208 BRITISH FLOWERING PLANTS chap. 



dry conditions. The cuticle is more or less thickened, 

 and there are often stomata on both sides. 



In the remaining genera of this family the flowers 

 form a corymbose umbel, i.e. a head consisting of 

 several branches which start from the same point, and, 

 though of different lengths, reach the same height, so 

 that the flowers form a plane. They are generally white, 

 sometimes greenish, and in a few species yellow or 

 reddish. The honey is exposed. 



CONIUM 



0. maculatum (Hemlock). — This is a very typical 

 Umbellifer. The flowers are several hundred in an 

 umbel, protandrous, small, white, and conspicuous from 

 their numbers. The plant is about 3 feet high, with 

 much-divided leaves, which if crushed have a nauseous 

 scent, though the actual flowers have a sweet smell 

 of honey. The petals are turned over at the tip, 

 but not so much so as in Eryngium, and perhaps 

 with the object of protecting the honey till the 

 flower is mature. At the opening of the bud the 

 anthers are scarcely ripe, but they soon arrive at 

 maturity, and raise themselves so as to stand directly 

 over the still immature stigma. When each anther has 

 shed its pollen it turns outwards and another takes its 

 place. When they have all had their innings, and 

 generally not until all the pollen has fallen, the stigmas 

 themselves grow upwards and take their turn. The 

 honey being open to all, the flowers are visited by many 

 small insects. 



Tittmann^ long ago remarked on the power pos- 

 sessed by plants of drawing themselves down under 

 the protection of the ground in winter by means 

 of the contraction of the roots. This is well shown 

 in several Umbelliferse, in some Compositse, in Dipsacus, 

 Beta, etc. In this species, according to De Vries,'- it 

 amounts to as much as 8 per cent. 



^ Flora, ii. (181 fl). ^ ^^^^ Zeitung, xxxvii. (1879). 



