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ATSTD OAEETA. 61 



aU 



Ijiii; ::;i;' three distinct modes in which the structure 



'-•-•'-: 1. As an undivided exalbuminous embry 



Blume, followed by Endlicher and Meisner, 



0^:f 2. As an embryo in the axis of copious albumen. This 



ginated with Gaertner, and was adopted by Hamilton, Eox 



Wm burgh, Wight, and 



an exalbimiinous embryo in two layers, a view first 



_ mulgated by Wight and Amott, and doubtfuUy 



ms Griffith. 



The manifest contradiction inyolved in these difierent modes of 

 i|i"- •::'; describing the same parts in a seed of considerable size induced 



i;riii;.t?t:; ^® t^ ta-k© the first opportunity of examining ripe and germinating 

 hill; ;i.^ seeds. This I have now been able to do for two seasons in the 



Calcutta Botanic Garden, and the structure is so simple, that it 



MM^ ^^ require much less time to describe it than has been occupied 



m thb enumeration of the views of previous observers. 



An inspection of the ripe seed of Barringtonia or Careya shows 

 at once that it is not perfectly homogeneous. A transverse section 

 of any part of the seed presents, as in Gaertner's plate of Barring- 

 tonia and Wight's of Careya, two concentric layers, separated by 

 a nng of darker-coloured tissue, which has an organic connexion 

 with both layers. A longitudinal section, as is shown in Gaertner's, 

 Wight's, and Lindley's plates, as well as in those of Griffith, ex- 

 hibits the central body extending throughout' the whole length of 

 the seed, and surrounded by the supposed albumen, from which it 

 18 separated on either side by a narrow line of darker-coloured 

 tissue. The shape of the central body is dependent on the shape 

 of the seed, and therefore varies in different species of the two 



genera ; but the relative position of the parts remains the same 

 in all. 



The microscope shows that both of these bpdies consist of ordi- 

 nary cellular tissue full of starch-granules ; but that the separating 

 layer, which is in organic connexion with both, consists of a very 

 thin or almost single layer of delicate wood-cells (pleurenchyma) 

 intermixed with barred and true (unrollable) spiral vessels. 



The integuments of the seed are readily separable in Careya ; 

 they adhere somewhat firmly both to the fruit and the seed in 

 ■Ba/rringtonia^ but can be detached with a little care from the em- 

 t^ryo, most easily near the plumule. An examination of the sur- 

 face of the embryo before germination shows that, except tw6 

 mmute and scarcely perceptible notches, first noticed by Griffith, 



e2 





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