ANATOMY AND PHYSIOLOGY 



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 the species of Bletia, both before and, as he believes, 

 after impregnation ; 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 forma- 

 tion, at least a minute areola is often visible in the sim- 

 ple grain, and in each of the constituent parts of cells 

 of the compound grain. But these areolae may per- 

 haps rather be considered as merely the points of pro- 

 duction of the tubes. 



" This nucleus of the cell is not confined to orchideae, 

 but is equally manifest in many other monocotyledo- 

 nous families ; and I have even found it, hitherto how- 

 ever in very few cases, in the epidermis of dicotyledo- 

 nous plants; though in this primary division it may 

 perhaps be said to exist in the early stages of develop- 

 ment of the pollen. Among monocotyledons, the 

 orders in which it is most remarkable are Liliaceae, 

 Hemerocallideae, Asphodeleae, Irideae, and Commeli- 

 neae. 



"In some plants belonging to this last-mentioned 

 family, especially in Tradascantia virginica, and several 

 nearly related species, it is uncommonly distinct, not 

 in the epidermis and in the jointed hairs of the fila- 

 ments, but in the tissue of the stigma, in the cells of 

 the ovulum even before impregnation, and in all the 



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