Sonder, Linnaea 28:233 (1856).
Synonymy: Not Applicable
Common name: Hooded water-milfoil, slender railfoil.
Slender aquatic herb, stems to 60 cm long; leaves all of one type, decussate (lowermost rarely in 3's, uppermost sometimes alternate), orbicular, pectinate, 4-13 mm long, with 12-16 pinnae.
Plants monoecious, flowers unisexual, solitary, each branch of the inflorescence with 1 rarely 2 male flowers each enclosed in a hooded bract, and 2-4 naked female flowers below; bracteoles of male flowers white, ovate to orbicular, c. 1.3 mm long, apiculate; those of females only c. 0.4 mm long; male flowers 4-merous, on a torus 0.4-1 mm long; sepals vestigial; petals red, 2.1-2.2 mm long, hooded, deciduous; stamens 8; anthers narrowly ovoid, tapering; styles and ovary 0; female flowers 4-merous, sessile; sepals, petals and stamens 0; styles tear-shaped, creamy yellow, stigmas non-fimbriate; ovary cylindrical, 0.8-1.3 mm long, 4-locular.
Fruits silvery-grey to reddish, cylindrical; mericarps cylindrical, 1.7-1.8 (rarely 1.5)mm long, rounded at the base, apex truncate, dorsal surface smooth.
Orchard (1986) Brunonia 8:, fig. 40.
S.Aust.: EP, SL, KI, SE. W.Aust.; Vic.; Tas.
Flowering time: Sept. — Jan.
SA Distribution Map based
on current data relating to
specimens held in the
State Herbarium of South Australia
A most distinctive species easily recognisable by its decussate pectinate leaves, hooded bract of the male flowers, non-fimbriate stigmas and large fruits.
Not yet available