METAMORPHOSIS. 



185 



Most interesting are the carpellodic stamens de- 

 scribed by Masters in the primrose (Primula vulgaris) ; 

 some of these were more or less petaloid, bilobed at 

 the apex and bearing a group of ovules on the midrib 

 of their upper portion ; others were much lobed, and, 

 besides the ovules in the position just mentioned, bore 

 also ovules along the margins of the lobes, which were 

 frequently in the form of elongated styles bearing a 

 terminal stigma (PI. XL VI, fig. 5). Some, again, 

 bore along the midrib, extending from the base two- 

 thirds of the way upward, a placenta-like ridge or 

 swelling bearing ovules on its upper, more swollen part 

 (PL XL VI, fig. 6) ; in some this placenta was very 

 short and bore only two ovules at the top (PI. XL VI, 

 fig. 7). It is, of course, a very rare, if not unheard 

 of, thing for carpels to bear ovules along their midrib, 

 and this phenomenon of the Primula demands explana- 

 tion. It can be understood by reference to the andro- 

 gynous stamens of Semper vivum, and to the theory of 

 anther-structure given on previous pages, from a con- 

 sideration of which it can be deduced that this midrib - 

 placenta of Primula corresponds to the two median 

 loculi of the anther and to the median lamellae (ovu- 

 liferous in Serrtperuivum, Papaver Blioeas, etc.) into 

 which, in abnormal stamens, the median loculi become 

 transformed. But these lamellae, at any rate, in some 

 types of anther, apparently correspond to the up- 

 turned basal lobes of the leaf fused together by their 

 outer margins, and again fused by the suture so- 

 formed, to the midrib of the leaf. Bub these fused 

 basal lobes may lose continuity with the margins of 

 the leaf and occur as a ventral excrescence* ; Masters 

 describes stamens of Primula in which the ventral 

 placenta is detached from the midrib and in the 

 position of a Narcissus-corona. The ventral enations 

 on the petals of some of these abnormal flowers must, 

 in this connection, not be forgotten. It is interesting 

 to note that many of the petaloid stamens with 



* See Narcissiis, 



