THE DICOTYLEDONES 



1613 



making up a corona, which is yellow in colour. Bees searching for the 

 nectar come into contact with the stigma first, since it projects; meanwhile, 

 during the sucking of the nectar, the lower surface of the insect is dusted 

 with pollen. Species of Epimediiim fiower early in the year when insect 

 visits are infrequent but self-pollination is possible if cross-pollination 

 fails because, as the flowers mature, they become erect and in this position 

 pollen may fall directly on the stigma. Automatic self-pollination may also 

 occur by the elongation of the style, so that the stigmatic surface comes into 

 direct contact with the anthers. 



Fig. 1467. — Geographical distribution of the genus Magnolia. 



The Magnoliaceae are a family of considerable interest not only from 

 a horticultural standpoint but also because of the primitive features dis- 

 played by many of the species. Hutchinson considers that the Magnoliaceae 

 may represent the ancestal type of Angiosperm, thereby reviving the earlier 

 suggestions of Hallier, while Arber and others have suggested a relation- 

 ship between the Bennettitales and the Magnoliaceae. 



There are nine genera and about seventy species which are distributed 

 mainly in tropical and subtropical partsofthenorthernhemisphere (Fig. 1 467). 

 The plants are mostly trees or shrubs, though a few are climbers. Anatomically 

 the wood shows a number of primitive characters and in some genera, e.g. 

 Drimys, can be compared with that of the Gymnospermae. (See Vol. I 

 p. 904.) Oil passages occur in the parenchyma. In the genus Magnolia 

 large stipules are developed which form a covering over each of 

 the young leaves and are shed as the leaves expand. The flowers are 

 terminal or axillary, usually solitary and oftsn of large size. In Magnolia 

 the perianth is cyclic, though it is spiral in the other genera. The androe- 



