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..
Aquatic herbs, with simple stems decumbent at the base. Leaves alternate, very various, dentate or pectinate-pinnatifid. Flowers perfect. Tube of the calyx adnate to the triquetrous ovary, the limb 3-4-parted. Petals none. Stamens 3-4. Styles 3-4, cylindric or conic-subulate stigmatic above the middle. Fruit bony, 3-4-angled, 3-4-celled, with 1 seed in each cavity. [Middle Latin, forward-creeping.]
Three or four species, natives of eastern North America, extending to the West Indies and Guatemala. Type species: Proserpinaca palustris L.
Emersed leaves linear-lanceolate to oblong, serrate; fruit sharply angled.
Leaves all pectinate-pinnatifid; fruit obtusely angled.
Proserpinaca palustris L. Sp. Pl. 88 1753.
Glabrous, simple or sometimes branched, 8'-2o' high. Emersed leaves oblong or linear-lanceolate, 10"-2' long, 1"-6" wide, sharply serrate, the submerged ones pectinate or pectinate-pinnatifid into stiff linear acute segments which are often serrulate, bearing a minute black spine in their axils; flowers solitary or several together, sessile in the axils of the emersed leaves; fruit about 2" long and 2" thick, sharply 3-angled, the faces concave, smooth or rugose.
In swamps, New Brunswick to Minnesota, Florida, Iowa, Texas and Central America. Also in Bermuda. July.
1791. Proserpinaca pectinacea T. & G. Fl. N A. 1: 528. 1840.
Resembling the preceding species, but usually smaller. Leaves all pectinate or pinnatifid, the segments shorter and rarely serrulate, more subulate, or capillary; calyx-lobes broader; fruit smaller, about 1 1/2" long by 1" thick, the faces flat or slightly convex, often wrinkled or somewhat tuberculate, the angles obtuse.
In sandy swamps near the coast, Maine to Florida, west to Louisiana. Summer.
Proserpinaca intermedia Mackenzie, from swamps in southern New Jersey and Georgia, is quite intermediate between the two above species and may be a hybrid between them.