366 M. Treviranus on the Structure of the Fruit of the Crucifera. 



it mostly nerveless; in Br aha grandiflora, however, and con- 

 fusa, Syrenia siliculosa, Smeloskia integrifolia,%cc, with one nerve ; 

 in Parry a exscapa, Macropodium nivale and Sisymbrium Sophia, 

 furnished with two of them. In his ' Catalogue of Plants found 

 in the Caucasus, fee. in 1829 and 1830, Petersb. 1831/ he gives 

 also to Sisymbrium binerve " dissepimentum hyalinum, fasciis 

 binis longitudinalibus insignitum" (p. 189). Of the plants here- 

 named I had at my disposal good specimens only of Macropodium 

 nivale. Sisymbrium Sophia and S. binerve, and in these I remarked 

 the following points : — In Macropodium there extended through 

 the middle of the whole septum a brighter streak free from the 

 tissue of rows of anastomosing cells which occupied the sides, 

 and which, above, where it originated from the base of the style, 

 had on each side a border of rows of more thickened cells, and 

 these borders appear to have been described by Meyer as two 

 nerves. In Sisymbrium Sophia also a tolerably broad band runs 

 through the whole length of the septum; it is not however 

 brighter but less transparent than the remaining substance, at 

 the same time it is more transparent in the middle than on the 

 two lateral borders, and these borders have undoubtedly been 

 taken for the two nerves by Meyer. Sisymbrium binerve, C. A. 

 M., has much the same condition, only the band is not so broad 

 here as in S. Sophia. If we understand by nerves, cords of fibrous 

 tubes and vessels, there is no trace of such in that which appears 

 as a nerve of the septum ; they are rather only bundles of long- 

 jointed cellular filaments, like those of which the central cellular 

 tissue of the style, the so-called conducting tissue, is composed, 

 as a prolongation of which, therefore, I do not hesitate to consider 

 those nerves, though unable at present to say in what kind of 

 relation to fertilization they stand in their distribution through 

 the septum. It is true that we observe no distinct nerves in the 

 septum of the majority of the Cruciferse, which however must 

 exist if these had the important destination alluded to ; but in 

 all siliques and silicles, if I am not mistaken, cellular filaments 

 may be discovered, which are distributed in a reticulated manner 

 between the two lamellae of the septum, and mostly toward their 

 borders where they retreat from one another, while in the middle 

 portion they are usually in close contact. The idea which, on 

 account of their distribution in a descending direction, is the first 

 that must present itself, that they are pollen-tubes, is opposed 

 by their being evidently composed of single elongated utricles, 

 and I have never succeeded in making out a continuation of them 

 to the ovules like that which Hartig figures from Capsella*. 

 If we seek to trace back the formation of the silique according 



* N. Thcorie, 39. f. 26, 27. 



