436 OX SEEDLINGS 



baccate in Muehlenbeckia, Coccoloba, and in a few species of 

 Polygonurn. It is adnate to the nut in several species of 

 Coccoloba. 



Reckoned according to the form and position of the embryo, 

 three different types of seeds have come under my observation. 

 In all cases the seed itself is trigonous, and conforms to the 

 interior of the fruit. The simplest form is represented by 

 Runiex obtusifolius. The embryo is straight or slightly curved 

 in conformity with the outline of the seed, as it is excentric 

 and lies along one of the three faces outside the endosperm. 

 The cotyledons are oblong, plano-convex, and somewhat longer 

 than the terete radicle. The fruit and seed of E. Patientia 

 are more decidedly narrowed to the base and ellipsoid ; the 

 embryo is excentric, as long as the seed, and therefore much 

 curved in conformity with it. The cotyledons are linear, 

 plano-convex, narrow, and longer than the terete radicle. 



The embryo of Eheum palmatum (fig. 621) is relatively 

 larger and generally slightly excentric, with broadly oblong 

 cotyledons, abruptly narrowed into the radicle which is short, 

 terete, and lies hi the narrow neck of the seed quite un- 

 covered by endosperm. The cotyledons are flat or more or 

 less folded longitudinally, and exceptional cases occur where 

 one is oblique to the other, and in one instance they were 

 twisted at right angles to one another so as to occupy the three 

 angles of the seed and thus attain the greatest possible size. 

 The fruit is broadly three- winged, and the inner wall is 

 greatly but unequally thickened, suberous, and so indents the 

 testa and endosperm in places as to make the latter appear 

 ruminated. 



The seed of E. oflicinale is not abruptly narrowed at the 

 apex so that the radicle remains embedded in endosperm. 

 The embryo as a whole is nearly if not quite central, with 

 narrowly oblong cotyledons slightly longer than the radicle, 

 and is relatively smaller than that of E. palmatum. 



The seed of Fagopyrum esculentum (fig. 619) is large, ovoid- 

 trigonous, rarely with the angles nearly obliterated and rounded. 

 The embryo is relatively very large, variously folded and con- 

 volute longitudinally, similar to what occurs in Geranium, 

 except that endosperm is here present and is nearly divided in 



