150 BULLETIN JARD. BOT. BUITENZORG, SÉRIE III, VOL. V. LiVR. 2. 



significance for germination. Experiments undertaken by several investigators 

 in Africa and in the Malay Archipelago show that the same fluctuations 

 in germination exist among ail types of fruits and even when the shell 

 has been removed. 



The embryo of Elaeis lies within a cavity in the endosperm compietely 

 surrounded by the endosperm tissue. (Text Figure 57). The cavity in which 

 the embryo Mes is in communication with the fissure in the endosperm 

 which we hâve seen is présent, and most Mkely is homologous with the 

 conspicuous cavity in the fruit of Cocos-nucifera. The opercuium caii be 

 readily removed in an intact state by breaking the shell. It is kept rigidly 

 in place on the one side by the embryo and on the other side by the 

 fibres and fleshy tissue of the pericarps which fill up the germ canal. 

 The position of the opercuium is seen in (Figures 82 and 83 Plate X). 

 The opercuium is a îlattened cône with a diameter slightly less than the 

 diameter of the canal. We hâve seen it in cross section in Figure 80 

 Plate IX. In Figures 96 and 97 Plate X we see its side and under 

 surface views respectively. From its upper convex surfaces branched 

 and umbranched fibres pass through the canal into the pericarp 

 (Figure 80 Plate IX) establishing a communication between the external 

 and internai environment of the embryo. Thèse fibres like those in 

 the pisifera fruit are made up of bast and conducting tissue. The fibres 

 together with the cork layer which holds them in place give a 

 roughened appearance to the cuter surface of the opercuium. The inner 

 and concave surface is smooth (Figure 97) provided in the center with a 

 tiny canal which ends blindly. Into this blind canal a nipple-like structure 

 from the center of the flattened end of the embryo fits (Figure 82 and 84 

 Plate X). It is obvious that such an arrangement allows for a distribution 

 of pressure from the growing embryo upon the opercuium so that it is 

 pushed straight out of the germ pore without rotation along the axis of 

 its diameter. 



In the fuily ripe seed the embryo when exposed shows definite 

 external differentiation. The haustorium is seen deliminated from the rest 

 of the embryo; it is aiso lighter in color. Figure 82 Plate X represents 

 an embryo taken from a ripe fruit. The constriction very near the middie 

 is the boundary line between the haustorium and the remaining part of 

 the embryo. In the haustorium itself longitudinal shallow furrows indicate 

 the beginning of the pronounced ridges characteristic of the growing 

 haustorium in later stages of germination. The portion of the embryo 

 above the haustorium exept for the nipple-like growth on the flattened 

 end, shows no outward differentiation. 



With the beginning of germination the embryo begins to elongate at 

 both ends, the haustorium eating its way into the endosperm and the 

 rest begins to push through the canal towards the exterior. The nipple 

 too elongates and becomes quite a conspicuous structure (Figure 84). 



