248 W. Lauder Lindsay’s Haperiments on the 
Yellow’ Red tint 
Name of Lichen. tint pre- predomi- 
dominant. nant. 
Parmelia cycloselis, . : — 
ceesia, : 5 . — 
fahlunensis, ‘ . — — 
Lamarckii, , , — 
multifida, . ; : — 
olivacea, —. : — —) 
omphalodes, phe — — 
perlata, : : : — 
pulverulenta, : ; — 
rupestris,  . : : = 
stygia, : — —_ 
Peltidea canina, . : : — — — 
aphthosa, . os 
horizontalis,. . j : — 
Pertusaria communis, ; — 
Psora testudinea, : : ; — 
Ramalina pollinaria, . , — 
scopulorum, _ 
Roccella fuciformis, . 5 : — 
Montagnei, . ; . — 
_ tinetoria, — 
Scyphophorus alcicornis, — 
digitatus, 5 a — 
fimbriatus, ; — 
gracilis, : : — 
pyxidatus, ; _-_ — —- 
gracilis, — : 
Solorina saccata, ; ‘ ; — 
Spiloma gregarium, . : — 
Squamaria candelaria, — 
Sticta crocata, . ‘ : —— 
scrobiculata, . : — 
Thelotrema lepadinum, : _ 
Urceolaria scruposa, . P ‘ — 
barbata, . . , : — 
Verrucaria leucocephala, ’ : — 
Explanation of Table II. 
This table serves fully to illustrate— 
I. The negative action of all acids in evolving the colorific principles 
of lichens, or converting them into coloured substances. 
II. The powerful action of certain alkalies and alkaline salts, especially 
ammonia and its compounds, in the production of colour-produc- 
tion and metamorphosis. 
