3. PROSERPINACA Linnaeus, Sp. Pl. 1: 88. 1753; Gen. Pl. ed. 5, 38. 1754.
Mermaid-weed, proserpinie [Ancient name used by Pliny for a Polygonum taxon; derivation uncertain; probably for Proserpina, Roman goddess of spring, or Latin proserpo, creep, alluding to habit]
Mitchell S. Alix
Robin W. Scribailo
Herbs, monoecious, aquatic or semiaquatic [terrestrial]; with taproot or fibrous and, often, adventitious nodal roots. Rhizomes present. Stems creeping to erect [decumbent to ascending], terete, unbranched proximally, often branched distally, glabrous or ± punctate, often with scattered, black, ascidiate trichomes. Turions absent. Leaves submersed or emersed, alternate, homomorphic, dimorphic, or heteromorphic; sessile or petiolate; blade entire or lobed to pinnatifid or pectinate, margins entire or serrate; with trichomes in axils of leaves and scattered on surfaces. Inflorescences usually racemes or cymes, rarely dichasia, in axils of unreduced, emersed leaves; bracteoles paired, alternate, opposite subtending emersed leaf, secondary and tertiary bracteoles sometimes present; flowers bisexual. Flowers 3(or 4)-merous; petals caducous, rudimentary, sometimes absent; stamens 3, in 1 antisepalous whorl; ovary 3(or 4)-locular. Fruit a nutlet, tan to brown, ovoid, obturbinate, or pyramidal, transversely 3-angled, with acute angles or shallowly 3-lobed, faces concave, flat, or curvilinear, without ridges, surfaces smooth, rugose, papillate, or tuberculate. x = 7.
Species ca. 2 (2 in the flora): North America, Mexico, West Indies, Bermuda, Central America, South America.
SELECTED REFERENCES Catling, P. M. 1998. A synopsis of the genus Proserpinaca in the southeastern United States. Castanea 63: 404–414. Fassett, N. C. 1953c. Proserpinaca. Comun. Inst. Trop. Invest. Ci. Univ. El Salvador 2: 139–162.
