434 SYSTEMATIC BOTANY. 



Properties. — They have no important properties. Hydropeltis 

 purpurea is said to be nutritious. 



Natural Order 10. Nymph^ace^. — The Water-Lily Order 

 {figs. 853 — 855), — Character. — Aquatic herbs. Xm yes floating, 

 peltate or cordate. Flowers solitary, large and showy. Sepcds 

 usually 4 (fig, 436, c, c, c, c), persistent, generally petaloid on 

 their inside. Petals numerous (fig. 436, p), deciduous, often 

 passing by gradual transition into the stamens (fig. 436, p, 

 1 , 2), in the same way as the sepals pass into the petals ; in- 

 serted on a fleshy thalamus below the stamens {fig. 607), Sta^ 



Fig. 853. 



Fig. 854, Fig. 855. 



Fig. 853. Flower of Yellow "Water-Lily {NuTphar lutea). Fig. 854. Ovary 



of Nuphar with numerous radiating stigmas. Fig. 855. Vertical sec- 

 tion of the seed of Nymphcea alba, sliowing the embryo enclosed in a 

 vitellus, and on the outside of albumen. 



')nens numerous, placed upon the thalamus; filaments petaloid 



{figs. 436, e, 1, 2, 3, 4, 5). Thalamus large, and forming a 



disk-like expansion, more or less surrounding the ovary, and 



having inserted upon it the petals and stamens {fig. 853). 



Carpels numerous, united so as to form a compound ovary {fig. 



854); owar^ many-celled (/_9'. 771); st7/les ahsent ; stigmas v&di- 



ating on the top {fig. 854), and alternate with the dissepiments. 



Fruit indehiscent, many-celled. Seeds numerous, attached all 



over the spongy dissepiments ; embryo minute, enclosed in a 



vitellus, and on the outside of farinaceous albumen {fig. 855). 



Diagnosis. — Aquatic herbs with floating leaves. Thalamus 

 large, and forming a disk-like expansion more or less surround- 

 ing the ovary. Carpels united so as to form a compound many- 

 celled ovary ; stigmas radiating on the top, and alternate with 

 the dissepiments ; ovules numerous, attached all over the dis- 

 sepiments. Embryo minute, on the outside of farinaceous albu- 

 men, enclosed in a vitellus. 



Distribution, ^-c. — The plants of this order are chiefly found 

 in quiet waters, throughout the whole of the northern hemisphere ; 

 they are, generally speaking, rare in the southern hemisphere. 



