CHAP. VII. SIZE OF THE COROLLA. 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, Serratula, Eriophorum. In the Composite, Cnicus 

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

 maphrodites and females, the former being the more frequent. 

 With Serrattda 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 EriopJiorum angustifoUum (Cyperaceae) 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, dioscious, and gyno-dioecious 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, Rhamnus catluirticus, 

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

 Labiatae, Scabiosa atro-purpurea, and Echium vulgare. 

 So it is, according to Von Mohl, with Cardamine 



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



the N. United States,' 2nd edit. f Sir J. E. Smith, ' Trans. 



1 856, p. 269. See also ' American Linn. Soc.' vol. xiii. p. 5!)'.). 



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



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

 Academy of Science,' Oct. 14, 



