94 Hooker. — Hydrothrix, anew genus of Pontederiaceae. 
EXPLANATION OF FIGURES IN PLATE VII. 
Illustrating Sir Joseph Hooker’s paper on Hydrothrix. 
All figures but Fig. i greatly enlarged. 
Fig. I. Portion of a plant of Hydrothrix of the natural size. 
Fig. 2. Portion of a stem and branch with flowers (partly from a drawing by 
Mr. Clarke). 
Fig. 3. Upper part of peduncle with the pair of flowers and their bracts enclosed 
in the spatha. 
Fig. 4. Another inflorescence with the pair of flowers still enclosed in the bract, 
but after protrusion through the spatha. 
Fig. 5. A pair of flowers enclosed in the bracts. 
Fig. 6. Corolla laid open showing the leaf and stamen, with the stigma applied 
to the anther. 
Fig. 7. Another corolla laid open and stamen. 
Fig 8. More advanced flowers with the bracts open and (the corollas having 
disappeared) the follicles advancing to maturity. 
Fig. 9. Ripe follicles and bracts. 
Fig. 10. Portion of wall of ovary, placenta and ovules. 
Fig. 11. Ovule. 
Fig. 1 2. Mature follicle. 
Fig. 13. The same laid open. 
Figs. 14 and 15. Seeds. 
Fig. 16. Longitudinal section of seed showing the albumen and embryo. 
Fig. 17. Longitudinal section of embryo showing the plumule, from a drawing 
by Mr. Clarke. 
Fig. 18. Portion of embryo with young plumule, from a drawing by Mr. 
Fawcett. 
Pig. 19. Section of a portion of stem. 
Fig. 20. Transverse section of portion of stem, showing, position of the 
peripheral vascular bundles and, b, resin-canals. 
Fig. 21. Superficial view of portion of leaf, showing the vascular bundle a and 
the resin-canals b. 
Fig. 22. Portion of tissue of the vagina showing cystoliths. 
Fig. 23. Portion of tissue of bract showing resin-canals and cystoliths. 
