626 



BOTANY OF THE LIVING PLANT 



Gynoecium, carpels 8-12, syncarpous, superior ; the stigma sessile, star- 

 shaped ; the rays of the star indicate the number of the carpels. The ovary 

 is unilocular : beneath each ray of the stigma (that is, at the junction of 

 the carpels that compose it) a flat partition extends radially towards the centre, 

 but without reaching it. The small and numerous ovules are borne super- 

 ficially on these plates. In others of the Poppy family the carpels may be 

 fewer, and in Chelidonium only two, as in the Cruciferae. Fruit, a dry capsule 

 opening by pores below the stigma. Seeds with oily endosperm : they are 

 scattered out by wind shaking the pore-capsule (see Fig. 244, p. 325). 



Pollination. The showy flower attracts insects which come to collect 

 pollen. There is no honey, and the flower is radial : it is not a highly special- 

 ised type. Promiscuous cross-pollination may follow from insect visits, but 

 self-pollination is also possible. Papaver somniferum, L., the Opium Poppy, 

 belongs to the family. 



Family : Cruciferae. Example : The Charlock. 



(19) The Charlock, or Field Mustard (Brassica Sinapis, Visiani), is the 

 common weed that colours cornfields yellow in early summer. It is an 

 annual, with stem and leaves bristly with stiff hairs. Its germination is 



Fig. 477. 



Charlock [Brassica Sinapis, Visiani) . I. flower, with parts slightly displaced. 



II. ripe and dehiscent fruit. III. floral diagram. 



shown in Fig. 3, p. 10. Its inflorescence is a raceme, but with the bracts 

 abortive (Fig. 179 C). The flower, which is of radial symmetry, consists of : 



Calyx, sepals 4, polysepalous, inferior ; in two pairs, the outermost being 

 antero-posterior, the inner lateral. 



Corolla, petals 4, polypetalous, inferior, with a long basal claw. They are 

 cruciform, and alternate with the sepals. 



Androecium, stamens 6, free, hypogynous: two are short and lateral, opposite 

 the lateral sepals : four are longer in two pairs, opposite the antero-posterior 

 sepals. 



Gynoecium, carpels 2, syncarpous, superior ; ovary bilocular, with many 

 ovules ; an ill-defined style, and a stigma with antero-posterior lobes. The 



