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ity of the innate, but otherwise, at least as represented in the best forms, 
sufficiently regular apothecium. But in that now to be considered — 
Acarospora — which constitutes our last section of Lecanora, though the 
species are equally all but confined to rupicoline and terricoline condi- 
tions, and the apothecia vary as much as, and similarly to those of the 
last, passing also at length into punctiform or pseudo-endocarpeine states, 
the stress of difference is on the exceedingly minute and innumerable 
spores. The question of the systematic value of deviations from the 
normal number of spores contained in the thekes may be said to be so far 
determined, that writers are generally agreed in subordinating lesser dif- 
ferences of the kind to the affinity indicated by the sum of other charac- 
ters of the lichen. And perhaps none will deny that Lecanora Sambuci, 
Nyl., (LZ. scrupulosa, Auctt.) and Rinodina sophodes, Koerb., are clearly 
referable to the groups to which they are in every other respect naturally 
akin, notwithstanding the variation in the contents of the thekes. Nor 
are we at all able to allow that the case is otherwise with the polysporous 
Purmelia colpodes, Ach. (Anzia, Stizenb.) this lichen being quite too 
closely associable with octo-sporous species to be well separated generi- 
cally from them. But why should we stop here? The more numerous 
such spores become, the less perfect (as seen abundantly in Theloschistes 
candelarius and Placodium vitellinum) they are; and when finally all 
attempt at estimation of difference of type has to be given up, and the 
spores are fairly inappreciable, should not this manifestly increase instead 
of diminishing the value of the other characters? That is surely an 
unsatisfactory evidence of affinity which brings together (as in Acaro- 
Spora, Stizenb. Beitr. 1. c. p. 169) lichens as incongruous as Lecanora cer- 
vina and L. constans, Nyl.; nor is it in fact certain, or even unlikely, that 
this aberration in the way of degradation may not recur in any genus or 
even group. The spores of L. constans (generally well comparable with 
Rinodina sophodes) are at length (as noted in the writer’s Obs. Lich. 1. ¢. 
5, p. 404) bilocular, and resemble ‘the younger conditions of the biscoc- 
tiform type; as if in fact the plant were a remarkable micro- and poly- 
sporous deviation from the type of L. sophodes, in which the final devel- 
opment of the spore peculiar to that type has been precluded.’ 
Tulasne (Mém. sur les Lich. p. 85) has touched but cursorily on the 
myriosporous! anomaly, but compares it, not without evident significance, 
to an irregularity of the same sort occurring in species of Spheria; as in 
other Fungi. 
1 This term sufficiently denotes the extreme of polysporous deviation, as 
observable in Acarospora, Biatorella, and Sporostatia of authors. But indications 
of less irregularity, and even of return to a normal condition are not wanting 
within the limits of these myriosporous groups; as in Lecanora oligospora, Nyl. 
Prodr. p. 80, ‘ thecis sporis 32-8,’ upon which the author of the species further 
remarks that the plant is possibly only a variety of L. cervina. Compare here the 
remarks of Miller, Principes de Classif. p. 12. 
