HOOKER LECTURE, 1917. 109 
It thus appears that convenience of application was at times admitted by 
Sir William Hooker as a factor in his method. 
Within the genus he grouped the species in a manner best illustrated in 
large genera, such as Cyathea and Alsophila. The species are arranged 
according to the complexity of branching of their leaves, from those which 
are entire or simply pinnate, to those with more complex branchings. In 
many genera the venation is used in diagnosis and grouping. A further 
segregation was made according to geographical distribution. These and 
many other characters are used ; but it appears that they are called in - 
for purposes of diagnosis rather than those of synthesis. The object of the 
author may have been in wish and intention to follow the dictates of 
Nature. But along with this went in practice the laudable desire to make 
the determination of species easy. 
That the arrangement shown in the ‘Synopsis Filicum’ resulted in 
something approaching to a natural grouping of the Filicales is undeniable. 
Anyone, in the light of present knowledge, can criticise it in detail. But to 
denounce it as thoroughly artificial (“ durchaus künstlich "), as Professor 
von Goebel has done, is grievously to underestimate the merits of a great 
systematic work *. 
Nevertheless, it must be confessed that the arrangement of the Sub- 
Orders of the Filicales in the ‘Synopsis’ was in some measure according to 
tradition, or to chance. Circumstance rather than conviction appears to 
have dictated it. The placing of the Gleicheniaces first coincides with the 
arrangement in the ‘Tentamen’ of Presl. The sequence of other families 
corresponds frequently, though not in detail, to that of the Prag Professor. 
The relegation of the Osmundacez, Schizeeaceze, Marattiacee, and Ophio- 
glossaceæ to the end of the book is probably a mere consequence of those 
families having been omitted from the ‘Species Filicum,’ and they appear in 
the ‘Synopsis’ as an addition (see Preface). Thus the arrangement of the 
Sub-Orders seems to have been for Sir William a relatively trivial matter, 
and it is certainly not according to Nature.  Dut the intra-generic and 
generie groupings are often those which will take permanent place as 
knowledge increases, though this is certainly not the case invariably. We 
conclude, then, that the permanent importance of the work centres in the 
specifie diagnoses, rather than in the limitation or arrangement of the genera, 
.or larger groups. In this respect it is characteristic of those systematic 
works which were produced under the belief in the Constancy of Species. 
The outlook of the Pre-Darwinian Systematist must have been highly 
unsatisfactory to any intelligent man. On the one hand, he found the 
* This verdict, expressed in ‘ Flora, 1896, p. 75, has been rebutted in detail elsewhere. 
* Studies in the Morphology of Spore-producing Members," Phil. Trans. vol. 192 (1899), 
p. 131. 
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