CRYPTOGAMIA LICHENES. 77 



bread. Without this addition, the flour would not have 

 produced more than 78f Ib. of bread; consequently, this 

 addition of 6 Ib. and 22 loths of lichen meal has occasion- 

 ed an increase of 32 f of good bread. It is known, that 

 3 Ib. of flour yield 4 Ib. of household bread. One Ib. of 

 lichen meal, added in the form of paste, gives an addition 

 of nearly 6 Ib., and therefore is equivalent in this view 

 to about 3 1 Ib. of flour, because it affords above 3-J times 

 more bread than this. But at present nearly all the Ice- 

 land moss collected in Germany is sent thiough Ham- 

 burgh to England, where it is used in brewing, and in the 

 composition of ship-biscuit, as it is said biscuit which con- 

 tains it as a constituent part is not attacked by worms, 

 and suffers little from the action of sea-water. This li- 

 chen, when deprived of its bitter principle, forms an ex- 

 cellent soup, and when coagulated, a good jelly ; and it 

 has been recommended in this prepared state as an excel- 

 lent substitute for sago, salop, and even for chocolate." 

 Edin. Phil. Journ. iii. 414. See also Mr NEILI/S paper on 

 Lichens, p. 737, .for some interesting particulars. 



2. C. glauca, depressed, membranous, thin, irregularly lobed, 

 greyish-white, beneath black and glossy. HOOK. Scot. ii. 57- Li- 

 chcn glaucns, LIGHTF. Scot. 838. WITH. iv. 57. Eng. Bot. t. 160t>. 

 Parmclia glauca, SPREXG. Syst. Veg. iv. 283. 



Hab. On stones in moors and on heather. Lamberton 



moor. 



The fronds form loose ' straggling <tufts, are thin and mem- 

 branous, irregularly lobed, the lobes ascending, laciniate 

 and curled, greyish-white, smooth, and somewhat glossy 

 above, but beneath very glossy black, wrinkled, the ends 

 of the lobes chestnut-brown. 



43. COLLEMA. 



1. C. crispum, blackish-green, circular, the disk granular or 

 warted, lobes of the circumference rounded, radiating, foliaceous, 

 cut and irregularly raised. GREV. Fl. Edin. 350. 



Hab. On rocks at Hudshead, at a part where the water 

 trickles down in wet weather. 



^ The different size of the central and external lobes is the 

 most obvious character." GREVILLE. The diameter of 



