THE TENDENCIES OF SYSTEMATIC BOTANY. 
257 
one thousand ; it should no more be contended that because a 
genus is a large one it must be cut up into a number of smaller 
ones, for the sake of convenience, than to determine that no 
genus shall consist of more or less than twenty species. Numbers 
are wholly beside the question, and convenience is not science. 
In this instance we think that the inference is sound that one 
of the tendencies of the systematic botany of the day is the 
unnecessary multiplication of genera. 
It may be urged that the evidence adduced of the reduction of 
one large genus does not warrant this conclusion. Perhaps it 
would not, if this were an isolated instance, but it is only one of 
too many. Without passing from the asci-bearing fungi we have 
in the genus Dothidea another analogous instance. The same 
flora, as cited above, contains eight genera in place of the one 
constituted by Fries. This is hardly the place to discuss the 
merits of the different genera proposed in the place of one which 
also was a very natural one and required no modification. To 
constitute a genus like Homostegia on the basis of the habitat 
of the species is so unsound that it only needs applying the 
same principle throughout the genus to convince any unpre- 
judiced reader of its absurdity. If one habitat is to be accepted 
as the characteristic of one genus, why not another? Manifestly 
these are only, at the most, sectional or specific differences ; or 
if generic in one case, why not in another ? If generic, then 
species of Dothidea found on grasses, on leaves, on ferns, on 
twigs, on herbaceous plants, &c., have each as good a claim to 
be regarded as distinct genera as Homostegia . 
Should this be considered insufficient, attention might be 
directed to the genus Sphceria, according to Fries, and the 
modifications proposed by more recent authors. Again, taking 
the same flora as our guide — which by-the-bye is by no means 
an extreme one, and does not include many proposed new 
genera — we find that forty-eight genera represent the old 
genus Sphceria , or rather as limited by Fries in 1846. Here 
again the limits of the primary genus were clearly defined, and 
the new genera have not been constructed for the reception of 
anomalous forms, but entirely by the breaking up of the parent 
genus. Botanists will comprehend at once the toleration with 
which we would accept the constitution of a new genus in 
which to place one or two anomalous species, which differed in 
some permanent, though it might be rather unimportant fea- 
ture, from the genus to which it had been affiliated. But there 
is not even this excuse for the majority of genera into which 
the species of Sphceria have been unceremoniously transferred. 
A little excuse may be made for the removal of species with 
a membranaceous perithecium from companionship with those 
in which the perithecium is more or less carbonaceous ; but 
VOL. XIV. — NO. LVI. S 
