262 



Stockard : Nectar-glands of Vicia Fab a 



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Explanation of plates 10 and xx 



All figures are from camera sketches. Fig. I with Leitz £ objective and three 

 ocular. Figs. 2, 3, and 6 with T ^ objective and 3 ocular. Tube-length 170 mm. 



Plate 10 



Fig. 1. Outline of the gland-area, showing the relation of its parts, eh, conical 

 hair ; nh, nectar-hair ; epc, epidermal cell-layer ; lc y lower cells. 



Fig. 2. Conical hair, be, basal cell ; ae, apical cell ; n, nucleus of apical cell. 



Fig. 3. Enlarged nectar-hair, be, basal cell ; nc, nectar-cell. 



Fig. 4. Epidermal cell preparing to give rise to the hair ; note the up-pushing of 



epidermal w r all and nuclear position, civ, cell-wall. 



Fig. 5. Similar cell to Fig. 4. in mitosis to give rise to the first cell of the hair. 



Fig. 6. Immature nectar-hair, showing the three-cell stage, be, basal cell. 



Fig. 7. Nuclear and cytoplasmic structure of the cells in the youngest gland-tis- 

 Sue. cp, indicates the position of epidermal cells. 



Plate ii 



Figs. 8, 9, and II. Immature gland-cells, before their contents becomes colored. 



Fig. 10. Mature epidermal gland-cell, shortly after secretion had begun. 



Fig. 12. Cells of youngest gland, showing enormous vacuoles and scarcity 01 



chromatin. 



Fig. 13. Three stages of the nectar -hair nuclei. 



very 



B, nucleus of hair in next gland down the axial stem. C, nucleus of hair in gland 

 just becoming mature. 



• Fig. 14. Youngest gland-cell preparing to form hair, showing cytoplasmic ar- 

 rangement and nucleus at this stage. 



Fig. 15. Cells of immature gland showing numerous plasmosomes in the nuclei. 



Fig. 16. Newly matured gland, first formation of large granules in the cytoplasm. 



Fig. 17. Secreting hair of an old gland, showing the marked contrast between the 

 staining of hair-contents and of basal and epidermal cell -substance. The hair stains 

 heavily with nuclear dies, so that the nuclei of its cells cannot be certainly determined. 



