This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Not Scop. 1777]
Small creeping glabrous perennial marsh herbs, the leaves reduced to linear terete septate hollow petioles, with simple umbels of white flowers. Bracts of the involucre several, small. Calyx-teeth acute. Petals concave, acute, incurved at the apex. Stylopodium conic. Fruit glabrous, globose, somewhat flattened laterality. Carpels nearly terete, the dorsal and intermediate ribs filiform, the lateral ones much larger and corky-thickened, the commissural faces each with a corky longitudinal projection; oil-tubes solitary in the intervals, 2 on the commissural side. Seed terete. [Greek, resembling the genus Lilaea.]
A genus of wide geographic distribution, usually regarded as monotypic
Creeping, rooting in the mud, 2'-5' long. Petioles linear-spatulate, very obtuse, generally l' - 3' long but sometimes much longer, about 1 1/2" thick, hollow, distinctly jointed by transverse partitions; peduncles somewhat exceeding the leaves; umbels 5-10-rayed, the rays 1 1/2"-3" long; fruit about 1" long.
In salt and brackish marshes, and on muddy river-shores, New Hampshire to eastern New York and Florida, west to Mississippi June-Aug.