212 BRITISH FLOWERING PLANTS chap. 



Heracleum 



H. Sphondylium (Hogweed). — This appears in some 

 localities to have complete flowers only. In others the 

 umbels of the second order are said to have male flowers 

 on the circumference, and those of higher orders to be 

 entirely male, or in some cases female. No less than 

 118 species of insects are on record as visitors of this 

 flower. In this respect it is pre-eminent. An allied 

 genus, Ferula, is supposed to have supplied Prometheus 

 with the rod or " ferule " in which he brought down 

 fire from heaven. 



SiLER 



S. trilobum. — Andromonoecious, with protandrous 

 hermaphrodite flowers. The male flowers are numerous, 

 and occupy the centre of the umbels. The plant is not 

 a native of Britain, but has become naturalised at 

 Cherry Hinton, near Cambridge. 



Daucus 



D. Carota (Carrot). — The flowers are white ; one or 

 a few in the centre, however, generally, but not always, 

 red. No satisfactory explanation of this has yet been 

 given. They do not appear to be of any functional 

 importance, and Darwin was disposed to regard them 

 " as a remnant of a former and ancient condition." ^ 

 A somewhat similar case of the appearance of red 

 colour occurs in the ray florets of Yarrow and the 

 Daisy. Darwin's suggestion of a primitive condition 

 iu Carrot seems unlikely, as red is a rare colour in 

 Umbelliferse. The red colour would tend to increase 

 the attractiveness, but it is so small that this hardly 

 seems a suflicient explanation. The flowers vary con- 

 siderably in size, those at the circumference, and 

 especially the petals on the outside, being the largest. 

 Schulz describes in Mid - Germany two forms : the 

 commoner has complete and male flowers on the same 



^ Forms of Flowers. 



