IN THE CLUSIACEÆ, MAGNOLIACEÆ, ETC. 85 
a supposition that cannot be entertained for a moment. As therefore the spiral vessels, 
at the period of the inversion of the ovule, starting from the hilar point, must have been 
contained within a simple sheath, an extension of the placenta, and as these vessels during 
the subsequent growth of the ovule, are found to ramify from this point over its whole 
surface, it is clear that the sheath which contains them must have become here extended 
with them, in the same manner, as has been ascertained by actual observation, that it 
really does grow over the primine in other cases. 
This may be rendered still more palpable by reference to a simple model. This mode 
of demonstration was first ingeniously suggested by St. Hilaire in his *Legons de Bo- 
tanique ' (p. 541), and I will here repeat it with some modifications. Let us suppose a 
simple flower with a tubular calyx, closed before æstivation, enclosing a tubular corolla, 
which again invests a superior ovary: we have here a good illustration of an erect ovule, 
the calyx representing the primine, the corolla the secundine, and the pistil the main body 
of the ovule or nucleus. Let us farther conceive the same floral model supported on a 
pedicel of equal length, and that the flower be suddenly bent down upon its pedicel, 
becoming glued to the calyx: we have thus an excellent representation of an anatropal 
ovule, where the former base of the flower is now become its summit, and vice versé ; the 
calyx, corolla, and pistil still remain the analogues of the primine, secundine, and body 
of the ovule: the foot of the calyx or torus, through which the nourishing vessels pass to 
promote the growth of the several parts, corresponds to the spot I have called the gangy- 
lode, and the adherent pedicel will represent the nourishing vessels enclosed in form of a 
sheath, or extension of the placenta, and the origin of the future raphe. It is evident, 
that during the subsequent growth of these tunics, this raphe must always remain 
exterior to the primine, as we see it in this model. Now if, as it has been contended by 
Dr. A. Gray, the arilliform coat of the seed of Magnolia be only the primine of the ovule 
enlarged in growth, and if, as he admits, the raphe be found within this coating, it is 
evident, referring to our model, that the pedicel must have become detached from the 
calyx, and made to penetrate not through the original point of its attachment to the 
torus (corresponding with the gangylode), but in some unaccountable manner, and for no 
purpose, must have pierced its way through the calyx near its summit (ata spot corre- 
sponding to the hilum in the ovule), and thus have insinuated itself inside the > 
traversing its whole length in order to form a new line of pommi dation of > pss 4 
proceeding from the base of the pedicel to the torus, within, instead of without, the Er À 
this is so manifest an improbability, as to carry conviction in the simple statement of . 
the fact. 
Doctor Asa Gray now candidly confesses that 
inner integument, and therefore the true chalaza, 
this Se would naturally lead him, he has, in great measure, renounced his peel 
argument of considering the fleshy covering and the crustaceous nut, the one , erac E 
of the primine, the other of the secundine, and has now most nn "p ER 
entirely new view of the subject, suggesting that these two seminal envelopes 
i ; i the primine, forming a 
in fact one coating, both proceeding from the simple increment of ‘ids på om in 
drupaceous testa; his words are, “the external coat of the ovule 
å 
he had overlooked the existence of the 
and to avoid the intricacies into which 
LI 
