Sagittaria rhombifolia

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Sagittaria rhombifolia

Description

Herb, perennial, to 100 cm tall, glabrous; rhizomes to 6 x to 4 cm wide; corms 1-4 x 0.6-2 cm. Leaves submersed or emerged; submersed leaves sessile, pale green, linear, 1-5 x 0.1-0.3 cm, apex acute, basal lobes absent, veins 1-3; emerged leaves petiolate, petiole more or less triangular, 13.5-68 x 0.6-1.5 cm, basal sheath to 23 cm long, blade pale green, linear-elliptic, elliptic-ovate, rhombiform, to subcordate, 8.5-20 x 0.2-15 cm, apex acute, basal lobes absent, base acute to rarely sub-cordate, veins 9-13. Inflorescence a simple scape of 2-10 whorls, emerged, 3.5-37 x 1-5 cm, whorls with 2-3 flowers; peduncle terete, 12-79 x 0.1-0.9 cm; staminate bracts united at base, delicate to coarse, elliptic, 6-22 mm long, apex round-acute to obtuse; carpellate bracts united at base, coarse, elliptic, 6-35 mm long, apex obtuse; staminate pedicels spreading, cylindric, 2.2-4.9 x 0.02-0.12 cm; carpellate pedicels erect in flower, spreading in fruit, cylindric in flower, becoming expanded in fruit, 0.5-2.5 x 0.2-0.55 cm. Staminate flowers: sepals erect, 9-11.5 x 4-6 mm, petals clawed, to 20.5 x to 13 mm, claws to 7 mm long, stamens 9-12, filaments glabrous, dilated, 2.3-3.8 x ca. 0.4 mm, anthers linear, 1-1.8 x 0.3-0.5 mm, apex round-acute, sterile carpels present. Carpellate flowers: sepals appressed in flower and fruit, nearly enclosing fruiting aggregate, 1.4-2.3 x 0.9-2.5 cm, petals white, yellowish, or pinkish clawed, 15-30 x 1.3-2.5 mm, claw ca. 5 mm long, without ring of sterile stamens Fruit aggregate 1.2-3 cm diam.; achenes obelliptic, 3.2-7 x 2-3 mm, not tuberculate, without glands, keeled, beak lateral, horizontal, 0.7-1.2 mm long.

Distribution

Argentina present, Guianas present, Southern America: Costa Rica (Costa Rica present)
from Costa Rica S to Argentina; more than 100 specimens examined, with 24 from the Guianas (GU: 22; SU: 2).