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ovaria, and especially the pericarp, the structure of which is very character- 

 istic. The ovaria, whether combined by their central axis, or more or less 

 distinct, always contain 2 ovula ; if 4, or sometimes but 1, are found, this 

 occurs only in genera stationed at the extreme limits of the group. They are 

 collateral, or more frequently placed one above the other, and then one is 

 usually ascending, and the other suspended. This position, which at first 

 sight appears singular, is very natural ; for the ovary is usually pierced by 

 the vessels of the style only in the middle, and it is at that point that the two 

 ovules are inserted, both at nearly the same height. If, therefore, they are 

 placed one above the other, it is indispensable that one should ascend, and the 

 other descend. These ovules may be considered peritropal, rather than either 

 ascending or suspended, or, in other terms, attached by their middle rather 

 than by either extremity." — " If the ovarium of a Diosmea is divided across, 

 its coat will be found to consist of two layers, the outer rather the most fleshy, 

 and the inner thin or almost absent on the side next the axis, the side which is 

 traversed from bottom to top by the vessels of the peduncle. These vessels, 

 at a certain height, meet those of the style, either at the point of its insertion 

 or below it ; united to these, they penetrate the cavity of the cell, the shell 

 of which they pierce, and there form funiculi, to which the ovula are attached. 

 Thus far the structure of Diosmese is little different from that of other Ruta- 

 ceous plants. But this becomes modified as the ovarium advances towards 

 the state of fruit. The endocarp hardens by degrees, and at the same time 

 separates from the sarcocarp. Its form resembles that of a bivalve shell, and 

 may be more especially compared to that of a muscle ; it presents two extre- 

 mities, one superior, the other inferior, two lateral faces which are more or less 

 convex, and two edges more or less acute, which unite them, the one external, 

 the other internal. The two valves are woody and touch at the edges, except 

 perhaps at a part of their inside where they are separated ; this space is filled 

 by a membrane which passes from one to the other : it is either slightly fleshy, 

 or, which is more common, extremely thin, thickened in the middle by the 

 passage of the vessels of the seed which penetrate it ; and as, after having 

 pierced it, they are almost immediately inserted into the seed, the latter appears 

 to be actually borne by the membrane itself. When the fruit is perfectly ripe, 

 the sarcocarp of each cell opens from above inwards, following a longitudinal 

 furrow, which had become visible some time previously. Its inner surface is 

 seen to be covered by projecting lignified vessels, which are directed obliquely 

 from the inner edge towards the outer, and are indicated externally by some 

 transverse projections. The endocarp is loose in the inside of the shell, unless 

 at its membrane, by means of which it continues to preserve some degree of 

 adhesion with the other parts ; but it soon opens, the two valves separate in 

 different directions, and force out the seeds. When this separation takes place, 

 the membrane is torn all round, and either falls away or sticks to the seed. 

 In the latter case it is found attached to the hilum, if one seed only has 

 ripened ; but then in removing it, the remains of the abortive ovule may be 

 found on one side. If both seeds have arrived at maturity, they are usually 

 seen one resting on the other by their contiguous flattened extremities, and the 

 membrane extends along their inner edge, being enlarged at their point of con- 

 tact, where two transverse prolongations are perceptible." 



M. A. de Jussieu then proceeds to point out the inaccuracy of calling, with 

 some, this endocarp an arillus, — a name which, as Auguste St. Ililaire some- 

 where remarks, has been applied to as many different things as the Linnaean 

 term nectarium ; or, with others, applying the same name to the persistent 

 membrane. 



Diosmece are nearly related to Rutacese, from which they differ in the re- 

 markable structure of their fruit , and in having two ovula in each cell ; with 



