(53 



horizontal diaphragm, the upper half of which consists of from 5 to 9 cells, 

 and the lower of 3 ; the cells of both being separated by membranous dissepi- 

 ments ; the placentae of the upper half proceeding from the back to the centre, 

 and of the lower irregularly from their bottom ; and by Mr. Don as a fleshy 

 receptacle formed by the tube of the calyx into a unilocular berry, filled with 

 a spongy placenta, which is hollowed out into a number of irregular cells. In 

 fact, if a Pomegranate is examined, it will be found to agree more or less per- 

 fectly with both these descriptions. But it is clear that a fruit as thus de- 

 scribed is at variance with all the known laws upon which compound fruits 

 are formed. Nothing, however, is more common than that the primitive con- 

 struction of fruits is obscured by the additions, or suppressions, or alterations, 

 which its parts undergo during their progress to maturity. Hence it is always 

 desirable to obtain a clear idea of the structure of the ovarium of all fruits 

 which do not obviously agree with the ordinary laws of carpological composi- 

 tion. Now, a section of the ovarium of the Pomegranate in various directions, 

 if made about the time of the expansion of the flowers before impregnation takes 

 place, shows that it is in fact composed of two rows of carpella, of which three or 

 four surround the axis, and are placed in the bottom of the tube of the calyx, 

 and a number, varying from five to ten, surround these, and adhere to the upper 

 part of the tube of the calyx. The placentae of these carpella contract an 

 irregular kind of adhesion with the back and front of their cells, and thus give 

 the position ultimately acquired by the seeds that anomalous appearance which 

 it assumes in the ripe fruit. If this view of the structure of the Pomegranate 

 be correct, its peculiarity consists in this, that, in an order the carpella of which 

 occupy but a single row around the axis, it possesses carpella in two rows, the 

 one placed above the other, in consequence of the contraction of the tube of the 

 calyx, from which they arise. Now, there are many instances of a similar ano- 

 maly among genera of the same order, and they exist even among species of 

 the same genus. Examples of the latter are, Nicotiana multivalvis and No- 

 lana paradoxa, and of the former Malope among Malvaceae ; polycarpous Ra- 

 nunculaceae as compared with Nigella, and polycarpous Rosacea? as compared 

 with Spiraea. In Primus I have seen a monstrous flower producing a number of 

 carpella around the central one, and also, hi consequence of the situation, upon 

 the calyx above it ; and, finally, in the Revue Encycloptdique (43. 762.), a per- 

 manent variety of the Apple is described, which is exactly to Pomaces what 

 Punica is to Myrtacea?. This plant has regularly 14 styles and 14 cells, 

 arranged in two horizontal parallel planes, namely, 5 in the middle, and 9 on 

 the outside, smaller and nearer the top ; a circumstance which is evidently to 

 be explained by the presence of an outer series of carpella, and not upon the 

 extravagant hypothesis of M. Tillette de Clermont, who fancies that it is due 

 to the cohesion of 3 flowers. The anomaly of the structure of the fruit of Pu- 

 nica being thus explained, nothing remains to distinguish it from Myrtaceae but 

 its leaves without a marginal vein, its convolute cotyledons, and pulpy seeds. 

 There are, however, distinct traces of dots in the leaves, and the union of the 

 vena? arcuatse, which gives the appearance of a marginal vein to Myrtaceae, 

 t ;ikes place, although less regularly, in Punica; the convolute cotyledons of 

 Punica are only in Myrtacea? what those of Chamsemeles are in Pomaceae, a 

 curious but unimportant exception to the general structure; and the solitary 

 character of the pulpy coat of the seeds will hardly be deemed by itself suffi- 

 cient to characterize Granateae. The place of Punica in the order will be pro- 

 bably near Sonneratia. There is no instance of a blue flower in the order. 



Geography. Natives of hot countries both within and without the tropics ; 

 great numbers are found in Suutb America and the East Indies, not many in 

 Africa, and a considerable proportion <>t the order in New Holland and the 

 South Sea Islands ; but the genera of those countries are mostly peculiar to 



