Fecundation in Orchidece and Asclepiadece, 711 



as in Cypripedium, but in many cases in the parenchyma or 

 internal cells of the tissue, especially when these are free from 

 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 adhering 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 perianthium. 



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 utricu- 

 lus or cell, namely in Bletia Tankervillice . 



In the utriculi of the stigma of this plant I have generally, 

 though not always, found a second areola apparently on the 

 surface, and composed of much larger granules than the ordi- 

 nary 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 impreg- 

 nation ; and in the latter state the utriculi are marked with 

 from one to three areolae of similar appearance. 



The nucleus may even be supposed to exist in the pollen 

 of this family. In the early stages of its formation at least 

 a minute areola is often visible in the simple grain, and in 

 each of the constituent parts or cells of the compound grain. 

 But these areolae may perhaps rather be considered as merely 

 the points of production of the tubes. 



VOL. XVI. 4 Y This 



