52 PARHELIA. 



b. effuse, squamulose ; the crowded squamules granulose at 



the margin, and passing now into a powdery crust. Lichen 



concolor, Dicks. PI. Crypt. Brit. 2, p. 18, t. 9, /. 8. Xanthoria, 

 Th. Fr. Lich. Scand.p. 147. Lecanora candelaria, a, Ach. Syn. 

 p. 192. Candelaria vulgaris, Mass.; Koerb. Syst. p. 120. 



On trees ; and now also on rocks ; common throughout the 

 northern States (Muhlenberg, in Hoffm. D. FL, 1796; where the 

 plant finds a place under the well-described Lichen candelaris; 

 as it does also under his Lecanora candelaria, a, in herb. Ach., 

 fide Th. Fr.) and found equally through the southern (Dr. Curtis, 

 etc.) to Texas (Wright) and as well in South America (Lindig 

 I. c.) b, has the same range; extending southward to Louis- 

 iana (Hale) and found also in the island of Cuba ( Wright Lich. 

 Cub. n. 79). This reduced form is certainly undistinguishable in 

 species from our a; and it does not appear to differ at all from 

 the commonly published states of the European lichen : which 

 compares with ours then much as the European T. polycarpus 

 and T. lychneus with the more luxuriant American. The exu- 

 berant development of fibrils is at length marked in a; and 

 suggests readily a comparison with some, in other respects often 

 well comparable forms, of our Physcia obscura. Though perhaps 

 less to be expected in b, it is probable that the fibrils of the 

 receptacle are not always wholly deficient even in this ; and 

 something like indications of them may be made out in Anz. 

 Lich. Ital. Sup. n. 131, if not also in Moug. & Nestl. n. 743, a. 



X. PARHELIA (Ach.) De Not. 



Apothecia scutellseform, sub-pedicellate ; the disk mostly 

 thin ; the hypothecium colourless. Spores ovoid, ellipsoid, 

 or oblong, simple, colourless. Spermatia oblong, constricted 

 at the middle and with mostly acute tips, or, rarely (n. 18), 

 needle-shaped and bowed ; upon sparingly branched, or now 

 sub-simple sterigmas. Thallus imbricate-foliaceous, lobate- 

 laciniate, appressed (rarely ascendant and E vermiform, very 

 rarely filiform and Alectorioid) sub-rnembranaceous ; more 

 or less densely, or now sparingly fibrillose, or rarely naked, 



beneath. Anatomy of the thallus given in Schweudener 



1. C. 3, p. 157. 



* Thallus glaucescent (varying also, rarely, to brown, or even 

 yellowish}. 



a. Stock of P. perlata. 



