258 



CONCLUDING REMARKS 



Chap. VI. 



Trees/ bushes, and herbaceous plants, both laTge 

 and small, bearing single flowers or flowers in dense . 

 spikes or heads, have been rendered heterostyled. So 

 have plants which inhabit alpine and lowland sites, dry 



land, marshes and water.* 



When I first began to experimentise on hetero- 

 styled plants it was under the impression that they 

 were tending to become dioecious ; but I was soon forced 

 to relinquish this notion, as the long-styled plants 

 of Primula which, from possessing a longer pistil, larger 

 stigma, shorter stamens with smaller pollen-grains, 

 seemed to be the more feminine of the two forms, 

 yielded fewer seeds than the short-styled plants which 

 appeared to be in the above respects the more mascu- 

 line of the two. Moreover, trimorphic plants evident- 

 ly come under the same category with dimorphic, and 

 the former cannot be looked at as tending to become 

 dioecious. With Lytlirum salicaria, however, we have 

 the curious and unique case of the mid-styled form 

 being more feminine or less masculine in nature than 

 the other two forms. This is shown by the large 



*Out of the 38 genera known 

 to include heterostyled species, 

 about eight, or 21 per cent., are 

 more ox less aquatic in their 

 habits. I was at first struck with 

 this fact, for I was not then aware 

 how large a proportion of ordinary 

 plants inhabit such stations. Het- 

 erostyled plants may be said in 

 one sense to have their sexes sepa- 

 rated, as the forms must mutually 

 fertilise one another. Therefore 

 it seemed worth while to ascertain 

 what proportion of the genera in 

 the Linnean classes Moncecia, 

 Dicecia and Polygamia, contained 

 species which live "in water, 

 marshes, bogs or watery places." 

 In Sir W. J. Hooker's ' British 

 Flora ' (4th edit. 1838) these three 

 Linnean classes include 40 genera, 

 17 of which (i.e. 43 per cent.) 



contain species inhabiting the 

 just-specified stations. So that 43 

 per cent, of those British plants 

 which have their sexes separated 

 are more or less aquatic in their 

 habits, whereas only 21 per cent, 

 of heterostyled plants have such 

 habits. I may add that the her- 

 maphrodite classes, from Monan- 

 dria to Gynandria inclusive, con- 

 tain 447 genera, of which 113 are 

 aquatic in the above sense, or only 

 25 per cent. It thus appears, as 

 far as can be judged from such 

 imperfect data, that there is some 

 connection between the separation 

 of the sexes in plants and the 

 watery nature of the sites which 

 they inhabit ; but that this does 

 not hold good with heterostyled 

 species. 



