70 ACGTYLEDONS. LICHENS. Collcma. 



t. 2313. (excl. the Syn. of Lick, exilis Lightf.} Conferva atro- 

 virens, Dillw. Conf. t. 25. Scylonema alro-virens, Agardh 

 Disp. Alg. Sitec. p. 39. 



HAB. Rocks, on the Highland mountains, not unfrequent. 

 32. USNEA. 



Universal receptacle subcrustaceous, rounded, branched, gene- 

 rally pendulous, having in the centre an elastic thread. Par- 

 tial recepl. orbicular, terminal, peltate, entirely formed of the 

 substance of the thallus and nearly of the same'colour, the cir- 

 cumference without a margin and generally ciliated. 



1. U.jftorida, thallus nearly erect roughish greenish grey with 

 very numerous fine horizontal fibres, branches patent subsimple, 

 apothecia plane very broad whitish ciliated, the ciliae radiating 

 long. Ach. Syn. Lick. p. 304. Lichen Jloridus, Lightf. 

 p. 897. E. B. t. 872. 



HAB. Branches of old trees, not very uncommon, Lightf. 



2. U. plicata, thallus pendulous smooth pale, branches lax much 

 divided subfibrillose the ultimate ones capiljaceotis, apothecia 

 plane broad ciliated, ciliae slender very long. Ach. Syn. Lich. 

 p. 305. Lichen plicatus, Lightf. p. 889. E. B. t. 257. 



/3. hirla, thallus nearly erect somewhat shrubby pale greenish 

 white very much branched subpulverulent and roughish, 

 branches very much divided flexuose intricate attenuated sub- 

 fibrillose. Ach. Syn. Lich. p. 305. Lichen hirtits y Lightf. 

 p. 895. E.B.I. 1354. 



HAB. a. On the branches of old trees, but not common. In the 

 B'arntimpen Linn, in the parish of Kirkpatrick, Dumfries-shire, 

 Dr. Burgess. (3. Upon old trees and in hedges, frequent, Lightf. 



3. U. barbata, thallus pendulous smoothish rounded thickish pale 

 greenish grey, branches divergent here and there fibrillose ca- 

 pillary at their extremity articulated below. Ach. Syn. Lich. 

 p. 306. Lichen barlatus, Lightf. p. 890. Lichen articulates, /3. 

 E.B.t.25S.f. 2. 



/3. articulala, thallus glabrous greenish grey glabrous, branches 

 elongate dichotomously divided articulated, articulations swel- 

 ling distinct, ultimate branches capillary fibrillose. Lichen ar- 

 ticulatus, u. E. B. t. 258. 



HAB. Branches of old trees in thick woods and pine-forests. 

 33. COLLEMA. 



Universal receptacle entirely of one substance, sub-gelatinous, 

 which in drying generally becomes hard and cartilaginous, 

 polymorphous (crustreform, fojiaceous or branched). Partial 

 recept. scutelliform, sessile (rarely subpedicellate), margined, 

 entirely formed of the substance of the thallus; the disk of the 

 sairie colour, rarely (in drying) coloured. 



