THE RIPE FRUIT OF A MANGO. 217 



and in the eyes of physiologists the true organic apex 

 of the seed. It is obvious, therefore, that in this case 

 the organic apex, and the apparent apex, are far ft'om 

 corresponding ; and this is a very common occur- 

 rence. 



The use of the vessels of the chalaza is doubtless 

 to convey from the junction of the pericarp and branch 

 {jig. 3.f.) the nutritious fluids required to enable the 

 embryo to develope, and to change, from an opaque 

 speck floating in jelly, to a large almond-like kernel. 



The embryo is a large almond-like kernel (Jig. 

 4. 6.\ composed of two plano-convex cotyledons, curved 

 almost into the form of a kidney, and adhering by a 

 point indicated externally by the small conical radicle 

 (fg. 4. a.). 



If you cut off" the cotyledons, so as to get the 

 radicle and plumule small enough to be conveniently 

 magnified about four times, you will see that those 

 tw^o parts form a centre or axis of growth represented 

 by two cones, of which the radicle (Jig. 5. «.), lying in 

 a niche of the cotyledons on the outside, is one, and 

 the plumule {Jig. o. b.), enclosed between the bases of 

 the cotyledons, is another. The cotyledons grow to the 

 axis by a narrow space (Jig. 5. c). 



The plumule ( figs. 6. and 70 is terminated at its 

 point by four extremely minute leaves, crossing or 

 alternating with each other in opposite pairs. Of 

 these plumular leaves, the larger pair (a. a.) is ex- 

 ternal, and partly overlies the smaller (b.). The coty- 

 ledons themselves, which are larger still, cross or 

 alternate with the outer pair of plumular leaves. 



