OF ARTS AND SCIENCES. 401 



in the light of our present knowledge of the spores and spermogones, 

 by Dr. Nylander, may still perhaps be regarded as between Physcia 

 {Parmelia § Physcia, Fr.) and Pannaria {Parmelia § AmpMloma and 

 Psoroma, Fr.) : and Eschweiler, it is 'observable, places his Lecidea 

 albo-virens (Lich. Bras, in Mart. Fl. Bras. 1, p. 256), which is clearly 

 Pyxine sorediata, as first observed by Montagne (PL Cell. Cub. in 

 Sagi-a's Hist. Cub. p. 188), in the near neighborhood of his Lecidea 

 (now Pannaria) micropkylla, in which, moreover, he only followed 

 Acharius. There are several points in Dr. Montagne's description 

 and illustration of his P. sorediata (Cuba, 1. c. p. 188), and especially 

 his figure b, seemingly indicating our present species, which is finally 

 very like smoothish states of the next, and may well occur without 

 any trace of its originally Physciaceous fructification ; in which case it 

 should hardly be separable from P. Cocoes {P. sorediata, Fr.), unless 

 by the color of its medullaiy layer, to be considered farther on. And 

 thus the remarkable development of the apothecia of P. Meissneri 

 mig-ht be taken as of value rather as enabling us to determine the true 

 structui'e and natural position of the genus, than- as a specific distinc- 

 tion ; but, however the final state of the new species may approach the 

 old, I have examined many hundreds of specimens of the latter, in its 

 best condition (P. Cocoes )3. sorediata), without finding the least trace 

 or indication of the originally Lecanorine fructification of the former. 

 Spores of P. 3feissneri, lineai'-oblong, and more than thrice as long as 

 wide, at first colorless and simple, an elongated sporoblast occupying 

 the centre, but soon becoming fuscescent, and the sporoblast separat- 

 ing into two roundish ones, which are connected by a narrow isthmus, 

 remaining at least until the central dissepiment appears : these sporo- 

 blasts finally increasing in size till they meet the walls of the spore, 

 when the well-marked limit of each, and the empty ends of the spore 

 beyond it look like other dissepiments and sporoblasts, and the spore 

 might be called 3-septate (comp. Montag. Cuba, 1. c, but the descrip- 

 tion, as I understand it, is not illustrated by the figure given ; and also 

 Eschweiler, 1. c, p. 246), which I think it is not. 



Pyxine Cocoes (Sw.), Nyh Enum. Gen. 1. c. p. 108. Lichen Co- 

 coes, Sw. in Ach. Prodr. p. 106. Lecidea, Ach. Meth. p. 84; Li- 

 chenogr. p. 216; Syn. p. 54. On Cocoa Palms in Jamaica, Swartz 

 (ex Ach.) ; and in Cuba, 3Ir. Wright. Also in Nicaragua, 3Ir. Wright 

 (U. S. N. Pacif. Expl. Exp.). Acharius distinguished this from his 



VOL. IV. 51 



