EXPLANATION OF PLATE III AND IV .—Continued. 



Fig. 11. — Transverse section of liypo-cotyledonary stem, showing four 

 fibro-vascular bundles. The xylem is shaded. The arrow indicates the 

 direction in which the bundles have rotated on their axes. Cf. text. 



Fig. 12. — Margin of section of the hypo-cotyledonary stem. The walls 

 of the outer layers of cells of the cortical tissue are cuticularised. 



Fig, 13. — Transverse section of a fibro-vascular bundle, from an unex- 

 tended hypo-cotyledonary stem. 



Fig. 14. — Transverse section of a fibro-vascular bundle, from a fully 

 extended hypo-cotyledonary stem. 



Fig. 15. — a — h. Series of transverse sections through plumule, hypo- 

 cotyledonary stem, and root ; showing the course and relative position of 

 the fibro-vascular bundles. The xyletu is always shaded, the phloem not 

 The arrows indicate the direction of rotation of the bundles on their axes* 



Fig. 16. — Diagram showing the course of the fibro-vascular bundles as 

 they might be seen in an ideal preparation of the plumule, &c., laid 

 open by cutting in a plane passing between the two plumular leaves. 



Fig. 17. — View of the apical papilla from above. 



Fig. 18. — Longitudinal section of the seedling, represented in fig. 2. 



Fig. 19. — Section of the apex of the feeder (as in fig, 18) under higher 

 power. The letters indicate the series of elongated cells, corresponding to 

 the series in the cortical tissue of the stem. 



Fig. 20. — The most curved part of the fibro-vascular bundle of fig. 18. 



Fig. 21. — Transverse section of young root. 



Fig. 22. — Transverse section of older root, from seedling of nine weeks. 



