EUPHORBIACE^E 477 



Euphorbia Peplus, L. 



Capsule as in E. Lathyris, but the pericarp does not split into 

 two distinct layers when mature. 



Seeds comparatively small, oblong, capped by a small, white, 

 funicular arillode, somewhat angled longitudinally, deeply pitted 

 with circular depressions and a long oblong one on each side of 

 the raphe on the ventral aspect, grey or glaucous, slightly depressed 

 or truncated at either end ; testa subcrustaceous, tegmen thin and 

 membranous ; raphe ventral ; chalaza inferior, orbicular, and convex 

 or somewhat elevated, and seated in an apical depression ; hilum and 

 micropyle superior, with the former lying in a depression formed by 

 the arillode, and oval in outline. 



Endosperm copious, fleshy, whitish. 



Embryo comparatively large, straight, colourless, central, some- 

 what shorter than the endosperm ; cotyledons oblong, orbicular, 

 entire, plano-convex or nearly flat, lying in the endosperm with 

 their backs to the axis ; radicle oblong, much narrower and also 

 longer than the cotyledons, tapering somewhat to an obtuse point, 

 which lies close to the micropyle. 



Germination. The radicle pushes into the soil, fixing the 

 young plant there, and develops root-hairs. The hypocotyl arches, 

 and as it rises up pulls the cotyledons out of the seed, which splits 

 irregularly during the process so as to facilitate their exit. In 

 moist soil and a moderately high temperature, the seeds germinate 

 in nine days. 



On the second day after appearing above the soil, the lower 

 part of the hypocotyl is straight and stout ; the upper part is still 

 curved downwards and much more slender. The cotyledons im- 

 mediately after leaving the seed are narrowly oblong, obtuse, entire, 

 glabrous, pale green, and sessile. 



Four days after appearing above soil the hypocotyl is nearly 

 straight, and the cotyledons are somewhat larger, oblong, obtuse, 

 entire and very shortly petiolate, with two short lateral nerves at the 

 base and one to two alternate ones upwards. 



Seedling. 



Primary root normal, annual. 



Hypocotyl pale green below, purple upwards, tapering into the 

 root, 1*9 cm. long. 



Cotyledons linear-oblong, obtuse, entire, tapering into the 

 petiole which is short and grooved above, 8 mm. long including the 

 petiole. 



Stem very similar to that of E. exigua. 



