Collema.] I.ICHENES. 207 



following species have a remarkably fetid smell, which has been com- 

 pared to that of the urine of mice. 



8. S. sylvdtica, Ach. (jtitted wood Stictci); thallus spreading 

 of a greenish-rusty hue (brown and glossy when dry) some- 

 what pitted and often rough with grey scattered granulations, 

 deeply divided into lohed and sinuated rather ascending seg- 

 ments, beneath tawny-brown downy and fibrous with pale naked 

 cyphellse, apothecia " on marginal segments vertical convex 

 dark-brown." — Ach. Syn. p. 236. — Lichen sylvatieus, Huds. — 

 E. Bot. t. 2298. Jacq. Coll. v. 4. t. 12. f. 2.—Pdtigera sylv., 

 Hoffm. PI. Lick. v. 1. /. 4./. 2.— Dill. Muse. t. 27. f. 101. 



Shady woods, about the roots of trees in mountainous countries : fre- 

 quent in Scotland. — The fructification is unknown to me, except from 

 the figures of Jacquin and Hoffman ; but Sir Jas. E. Smith confirms 

 the correctness of these by the recollection of a fine specimen in that state 

 sent by Dr. Burgess to Dr. Hope. The apothecia are terminal, on pe- 

 culiar segments of the frond and are very similar to those of a Peltidea, 

 to which genus (his Peltigera) Hoffmann indeed referred it ; but from 

 which it is distinguished by the presence of cyphellce the underside of the 

 frond. 



** Thallus, in a moist state, of a gelatinous substance. 



FAM. X. COLLEMATEiE. 



20. Colle3IA. Ach. Collema. 



Thallus entirely of one substance, gelatinous, when dry gene- 

 rally becoming liard and cartilaginous, polymorphous, granulated, 

 foliaceous, lobed, laciniated or branched. Apothecia (sct/tellcc) 

 orbicular, sessile (rarely stipitate), bordered, entirely formed of 



the substance of the thallus, the disk sometimes coloured 



Named from y.o?.Xa, gluten ; on account of the gelatinous nature 

 of the whole plant. — In drying, these plants are necessarily much 

 altered in form, and from this and their variable character there 



i«- considerable difficulty in the determination of the Bpecies. 

 * Thallus somewhat crustaceans, uniform. 



1. C. nigrum, Ach, {inky Collema); crust of a sooty-black 

 composed of very minute imbricated lobed and cut leaflets the 

 margin bluish, apothecia scattered small black at first bordered 



and concave at length convex. — Adt. Syfl, p. 306. — Lulu n ///</</; 



//„,/,.— /;. Bot t. 1161. 



()n shady rocks, especially such as arc calcareous. This Uckenfanaa 

 ink-like stems upon the rocks on which it grows. 



** Thallus mtlu r broadly lobed over tin whole surface, imbricated, 

 plaited, spreading, and becoming very turgid when "-it. 



•J. ('. mi er o p kjUum, Ach. (smaU-lobed Collema); lobes of the 

 thallus crowded imbricated minute pulpy much divided) ulti- 

 mate segments roundish crenulate somewhat convex, apothecia 



