EXPLANATION OF PLATE XIX— Continued. 



chlorophyll -corpuscles are still large and consistent, and appear to 

 have come into contact with the starch-grains only after these had 

 attained a considerable size. Chlorophyll-corpuscles destitute of 

 starch are seen lying near those which contain it, and they may 

 possibly have been formed by the division of the latter ; this view 

 is supported by the frequent occurrence of elongated forms (see also 

 Trecal, he. oit., plate vi, fig. 62), 

 Pigs. 14, 15. — From the epidermis of the stem of Philodendron grandi' 

 folium. 



Fig. 14. — Young cells, with newly-formed stafbh-forming-cor- 

 puscles. 



Fig. 15. — «, an older stage : the corpuscles are covered with small 

 starch-grains ; b, two parietal nuclei surrounded by corpuscles as 

 in a. 

 Figs. 16 — 20. — From the pith of the rhizome of Amomum cardamomum. 



Fig. 16. — Very young cells, with six starch-forming- corpuscles. 



Fig. 17. — Starch-forming-corpuscles with very small starch-grains 

 near the nucleus. 



Fig. 18. Young cell with nucleus and starch-grains j to the pos- 

 terior ends of the latter starch-formiug-corpuscles are attached. 



Fig, 19. — Older starch-grains, with starch-forming-corpuscles 

 attached to their posterior ends ; a, fresh, h and c treated with tinc- 

 ture of iodine. In this stage the corpuscles are very delicate, and 

 can only be seen with diflBculty in the fresh state. 



Fig. 20. — Mature starch-grains. The compound grain has been 

 formed by the coalescence of two grains, which were developed at 

 opposite points by the starch-forming-corpuscles. 

 Figs. 21 — 23. — From the cortical parenchyma of a young potato. 



Fig. 21. — Young cell of the external cortex, with very small starch- 

 forming-corpuscles collected about the nucleus. 



Fig. 22. — Starch-forming-corpuscles, with young starch-grains 

 round the nucleus. 



Fig. 23. — Starch-forming-corpuscles, with large and distinctly 

 stratified starch-grains. 

 Figs, 21 — 29, — From the endosperm of Melandryum macrocarpum. 



Fig. 21. — Two young cells with parietal nuclei, and a thin lining 

 layer of protoplasm. The starch-forming-corpuscles are in process of 

 development, and form hemispherical protuberances. 



Fig. 25. — Young cells from the peripheral portion of the endosperm : 

 the starch-forming-corpuscles are fully developed, but contain no 

 starch as yet. 



Fig. 26. — The corpuscles, spherical at «, spindle-shaped at b, con- 

 tain minute granules. 



Fig. 27. — A later stage : the starch-grains have become larger and 

 more numerous. 



Fig. 2S. — Elongated starch-grains, which have been formed by 

 spindle-shaped-corpuscles. 

 Figs. 30—32. — From the endosperm of Beta tngyna. 



Fig. 30. — Young cell : the corpuscles are numerous in the proto- 

 plasm around the nucleus, and less so in other parts. 



Fig. 31. — A somewhat older cell with corpuscles, shortly before the 

 commencement of the formation of starch. 



Fig. 32. — Mature compound starch-grain from a nearly ripe seed. 

 Figs. 33 — 15. — From the tuber and the root of Phajvs grandifolius {Bletia 

 Tankervillice. 



