DEVELOPMENT OF PLANTS 



397 



tions. Few plants have greater vitality. A bit of a twig and 

 often a portion of a root is capable of developing buds and so 

 starting the shoot. Trees are often pointed out that have origi- 

 nated through the careless sticking of a twig in the soil and 

 several of the willows are naturally propagated by their twigs 

 which are easilv broken off bv the winds. Their unusual ability 



Fig. 297. Flowers and seed of the willow (Salix) : A, winter appear- 

 ance of a flowering twig, each boat-shaped scale concealing an ament. 

 B, pussy willow stage of flowering, the aments emerging from the scales 

 and exposing the hairy bracts that conceal the flowers. C, ament of pis- 

 tillate flowers in full bloom. D, pistillate flower, consisting of a compound 

 pistil of two carpels — b, bract; ;;, nectar gland. E, ament of staminate 

 flowers. F, staminate flower of two stamens. G, ament of mature pistils 

 which are opening to discharge the seeds. H-I, successive stages in the 

 opening of the pistil. /, a seed with circle of hairs at base forming a para- 

 chute for dissemination. 



to form numerous buds is well shown in the pollarded willows 

 where the branches have been cut back and a large number of 

 shoots develop about the wound. Perhaps the stimulus of the 

 wound also awakens some of the dormant buds (page 100). The 

 flowers, as in Typha, are arranged on an elongated axis forming 



