1902] ON THE DEVELOPMENT OF CERTAIN PIPERACEAE 325 



The contents of the cells of the embryo in the seed seem to 

 be chiefly protoplasmic. The cells of the endosperm possess 

 large nuclei and are filled around this with a substance evidently 

 chiefly proteid in nature, and probably similar in function to that 

 to be mentioned in Heckeria and Peperomia. From the time the 

 ei^ht-nucleate embryo sac is formed the nucellus swells rapidly, 

 and by the time the endosperm-nucleus begins to divide the cells 

 of the nucellus are beginning to fill up with starch. In the ripe 

 seed the cells of the nucellus are solidly packed with starch 

 {^figs, i4y 15, psp^, except the cells near the micropyle and those 

 of the peripheral layer of the nucellus generally, in which the 

 starch grains are smaller and there is a somewhat larger propor- 

 tion of protoplasmic contents. The crushed and distorted 

 nuclei of the starch-filled perisperm cells are distinguishable 

 even in the mature seed. 



No seeds of this species capable of germination were avail- 

 able, but it is natural to suppose that the process of sprouting 

 must resemble closely that to be described in Heckeria and 

 Peperomia, in which genera the structure of the ripe seed is 

 essentially that just described. 



II. THE DEVELOPMENT AND GERMINATION OF THE SEED OF 



HECKERIA. 



Material of both H. umbellata and H. peltata was available, 

 but a complete study was made of the former only. 



The ovary of this form arises as a ring-like outgrowth of the 

 axis of the spike above a slightly peltate bract {fig. 16), and 

 between the two stamens, which appear somewhat earlier than 

 the carpels. The edges of this ring soon become three-lobed, 

 probably indicating the presence of three carpels in the ovary ; 

 and as the walls of the ovary close in above, each lobe stretches 

 out to form a somewhat elongated division of the stigma {figs. 

 22, 24, si). From the time the carpels close in above the ovule 

 until the fruit is ripe, there are found scattered through the car- 

 pellary tissue oil-secreting cells, the protoplasts and nuclei of 

 which remain active until a very late stage of development {figs. 

 //, 22, 24, oc). In the mature fruit these are still present and 



