RICCIACE^. 731 



* * Thalhis with, white scales beneath [dark purple in n. A), the margin naked. 

 2. R. sorocarpa, Bisch. Thallus 3-8" iu diameter, pale green becom- 

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

 long-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 X. Y.- 

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



"3. R. lamellosa, 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. nigrella, 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. arvensis, 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 subs])atu- 

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

 inconspicuous or nearly wanting ; capsules aggregated toward the apex ; 

 spores 71-84/i broad, dark fuscous, reticulate, with pellucid margin. 7— Var. 

 HiRTA, Aust., decidedly ciliate and w^ith spine-like hairs scattered over the 

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

 (84- 101 /t) 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 7 1 - 83 yu broad, 

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

 N. J. to 111., and southward. 



§ 2. SPONGODES. Thallus ivith large air-cavities usually opening bi/ pits 

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

 ichich are prominent beneath; spores 41-51/i broad, obtusely angular or 

 globose ; terrestrial. 



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

 divisions l)ifid 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. lutescens, Schwein. Orbicular, 1 - 1^' in diameter, light green ; 

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



