Aquarius paniculatus (Micheli) Christenh. & Byng
Basionym : Echinodorus paniculatus Micheli[1]
Synonyme :
Echinodorus paniculatus var. brevifolius Hauman
Echinodorus paniculatus var. dubius Fassett
Echinodorus paniculatus f. latifolius Chodat & Hassl.
Occurrence:
From Mexico to northern Argentina.
Ecology
Grows in various flooded habitats, including roadside ditches and other disturbed habitats. From sea level to 1400 m.
Morphology General habit
Perennial, from rhizomes, glabrous, to 200 cm
Morphology Leaves
Leaves emersed, blade lanceolate, 5 - 7-veined, 8 - 30 cm long, 1 - 12 cm wide, lacking glaucous markings, apex acute, base attenuate to truncate, petioles triangular in cross-section, 16 - 80 cm long, 8 mm diam., base with sheath up to 22 cm long
Morphology Reproductive morphology Fruits
Fruit oblanceoloid, 4 - 6 ribbed, keeled, ovoid, 1.5 - 3 mm long, 1 mm wide, beak terminal, erect, 0.1 - 0.8 mm.
Morphology Reproductive morphology Inflorescences
Inflorescence paniculate or racemose, of 4 - 11 whorls, each 5 - 21-flowered, erect or rarely prostrate, leaves pendulous, spreading, up to 40 cm long, 30 cm wide, leaf spike and pedicel triangular in cross-section, up to 120 cm long, 7 mm in diameter, bracts lanceolate, fused flat at the base, coarse, shorter than the flower stalks underneath, 1 - 5.5 cm long, 4 - 8 mm wide, 8 - 15-veined, pointed tip, flower stalks spread out in flower and fruit, round, 1 - 4 cm long, 0.5 mm diam. flowers 3 - 4.5 cm in diameter, sepals and petals spreading, sepals ca. 15-veined, c. 6 mm long, ca. 4 mm wide, veins without papillae, petals white, without claws, overlapping, ca. 23 mm long, ca. 17 mm wide, stamens 19 - 22, anthers many-sided, ca. 2 mm long, filaments c. 1.5 mm long, carpels numerous
Although Echinodorus paniculatus is easily recognized by its triangular leaf stalks and stems, it has very variable leaf blades. In full sunlight the leaves are very narrow, but in shady habitats the leaves become much broader and sometimes almost heart-shaped. These broad-leaved forms have been treated by some authors as different variations (Hauman 1915; Fassett 1955). As the differences are of a purely ecological nature, these variations are not accepted here. Haynes & Holm-Nielsen (1994) listed the following names as synonyms of Echinodorus paniculatus: E. cylindricus Rataj, E. macrocarpus Rataj (E. pubescens) and E. glaucus Rataj. These species are very different from each other and are easily distinguished from E. paniculatus by spherical leaf stalks and wax covering (E. cylindricus and E. glaucus) or pubescence (E. pubescens), so that they are maintained as separate species.
Phenology
Flowering and fruiting throughout the year. [1]
