400 PROCEEDINGS OF THE AMERICAN ACADEMY 



Physcidia Wrightii. Physcia ? Wrightii, Tuckerm. Suppl. 2, in 

 Amer. Journ. Sci., 28, p. 204. On vai-ious trees, in dense woods, in 

 the island of Cuba, 3Ir. Wright. Thallus foliaceous (with much of the 

 aspect of Physcia proper, as also of smooth states of P. Domingensis, 

 Montag.), suborbicular, thin, narrowly lobed ; the largest states four 

 inches in diameter, and the flat or flattish lobes often exceeding, in 

 such states, a line in width, but perhaps as common in smaller and 

 more narrowly divided conditions ; imbricated now closely, with even a 

 subconnate aspect, and now very loosely, when the delicately linear lobes 

 appear often as if ciliated ; irregularly and above somewhat palmately 

 many-cleft ; sending out here and there terete, simple, or rarely a little 

 branched, finally crowded, coralloid branchlets, the longest of which ex- 

 ceed three lines in length ; from pale greenish becoming greenish-straw- 

 colored (the larger states often darker, or even glaucescent), and at 

 length a little yellowish, when the color of the fruit is also intensified. 

 Hypothallus of very delicate, colorless, much-branched, anastomosing 

 filaments (resembling those of Parmelia {Amphiloma) gossypina, 

 Montag. Cub. p. 217, but less slender), Avhich are closely intertangled 

 into a sometimes dense, but more commonly thinnish, and at length 

 even obsolescent web. Apothecia scattered, middling-sized (about a 

 line in diametei'), or largish; the inflexed, plicate-crenulate (or, as it 

 were, effigurate) margin becoming flexuous-lobulate, when the cxciple 

 reaches two or even three lines in diameter ; the naked, waxy disk 

 varying in color from pale yellow to orange, and imposed upon a thin- 

 ner, colorless hypothecium, which rests upon the white medullary layer. 

 Spores in eights, in club-shaped spore-sacks, smallish, colorless, acicular, 

 commonly tri-septate (tetrablastish), but at length (if I mistake not) 

 pluriseptate (pleioblastish), the length from eight to sixteen times ex- 

 ceeding the diameter. Paraphyses indistinct. Spermogones not 

 observed. — But beside this typical condition of the plant before us, 

 there occurs (and is represented by a large set of specimens) another, 

 which, though inseparable in essential characters, differs so much as to 

 appear at first sight scarcely congenerical. " Hypothallus optimas 

 prajbet differentias, sed in speciminibus perfectis et junioribus observan- 

 dus." Fr. Lich. Eur. p. 130. It has been observed already, that the 

 lichen above described recedes obviously from Physcia in its pannose 

 hypothallus, in which it approaches Pannaria, and especially the aber- 

 rant tropical type {Pann. gossypina, Montag.) which Dr. Nylander 

 (Enum. Gen. p. 110) has provisionally connected with his genus Am- 



