RicciACEi*:. 731 



■:> * Thallus with white scales beneath {dark purple in n. 4), thr marqin naked . 



2. R. SOroc&rpa, Bist-h. Thallus 3-8" in (lianiotor, jkiIo f^rocn hecom- 

 ing whitish, finely reticulate, suhradiately or (lirlxjtoiiiously divideil, the olv 

 loug-linear segments subacute, deeply sulcato, Avith a few inconspicuous scales 

 toward the ajjex not extending beyond the margin ; margins erect when drv; 

 sjiores issuing through chinks early appearing along the groove a!)ove. — 

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

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



3. R. lamellbsa, Haddi. Thallus pale green, elegantly reticulated, suh- 

 radiately divided, the divisions obovate or obcordate, I)ifid or 2-lobed, 2- .'i" 

 long, channelled at the apex, with membranous a.scending 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 

 j)uri)le beneath and furnished with transverse semicircular scales not ex- 

 ceeding the margin. — Rocky ground, X. Y. {Turrc//), and Chester, Tenn. 

 {Porter). (Eu.) 



* * * Thallus more or less ciliate, naked beneath or obsoleteli/ squamous along 

 the extreme edcje. 

 .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 subspatu- 

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

 inconspicuous or nearly wanting ; cap.sules aggregated toward the apex ; 

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

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

 ui)per surfiK-e; divisions broader, more obtuse; spores nearly black, larger 

 (84-101 ;u) and smoother. — Cultivated fields and (the var.) rocky places, 

 Closter, N. J. {Austin). 



6. R. Lescuri^na, 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, clo.sely ciliate with short obtuse spine-like white hairs ; 

 capsules scattered, chiefly near the base of the divisions ; spores 71-83/1 broad, 

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

 N. J. to 111., and southward. 



§ 2. SI'ONGODES. Thallus u-ith large air-rarities usiatlly opening bij pits 

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

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

 globose ; tt'rresfri<d. 



7. R. cryst^Uina, L. Orbicular, 6-9" broad, the obcordate or cuneato 

 divisions l)ifid or i! lolied, flat above and the surface nnich broken up into jiit:*, 

 the margins subcrenate ; capsules .scattered ; spores i.^suing through the Ujiper 

 surface. — On mud flats. 111. {//all), west and southward. (Ku.) 



8. R. lutesceilS, Schwein. Orbicular, 1 - H' in diameter, light green ; 

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



