544 SCIENTIFIC AND APPLIED PHARMACOGNOSY 



eastern Africa. The plumose awns at the summit of the seeds are 

 usually removed before exportation (Fig. 233). 



Description. Hemi-anatropous, oblong-lanceolate or spatulate, 

 acute or acuminate, unevenly flattened and in transverse section 

 deltoid or plano-convex, 8 to 15 mm. in length, 3 to 5 mm. in breadth, 

 1 to 1.5 mm. in thickness; externally yellowish-green, covered with 

 long hairs giving a silky appearance to the seed, the raphe extending 

 as a distinct ridge from the hilum about half the length of the seed; 

 fracture short; internally whitish, endosperm about 0.2 mm. in 



FIG. 233. A dehiscent follicle of strophanthus showing plumose seeds. 



thickness, embryo 6 to 12 mm. in length and 1 to 2 mm. in breadth, 

 cotyledons plano-convex, about 1 mm. in breadth, hypocotyl conical, 

 2 mm. in length; inodorous except when broken; taste very bitter. 



When treated with 90 per cent sulphuric acid the endosperm, in 

 about 65 per cent of the seeds, becomes green, turning to brownish- 

 green and not reddish; the cotyledons become red or purple and 

 finally green, in some instances. 



Inner Structure. (Fig. 234.) Outer epidermal layer having 

 numerous, non-glandular hairs, which are from 0.200 to 0.800 mm. 

 in length, usually more or less bent, thin-walled and slightly lignified, 

 thickened and porous at the base; an inner layer of somewhat col- 



