IYDROCHARIDACE®. 81 
8 outer oblong, hooded, subherbaceous, the 8 inner scarcely larger, 
oblong, subpetaloid: stamens 9, more rarely 3; filaments short and 
monadelphous, or absent. Female flowers solitary, sessile, from a 
1-leaved sessile axillary spathe, which is 2-toothed at the apex; tube 
of the perianth coloured, adhering to the ovary, and extending to a 
great length beyond it; limb 6-partite, the 3 outer segments oblong, 
hooded, herbaceous, the 3 inner scarcely larger, oblong, reflexed, 
petaloid : stamens 3 or 6, usually reduced to sterile filaments, rarely 
with subsessile anthers: ovary adhering to the base of the tube of 
the perianth, 1-celled, with 3 parietal placenta, each of which bears a 
few ovules; style single, very long, capillary, adnate to the tube of 
the perianth ; stigmas 3-notched or bifid. Fruit “ oblong, coriaceous, 
few-seeded.” ( Gray.) 
Stems submerged, brittle, with verticillate ovate or oblong or strap- 
shaped leaves and minute flowers, the female with the lilac perianth 
limb resting on the surface of the water. The male flowers are said 
to break off and float on the water; but they are unknown in this 
country. 
Name derived from é\@dec, marshy. 
SPECIES I—ELODIA CANADENSIS. WMichauz. 
Pirate MCCCCXLVI. 
Anacharis Alsinastrum, Bab. in Ann. Nat. Hist. Ser. IL. p. 83. Engl. Bot. Suppl. No. 
2993. Man. Brit. Bot. ed. vi. p. 323. 
A. Alsinastrum, A. Nuttallii, and A. Canadensis, Planch. in Ann. Nat. Hist. Ser. II. 
Vol. I. p. 86. 
Udora Canadensis, Nutt. Gen. N. Americ. Pl. Vol. II. p. 242. 
Apalanthe Schweinetzii, Planch. Ann. Nat. Hist. Ser. II. Vol. I. p. 87. 
Leaves in verticils of 3 (more rarely 4) or the lower ones opposite, 
oval-oblong or oyate-oblong or lanceolate-oblong or strapshaped, very 
finely and obscurely serrulate. Stigmas reflexed, often 3-lobed. 
A North American plant, noticed in 1842, in a pond at Dunse 
Castle, Berwickshire, by the late Dr. G. Johnston; from thence it 
spread to the River Whitadder, and probably from the same place 
was carried to the pond in the Botanic Garden at Edinburgh, whence 
it has been taken to other places in the neighbourhood. Shortly 
before the year 1847, it appears to have been introduced with timber 
from North America to the canal basin at Foxton, near Market Har- 
borough, Leicestershire ; and from this second centre it has now 
spread over the greater part of England. In Ireland, at the date of 
the publication of the “ Cybele Hibernica,” 1866, it was still rather 
VOL. Ix. M 
