Piqott. — Notes on Nothopanax arboreum. 



609 



velopment of the endosperm it protects^ from destruction the region of the 

 nucellus between itself and the chalaza.j^ This in the ripe seed is intercalated 

 between the integument and the endosperm or embryo. Hence in those 

 cases?a' 'greater or less amount oi'Jperisperm is formed." 



Fig. 12. — Longitudinal section of embryo-sac, showing 

 position of hypostase and large inner cells of the 

 integument, arillus, and relative size of the ovule 

 and ovary-cavity near the beginning of the forma- 

 tion of endosperm, x 28. 



Fig. 13. — Lower portion of 12. X 175, 



The hypostase found in Nothopanax arboreum was traced for some time 

 after the formation of endosperm, but was lost sight of later, and could not 

 be seen in the seed. In many radial longitudinal sections in the endosperm 

 stage the hypostase could not be seen at all. 



Embryo-sac. 



Many intermediate stages in the development of the embryo-sac were 

 missed, owing to the extreme difficulty of sectioning the hard-walled ovary 

 with the ovule in situ. Every precaution was taken. In the younger ones 

 the base of the ovary-wall was cut immediately and before fixing. Later, 

 when the ovule had achieved full size, it was removed from the ovary, and 

 fixed in acetic acid, in place of osmic chromic formerly used. A vacuum 

 process was also adopted. The results were, on the whole, better. 



20— Trans. 



