GL. XXI.] 33. SPARGANIUM SIMPLEX. 437 



a sheath, which is membranaceous on the sides ; the lower 

 leaves, when cut across, are triangular, with smooth interior 

 surfaces: the upper are somewhat concave, and do not exhi- 

 bit a triangular section. Besides, the leaves are almost all 

 longer than the stem, frequently two feet high, and scarcely 

 the breadth of a little finger, uniformly small throughout, 

 smooth and entire, tapering at the point, and furnished with 

 parallel soft nerves. Their cellular texture is spongy and 

 compound ; the cells full of air. There are slits on both 

 sides of the leaves. In their centre rises a simple flower- 

 stalk, which carries below two petiolated spherical flower-tufts, 

 and above one stalk less female tuft, and several stalkless male 

 spherical flower tufts. The individual female florets consist 

 of three or four lanceolate scales or leaflets, in the centre of 

 which rises, on an oval germen, the simple, green, sometimes 

 cleft pistillum, having the stigma placed laterally at its sum- 

 mit. The male flowers cont^n, in the centre of tlie some- 

 what spoon-shaped scales, imperceptibly dentated at the top, 

 commonly three €laments of a white colour, on the top of 

 which stand the bilocular straw-yellow antherae, containing 

 an ovail pollen. The fruit is a brown nut, or drupa, contain- 

 ing in the centre of the albuminous matter^ the unevolveid - 

 embryon in a reversed positixjii. 



Diagnosis and Affinity, 



'The most nearly related species is Sp. raraosum. But 

 this species is much larger, its flower-stalk is branchy, the 

 sides of the leaves are concave, not smooth. The scales of the 

 calyx are also of a deeper brown colour. Sparg. nutans^ on 

 the other hand, has leaves entirely of a grass shape, swim- 

 ming on the surface of the water, rather concave, and very 

 long ; the flower-tuft is much smaller, and only the one that 

 is uppermost is male. This genus evidently borders on 

 Typha. I also find Chrysithrix related to it, the divided 

 shaft of which pushes out laterally the flower-tuft. Acorus 

 and Orontium form the transition to the Aroideae, to which 

 these plants belong ; (Anleit. ii. 127.) 



