MORE MARRIAGE CUSTOMS. 



109 



males would certainly fall or blow out upon the 

 females beneath them. But the plant prevents 

 that catastrophe by a very simple dodge, which 

 we shall have occasion to notice in many other 

 parallel cases. The flowers open from below up- 

 ward ; thus the females mature first, and are fer- 

 tilised by insects which bring to them pollen from 

 other plants already rifled ; later on the males 

 follow suit, and their pollen is carried off by the 

 visiting insect to the female flowers on the next 

 plant it visits. Indeed, you may gather by this 

 time how great a variety of devices natural selec- 

 tion has produced for securing this great deside- 

 ratum of fresh blood, or cross-fertilisation, from a 

 totally distinct plant colony. 



A much commoner English wild-flower than 

 the arrowhead shows us another form of early 

 threefold blossom. I mean the water-plantain 

 (Fig. 21), a pretty feath- 

 ery weed, which grows by 

 the side of most ponds 

 and lakelets. In the wa- 

 ter-plantain you have a 

 flower of both sexes com- 

 bined; it consists of three 

 green sepals, forming a 

 protective calyx ; three 

 delicate pinky-white pet- 

 als, forming the corolla; 

 six stamens — that is to 

 say, two rows of three 

 each ; and a number of 

 small one-seeded carpels, 



exactly as in the buttercup, which occupies, in 

 fact, the corresponding place among the fivefold 

 flowers. 



Fig. 21. — Flower of water- 

 plantain. The male and fe- 

 male parts are in the same 

 blossom. 



