Botany and Zoology. 155 
Finally, hybrid oaks are discussed; and six well determined ones 
are enumerated as known to the writer, three of which have been 
described as species, namely: @. Leana, Q. tridentata, and . 
inuata, One parent of four of these hybrids is @. imbricaria ; 
es that Q. heterophylla of Michaux is received, not as a hybrid, 
ut as a well-marked species, of the Phellos, laurifolia, and aquat- 
ica group. Dr. Engelmann’s six real hybrids are all of the Black 
oak group: this group never crosses with White oaks; and no 
hybrid of the latter group is known to our author. The black 
oaks are now unknown in Europe; but we learn that they existed 
germinated; in fact, as far as I know, no difference in fertility or 
germinating power between them and the acknowledged species 
has been discovered. The seedlings of such questionable individ- 
struggle for existence.” There is another reason, to us & MO” 
probable one. The hybrid tree, when isolated in cultivation, 18 
likely to self-fertilize and so be continued in its progeny; but in 
its native forest, surrounded and dominated by its two parents, 
its female flowers will almost inevitably be fertilized by the pollen 
ber of the Annales des Sciences Naturelles, an interesting and 
porthy tribute by Dr. Bornet to the director ~g companion a 
: ft 
his studies and researches, to whom eft the sacred duty 0 
completing them, so fa possible. To the full biography 18 
; i 
