Chap. Vn. SIZE OF THE COEOLLA. 307 



the same form. It is well known that this species is strongly 

 proterogynous, and I found that the protruding stigmas of both 

 the hermaphrodite and female flowers were penetrated by pollen- 

 tubes, whilst their own anthers were immature and had not 

 escaped out of the bud. Plantago media does not present two 

 forms ; but it appears from Asa Gray's description,* that such 

 is the case with four of the North American species. The co- 

 rolla does not properly expand in the short-stamened form of 

 these plants. 



Cnicus Berratula Eriopkorwm. — In the Compositse, Onicus 

 palmtris and acaulis are said by Sir. J. E. Smith to exist as her- 

 maphrodites and females, the former being the more frequent. 

 With Serratula tinctoria a regular gradation may be followed 

 from the hermaphrodite to the female form ; in one of the latter 

 plants the stamens were so tall that the anthers embraced the 

 style as in the hermaphrodites, but they contained only a few 

 grains of pollen, and these in an aborted condition ; in an- 

 other female, on the other hand, the anthers were much more 

 reduced in size than is usual. Lastly, Dr. Dickie has shown 

 that with Mriophorum angustifoUum (Cyperacese) hermaphro- 

 dite and female forms exist in Scotland and the Arctic regions 

 both of which yield seed.f 



It is a curious fact that in all the foregoing poly- 

 gamous, dioecious, and gyno-dicecious plants in which 

 any difference has been observed in the size of the 

 corolla in the two or three forms, it is rather larger in 

 the females, which have their stamens more or less or 

 quite rudimentary, than in the hermaphrodites or males, 

 This holds good with- Euonymus, Ehamnus ccdharticus. 

 Ilex, Fragaria, all or at least most of the before-named 

 Labiatse, Seahiosa atro-pirpurea, and Eohium vulgare. 

 So it is, according to Von Mohl, with Cardamine 



* 'Manual of the Botany of 1862, p. 53. 



the N. United States,' 2nd edit. t Sir J. E. Smith, 'Trans. 



1856, p. 269. See also ' American Linn. Soo.,' vol. xiii. p. 599, 



Journal of Science,' Nov. 1862, Dr. Dickie, 'Journal Linn. Soc. 



p. 419, and ' Proc. American Bot.' vol. ix. 1865, p. 161. 

 Academy of Science,' Oct. 14, 



X 2 



