230 BRITISH FLOWERING PLANTS chap. 



Willis, on the contrary, in Cambridgeshire they are 

 more numerous. The plant bears hairs of three 

 kinds — (l) long and simple; (2) long and seated on a 

 dark gland; (3) short ones, sometimes very numerous. 



S. succisa (Devil's Bit). — Fifty to eighty deep-blue 

 florets are united in one hemispherical head. The corolla 

 has generally 4, but sometimes 5 lobes, of which the 

 outer one is larger than the rest. The life-history of the 

 flower resembles that of S. arvensis. Some plants have 

 flowers in which the stamens are more or less atrophied, 

 and which are smaller than the complete ones. These 

 appear to be much more numerous in some places than 

 in others ; near Homburg Magnus estimated them at 

 10 per cent, Schulz in Brunswick and Halle at 30 

 per cent. Turner^ describes the plant as trimorphous 

 — with hermaphrodite, and two female forms, one 

 with a straight and the other with a bent style. The 

 flower-heads are much visited by insects. The stem is 

 pubescent. 



S. Columbaria. — The heads contain 70-80 pale 

 purplish florets. The life-history, which is similar to 

 that of the two preceding species, was well described by 

 Sprengel. The outer florets are half again as large as 

 those of the next and inner rows. Plants with female 

 flower-heads appear to be less common than in the 

 preceding species. The insects recorded as visitors are 

 much less numerous. When young the flower-heads 

 turn over at night, thus protecting the florets from rain 

 and cold. The stem is clothed, especially on the upper 

 part, with downward-pointing hairs. 



COMPOSITE 



The Compositse agree with the Dipsaceae in having 

 flower-heads composed of a large number of florets. 

 The stamens which are 5, or rarely 4, in number, 



1 Nature, xl. (1889). 



