BY CUTHBEKT ttALL. 5l9 



lobes are brought downwards so as to ensheath the radicle, which 

 is short and thick, while the petioles are also short. In germin- 

 ation, the hypocotyl remains subterranean, no growth of it 

 taking place as is usual in the other Eucalypts, but, to com- 

 pensate for this, great growth and elongation of the petioles 

 occurs, thus carrying the cotyledons well up above the ground. 

 This is the reason E. emarginata has cotyledons with longer 

 petioles than any other Eucalypt. 



(iii.)In the Y-shaped cotyledons, such as of E. squamosa^ the 

 folding is still further modified. One limb of each cotyledon 

 passes through the notch in the other, and thus interlocked, all 

 four bend downwards to embrace the radicle, which, consequently, 

 is now in contact with all four limbs, not with the inner two, as 

 occurs in the other methods. The outer surface of all four is in 

 contact with the testa. It will thus be seen that the plumule 

 is very well protected by the interlocking of the limbs, and thus 

 it and the radicle are able to withstand dessication. Figures A, 

 B, C, of Plate Ixix., illustrate diagrammatically a transverse section 

 through the lower part of the embryo of each of the three types. 



Third Cotyledon. — Very rarely, different species may be ob- 

 served to possess three cotyledons. I have seen this in E. 

 coriacea, E. elceophora, E. eximia, E. Bosistoaiia, E. pilularis, E. 

 Stuartiana, and E. microcorys. The primary leaves are then 

 generally in whorls of three, and when they become alternate, 

 the tripartite arrangement is obscured. Again, after being in 

 whorls of three, they may revert to the paired arrangement. In 

 both these instances, a division of the embryo into three has 

 occurred. Again, three cotyledons may be followed by paired 

 leaves, showing that one cotyledon has been subdivided. I have 

 even observed a pair of cotyledons followed by leaves in whorls 

 of three. This tripartite arrangement, I have also observed in 

 Angophora lanceolnta, and it is common in hybrid Carnations. 



Primary Leaves.^This research has established, beyond all 

 doubt, that the so-called " sucker "-leaves are of the same form as 

 the seedling-leaves, and has confirmed the opinion expressed by 

 me in a paper on "The Eucalypts of Parramatta" [These Pro- 



