MICROSCOPICAL MEMORANDA. 223 



Mr. Griffith adds, I have lately looked at Isoetes capsularis, Roxb. ; 

 it is an instructive plant, for it shows that botanists are mistaken in 

 their supposition as to the male. In Roxburgh's plant the contents of 

 the sporangium are sometimes of two sorts, but both have the same 

 origin, both are precisely similarly constituted, except perhaps as to 

 contents ; and the largest of these, the males of authors, become after- 

 wards like the others, but larger. There can be no doubt that in all 

 these plants the true sporules or seeds are thus produced by division of 

 an original simple cell or its contents. Isoetes and Azolla prove, too, a 

 thing of some importance, that the dissimilar organs which have so 

 puzzled botanists may have a similar origin. The true male of Isoetes 

 will probably turn out to be the oblong, cordate, fleshy laminae above 

 the female. On the male my observations were stopped by indisposi- 

 tion. As a male it is certainly anomalous ; it is probably, I conjecture, 

 developed originally within the leaf, and the scale between it and the 

 female is probably analogous to the indusium of ferns. The most in- 

 structive plant is Anthoceros (which is not a Hepaticd), for this may 

 explain Ferns, by showing that a pre-existing organ, to be acted upon 

 by the male influence, is not necessary. Endlicher says Isoetes has no 

 stomata ; De Candolle figures them in his " Organographie ;" in /. cap- 

 sularis they are very evident : no matter whether emerged or submerged, 

 all plants having a cutis have stomata. Proc. Linntean Society, Dec., 

 1841. 



Valentine's Supplementary Observations on the Development of the Theca, 

 and on the Sexes of Mosses. The author commences his letter by sta- 

 ting, that subsequent observations have induced him to concur entirely 

 with the views of Professor Mohl as to the sporules of Mosses being 

 developed by four in a mother cell, a fact which he was led to doubt in 

 his former communication, printed in the 17th volume of the Society's 

 Transactions. The present paper contains a detailed account of the 

 development of the theca in (Edipodium Griffithianum, which exhibits a 

 beautiful example of the tetrahedral union of the sporules. In this moss 

 the four sporules in each mother cell are piled on each other so as to 

 form a cone with a triangular base, and they appear to be connected 

 with each other in the young state by a very minute stalk which is 

 situated at the conjunction of three radiating lines. This connexion is 

 perhaps in most instances dissolved at an early period, and the sporules 

 recede a little from each other, but are still kept in the triangular form 

 by the mother cell. It is not uncommon, however, to find the con- 

 nexion unbroken after the sporules have arrived at maturity, and in these 

 instances there seems to be a general adhesion at the opposing faces of 

 the sporules. 



The author concludes his paper with some remarks on the analogy 

 that exist between sporules and pollen, which, he observes, is so re- 

 markable, and the particulars so numerous, that the essential identity 

 of the two can be scarcely a matter of opinion. Proc. Linn. Soc. t 

 1839. 



