38 MR. CHARLES KNIGHT ON THE 
be changed or influenced by its matrix, from which it draws nourishment; and plants which 
differ only in their chemical properties should be considered to be the same. Dr. Lind- 
say, in his valuable paper on “ Chemical Reaction as a specific character in Lichens,” 
comes to the conclusion that the frequent uncertainty of results, the inconstancy of 
colour-reaction even in the same species, render it impossible to place confidence in 
chemical characters as a means of diagnosing botanical species. 
The number of species collected of the genus Stigmatidium, viz. eight, in a collection 
of about sixty species, is worthy of notice. Dr. Nylander, in ‘Synopsis Lichenum 
Nove Caledoniz,’ mentions only three species in a collection of 220 Lichens; and 
among these it is observed that he includes Stigmatidiwm elegans, whose apothecia are 
elongate and dendritico-ramose. If this arrangement be admitted, we should include also 
among the New S. Wales species Graphis subtricosa and Graphis subintricata. The genera 
Graphis and Stigmatidiwm require revision. I have consulted the last edition of the 
* Lichen Flora of Great Britain,' and have followed Leighton's definition. 
The generic place of Lecanora corysta (sp. n.) is uncertain. The apothecia are 
crowded together in sets of four or five; a thin section of the apothecia shows that they 
are separated from each other only by the slight intervention of scattered gonidia without 
a trace of a proper excipulum. A further exploration in New South Wales may discover 
other allied species; until then it can conveniently remain among the Lecanore. 
Aphtholoma conspicua (sp. n.) is still more perplexing. The singular capillary texture 
of the white tubercles in which the apothecia are immersed, and the black torus 
springing from the matrix, are charcters widely different from those of any Lichen known 
to me. 
Not less interesting is Platygrapha albo-vestita (sp. n.); the white thin thalline 
covering of the irregular-shaped disk of the apothecia gives it very much the aspect of a 
Graphis, while the great size of the solitary murali-divided spores furnishes a most dis- 
tinctive character. | 
Lecanora parella, Г. It is observed that Dr. J. Müller, in Flora, No. 39, р. 484, 
advocates the transfer of this Lichen, with its allied species, to the genus Pertusaria. 
It is well to notice how, one after another, the Lichens arranged under Dr. Nylander's 
sections, “ Stirps Lecanore einerez et L. tartaree,” are being transferred to Pertusaria. 
There are others left for similar treatment—for instance, Lecanora verrucosa and L. cal- 
carea. In respect of Lecanora bryontha, Th. Fries (in ‘ Lich. Scand.’ p. 314) transfers 
it to Pertusaria, an arrangement which the extraordinary thickness of the parietes 
of the solitary spores and the clathratim-ramose paraphyses amply support; on the 
other hand the thin envelope of the spores of L. parella is an obstacle in the way 
of the proposed transfer to a genus quite remarkable for the great thickness of the 
sporal envelope. It may be added that the intricate ramose paraphyses and double 
envelopes of the large spores of Lecanora gemmifera, Th. Fries, render it likely that it 
too belongs to the genus Pertusaria. 
Lecanora punicea, Ach., might conveniently be placed in Massalongo's genus Hema- 
tomma. The many septate acicular spores support the arrangement of those lichenolo- 
gists who have removed the allied species Lecanora ventosa, Ach., Г. coccinea, Dicks., 
