228 THE UNIVERSITY SCIENCE BULLETIN. 



DESCRIPTION OF PLATES. 

 PLATE I. 



Fig. 1. Section of leaf showing part of a large vein. X 300. a, upper 

 epidermal cell; b, mucilaginous wall; c, palisade cell; d, water-storage cell; 

 e, spongy parenchyma; v, vein; /, stellate hair; g, glandular hair. 



Fig. 2. Cross section of leaf. X 285. s, stoma. The rest of the index 

 is the same as in fig. 1. 



Fig. 3. Long glandular hair. X 200. a, apex, b, basal cell; c, proto- 

 plast shrunken away from wall. 



Fig. 4. Lower portion of long glandular hair from section of the petiole. 

 X 325. b, basal cell; d, cutinized wall; e, cuticle. 



Fig. 5. Longitudinal section through stellate hair, showing peculiar re- 

 action in chloroidide of zinc; stipled, orange yellow; shaded, purple. X 325. 



Fig. 6. Cross section of leaf showing stellate hair over vein; index same 

 as fig. 1. X 325. 



Fig. 7. Simple clothing hair from section of petiole. X 325. 



Fig. 8. Short glandular hair. X 325. a, plasmolysed protoplast; b, 

 basal cell. 



PLATE II. 



Fig. 9. Surface view of leaf, showing relation of hairs to the veins. 

 X 200. a, long glandular hair; b, short glandular hair; c, stellate hair; 

 d, stoma; e, vein. 



Fig. 10. Tangential section of leaf. X 200. a, palisade cells; b, border 

 parenchyma; c, tracheal tube. 



Fig. 11. Tangential section of leaf, showing frequency of the mucilage 

 cells. X 200. r, stoma; h, hair; m, mucilage. 



Fig. 12. Tangential section of leaf, above a vein, showing frequency of 

 mucilage cells there. X 200. 



Fig. 13. Cross section of large vein. X 100. a, thin-walled cells; 

 p, phloem; x, xylem; m, mucilage. 



PLATE III. 



Fig. 14. Cross section of stem, showing the regions and the wedged 

 effect of bast and medullary rays. X 15. c, cortex; b, bast; p, phloem; 

 X, xylem; m, mucilage; me, medullary ray; s, starch in pith. 



Fig. 15. Section of stem, showing rings in xylem. X 150. a, epidermis; 

 b, thin-walled parenchyma; c, coUenchyma; d, second thin-walled collen- 

 chyma; e, starch sheath;/, bast fiber; g, leptome elements; h, phloem; ^, cam- 

 bium; j, water tubes; k, wood parenchyma; I, pith; m, mucilage channels; 

 n, medullary ray. 



Fig. 16. Cross section of root. X 15. c, cork; b, bast; p, phloem; 

 X, xylem; mr, medullary ray; r, rootlets leaving the root. 



Fig. 17. Cells of cortex of seedling root. X 325. e, elaioplasts. 



Fig. 18, Cells of cortex of older root. X 325. Showing elaioplasts. 



