512 ON THE ORGANS AND MODE OF FECUNDATION 



and although it seems to be on the surface is in reality 

 covered by the outer lamina of the cell. There is no regu- 

 larity as to its place in the cell; it is not unfrequently 

 however central or nearly so. 



As only one areola belongs to each cell, and as in many 

 cases where it exists in the common cells of the epidermis 

 it is also visible in the cutaneous glands or stomata, and in 

 these is always double, — one being on each side of the 

 limb, — it is highly probable that the cutaneous gland is in 

 all cases composed of two cells of peculiar form, the line of 

 union being the longitudinal axis of the disk or pore. 



This areola, or nucleus of the cell as perhaps it might be 

 termed, is not confined to the epidermis, being also found 

 not only in the pubescence of the surface, particularly Avhen 

 711] jointed, as in Cypripedium, but in many cases in the 

 parenchyma or internal cells of the tissue, especially when 

 these are free from the deposition of granular matter. 



In the compressed cells of the epidermis the nucleus is 

 in a corresponding degree flattened ; but in the internal 

 tissue it is often nearly spherical, more or less firmly ad- 

 hering to one of the walls, and projecting into the cavity 

 of the cell. In this state it may not unfrequently be found 

 in the substance of the column, and in that of the perian- 

 thium. 



The nucleus is manifest also in the tissue of the stigma, 

 where, in accordance with the compression of the utriculi, 

 it has an intermediate form, being neither so much flattened 

 as in the epidermis, nor so convex as it is in the internal 

 tissue of the column. 



I may here remark, that I am acquainted with one case 

 of apparent exception to the nucleus being solitary in each 

 utriculus or cell, namely in Bletia Tanhervillice . 



In the utriculi of the stigma of this plant I have gene- 

 rally, though not always, found a second areola apparently 

 on the surface, and composed of much larger granules than 

 the ordinary nucleus, which is formed of very minute 

 granular matter, and seems to be deep seated. 



Mr. Bauer has represented the tissue of the stigma in 

 this species of Bletia, both before and as he believes after 



