62 COTYLEDONS OF CAREYA, ETC. [BOOK i. 



A cohesion of the cotyledons takes place in those embryos 

 which Gsertner called pseudomonocotyledonous, and Richard 

 macrocephalous. In the Horsechesnut, the embryo consists 

 of a homogeneous undivided mass, with a curved horn-like 

 prolongation, of one side directed towards the hilum. If a 

 section be made in the direction of the axis of the horn-like 

 prolongation, through the whole mass of the embryo, a slit 

 will be observable above the middle of the horn, at the base 

 of which lies a little conical body. In this embryo the slit 

 indicates the division between the two bases of a pair of 

 opposite confluent cotyledons ; the conical body is the plu- 

 mule, and the horn-like prolongation is the radicle. In 

 Castanea nearly the same structure exists, except that the 

 radicle, instead of being curved and exserted, is straight, and 

 inclosed within the projecting base of the two cotyledons ; 

 and in Tropseolum, which is very similar to Castanea in 

 structure, the bases of the cotyledons, are slit into four little 

 teeth inclosing the radicle. The germination of these seeds 

 indicates more clearly that the cotyledonary body consists of 

 two and not of one cotyledon ; at that time the bases of the 

 cotyledons, which had been previously scarcely visible, sepa- 

 rate and lengthen, so as to extricate the radicle and plumule 

 from the testa, within which they had been confined. 



Mr. Griffith states that in Careya herbacea, " The fleshy 

 body which constitutes the entire mass of the seed, after the 

 removal of the testa, consists of a peripheral fleshy mass and 

 a central subulate body firmly adherent with it, of similar 

 texture, and having its apex directed towards one side of the 

 hilum. At the opposite extremity the outer mass is sur- 

 mounted by a number of colourless scales, surrounding and 

 concealing other more minute scales, which occupy the 

 extremity of the central subulate body. There are no traces 

 of cotyledonary division, and the subulate body, excepting 

 at its divided upper extremity, is continuous with the rest of 

 the fleshy mass. The commencement of the germination 

 takes place while the seeds are still inclosed in the fruit. 

 The integument is ruptured longitudinally, and generally with 

 some degree of regularity along the apex ; from this opening 

 are exserted pale greenish scaly leaf-like bodies, consisting 



