Trapa. tetrandria monogynia. 429 



and caducous, the inferior pair at first simple and filiform; 

 but becoming ramous by age, permanent. 



Peduncles axillary, solitary, shorter than the petioles, one- 

 flowered, incurved until the blossoms begin to decay, after 

 which they bend down under the surface of the water, where 

 the fruit grows, and comes to maturity. Flowers pure white, 

 expanding above the surface of the water late in the afternoon. 

 Calyx four-leaved, in opposite pairs, leaflets lanceolate, villous, 

 one of the pairs permanent. Corol contracted. Petals four, 

 contracted into a tube at the base by the firmness of the calyx, 

 above much broader, and expanding; margins much curl- 

 ed. Nectary cup-shaped, on the top of the germ, round the 

 swelled base of tbe style, eight grooved, with the margins 

 minutely lacerate, and curled. Filaments four, incurved. 

 Anthers oval, incumbent. Germ inferior, obconical, two- 

 celled, with one ovulum in each attached to the top of the 

 partition. Nut inferior, of a turbinate triangular shape, a 

 hard li«>neous texture, and a blackish brown colour, armed 

 with two, strong, straight, conic, barbed spines, from the up- 

 per angles; elegantly embossed, one-celled, not opening, but 

 having a perforation in the top for the embryo to pass, which 

 is o-uarded with a circle of stiff converging bristles from its 

 margin, forming a conical roof over the aperture. Seed single, 

 conform to the nut. lntegnment single, of a slightly brown 

 colour, thin, but rather tough, and adhering firmly to the 

 perisperm. Perisperm conform to the seed, white and of a 

 firm cartilaginous texture. Embryo in the apex of the pe- 

 risperm. 



Obs. This is evidently a species perfectly distinct from na- 

 tans, and bicomis. From the former it differs in having only 

 two horns, and from the latter in the horns being straight, ve- 

 ry sharp, and barbed. 



The nuts are sold in the markets when in season, their ker- 

 nels being much esteemed by the Hindoos. 



