CHAP. II. THE COMMON OXLIP. 57 



the primrose, when legitimately and naturally ferti- 

 lised, yield on an average many more seeds per capsule 

 than the cowslip, namely, in the proportion of 100 to 

 55. When illegitimately fertilised they are likewise 

 more fertile than the two forms of the cowslip, as shown 

 by the larger proportion of their flowers which set cap- 

 sules, and by the larger average number of seeds which 

 the capsules contain. The difference also between the 

 number of seeds produced by the long-styled and short- 

 styled flowers of the primrose, when both are illegiti- 

 mately fertilised, is greater than that between the num- 

 ber produced under similar circumstances by the 

 two forms of the cowslip. The long-styled flowers of 

 the primrose when protected from the access of all in- 

 sects, except such minute ones as Thrips, yield a con- 

 siderable number of capsules containing on an average 

 19.2 seeds per capsule; whereas 18 plants of the long- 

 styled cowslip similarly treated did not yield a single 

 seed. 



The primrose, as every one knows, flowers a little, 

 earlier in the spring than the cowslip, and inhabits 

 slightly different stations and districts. The primrose 

 generally grows on banks or in woods, whilst the cow- 

 slip is found in more open places. The geographical 

 range of the two forms is different. Dr. Bromfield re- 

 marks * that " the primrose is absent from all the in- 

 terior region of northern Europe, where the cowslip is 

 indigenous." In Norway, however, both plants range 

 to the same degree of north latitude, f 



The cowslip and primrose, when intercrossed, be- 



* 'Phytologist.' vol. iii., p. 694. la France,' 1840, torn. ii. p. 376. 



t H. Lecoq, ' Geograph. Bot. de With respect to the rarity of P. 



1'Europe,' torn, viii., 1858, pp. 141, veria in western Scotland, see 



144. See also ' Ann. and Mag. of H. C. Watson, ' Cybele Britan- 



Nat. Hist,,' ix., 1842, pp. 156, 515. nica,' ii. p. 293. 

 Also Boreau, ' Flore du centre de 

 6 



