DEGENERATION. 99 



fertilised catkins and oak-kinds. Nevertheless, they 

 are entomophilous, for their pollen, their arrangement 

 in large masses, and their dark purple colour, suffi- 

 ciently serve to entice numerous insects. 



The spurges (Euphorbiacece] are a very interesting 

 family of the same sort, exhibiting every gradation 

 from perfect corolliferous blossoms to the most de- 

 graded flowers in all nature. Our English species have 

 no true petals ; but some exotic forms are truly 



FIG. 38. Hermaphrodite perfect flower of South European flowering ash (Fraxinus 

 ornus) ; white, with four-lobed corolla. 



dichlamydeous ; and from them we can trace a gradual 

 decline, through plants like dog's mercury (Figs. 33 and 

 34, Mercurialis perennis\ which has a green calyx, but 

 no corolla, to very degenerate green blossoms like our 

 own spurges (Euphorbia}, which consist of several ex- 

 tremely simplified flowers, collected together in a 

 common involucre (Fig. 35). Each separate male 

 floret is here reduced to a single stamen, raised on a 

 short peduncle, and with a distinct joint at the spot 

 where the petals once stood. It is worthy of notice, 



H 2 



