466 Mr. Valentine on the Development of the Theca, 



often mixed with jointed pellucid filaments, "Jila succulenta" of Hedwig, and 

 in some cases accompanied by the supposed stamens, which in others grow 

 on a different part of the same plant (monoecious), or on a distinct plant 

 (dioecious). The object of this paper is chiefly to explain the anatomy of 

 these pistilla, their structure being such as to throw considerable light upon 

 the sexual theory. I was first led to examine this subject by discovering the 

 highly curious fact, that the setae of Mosses and the Jungermannias terminate 

 downwards in a cone, which is inserted within a corresponding cavity of the 

 branch, to which it has but a very slender attachment ; or, in other words, that 

 the seta has very little if any organic connexion with the plant. This struc- 

 ture appeared to be so anomalous, that 1 determined on the first opportunity 

 to investigate the cause. The following observations are the result*. 



In the very young state the pistillum contains a single unconnected oval 

 transparent body or cell, which is situated about one third from the base. 

 The pistillum, as yet, has not begun to enlarge, but is of one uniform diame- 

 ter. The cell is present before the apex of the pistillum has burst open to 

 form the stigma ; and consequently before there is any communication, by 

 means of the tubular style, with the external air. This canal, however, is 

 formed before the bursting open of the apex, and leads directly down to the 

 cell, which appears to be situated in its lower extremity. The cell may be 

 distinguished through the walls of the pistillum with the assistance of a good 

 WoUaston doublet, and I have succeeded in dissecting it out uninjured. It 

 was of a firm texture, a quality depending probably on the thickness of the 

 membrane ; it was also beautifully pellucid, and contained a quantity of 

 moving particles. Upon pressing it with a piece of talc it burst, and the 

 moving particles escaped. Its diameter was between the one thousandth and 

 the one five-thousandth of an inch. Generally one or two only of the pistilla 

 in the same bud arrive at perfection, and the abortive ones are destitute of 

 this cell ; whilst, on the contrary, in Brt/um Ugulufum nearly all the pistilla, 

 sometimes amounting to between twenty and thirty, become fruit, and in 

 every one of them may the cell be detected. Bryinn roseum very rarely 



* Since this was written, I liave been favoured by Mr. Brown witli a sight of Hedwig's Fundamentum 

 Historic, &c., in which this structure is figured. It is surjjrising that this remarkable peculiarity should 

 not be anywhere noticed, either by Hooker, Greville, or, indeed, any of tlie British muscologists. 



