146 Bulletin Jard. Bot, bui tenzorq, Série 1 H, Vol. V . Livr. 2. 



10). The pisifera fruit is a favorable object for study of the relationship 



of parts. 

 11). The operculum in the pisifera fruit in contact with the endosperm 



is fully developed in spite of the absence of a shel!. 



The endosperm. 



Endosperm in the sensé that it is used in this paper is the tissue of 

 the seed that is absorbed by the haustorium for the growth of the young 

 plant. The origin of this tissue has not been determined. This phase of the 

 work is being pursued by my former colleague Dr. C. Heusser. The term 

 endosperm is in gênerai use for that structure in palm seeds. 



The embryo in palms in gênerai, is comparatively small, occupying but 

 a small space in the seed. If we return to the plate showing the various 

 fruits in cross and longitudinal section (Figures 58 to 69 Plate VllI), we 

 find that the endosperm or kernel is a highly variable thing. The size 

 of the endosperm is dépendent upon the same environmental factors 

 which influence the size of the fruit itself. Thèse factors may be gênerai 

 nutrition of the whole plant, the number of female flowers produced per 

 brandi of an inflorescence, the number of fruit set, the number of embryos 

 that develops within a given fruit etc. The largest kernel is found in the 

 so-called macrocarya variety described by Beccari (I.c.) and the smallest 

 in the so-called pisifera variety. Thèse two extrêmes are in my opinion 

 reactions to definite environmental factors and are not to be considered as 

 normal forms. Bunches that set only a few fruits very often show those 

 abnormally large fruits. I hâve already stated before that the pisifera 

 variety is very likely a pathological form. 



When not mutually influenced by the pressure exerted upon each other 

 as is the case when two or more endosperms are présent within a seed, 

 the endosperm tends to be more or less egg-shaped. When the kernel is 

 removed from the shell it is very dark brown almost black in color. The whole 

 surface of the kernel is covered with a very finely branched net of fibres. 

 The kernel itself is quite hard and résistant after it has been exposed to 

 the air for a time. In the fresh state after cutting through the cork layer 

 surrounding the inner tissue the endosperm offers little résistance to the knife. 



The layer surrounding the endosperm proper consists of three kinds 

 of cells — an outer layer of two or more cells with thick walls and small 

 lumina — then follows a thick layer of cells with black contents and light 

 colored walls. Thèse cells may be seen in their long or short axes (Figure 

 146 Plate XVII) and finally a third layer the inner one very much like the 

 outer one. In describing this integument Hanausek (WlESNER I.c. p. 696 — 701) 

 States that the inner of the three layers shows cells with granular contents. 



The cells within the cork layer are the nutritive cells which are 

 ultimately absorbed by the haustorium. In the freshly picked fruit the cells 



