Rev. W. A. Leighton on the Lichens of Spitzbergen. 441 
regarded as reaction at all. He gives a most interesting tabular 
arrangement of parallel forms in which the reaction does and 
- does not occur :— 
K luteo tinctz colore. K non colorate. 
Cl. endiviefolia. Cl. alcicornis. 
Cl. cervicornis. Cl. verticillata. 
Cl. cariosa. Cl. pyxidata. 
Cl. lepidota. Cl. degenerans. 
Cl. eemocyna. Cl. gracilis. 
Cl. pungens. Cl. furcata. 
Cl. delicata, var. subsquamosa. Cl. squamosa. 
Cl. macilenta. Cl. bacillaris. 
Cl. rangiferina. Cl. silvatica. 
Under Cl. lepidota, bellidiflora, and cornucopioides re8pectively 
two species would appear to be comprised, distinguishable by a 
different reaction, as we have also ourselves remarked in our 
testings among the large collections of the Hookerian Herbarium. 
The work is arranged according to a modified Massalongo- 
Koerberian system. It includes 246 species and varieties, 
which, if classified after Nylander’s system, may be thus dis- 
tributed :— 
Collemei ...... 8 Brought forward 44 
SL. ons ss 1 Peltigerei ..... 12 
Spherophorei .. 2 Parmelie: ...... 17 
Stereocaulei.... 3 Gyrophorei .... 9 
Smeoniet...... 17 Lecanorei ...... 61 
Le a Lecideei........ 76 
Ramalinei. ..... 5 Graphidei...... 3 
Cetrarie) ..... .. 7 Pyrenocarpel.... 24 
Total 246 
_ Of these the following are described as new :-— 
Lecanora coriacea, Gyrophora discolor, Lecidea (Toninia) con- 
jungens, Lecidea (Biatora) collodea, L. pullulans, L. scrobiculata, 
L. impavida, L. associata, L. (Sporostatia) tenuirimata, L. (Buel- 
ha) vilis, Arthonia excentrica, Verrucaria extrema, V. rejecta, 
V. (Arthropyrenia) conspurcans. 
The learned author has detected a useful chemical criterion of 
allied species of Lecidea by the application of the solution of 
iodine to the stratum medullare of the thallus, which by reac- 
tion it turns of a blue colour in some species, whilst in others 
there is no reaction. Of this discovery he thus speaks :—“ Hane 
notam accuratis lichenologorum studiis enixe commendamus, 
