ii FORM-VARIATIONS 95 



M. Boudier, of Montmorency, says, in valuable notes 

 which he has kindly written down for me in answer 

 to many queries, " plants growing in dry, unprotected 

 soil are small and dwarfed, while the same species 

 living in moist soil are more vigorous, more developed, 

 and especially much taller. A common species, 

 Serratula tinctoria, grows indiscriminately in dry and 

 in moist soil ; in dry and unprotected stations it seldom 

 is over ten or twenty centimetres' in height, while 

 in moist soil it easily attains one metre (100 centi- 

 metres). The common dandelion '(Taraxacum dens 

 leonis] has in dry soil leaves which are much more 

 irregular and incised, while they are hardly dentate 

 in marshy stations, when it is called Taraxacum 

 palustre" Individuals of the same species grow- 

 ing near the sea-shore differ markedly from those 

 growing far inland. Similarly species, such as some 

 Ramuiculus^ which can live under water as well as in 

 the air, exhibit marked differences when considered in 

 their different stations, as is well known to all. 

 These differences may be important enough to induce 

 botanists to believe in the existence of two different 

 species when there is only one. A century and 

 a half ago, G. Bauhin and Tournefort described two 

 different species of Coriander. But Fabrejou, a 

 botanist of that time, who has written a large treatise 

 on systematic botany, under the title, Description des 



