70 ACOTYLEDONs. — LICHENS. Collema. 



t. 2313. {exd. the Syn. nfLich. exilis Light/.) Conferva atro- 

 virens, Dillw. Ccnf. t. 25. Scytoncma atro-virens, Agardk 

 Disp. Alg. Suec. p. 39. 

 Hab. HockSj on the Highland mountains, not unfrequent. 



32. USNEA. 



Universal receptacle subcrustaceous, rounded, branched, gene- 

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

 tial recept. orbicular, terminal, peltate, entirely formed of thq 

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

 cumference without a margin and generally ciliated. 



1. \}. Jlorida, 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. 'Uch. p. 304. Lichen Jloridus, Lightf. 

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



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



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

 divided sublibrillose the ultimate ones capillaceous, apothecia 

 plane ijroad ciliated, cilise slender very long. Jch. Syn. Lich. 

 p. 30.1. Lichen pUcalus, Light/, p." 889. E. B. t. 257. 



(3. hirta, thallus nearly erect somewhat shrubby pale greenish 

 white very much i)ranched subpulverulent and roughish, 

 branches very much divided flexuose intricate attenuated sub- 

 fibrillose. Jlch. Syn. Lich. p. 305. Lichen hirtus, Light/. 

 p. 895. E.B. t. \3b4. 



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

 Barntimpen Linn, in the parish of Kirkpatrick, Dumfries-shire, 

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



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

 greenish grey, branches divergent liere and there fibrillose ca- 

 pillary at'their extremity articulated below, jlch. Syn. Lich. 

 p. 306. Lichen barhalus, Lighf/.p. 890. Lichen articulatus, /3. 

 E.B.t.25S. f2. 



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

 elongate dichotomously divided articulated, articulations swel- 

 ling distinct, ultimate branches capillary fibrillose. Lichen ar- 

 ticulatus, a. 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 becom.es hard and cartilaginous, 

 polymorphous (crustsform, foliaceous or branched). Partial 

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

 entirely formed of the substance oi'the thallus; the disk of the^ 

 same colour, rarely (in drying) coloured. 



