, the divisions linear, 

 channelled, with entire narrowly membranous margins, green above, dark 

 purple beneath and furnished with transverse semicircular scales not ex- 

 ceeding the margin. Rocky ground, N. Y. (Torrey), and Chester, Penn. 

 (Porter). (Eu.) 



* * * Thallus more or less ciliate, naked beneath or obsoletely squamous along 

 the extreme edge. 



5. R. arv^nsis, Aust. Thallus much divided, 3-9" broad, papillose- 

 reticulate, dull green both sides, becoming fuscous above, the flat margins at 

 length purple ; divisions sulcate, dichotomous, the linear-elliptic or subspatu- 

 late lobes acutish and obsoletely emarginate ; cilia whitish, very short and 

 inconspicuous or nearly wanting; capsules aggregated toward the apex; 

 spores 71-84 /* broad, dark fuscous, reticulate, with pellucid margin. Var. 

 nf RTA, Aust., decidedly ciliate and with spine-like hairs scattered over the 

 upper surface; divisions broader, more obtuse; spores nearly black, larger 

 (84- 101 /i) and smoother. Cultivated fields and (the var.) rocky places, 

 Closter, N. J. (Austin). 



6. R. Lescuriana, Aust. Stellately or subcruciately divided, the obcor- 

 date or cuneate-linear divisions 2 - 6" long, punctate-reticulate, subglaucous 

 or ashy-green both sides or becoming purple beneath, the slightly concave 

 lobes emarginate, closely ciliate with short obtuse spine-like white hairs ; 

 capsules scattered, chiefly near the base of the divisions ; spores 71 - 83 /A broad, 

 dark brown, reticulate, not margined. Cultivated fields and rocky grounds, 

 N. J. to 111., and southward. 



2. SPONG6DES. Thallus with large air-cavities usually opening by pits 

 through the upper surface, and with slight depressions over the capsules 

 which are prominent beneath; spores 41-51/* broad, obtusely angular or 

 globose ; terrestrial. 



7. R. crystallina, L. Orbicular, 6-9" broad, the obcordate or cuneate 

 divisions bifid or 2-lobed, flat above and the surface much broken up into pits, 

 the margins subcrenate ; capsules scattered ; spores issuing through the upper 

 surface. On mud flats, 111. (Hall), west and southward. (Eu.) 



8. R. lut^SCens, Schwein. Orbicular, 1 - 1% in diameter, light green ; 

 divisions 6-8, linear, 2-3 times forked, narrowly channelled, obcordate and 



