210 BOTANY OF THE VOYAGE OF H.M.S. HEUALD. 
them corresponds to a third. A little attention also enables tlie observer to see that those rays wliicli are 
terminated by a little head answer always to one another. The space between these heads is largest in a 
dry slice, and least in a moist one. The central cavity is sometimes empty, and sometimes filled with a 
substance composed of very minute globules, reaching occasionally to the very tips of the rays. It is evi- 
dent that these starry cavities represent so many hoUow^s of cells, which still preserve their radii of com- 
munication, though the primitive parietesare obliterated; and in some instances the' cavities only remain in 
the fonn of ovoidal cells, ^\ hich still can be restored to their original configiu-ation by immersing the por- 
tion of albumen in Canada balsam. I have dried a carefully-cut slice of the ivory, and then subjected it to 
the mfluence of Canada balsam, which rendered it so perfectly diaphanous as to be scarcely discernible by 
the naked eye from the balsam. This process has the effect of restoring the cells to their normal structure : 
they become six-rayed, the tubes correspond exactly with each other, and every one Is tipped with a swollen 
head, and more or less filled with the globular substance of which I have spoken. Thus we see revealed the 
whole orgaaiization of Vegetable Ivory, wjiich is merely a prismenchyme with thickened cells, in which the 
rays of communication arc preserved. The closest scrutiny has not enabled me to detect, In the thick 
portion of the cells, the smallest trace of those layers of growth which have been detected by Valentin, 
especially in the Soya carnosa and Orcodoxa regia, etc. This substance, which appears continuous, is 
very analogous to that which Schleiden and Theodore Vogel, in their researches into the nature of the 
albumen, have found in the albumen oi IPhcsnix dactylifei'a ; only that in the latter there is no starry dis- 
position of the tubes, and the hollows of the cells are elongated into two, or, at most, into three, radii of 
communication." Morren has well observed, at page 72, " L'ivoire qu'on retire de ces gralnes n'est 
autre chose que I'albumen, qui de laiteux, qu'il etait d'abord, d'albumineux qu'il etait ensulte, a fiui par 
acquerir la consistence du blanc d'amande, pom- passer enfin a I'etat dur, elastique, et blanc, qui I'a fait com- 
parer a l'ivoire." 
" It is a no less curious fact," says Sir W. J. Hooker {' Hooker's Journal of Botany,' vol. i. p. 211), that 
this hard ebumeous mass again reverts to its former soft state in the process of germination. This I have 
frequently had the opportunity of witnessing. Our seeds were mostly sown in pots, one in each pot, and 
buried two inches or more under the earth. The first symptom of vitality became apparent by the protrusion 
of a strong stout fibre, which quickly took a downward direction, and, elongating some inches, produced 
from the opposite extremity a new plant, which soon developed itself in the air, while from its base the true 
roots descended (see Plate XLV. fig. 8). Gradually the seed, so recently buried, emerged to the surface, there 
lying on the earth ; or, more frequently, it was forced out of the pot, hanging over the edges, and suspended 
by the strong fibre before alluded to; which thus forms a medium of communication, by its vessels, between 
the seed and the very base of the young plants (the collum), or point of junction of the root and stem. 
The seed was broken at this time, and the inside found to have become a soft substance, half pulp and half 
milk, which feeds the young plant, until it is old enough to derive its nutnment wholly from the soil, viz., 
when the plant is a year or more old. If the seed be then tapped with a hard instrument, its sound will 
indicate its emptiness ; and the fracture of the old shell (testa) will exhibit nothing in the interior but a 
half-dried pulj), lining the inner integument of the seed. Henceforward, the plant depends upon the soil 
for its nourishment." 
In habit, the PliyleJephas macrocarpa resembles the Co}'ozo Colorado {Mais mehmococca, Gasrtu.) ; so 
much so indeed, that at first sight the two are easily mistaken for each other. Both have trunks which, 
after creeping along the ground a few yards, ascend, and attain about an equal height. Their leaves also 
resemble each other ; and their fruit grows in a similar way, attached to comparatively short peduncles. 
The habit, however, is nearly the only link which connects Fhytelq,lias with the order of Palms : its slm- 
pie spadix, Its miperfect flower, its indefinite number of stamens, and its embryo situated in the axis of 
a fleshy albumen, separate it from Palms, and proclaim it (in conjunction with other characters which it 
presents) a member of Endlicher's Class !^j^adiciJlor<,, and Lindley's Alliance Arales, Botanists enumerate 
