OF ARTS AND SCIENCES. 401 



philoma. And Pannaria (proper) furnishes similar degenerations of 

 the foliaceous type to that we are about to describe, but scarcely a 

 hypothallus offering in the young state the precise features of this. 



Physcidia squamulosa, sp. nov. : hypothallo fibrilloso radiante 

 demum byssino-pannoso granula squamacea albida mox lobulata ramu- 

 lis coralloideis nunc obsessa crustaceo-coacervata pi'oferente ; apothe- 

 ciis planis crenulatis dein flexuoso-lobatis subaurantiis. Sporae acicu- 

 lares, gracillimte, diam. 6 - 12-plo longiores. On trees, in dense forests 

 in Cuba, Mr. Wright. Thallus crustaceous, of minute, roundish scale- 

 like granules, scattered over the hypothallus (which does not attain at 

 once to its pannose development, but appears at first as rather sparse, 

 elongated, radiant, white fibrillas), becoming later lobulate, and often 

 beset with coralloid branchlets, as in P. Wrightii, and finally crowded 

 together into a granulose white crust. Apothecia very like those of 

 P. Wrightii and equally large, perhaps more commonly orange : 

 spores as in that, or possibly a little slenderer. As respects habit, 

 a Lecanora ; but in fact a degeneration of the foliaceous type ex- 

 pressed by Physcidia Wrightii. Large sets of specimens of both 

 lichens have afforded me no clear indication of the passage of one into 

 the other ; but such passage appears probable. 



Pannaria flabellosa, sp. nov. : thallo minuto livido-cineras- 

 cente, laciniis lineari-angustatis dissectis, centralibus teretiusculis con- 

 gestis, periphericis flabelliformi-expansis planis striatis, hypothallo 

 viridi-cterulescente ; apotheciis minutis biatorinis sparsis, margine in- 

 tegerrimo mox viridi-cjeruleo (nigro) discum planum rufum (nigri- 

 cantem) vix superante. Sporas octonae, oblongo-ellipsoidese, dein sub- 

 dactyloideiE, tetrablastae, diam. 2J--3-plo longiores. On talcose schist 

 and on granite in Vermont, Mr. Frost. A minute species, occurring in 

 rounded or irregular patches, smaller in its parts than P. crossophylla ; 

 found on similar rocks in Vermont by Mr. Russell, and described in 

 this journal, 4, p. 404, — and comparable rather, except as regards 

 size, with P. tryptophylla ; from which it differs in the color and divis- 

 ion of its thicker, narrower, plano-convex, or, in the circumference, 

 flat, but never concave, finely striate lobes, which never become gran- 

 ulose-corallinoid. The apothecia are not a little like those of P. nigra 

 (Huds.), Nyl. Lich. Seand. p. 126 (^Collema nigrum, Ach. ; Parm. tryp- 

 tophylla, var. corallinoides, Auct.), with which (separated by Koerber 

 and other late writers as a distinct generic type of CoUemacei) the 

 spores also appear to connect it. But the thallus sufficiently distin- 



VOL. V. 51 



