362 Hill and de Frame.— On the Classification of Seed-Leaves . 
Mr. Compton correlates the final root-structure with the cotyledonary 
bundles, and takes no count of the root-structure which first results from 
the arrangement of the seed-leaf traces ; we do exactly the reverse, and it 
appears that this is the cause of the misconception. 
The polycotylous condition is an heritable quality, and since it appears 
to be generally, but not universally, agreed that the primitive condition was 
dicotyledonous, the presence of many seed-leaves, many of which may be 
whole cotyledons, in a seedling has to be accounted for. 
This is, of course, a difficult matter, since we cannot ‘have our cake 
and eat it ’ ; in other words, we cannot dissect a seedling and also examine 
its progeny. 
It appears not improbable that in the course of descent the half or the 
subsidiary cotyledons of an ancestor should become of increasing importance 
in succeeding generations until they became whole or half-cotyledons 
respectively. 
This was our meaning in saying that a half-cotyledon could arise by 
the ‘ promotion ’ of a subsidiary cotyledon. The same goal can be arrived 
at in different ways, so that, for us, it is not unthinkable that a ‘half- 
cotyledon ’ is sometimes the half of a whole cotyledon, whilst in other 
instances it represents a promoted subsidiary cotyledon . 1 
In view of Mr. Compton’s account 2 of the ‘ Theories of the Anatomical 
Transition from Root to Stem which is an admirable exposition of the 
different views of the various schools of anatomists especially in relation to 
seedling structure, it would appear to be unnecessary to consider in detail 
M. Dauphine’s criticism 3 of our work on the Centrospermae . 4 It may, 
however, be remarked that this particular investigation was a continuation 
of our work on seedling anatomy, carried out from the phylogenetic point 
of view and commenced some thirteen years ago ; in which investigation 
we, in common with most other British workers in the same field, considered 
the vascular tissues in the gross. In writing the paper on the Centrosperms 
we fully recognized the high value of M. Chauveaud’s work on the same 
group, but we did not think it desirable to make reference to it since such 
reference, to be of any value, would have involved a long consideration of 
the views of the different schools of thought and would have tended to 
obscure our main line of work. 
University College, 
London. 
1 See Hill and de Fraine : Ann. Bot., 1909, vol. xxiii, p. 222. 
2 New Phyt., 1912, vol. xii, p. 13. 
3 A. Dauphine : Sur le developpement de l’appareil conducteur chez quelques Centrospermees. 
Bull. Soc. Bot. France, 1913, vol. xiii, p. 312. 
4 Hill and de Fraine : On the Seedling Structure of Certain Centrospermae. Ann. Bot., 1912, 
vol. xxvi, p. 175. 
