332 Extracts from Mr. Bentham’s Address. 
established on the authority of detached leaves or fragments of 
leaves alone. 
known leaf, presume to determine, not only its natural order 
and Hee ‘but its precise characters as an unpublished species? 
It is true that monographists have sometimes published new 
— founded on specimens without flower or fruit, — 
m collateral circumstances of habitat, collector's notes, ne- 
ral resemblance, &c., they had good reason to believe really qe 
longed to the genus ‘they were occupied with; but then they 
had the advantage of ascertaining the general facies derived 
from insertion, relative position, presence or absence of stipular 
appendages, &e., besides the data supplied by the branch itself. 
And with all these aids, even the elder De Pandaile, than whom 
no botanist was more sagacious in judging of a genus from 
general — proved to have been in several instances far 
in the genus, and even Order, to which he had attributed 
species described from leaf-specimens only. rarest” 
in th a Seameee idea of the aspect of vegetation, and thus 
give some clue to certain physical conditions of the country; 
but they alone can afford no indication of genetic affinity, or 
consequently of origin or successive geographical distribution. 
Lesquereux, in speaking of Cretaceous ne or rather 
forms of leaves,” beatae es, in a note to r on Fossil 
Plants from Nebraska (this Journal, cc os i 1868, p 
103), that “it is well aie that when the w oe 
eaves or mere fragments of leaves. . But as poloonisiee 
have to recognize these forms described and figured, to com 
them and use them for reference, it is necessary to affix to 
specific names, and therefore to consider them as species.” 
But the investigators of the tertiary floras of Central and South- 
ern Europe have acquired the habit, not only of neglecting this 
distinction and naming and trea treating these forms of leaves as 
species equivalent to those established on living plants, but of 
