CRTJCIFEPt^E 



155 



Seed oblong, short, blunt at each end, where it is very fre- 

 quently obliquely compressed or truncate, smooth and minutely 

 reticulated with small su- 

 perficial areas that swell 

 up in water, yellow ; hilum 

 basal, overlying the cha- 

 laza and contiguous to 

 the micropyle ; raphe 

 none. 



Endosperm absent. 



Embryo doubled upon 

 itself, comparatively large, 

 and occupying the whole 

 interior of the seed, pale 

 yellow ; cotyledons oval- 

 oblong, obtuse, entire, 

 shortly petiolate, showing 

 a midrib and a few short, 

 alternate, ascending lateral 

 nerves, obliquely incum- 

 bent, nearly as long as the 

 interior of the seed ; radicle 

 terete or more or less ob- 

 tusely angled, traversing 

 one edge of the dorsal 

 aspect of the seed, and 

 then suddenly bent towards 

 the micropyle at one corner 

 of the oblique, rhombus- 

 shaped dorsal aspect, 

 longer than the seed by its 

 traversing one end as well 

 as the dorsal face of the 

 embryo. 



Seedling (fig. 163). 



Primary root long, 

 tapering, fibrous, annual. 



Hypocotyl erect, terete, 

 pale green, or sometimes 

 stained with red, becoming 

 thicker up wards, with a few scattered adpressed hairs; 8-18mm.long. 



Cotyledons oval, obtuse and rounded at the apex after germina- 



f 



PIG. 163. Sisymbrium officinale, x 2. 



