II VIOLACE^ 101 



gences in appearance to important modifications in 

 structure. Taking these latter first, 222 flowers showed, 

 in addition to the ordinary spur, saccate protuberances 

 at the base of the petals, suggesting incipient spurs, and 

 65 flowers two, three, or four spurs each. Of these 65, 

 3 possessed four spurs, 18 three spurs, and 44 two spurs 

 each. Two of the flowers with four petalline spurs 

 showed traces of a fifth rudimentary spur." Elsewhere, 

 however, he found the proportion of abnormal fiowers 

 much smaller. 



" On the other hand, in V. sylvestris, out of 1000 

 flowers gathered at the beginning of May 1900, in the 

 wooded country about Farley and Chelsham, where the 

 plant is very distinct in appearance, only 4 fiowers were 

 normal, the remaining 996 were distinguished by 

 the appearance at the bases of the petals of the slight 

 protuberances which suggest to my mind incipient spurs. 

 In the case of two flowers an auxiliary spur had been 

 developed from one of these sacs." Again, in F. Rivini- 

 ana, the " examination of 1000 flowers gathered between 

 Bookham and West Humble showed that as many as 890 

 were marked by the formation of distinct sacs at the base 

 of the petals (in addition to the usual spur). Thirteen 

 of the remainder possessed the common feature that 

 some or all the petals were lobed in a varying degree." 

 Mr. Britton suggests that the tendency to frequent 

 variation in the larger flowers may be due to the fact 

 that they seldom produce seed, and consequently that 

 the tendency to variation is not suppressed by cross- 

 fertilisation. 



V. odorata. — The flowers are small, dark, and often 

 more or less concealed by the leaves, but, on the 

 other hand, make their presence known by their sweet 

 scent. According to MacLeod^ the concavity of the 

 pistil secretes a fluid which moistens the proboscis of 

 the insect, and thus causes the pollen to stick to it. 

 Sprengel, in his description of V. odorata, gives the 

 following list of questions and answers as regards this 



' Bot. Jaarh. vi. 



