scp AME eif Lon c EU SaaS 
DISTINCTIVE CHARACTERS OF QUERCUS AND CASTANEA. 179 
the entire surface, being only the indurated teeth of the zones ; and, 
were the obsolete ones of Q. fissa drawn out into spinous processes, 
there would be the most striking resemblance between the two fruits. 
I admit that the regular dehiscence of Castanea is a point of some 
importance, but its morphological value is considerably diminished 
when it is borne in mind that in this case dehiscence is not the solu- 
tion of a cohesion between single organs, for each valve is not a bracteal 
leaf, but a congeries of such organs; that in the cupped Oaks the 
small size of the involucre renders dehiscence unnecessary, and the 
cupule remain consequently at all ages entire; that in the Chlamydo- 
balani, and also in Q. fissa, the involucre does split, irregularly it is 
true, being thus intermediate between the indehiscent Quercus and 
the valvular-splitting Castanee ; whilst in Q. fagiformis, according to 
Miquel, it opens in three almost regular valves, approaching both in 
this respect and in the echination of its surface still closer to that 
genus. 
But it is more particularly the cotyledonar structure which compels 
me to dissent from the location of the plant in question in the genus 
Quercus. The foregoing remarks will show the comparatively slender 
importance I attribute to the characters on which those who differ 
from me have chiefly relied. I am not aware, however, that any writer 
has hitherto expressly impugned the value of such a marked difference 
as that between flat and plaited cotyledons. The number of these 
organs furnishes primary characters for the classification of Pheenoga- 
mous plants, and their structure, combined with other subordinate 
marks, is of sectional value in Melastomacee, Combrelacee, and other 
families ; and I cannot call to mind any other genus comprising plants 
differing as Q. Robur and Q. fissa do in this respect. I could easily 
understand the junction of Castanea and Quercus by one with such a 
decided leaning to synthesis as Mr. Bentham ; but I confess myself — 
unable to appreciate the grounds on which this distinguished botanist, 
whilst retaining both genera, has relied, as it appears to me, on quite 
subordinate marks for their separation, and passed over one of primary 
consequence. : 
2. It may be separated as the type of a genus.—1l have stated above 
the particulars in which Q. fissa differs both from Quercus and Castanea, 
as at present generally understood. Though not myself disposed to 
go as far as Dr. Hooker and Mr. Bentham in the reduction of genera,— 
N 2 
