138 HETEROSTYLED TRIMORPHIC PLANTS. Chap. IV. 



are considered, there are five distinct sets of males. 

 Two of the three hermaphrodites must coexist, and 

 pollen must be carried by insects reciprocally from one 

 to the other, in order that either of the two should be 

 fully fertile; but unless all three forms coexist, two 

 sets of stamens will be wasted, and the organisation of 

 the species, as a whole, will be incomplete. On the 

 other hand, when all three hermaphrodites coexist, and 

 pollen is carried from one to the other, the scheme 

 is perfect; there is no waste of pollen and no false 

 co-adaptation. In short, nature has ordained a most 

 complex marriage-arrangement, namely, a triple union 

 between three hermaphrodites, — each hermaphrodite 

 being in its female organ quite distinct from the 

 other two hermaphrodites and partially distinct in 

 its male organs, and each furnished with two sets of 

 males. 



The three forms may be conveniently called, from 

 the unequal lengths of their pistils, the long-styled, mid- 

 styled, and short-styled. The stamens also are of un- 

 equal length, and these may be called the longest, mid- 

 length, and shortest. Two sets of stamens of different 

 length are found in each form. The existence of the 

 three forms was first observed by Vaucher,* and subse- 

 quently more carefully by Wirtgen ; but these botanists, 

 not being guided by any theory or even suspicion of 

 their functional differences, did not perceive some of the 

 most curious points of difference in their structure. I 

 will first briefly describe the three forms by the aid of 

 the accompanying diagram, which shows the flowers, 

 six times magnified, in their natural position, with their 

 petals and calyx on the near side removed. 



* Hist. Phys. des Plantes und dessen Formen," 'Verhand. 

 d Europe' torn, ii., 1841, p. 371. des naturhist. Vereins fur preues. 

 wirtgen, TJeber Lythrum salicaria Kheinl.,' 5. Jahrgang, 1848, S. 7. 



