88 The Waterlilies. 



division between the carpels lies in the middle of each partition and 

 extends from a point in the wall of the ovary a little farther in than the 

 back of the ovary cells to a point in the central axis distinctly farther in 

 than the inner edge of the cells. On each side of this line is a smooth 

 face of square or columnar epidermal cells ; the two sides are in contact. 

 This epidermis is backed by two layers of closely packed rectangular 

 cells ; then comes a line of open spongy tissue, then a single layer of 

 parenchyma supporting the epidermis which lines the cells of the ovary. 



This epidermis is composed of short columnar cells of highly glandular 

 nature ; each one bulges out into the cavity with a round, turgid end. 

 They doubtless secrete the mucilage which fills the ovary. The axis of 

 the ovary is composed of spherical cells with large intercellular spaces in 

 N. zanzibariensis X ; in Eu-castalia (A^ alba candidissima, odorata, (uberosa) 

 the spaces are so large that the cells are drawn out into several broad 

 arms. Many stellate idioblasts were present in N. odorata. In the upper 

 parts the tissues of the axis become solid. The process in which it termi- 

 nates is firm and composed of thin-walled parenchyma ; the cells are often 

 slightly elongated and arranged in rows bending from the center out to the 

 periphery. A regular epidermis of small cubical cells covers the process. 



The stigma is marked with a number of narrow radiating furrows, one 

 between every two carpels and one along the ventral suture of each. 

 Indeed, the ventral sutures are scarcely closed and are easily torn apart. 

 The stigmatic papillae (Fig. 37, c) are crowded as close as they can stand 

 and consist of rows of 2 to 8 short cylindrical cells. The terminal one is 

 rounded and contains large, oily-looking bodies. In Hydrocallis the cells 

 separate from one another and the stigma is covered with a moist, 

 powdery mass of oily-looking cells, some of which remain attached to 

 each other in strings. 



The carpellary styles have numerous mucilage hairs on the epidermis 

 and are made up internally of spherical cells loosely laid together. On the 

 clavate apex of the styles of N. amazonum, the epidermis has a slightly 

 corrugated cuticle, and the cells contain a pink-purple pigment. 



The vascular system of the ovaiy presents certain regular features. 

 From the complicated plexus in the base of the receptacle the immediate 

 connections have not been worked out, but sooner or later there is 

 separated a ring of bundles which ascend with numerous branchings and 

 anastomoses in and just outside of the lacunar tissue of the ovary wall, 

 and a ring which ascend in the central axis near the edges of the cells of 

 the ovary. In N. odorata another bundle passes up the centre of the axis 



