THE FLOWERING PLANT. 101 



PLATE XXIV. 



THE FLOWERING PLANT. THE LEAF AND FLOWER. THE REPRODUCTIVE ORGANS, 



AND DEVELOPMENT. 



FIG. I. Transverse section across the oldest leaf of a young bean-plant. 

 The whole leaf was rolled up and cut in the fresh state. D. 3. 



FIG. II. A portion of the epidermis of the same stripped off, showing the characters 

 and relations of the stoma and guard-cells, the subsidiary cells, and the trichome. D. 4. 



The glandular hairs arise as central cells of a series, similarly to the trichome 

 figured. 



Examined fresh in water, the details of cell-structure being drawn after treatment 

 with 1 p.c. osmic acid. 



FIG. III. Slightly diagrammatic representation of a developing stoma. 

 The entire parent cell is drawn, and the septa by which it was divided up are num- 

 bered i. to iii., in order of development ; iii. would have finally split to form the stoma. 



The specimen figured was obtained from near the edge of a young leaf. Fresh. F. 3. 



FIG. IV. Section through a stoma of Fig. I. F. 4. 



FIG. V. Median longitudinal section of a Buttercup, x 3. 



FIG. VI. Similar section of a Bean-flower, x 2. 



FIG. VII. Transverse section of the anther of a nearly matured Buttercup. Alcohol 

 and weak glycerine. D. 2. 



By ciitting the whole flower-head between the finger and thumb, most instructive 

 sections may be obtained, cut at all possible levels. 



FIG. VIII. A small portion of Fig. VII., more highly magnified. F. 3. 



FIG. IX. Three pollen-grains, teased out from the stigma of an open Buttercup. (See 

 Fig. XL) 



Taken in the order numbered, they represent stages in the development of the pollen 

 tube. Such stages may be obtained with ease, by object-glass culture in a saccharine fluid. 

 1 p.c. osmic acid. D. 3. 



The smaller nucleus js stated by Strasburger (143) to be alone the active agent in 

 fertilisation, 



