183 
Evernia, Borrera, Ramalina, Lecidea, Isidium, Sphxrophoron; spe- 
cies of which yield fine red colouring matters: and Parmelia, Sticta, 
Cetraria, Nephromia, Solorina, Scyphophorus, Stereocaulon, Borrera, 
Lecidea, Peltidea, Colloma; some of which furnish good brown 
colours. 
XIX. Among the general results of my experiments, it appears that, 
of 540 specimens examined,— 
22 gave rich purple or red colours to ammonia alone (7. e., by 
simple maceration). 
8 gave brown colours to ditto. 
93 alcoholic solutions gave rich purples or reds, on the addi- 
tion of ammonia. 
81 ditto, well-marked brown, ditto. 
127 ditto, ditto orange, ditto. 
42 ditto, ditto greenish yellow, ditto. 
79 alcoholic solution struck a deep blood-red, with solution of 
chloride of lime. 
XX. The whole subject of the intimate chemistry of the lichen co- 
louring matters is in a very unsatisfactory condition, demanding 
reinvestigation, and Dr. Lindsay therefore repeated that the 
branch of the natural history of the lichens, to which, in this 
and previous papers, he had endeavoured to draw scientific 
attention, would form a worthy and remunerative object of 
research to the botanist, chemist, and wholesale manufacturer. 
Potamogeton from Lough Corrib. 
‘On a species of Potamogeton from Lough Corrib, and other 
plants;’ by J. Kirk, Esq., Coventry: communicated by Professor 
Balfour. 
Mr. Kirk considered the Potamogeton as allied to P. longifolius 
of ‘English Botany Supplement, and remarked : — “ My specimens 
differ from the plate in E. B. S. in having most of the leaves on long 
stalks, and in the absence of the apiculus. The specimen there 
figured was picked up floating in Lough Corrib, in July, 1835, 
by Mr. J. Ball, ‘ whilst sailing between Ma’am and Cong,’ and given 
by him to Mr. Babington, and is the only specimen known to have 
been found in the British Islands up to September, 1853. The most 
striking character in my specimen is the singular and prominent mid- 
rib, the central portion of which consists of three longitudinal veins or 
ribs running closely parallel with each other, whilst on either side are 
three to six ribs running closely parallel to them, but rather more 
