SIR J. LUBEOCK^PIIYTOBIOLOGTCAL OESERYATIONS. 



303 



alft'ays the same. I shall suggest a reason for the difference 



further on. 



Sroad Cotyledons. 



I now pass to species witli broad cotyledons. The Acorn, Nut, 

 Bean {Phaseolus, fig. 53), and Pea aff rd familiar cases, in which 



Fig. 54. 



Fig. b?>. 



ft 



ar 



F 



ig. 55. 



Fig, 53, Phascolus midfiflorus. Section of seed parallel and vertical to coty- 



""ledons, three fourths nat. size, a, a, auricles ; ar, arillode. 



Fig. 54. Rlcimissangidiieus. A. Longitudinal section of seed, nat. size. B. Trans- 



'^ Terse section of seed, nat. size; 



Fig. 66. Hipiyophae rhamnoides, A. Longitudinal section of seed, X 4. B. 



'Transverse section of seed, dd, depressed line. 



the two broad, fleshy, thickened cotyledons conform to and occupy 

 the whole seed. In the Castor-oil plant {Riciniis, fig. 11) the 

 seed (fig, 54) is ovoid, oblong, somewljat compressed dorso- 

 Tentrally, and beautifully mottled, while the projecting knob at the 

 hilum gives it very much the appearance of a beetle or large tick. 



The perisperm 



abundant, fleshy, white, and surrounds the 



embryo. The embryo is straight, flat, large, central, and white; 

 the cotyledons broad, obtuse oblong, and approximately following 

 the general outline of the seed. In Ilippophne (fig. 14) we have 

 a somewhat similar case ; but the cotyledons are fleshy and occupy 

 almost the whole of the seed (fig. 55). In Euonymiis, agaui, 

 the seed is obovoid, slightly compressed laterally. The peri- 

 sperm is abundant, fleshy, firm, and white, entirely surrounding 

 the embryo. The embryo is straight, flat, central, pale green, 

 extendin^^ very nearly fi*om one end of the seed to tlie other. 

 The arrangement is very similar in the Apple, In the Plax the 



