II CRUCIFERiE 77 



(Fig. 45), or accumbent (Fig. 46), as in the Wall- 

 flower [Cheiranthus Cheiri). 



The order is generally divided into two great groups 

 ■ — (1) those with a dehiscent pod, (2) those with an 

 indehiscent pod, containing one seed or several separated 

 by partitions. The first group again falls into two — 

 Siliquosse, in which the pod is three to four times as 



Fig. 46. — Sections of seed of Wallflower {Gheiranthus Cheiri). x 10. R, radicle ; 

 C, cotyledon. The radicle is accumbent, or parallel with the edges of the 

 cotyledons. 



long as broad, and Siliculosae, in which it is globular 

 or broad and more or less compressed. The compression 

 is sometimes parallel to the partition, as in Alyssum or 

 Draba ; sometimes at right angles to it, as in Capsella 

 (Shepherd's Purse) or Lepidium (Cress). 



The edges of the leaves in some species (Cardamine 

 and Nasturtium) produce buds. 



Gheiranthus 



C. Cheiri (Wallflower) is glabrous, or with adpressed 

 hairs, forked from the base. Forked and stellate hairs 

 are frequent in this family ; they afford a better pro- 

 tection from loss of moisture by the plant, and also 

 a more efficient shade from excessive sunlight than 

 would simple hairs. The flowers are rather, large, and 

 vary in colour from pale yellow to deep red. There are 

 two nectaries situated at the base of the two short 

 stamens. The honey sinks into the depressions at the 

 base of the sepals. The anthers open inwards, and 

 almost close the mouth of the flower. It is visited by 

 bees and flies ; those with short probosces cannot reach 



