Part 7 - UNC Herbarium

PONTEDERIACEAE 928
A genus of 7-8 species, native of tropical America and Africa, but now introduced widely in warm regions. References: Cook in
Kubitzki (1998b); Horn in FNA (2002a).
* Eichhornia crassipes (Martius) Solms-Laub, Water Hyacinth. Cp (GA, NC, SC, VA), Pd (GA, NC): ponds, ditches,
sluggish water; uncommon, introduced from South America. June-September. E. crassipes is "generally considered the world's
most serious aquatic weed" (Rosatti 1987). Originally native to tropical South America, E. crassipes is now a widespread
naturalized weed throughout the tropics and subtropics. In the northern part our area, water hyacinth is rare, probably not long
persisting. Further south, it can be an aggressive aquatic weed. [= RAB, C, F, FNA, G, GW, K; = Piaropus crassipes (Martius)
Rafinesque – S]
Heteranthera Ruiz & Pavón 1794 (Mud-plantain)
(also see Zosterella)
A genus of 10-12 species, of tropical and temperate America and tropical Africa. References: Cook in Kubitzki (1998b); Horn
(1998)=Z; Horn in FNA (2002a). Key based in part on FNA.
1 Leaves narrowly linear, 20-50× as long as wide, the base attenuate; flowers solitary, the corolla yellow; stamens and anthers
all alike ......................................................................................................................................................................... H. dubia
1 Leaves reniform, 0.5-1.5× as long as wide, the base cordate; flowers 1-several, the corolla white or pale blue; stamens and
anthers dimorphic.
2 Spathe with 2-several flowers; perianth tube 3-12 mm long.
3 Anthers and filaments with dark purple hairs; internode below the spathe < 1 cm long; spike with (3-) 7-16
flowers, typically elongating well out of the spathe...............................................................................H. multiflora
3 Anthers and filaments with white hairs; internode below the spathe > 1 cm long; spike with 2-8 flowers, typically
mostly included within the spathe......................................................................................................... H. reniformis
2 Spathe with solitary flower; perianth tube 11-45 mm long.
4 Vegetative stems elongating only in water deeper than 5 cm; blades of petiolate leaves oblong to ovate, the base
truncate to cuneate; perianth tube 15-45 mm long ....................................................................................[H. limosa]
4 Vegetative stems commonly elongating; blades of petiolate leaves round to oblong, the base cordate to truncate;
perianth tube 11-29 mm long ........................................................................................................... [H. rotundifolia]
Heteranthera dubia (Jacquin) MacMillan, Water Stargrass. Mt (NC, VA), Pd (VA), Cp (VA): streams, rivers; uncommon
(rare in NC). August-September. Québec west to WA, south to Cuba and Central America, but rare or absent in much of the se.
United States. The attribution of this species to SC is in error (as by Kartesz 1999), based on a misidentified specimen (C. Horn,
pers. comm.). [= RAB, F, FNA, GW, K, W; = Zosterella dubia (Jacquin) Small – C, G, S]
Heteranthera multiflora (Grisebach) Horn. Cp (NC, VA): in shallow, stagnant water in floodplains, or emersed on mud;
rare (NC Watch List). June-October. IL west to NE, south to MS; also on the Atlantic Coastal Plain from NJ south through PA
to ne. NC; also in South America (Brazil, Paraguay, Argentina, and Venezuela). [= C, FNA, K, Z]
Heteranthera reniformis Ruíz & Pavón. Cp (NC, VA), Pd (GA, NC, SC, VA): in shallow, stagnant water in floodplains,
or emersed on mud; uncommon (SC Rare). June-October. CT west to NE, south to FL and TX and into South America. First
reported for South Carolina by Hill & Horn (1997). [= RAB, C, F, FNA, G, GW, K, S, W, Z]
Heteranthera limosa (Swartz) Willdenow occurs east to TN, KY, and FL (Kartesz 1999); it is attributed to VA in Small
(1933), but the documentation is not known. [= FNA, C, F, G, K, S, Z]
Heteranthera rotundifolia (Kunth) Grisebach. Ponds. Midwestern, as a rare disjunct east to c. KY (Larue County) (Medley
1993). [= FNA, C, K, Z]
Pontederia Linnaeus 1753 (Pickerelweed)
A genus of 3-6 species, from North America to South America. References: Lowden (1973)=Z; Cook in Kubitzki (1998b); Horn
in FNA (2002a).
1 Floral tube villous when young, essentially glabrous to sparsely glandular in maturity; leaves primarily ovate to triangularlanceolate,
2.2-21 cm wide, the base generally cordate or truncate (rarely cuneate).............................. P. cordata var. cordata
1 Floral tube persistently pubescent with short glandular hairs; leaves lanceolate, 0.4-8.3 cm wide, the base generally cuneate
to truncate ..........................................................................................................................................P. cordata var. lancifolia
Pontederia cordata Linnaeus var. cordata, Heartleaf Pickerelweed. Cp, Pd (GA, NC, SC, VA), Mt (NC): marshes, pondshores,
lake-shores; common, uncommon in Piedmont, rare in Mountains. May-October. Nova Scotia west to MN, south to FL
and TX; Belize; s. Brazil, Argentina, Paraguay, and Uruguay. The recognition of infraspecific taxa in Pontederia cordata is
controversial and requires additional study. P. cordata exhibits tristyly, an interesting breeding system. Each plant has one of 3