Monographs Details: Sagittaria guayanensis Humb., Bonpl. & Kunth subsp. guayanensis
Authority: Haynes, Robert R. & Holm-Nielsen, Laurtiz B. 1994. The Alismataceae. Fl. Neotrop. Monogr. 64: 1-228. (Published by NYBG Press)
Synonyms:Sagittaria echinocarpa Mart., Alisma echinocarpum (Mart.) Seub., Sagittaria seubertiana Mart. ex Seub., Echinodorus guianensis (Kunth) Griseb., Lophiocarpus guayanensis (Kunth) Micheli, Lophiocarpus seubertianus (Mart. ex Seub.) Micheli, Lophotocarpus guayanensis (Kunth) Griseb., Lophotocarpus seubertianus (Seub. ex Mart.) Buchenau, Sagittaria seubertiana Mart. ex Seub., Sagittaria guayanensis Kunth, Sagittaria echinocarpa Mart.
Description:Subspecies Description - Perennial herbs from corms, glabrous or sparsely pubescent, to 50 cm tall; corms 2.5 cm long, 3 cm diam. Leaves submersed or floating; submersed leaves sessile, pale green to greenish-brown, phyllodial, 4-7 mm long, 4-8 mm wide, the veins 3-5, the apex round acute to obtuse, the basal lobes present, the basal sheath absent; floating leaves petiolate, the petioles triangular, to 42 cm long, 0.5-6 mm wide, the basal sheath to 10 cm, the blades pale green, sagittate, 3.5-10.5 cm long, 1.5-8.5 cm wide, the veins 11-13, the apex round-acute, the basal lobes present, the tips separated by 0.7-6.5 cm, with 3-4 veins. Inflorescence a simple scape of 1-7 whorls, floating, 0.9-9 cm long, 0.6-4 cm wide, the whorls with 3 flowers; peduncles terete, 10.9-22 cm long, 0.9-5.5 mm wide; staminate bracts separate, lanceolate to linear, delicate, 2.8-5.5 mm long, the apex round acute to obtuse; carpellate bracts separate, broadly lanceolate, delicate, 9.4-15 mm long, the apex obtuse; staminate pedicels spreading to erect, cylindric, glabrous to densely pubescent 7.1-18 mm long, 0.4-1.2 mm diam.; carpellate pedicels erect to spreading, in flower, spreading to reflexed in fruit, cylindric, glabrous or rarely pubescent, 0.6-2.1 cm long, 1.2-2.1 mm diam. Staminate flowers with sterile carpels, the sepals erect, 5.5-10 mm long, 3.8-5.2 mm wide, the petals clawed, 6-8.4 mm long, 4-6 mm wide, the stamens 6, the filaments glabrous, cylindric, ca. 1.5 mm long, ca. 0.2 mm wide, the anthers linear, 0.6-1.5 mm long, ca. 0.3 mm wide, the apex round acute; carpellate flowers with ring of sterile stamens, the sepals erect in flower and fruit, 4.5-10 mm long, 2.5-10 mm wide, the petals clawed, 0.8-1 cm long, 0.5-0.7 cm wide. Fruit aggregate 0.5-1.8 cm diam.; achenes oblanceolate, beaked, keeled, 1.7-2.2 mm long, 1.2-1.5 mm wide, the faces tuberculate, without glands, with 1-3 lateral wings, the margins echinate, the beak lateral, erect, 0.2-0.5 mm long.

Discussion:No commercial names are known. The species requires considerable light and high temperatures. It is of limited value in aquariums (De Wit, 1971).

Sagittaria guayanensis was separated by Bogin (1955) into two subspecies, ssp. guayanensis from the Neotropics and ssp. lappula (D. Don) Bogin from the Paleotropics. Bogin (1955) indicated the two subspecies could be separated by the shape and size of the fruit in addition to their distribution. ssp. lappula has compressed achenes that are more than 2.5 mm long, whereas ssp. guayanensis has plump achenes that are less than 2.5 mm long. Our research supports the conclusions of Bogin (1955).

The name of the specific epithet has often been spelled as guyanensis (Bogin, 1955; Haynes, 1984; Holm-Nielsen & Haynes, 1986). Kunth (1815), however, clearly spelled the epithet as guayanensis. According to article 73 of the ICBN (Greuter et al., 1988), the original spelling should be retained unless it evidently is a typographical error. The Colombian province [commissario] is Guainia, and the inclusion of an "a" prior to the "y" in guayanensis was intentional.
Distribution:Mexico North America| Campeche Mexico North America| Chiapas Mexico North America| Jalisco Mexico North America| Nayarit Mexico North America| Oaxaca Mexico North America| Tabasco Mexico North America| Guatemala Central America| Jutiapa Guatemala Central America| Petén Guatemala Central America| Santa Rosa Guatemala Central America| Honduras Central America| Comayagua Honduras Central America| El Paraíso Honduras Central America| Jutiapa Guatemala Central America| Francisco Morazán Honduras Central America| Olancho Honduras Central America| Santa Bárbara Honduras Central America| Valle Colombia South America| El Salvador Central America| Chalatenango El Salvador Central America| La Unión El Salvador Central America| Nicaragua Central America| Chontales Nicaragua Central America| Río San Juan Nicaragua Central America| Zelaya Nicaragua Central America| Costa Rica South America| Guanacaste Costa Rica Central America| Panama Central America| Coclé Panamá Central America| Panamá Panama Central America| Jamaica South America| Saint Elizabeth Jamaica South America| Dominican Republic South America|