C YSTOSPERME^E. 191 



the part of the plant first formed ; it is to invert in fact the 

 natural order of things 



In the third volume of the " Memoires du Museum," 1817, 

 there is a paper by M. Leon le Clerk, on the genus Pro- 

 lifera. In this paper Vaucher's error in reference to growth 

 of the species by shoots is pointed out, and the formation 

 of circular bodies or sporangia noticed. M. Leon le Clerk was 

 not satisfied, however, that these bodies were formed by the 

 union of the endochrome of two cells, as they doubtless usually 

 are. " But it will be asked," he remarks, " what cause 

 determines the formation of the green matter into the globule 

 which we have described. To this question we frankly avow 

 our ignorance. We can only give the assurance that this for- 

 mation takes place without any kind of union with another 

 filament, as we had at first suspected from analogy to the 

 Conjugates. Perhaps, pre-occupied by the same analogy, one 

 might be led to suppose that two neighbouring divisions of 

 the same filament united their green matter to form the re- 

 productive globule. This supposition vanishes however upon 

 the slightest examination. The two divisions indeed bor- 

 dering on that which contains the grain present often the 

 green matter in its integrity, and if there be need for a fact 

 still more decisive, it has occurred to us often to meet with 

 not only two contiguous inflated cells, but three or four adjacent 

 cells all equally in fructification." 



These two facts, mentioned by M. Leon le Clerk, do not 

 at all disprove the general rule, that the globules or sporangia 

 are formed by the union and condensation of the endochrome 

 of two cells. The correctness of the first statement is very 

 questionable; it has never occurred to me to notice endo- 

 chrome in the cells on both sides of the sporangium, and I 

 am certain that where this body is perfectly formed the 

 greater portion of the green matter of the cells on one side or 

 other of it will invariably be found to have quitted that cell. 



With regard to the second particular, viz. the occurrence 

 of more than one sporangium in contiguous cells, this I think 

 can scarcely be regarded as an exception to the rule, at least 

 it admits of explanation. The occurrence of two contiguous 



