4 
CRYPTOGAMIA. ALG^. Lichen. 
B. (2) Crustaceous, with Tubercles. 
L. fagin'eus. Tubercles, white, mealy; crust white. 
Hqffm. Enum. 2. 4. and 7. 5 —( E. Bot. J713. E.)— Mich. 53. 2 and 1— 
Bill. 18. II. A. B. 
At first powdery, when older granulated. Tubercles nearly flat, white, with 
a thin border. Dill. (This species is extremely bitter. 
Variolaria amara. Achar. Hook. E.) On the bark of beech, horn-beam, 
&c. P. Jan.—Dec. 
Var. 2. Tubercles whitish, wrinkled; crust ash-colour. 
Bill. 18. 11. C. D. 
Dillenius thinks these the same as 1 j C. growing <Jn the smoother bark of 
younger trees, and D. as old and growing on walls. 
(Bitter Powdery-shielded Lichen. L. fagineus. Linn. Huds. and E. 
Bot. L. albescens. Gmel. Syst. Veg. and Huds. E.) On the bark of 
horn-beam, beech, and ash. Huds. And lime trees. Mr. Hollefear. 
P. Jan.—Dec. 
L. betuli'nus. Tubercle white, central; crust white. 
(E. Bot. 2281. E.) 
Ci'ust nearly half an inch diameter, circular, thin, fibrous. Tubercle solitary, 
hemispherical, nearly the size of a hemp seed. Huds. 
(Birch-bark Lichen. Opegrapha betulina. E. Bot. E.) On the trunk 
and branches of birch. A. Sept.—April. 
L. lac'teus. Tubercles white, not bordered, hemispherical: crust 
white. 
Jacq. Coll. iii. 4— Hoffm. Enum. 4. 6—(E. Bot. 2410. E.) 
Tubercles sometimes very pale greenish brown in the centre. On rocks and 
stones. Huds. 526. P- Jan.—Dec. 
(Milky-white Lichen. Variolaria lactea. E. Bot. Achar. Hook. E.) 
L. atro-al/bus. Tubercles white, not bordered; crust black. 
Jacq. Coll. ii. 14. 1. 
It is difficult to say which colour forms the crust. Linn. Crust wide 
spreading, thin, firmly adhering, mealy, rough, black, thickly set with 
very small sub-sphaeroidal tubercles, of a grey white colour. Jacq. Crust 
either blue grey, black or white, or rather, the proper crust is black, but 
this is very thin, very closely adhering, not always present, and then its 
place is sometimes supplied by the outer grey coat of the tubercles 
spreading upon the stone. Tubercles black, but before the crust which 
envelopes them breaks open they appear grey ; border none. 
(Bl ack and White Lichen. On rocks. On Muggleswick Fell, Durham. 
Mr. Winch. E.) On flints in the Isle of Wight. P. Jan.—Dec. 
Var. 2. Tubercles both black and white; border none. 
Such is the case in specimens with which Mr. Relhan and Mr. Dickson 
favoured me. Linnaeus seems, in his different works, to have described 
both these under the nam eatro-albus. I find no figure of this 2d variety, 
which grows upon peat earth as well as upon rocks. 
L. sim'plex. Tubercles black, plaited and wrinkled, of different 
shapes; crust none. 
