INTRODUCTION. 13 



as andro-dioecious. But, after making inquiries from 

 several botanists, I can hear of no such cases. Lecoq, 

 however, states,* but without entering into full details, 

 that some plants of Galtha palustris produce only male 

 flowers, and that these live mingled with the her- 

 maphrodites. The rarity of such cases as this last one 

 is remarkable, as the presence of hermaphrodite and 

 male flowers on the same individual is not an un- 

 usual occurrence; it would appear as if Nature did 

 not think it worth while to devote a distinct indi- 

 vidual to the production of pollen, excepting when 

 this was indispensably necessary, as in the case of 

 dioecious species. 



I have now finished my brief sketch of the several 

 * cases, as far as known to me, in which flowers differing 

 in structure or in function are produced by the same 

 species of plant. Full details will be given in the fol- 

 lowing chapters with respect to many of these plants. 

 I will begin with the heterostyled, then pass on to 

 certain dioecious, sub-dioecious, and polygamous species, 

 and end with the cleistogamic. For the convenience of 

 the reader, and to save space, the less important cases 

 and details have been printed in smaller type. 



I cannot close this Introduction without expressing 

 my warm thanks to Dr. Hooker for supplying me with 

 specimens and for other aid; and to Mr. Thiselton 

 Dyer and Professor Oliver for giving me much in- 

 formation and other assistance. Professor Asa Gray, 

 also, has uniformly aided me in many ways. To Fritz 

 Miiller of St. Catharina, in Brazil, I am indebted for 

 many dried flowers of heterostyled plants, often accom- 

 panied with valuable notes. 



' G^ographie Botanique,' torn. iy. p. 488. 



