(184 ) 
This group is strictly analogous to Rinodina in Lecanorei, as that 
represents Physcia; it is however, in one respect, more interesting than 
either of the others named, as expressing most fully the differentiation of 
the brown spore. As indicated by De Notaris, Buellia embraced both 
effigurate and uniform types, but was expressly confined to bilocular 
species. Massalongo next, availing himself of the distinction by Flotow, 
on certain peculiarities of the exciple, of two marked Lecidee allied to 
Buellia (Catolechiaand Diplotomma) separated from the latter its effigurate 
species (Diploicia) and having elevated the quadrilocular Lecidea para- 
sitica to the rank of a separate genus (Leciographa) finally gave effect to 
a suggestion of De Notaris by distinguishing Rhizocarpon ; thus consti- 
tuting what might have been called the Buwelliei. The criticism which 
followed found especial expression in the nearly contemporary emendations 
of Anzi,and Th. Fries. These writers both united the effigurate members 
of the group in a single genus (Catolechia) and the latter, taking advan- 
tage of the fact that the bilocular spore, here as elsewhere, varies now to 
quadrilocular, availed himself of it to refer Leciographa to Buellia; as 
Anzi, equally with Fries (Zich. Arct.) reduced Diplotomma to Rhizocarpon. 
It was left then to Stizenberger to subordinate the distinction of the 
effigurate species; and nothing remained, at last, of the Buelliei, but 
Buellia and Rhizocarpon. But Rhizocarpon, Mass.,! expresses only the 
completion of a process of differentiation of the spore, the earlier stages 
of which are expressed by Buwellia; and the difficulties in which the 
attempt to keep the two apart is entangled, obvious enough already in 
critical instances in both, and as well in the very uncertain Catallarie of 
authors, find at last their full manifestation in the final arrangement of 
Dr. Fries (Gen.). Another solution of the problem had not indeed 
escaped the attention of the accurate writer cited. ‘‘ Negari quoque non 
potest,” he says, “ haud parvam inter Buelliam atro-albam et Rhizocarpon 
petreum, inter B. scabrosam et Rh. geographicum, etc., adesse afinitatem, 
quare forsan haud immerito possint hec genera in unum redigi” (Lich. 
Arct. p. 226) which had indeed already been done, in Lecidea, Naeg. It 
might well appear then far from difficult to conceive, with Naegeli, and 
Nylander, that the saxicoline Buellig and Rhizocarpa constitute parts of 
but a single series of most intimately related lichens; a series explained 
still further by known forms of the one group which yet scarcely advance 
beyond stages of evolution characteristical only of the other; but it was 
left to the Californian B. oidalea to complete the history, and shew that 
the corticoline Buellie vere culminate, no less than the Diplotommata, in 
corticoline Rhizocarpa. This were indeed plainly presumable from the 
point of view of the present memoir; and is in strict analogy with what 
is now known of Rinodina: but the exhibition of the muriform spore in 
1 This name (Massal. Ric. p. 100) is later than Buellia ; and can hardly derive 
any precedence from having been used, in another sense, by Decandolle. 
