330 THE LOWER DICOTYLEDONS. 



where there is plenty of air and sunlight? How does the 

 arrangement seem advantageous with regard to (1) the 

 pollination of the flowers, (2) the ripening of the fruits, 

 (3) the dispersal of the fruits ? 



Examine a flower (Fig. 133), noting the green urn-like tube 

 from the edge of which arise the five green sepals, the five 

 white or reddish petals, and the numerous stamens; the 

 petals are attached by a narrow base, as in Buttercups, while 

 the sepals have broad bases. Examine the sepals carefully, 

 noting the appendages which fringe the edges ; are all the 

 sepals fringed on both sides, or are any of them fringed on 

 one side only, or not fringed at all ? Examine a flower-bud 

 and see whether the relative positions of the sepals throw light 

 on the distribution of the fringes. 



The Dog Eose has no honey, but the flowers (June to 

 August) are visited by various insects for pollen. Note the 

 numerous styles, each with a slightly dilated stigma, which 

 project a little from the mouth of the flower-tube. Cut a 

 flower down through the middle of the tube and trace the 

 styles down to the ovaries which are inserted all over the 

 lower part of the tube. The stigmas become receptive practi- 

 cally at the same time that the anthers open, but insects 

 generally alight on the stigmas first, and thus bring to 

 them pollen from previously visited flowers. 



Examine twigs showing various stages in the formation of 

 the fruits ("hips"), noting that the sepals become bent down- 

 wards but do not fall off before the fruit ripens and turns 

 red. Note the shape of the fruit (from what part of the 

 flower is the red fleshy "hip" formed?), the narrow mouth 

 of which is blocked with woolly material ; on the rim of the 

 urn notice the five scars where the sepals have fallen. Cut 

 the " hip " in two longitudinally, noting its thick wall and 

 the numerous seed-like bodies (really fruits, akenes, since 

 each is formed from an ovary) within it, and the white 

 threads (bundles) passing from the flower-stalk into the 

 wall of the " hip." Why is one side of each akene curved 

 and the other two sides flat ? Note the slender thread (style) 

 at the top of each akene, also the stiff brittle hairs covering 

 the akenes and the inner surface of the " hip." The akenes 

 are dispersed by birds, which are attracted by the bright 

 colour of the fleshy " hip." 



