346 naiades. [Naias. 



more leaf-like or Bmall bracts. Ovary sessile, tapering into a bifid style. — 

 N. indica, Cham., and N. tenuifolia, Br. ; Kunth, Enum. iii. 113. 



Hongkong, Wright. Common in tropical Asia, extending on the one hand into Europe, 

 on the other into Australia. I find no difference whatever between the Indian and the S. of 

 France specimens. Some from near Berlin are stiffer, with shorter more recurved and more 

 distinctly toothed leaves, but the Indian ones are also variable in these respects. 



Order CVIII. ALISMACE^J. 



Perianth of 6 segments, either all similar or 3 outer small and sepal-like, and 

 3 inner ones large and petal-like. {Stamens 6, 9, or indefinite. Ovary of 3, 

 6, or many carpels, either distinct from the first or separable when in ripe 

 fruit, each with 1, 2, or many ovules. Seeds consisting, within the testa, of 

 a homogeneous mass, usually considered as an undivided embryo without albu- 

 men. — Marsh or water plants, with radical leaves and leafless flowering stems, 

 or rarely with leafy stems. Flowers in terminal umbels, panicles, or racemes. 



A small Order dispersed over the greater part of the world. 



1. SAG-ITTARIA, Linn. 



Flowers unisexual. Perianth of 3 outer herbaceous segments and 3 larger 

 inner ones, petal-like and very delicate. Stamens numerous, carpels numer- 

 ous, 1 -seeded, in a dense globular head. — Aquatic herbs. Leaves long- 

 stalked, usually cordate or hastate. Flowers in a raceme or narrow panicle, 

 the lower ones female, the upper male. 



A small genus dispersed over the northern hemisphere and extending into S. America. 



1. S. cordifolia, Roxb. ; Kunth, Enum. iii. 161. — An annual, growing 

 in tufts at the bottom of the water. Leaves floating on the surface, broadly 

 ovate or orbicular, and deeply cordate, 1^- to near 3 in. long. Scapes shortly 

 emersed, bearing a raceme of 2 or 3 to 6 or 8 in. long. Flowers in clusters 

 of 2 or 3, the lower female ones sometimes with a few stamens also, the upper 

 ones male only. Carpels very numerous (3 to 400), much flattened, with a 

 deeply-toothed edge. 



Hongkong, Harland. Frequent in standing waters in India, extending westward into 

 E. Africa, and eastward over the Archipelago. 



Order CIX. HYDEOCHARIDE-ffi. 



Flowers mostly unisexual. Perianth of 3 or 6 segments, either all petal- 

 like, or the 3 outer ones smaller and herbaceous, with a tube adherent to the 

 ovary in the females, without any tube in the males. Stamens 3 to 12. Ovary 

 inferior, 1-celled, with 3 parietal placentas, or 3-, 6-, or 9-celled. Styles 3, 

 6, or 9, with entire or 2-cleft stigmas. Fruit small, ripening under water, in- 

 dehiscent. Seeds several, without albumen. — Aquatic herbs. Leaves undivided. 

 Flowers inclosed when young in an involucre or spatha of 1 to 3 leaves or 

 bracts. 



A small Order, widely diffused over the globe. 



