446 



ON SEEDLINGS 



FIG. 289. Phaseolus multiflorus. A, 

 longitudinal section of seed through 

 the cotyledons : r, radicle ; c, coty- 

 ledon ; t, testa. B, longitudinal section 

 of seed in plane of cotyledons, with- 

 out removing a cotyledon : a a, auricles 

 of cotyledons ; r, radicle ; ar, minute 

 arilloid. Three-quarters nat. size. 



Phaseolus multiflorus, Willd. (fig. 289). 



Fruit a legume, linear, laterally compressed, many-seeded, de- 

 hiscing along both sutures. 



Seed transversely oblong, with unequal ends (the larger con- 

 taining the apical ends of the cotyledons), much compressed laterally 



but convex on both surfaces, 

 smooth, shining, with black 

 markings on a pink ground 

 especially conspicuous towards 

 the hilum, with two minute aril- 

 loid processes near the hilum on 

 the ventral edge ; hilum oblong- 

 linear, pale-coloured, near the 

 middle of the ventral edge ; 

 micropyle rather conspicuous, 

 near one end of the hilum. 

 Endosperm absent. 

 Embryo very large, curved, 

 conforming in outline to that of 

 the seed, pale creamy white ; 

 cotyledons large, fleshy, obovate 

 and plano-convex, or subconcave on the inner contiguous faces 

 when dry, forming a hollow between them ; radicle stout, tapering 

 to an obtuse point, and curved round towards the micropyle, 

 protruded from and accumbent to the cotyledons ; plumule large 

 and well developed, lying between the cotyledons. 



Phaseolus vulgaris, L., var. (fig. 290). 



Primary root tapering, flexuose, abundantly furnished with 

 lateral rootlets, rather fleshy, colourless, annual. 



Hypocotyl stout, fleshy, terete, pubescent, rooting at the base 

 and suddenly narrowed into the root, 7 cm. long, 4-5 mm. thick. 



Cotyledons carried above ground by the hypocotyl, fleshy, oblong, 

 obtuse, falcate, turned to one side of the stem, longitudinally 

 wrinkled, pale green, thick, never foliaceous. 



Stem herbaceous, erect, subterete or slightly ridged by lines de- 

 current from the base of the petioles, pubescent ; 1st internode 

 2-4 cm. long. 



Leaves compound, pinnately trifoliolate (first pair opposite and 

 unifoliolate), cauline, alternate, stipulate, petiolate, pubescent, 

 petioles subterete, pubescent, channelled on the upper side, pale 

 green ; stipules lanceolate, acute, entire (those of the primary and 



