208 THE UNIVERSITY SCIENCE BULLETIN. 



DESCRIPTION OF PLATES. 



PLATE I. 



Fig. 1. Hairs taken from a leaf. X 45. 



Fig. 2. High-power drawing of hair from leaf, showing: t, terminal cell; 

 m, middle cell; b, basal cell. X 450. 



Fig. 3. Surface of a leaflet of loco weed, showing: /, tracheal system 

 within the tissue; e, epidermal cells; s, stoma; c, cuticular ring at base of hair; 

 h, hair. X 90. 



Fig. 4. Cross section of a leaflet at the edge, showing: e, epidermis; b, 

 basal cell of hair; h, hypoderm; p, palisade cells; s, stoma; vb, vascular bundle. 

 X 115. 



Fig. 5. Cross section of a leaflet at the midrib. X 115. 



PLATE IL 



Fig. 6. Diagram of a cross section of the petiole, showing: e, epidermis; 

 b, bast tissue; p, phloem; x, xylem. X 40. 



Fig. 7. Cross section of a vascular bundle of the petiole, showing: 

 e, epidermis, with h, hair; c, cortex; s, starch sheath; t, bast tissue; p, phloem; 

 X, xylem; pi, pith. X 90. 



PLATE III. 



Fig. 8. Diagram of a cross section of the stem, showing: b, bast tissue; 

 p, phloem; x, xylem. X 15. 



Fig. 9. Cross section of vascular bundles of the stem, showing: b, bast 

 tissue; p, phloem; x, xylem; mr, medullary ray; pi, pith. X 90. 



Fig. 10. Longitudinal section of a vascular bundle of the stem, showing 

 the same tissues. X 90. 



PLATE IV. 



Fig. 11. Diagram of a cross section of the root, showing: c, cork; p, 

 phloem; x, xylem; mr, medullary ray. X 17. 



Fig. 12. Cross section of a portion of the xylem of the root, showing: 

 mr, medullary ray; wt, water tube; wp, wood parenchyma; wf, wood fibers. 

 X90. 



Fig. 13. Cross section of a portion of the vascular bundle of the root, 

 showing: p, phloem; mr, medullary ray; x, xylem. X 90. 



Fig. 14. Diagram of a cross section of the peduncle, showing: e, epi- 

 dermis; b, bast tissue; p, phloem; x, xylem. X 30. 



Fig. 15. Cross section of a vascular bundle of the peduncle, showing the 

 same tissues. X 90. 



