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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN [Vol. 9, No. 2 



2. Sagittaria guyanensis H.B.K. Nov. Gen. & Sp. 1: 250. 1815. 



Perennial. Leaves floating or submerged, usually floating with cordate, obtuse 

 blades 1.2-6.5 x 1-7.5 cm, their basal lobes 1-3.5 x 1-3 cm, the rare submerged 

 leaves modified into phyllodia 3-5 x 0.5- 1.0 cm, the petioles lax, 10-40 cm long. 

 Scapes simple, 12-40 cm long, with 2-5 whorls of submerged or floating flowers. 

 Bracts connate at the base, 0.6-2 x 0.3-0.8 cm, only slightly thickened, appressed 

 to the scape. Plant glabrous or sparsely to thickly pubescent. Pistillate flowers 

 with thickened and recurved pedicels 1.5-4.0 cm long, typically with a ring of 

 6-9 functional stamens; sepals triangular, 1-1.5 x 1-1.5 cm, closely appressed to 

 the receptacle at maturity; petals white, oblong, about the same size or slightly 

 longer than the sepals. Staminate flowers with divaricate and somewhat filiform 

 pedicels 2-5 cm long; stamens 9-12, the filaments linear, glandular to glabrous, 

 1.8-2.3 mm long, the ovate anthers 0.8-1.1 x 0.5-0.7 mm, Mature pistillate heads 

 1.2 cm in diameter; achenes 1.5-3.5 x 1.3-3 mm, their wings typically crested, 

 the cresting occasionally reduced or obsolete, the faces typically echin ate- winged 

 or -ribbed, occasionally unadorned, the beak 0.3-0.8 mm long, occasionally obso- 

 lete, laterally to obliquely inserted. 



1. Mature achenes plump, small, less than 2.5 mm long. New World. 



2a. subsp. guyanensis. 

 1. Mature achenes compressed, large, more than 2.5 mm long. Old World. 



2b. subsp. lappula. 



2a. Sagittaria guyanensis subsp. guyanensis. 



Sagittaria ecbinocarpa Mart. Amoen. Bot. Monac. 6. 1829. 

 Alisma ancile Mart, ex Steud. Nom. ed. 2. 1: 49. 1840. Nomen nudum. 

 Sagittaria bracteata Willd. ex Kunth, Enum. PI. 3: 161. 1841. Nomen nudum. 

 Alisma echinocarpum (Mart.) Seub. in Mart. Fl. Bras. 3(1): 105. 1847. 

 Sagittaria seubertiana Mart. Fl. Bras. 3(1): 110. 1847. 



Echinodorus guyanensis (H.B.K.) Griseb. Fl. Brit. W. Ind. 505. 1864. (as guianensis .) 

 Lopbiocarpus guyanensis (H.B.K.) Micheli in DC. Monogr. Phan. 3: 62. 1881. 

 Lopbiocarpus seubertianus (Mart.) Micheli in DC. Monogr. Phan. 3: 64. 1881. 

 Lophotocarpus guyanensis (H.B.K.) J.G.Sm. Missouri Bot. Gard. Rep. 6: 35. 1895. 

 Lophotocarpus guyanensis var. echinocarpus (Mart.) Buch. Pflanzenreich 4(15): 36. 

 1903. 



Lophotocarpus guyanensis var. typicus Buch. Pflanzenreich 4(15): 36. 1903. 

 Lophotocarpus seubertianus (Mart.) Buch. Pflanzenreich 4(15): 36. 1903. 



Achenes plump, 1.5-2.3 x 1.3-2 mm, the wings shallowly crested, occasionally 

 smooth, the faces 1-3 winged, typically strongly echinate, occasionally smooth or 

 unadorned. (FIG. 5a, b.) 



Type collection: Humboldt s.n. "In swamps, Province of Guiana near the 

 Monastery of Don Felix Farreras and the city of Angostura," Colombia (holotype 

 presumably at Berlin, not seen, frag, of holotype MO). 



Distribution: Throughout tropical America, except in the higher mountains. 

 Collections examined from North America: Dominican Republic, El Salvador, 

 Guatemala, Honduras, Mexico, Panama; from South America: Argentina, Bolivia, 

 Brazil, British Guiana, Colombia, Dutch Guiana, Ecuador, Paraguay, Peru. (Fig. 5.) 



2b. Sagittaria guyanensis subsp. lappula (D. Don) Bogin, comb. nov. 



Sagittaria triflora Noronha, Verh. Bat. Genootsch. 5, Rel. PI. Jav. 26. 1790. Nomen 

 nudum. 



Sagittaria lappula D. Don, j?rodr. Fl. Nep. 22. 1825. 



Alisma lappula Ham. ex D. Don, Prodr. Fl. Nep. 22. 1825. Nomen nudum. 

 Sagittaria pusilla Blume, Enum. PI. Jav. 34. 1827. 

 Alisma hamiltonianum Wall. Cat. 175. 1828. Nomen nudum. 

 Alisma pubescens Ham. ex Wall. Cat. 175. 1828. Nomen nudum. 

 Alisma stellatum Ham. ex Wall. Cat. 175. 1828. Nomen nudum. 



