Trapa, TETRANDRIA MONOGYNIA, 429 
and caducous, the inferior pair at first simple and. filiform; ; 
,but becoming ramous by age, permanent, . r 
Peduncles axillary, solitary, shorter than the petioles, o 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.’ Coro/ 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. Neetary cup-shaped, on the top of the germ, round the 
swelled base of the style, eight-grooved, with the margins! 
minutely lacerate, and curled. Filaments four, incurved. 
_Anihers oval, incumbent. Germ inferior, obconical, two- 
celled, with one ovulum in each attached’ tothe top of the 
partition. Mut inferior, of a turbinate triangular shape, a 
hard ligneous 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 guarded with a circle of stiff converging bristles from its 
margin, forming’ a conical roof over the aperture. Seed single, 
conform to the nut, Jntegument single, of a slightly brown 
colour, thin, but rather tough, and adhering’ firmly to the 
perisperm. Perisperm conform to the seed, white and of # 
firm cartilaginous texture. Embryo in the apex of the ee 
risperm. 
Obs, This is evidently a species perfectly distinet from nae 
tans, and bicornis, From the former it differs in having only” 
two horns, and from eit Tatter'i in noes Dae aight, ve~ 
ry sharp, and barbed. byes eae 2 i ae coniage 
The nuts are sold in sais tininiiakcietlee in season, thet ker 
rete i= psteeme ade tanaragl es 
2 eae Pee Fi - 4 7 ; ne 
Ss EE ies 2 : ae s¥Gah ‘ ' : ae Ret Be 
