148 NEW LICHENS. 
species ; and hence may have arisen some confusion. Our 
own species I suppose to correspond with the T. intermedium, | 
‘Schrad. of Koch’s Synopsis; and with the var. . fulvipes 
there described. Some of the specimens agree. 
Although in its full-grown state Thesium linophyllum is 
evidently parasitical, it presents several characters at variance 
with those required by a true parasite ; and at the conclusion 
of some experiments in which I am at present engaged, I 
hope to make some addition to its history as well as to 
that of Cuscuta. 
Tas. IV. Fig 1. represents the root of Thesium linophyllum - 
attached to the roots of its supporters; f. 2. A slightly 
magnified tubercle attached to a large root; f. 3. A longi- 
tudinal section of a tubercle, shewing the spongiol pu 
into the root of Lotus corniculatus; magnified; f. 4A 
transverse section of the same parts ; magnified. 
New Licuens, principally from the Herbarium of ŠIR 
. WinLiAM J, Hooker; dy Tuomas ae M.D. 
LECIDEA, Ach. 
1, L, crystallifera, Tayl.; crusta cornea, spun concava, 
cinerascenti, solidangulato-rimosa, subtus nigrescenti ; af 
__ theciis majoribus, substipitatis, stro-glancescentibaM a: 
ccc tenuem. demum excludentibus. — — 
. Has andy cla y; Swan River; Mr. James. n 
T greenish granules, resting on a layer of snow-W. 
ee _ dense matter, which likewise rising up in certain spo 
E. preda x obconical stipes of theapothecium. - Disk 
E 25 En oce beu lamina pde » Y 
