IN THE CLUSIACE^, MAGNOLIACEiE, 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 slieath, 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 maimer, 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 wiU here repeat it with some modifications. Let us suppose a 

 simple flower with a tubular calyx, closed before sestivation, 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 coroUa the secundine, and the pistD. 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 versa; the 

 calyx, coroUa, 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 wiU 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 ariUiform 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 coatiag, 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 neai" its sum m it (at a spot corre- 

 sponding to the hilum in the ovule), and thus have insinuated itself inside the calyx, 

 traversing its Avhole length in order to form a new line of communication of the vessels 

 proceeding from the base of the pedicel to the torus, within, instead of without, the calyx : 

 this is so manifest an improbability, as to carry conviction in the simple statement of 

 the fact. 



Doctor Asa Gray now candidly confesses that he had overlooked the existence of the 

 inner integument, and therefore the true chalaza, and to avoid the intricacies into which 

 tliis admission would naturally lead him, he has, in great measure, renounced his former 

 argument of considering the fleshy covering and the crustaceous nut, the one as a product 

 of the primine, the other of the secundine, and has now most ingeniously substituted an 

 entirely new view of the subject, suggesting that these two seminal envelopes constitute 

 in fact one coating, both proceeding from the simple increment of the primine, forming a 

 drupaceous testa ; his words ai-e, " the external coat of the ovule becomes drupaceous in 



