EUPHORBIACE^ 



483 



embryo, but thinnest at the sides, yellowish or creamy white, 3 mm. 

 wide on the ventral and dorsal faces. 



Embryo straight, large, colourless ; cotyledons thin, slightly 

 curved at the sides and running through almost the whole length 

 of the seed, closely applied with their backs to the placenta, but so 

 far apart internally (at least when dry) as to leave an ellipsoid hollow, 

 1 cm. wide and 4-4-5 mm. deep, oblong in outline, with a distinct 

 midrib, trinerved for the lower two-thirds, and then alternately penni- 

 nerved, obtuse or subtruncate at the apex, cordate at the base. 



Hevea Spruceana, 31 all. 

 Arcj. (fig. 641). 



Primary root very strong, 

 long, and tapering down- 

 wards. 



Hypocotyl very short, 

 stout, subterranean, glabrous, 

 pinkish and mottled with 

 yellow. 



Cotyledons very large and 

 wide, petiolate, subterranean 

 and remaining in the seed till 

 they decay after absorbing the 

 endosperm ; petioles flattened 

 above, convex on the back, 

 dilated and semi-amplexicaul 

 at the base, glabrous, green, 

 of unequal lengths when the position of the seed during germination 

 necessitates it for the convenience of exit of the plumule ; the 

 longer 10'5 mm. long ; the shorter 7'5 mm. 



Stem erect, subcompressed in the young state, glabrous, deep 

 dull green, soon becoming woody ; 1st internode 12-20 cm. ; 2nd 

 about 3 mm. long. 



Leaves compound, cauline, alternate (first two opposite), stipu- 

 late, petiolate, with the leaflets subsessile or narrowed to a very 

 short petiolule, alternately incurvinerved, reticulate, entire, glabrous, 

 somewhat shining or glossy, deep olive-green on the upper surface, 

 suffused with a glaucous-purple beneath (at least when young) ; 

 stipules small, subulate, acute, pale green, interpetiolar in the 

 primary pair ; petioles subterete, stout or dilated at the base, and 

 tapering upwards, narrowly channelled on the upper surface, deep 

 dull green, glabrous. 



Nos. 1 and 2. Opposite, digitately trifoliolate ; leaflets oblong - 



FIG. 641. Hevea Spruceana. 

 One-fourth nat. size. 



