BY CUTHBERT HALL. 477 



hypocotyl is subterranean, and the failure of this to elongate, by 

 growth in germination, is compensated for by the great elonga- 

 tion by growth of the petioles, so as to raise the laminae well 

 above the ground. A similar condition obtains in Aiigophora 

 cordifolia, where the hypocotyl is short, and the petioles long. 

 E. calofjhylla and E. Todtiana also have fairly long petioles. 



Radicle. —A series of sections of the seeds for microscopic 

 examination would be necessary to give the shape and length of 

 the radicle, and with such small seeds as the majority of the 

 species possess, this would be difficult of accomplishment. As 

 far as I have been able to observe, in the larger seeds, the radicle 

 is short, thick, and truncate, resting on the lower pole of the 

 seed from which it emerges in the corymbosa-groxx^; or against 

 the hilum, from the neighbourhood of which it emerges, in the 

 globulus- and allied groups. 



Cotyledon- Leaves. — Lubbock states that, in the great majority 

 of plants, the cotyledons are entire. In tlie Eucalypts, however, 

 emargination in a greater or less degree is more common, and in 

 some species, reaches an extreme degree. As this appears to be 

 a response to Australian xerophytic conditions, it indicates that 

 the species with simpler, entire cotyledons are those of the more 

 primitive type; while those, with emarginate cotyledons, are of 

 the more evolved and developed type, and this bears out the 

 researches on the botanical and chemical characters of the genus. 

 Botanically and chemically, the " Bloodwood "- or coryrabosa- 

 group has been considered the most primitive, and to most closely 

 approach the allied genus Angophora, and the seedlings bear this 

 out. Iti my companion paper to this, "The Seedlings of the 

 Angophoras," (Proc. Roy. 8oc. N. S. Wales, Vol. xlvii.), I have 

 sliown that all, except A. cordifolia, have reniform, entire coty 

 ledons. Those of E. corymbosa and its congeners are of the same 

 form, and quite indistinguishable. The primary leaves, however, 

 serve to separate them, as in the Corymbosas they are petiolate, 

 and alternate after the first or second pair, in many cases 

 becoming peltate as well. Both, however, have stellate hairs on 

 the early leaves. After growing the seedlings of such a large 

 number of species, and comparing them, it was seen that a very 



