Common name: Dense Waterweed, Leafy Elodea, Egeria, Anacharis, Brazilian Elodea
Egeria densa Planch. APNI*
Synonyms: Elodea densa (Planch.) Casp. APNI*
Anacharis densa (Planch.) Vict. APNI*
Description: Attached submerged aquatic perennial; stems to 1.5 (-5) m long, multi-branched, rooting at the lower nodes, buoyant, so most of the growth is near the surface; upper internodes crowded, shorter than the leaves.
Leaves sessile, in whorls mostly of 4 or 5 (rarely 3 or 6–8), to 4 cm long and 2–5 mm wide, often curved backwards, margins minutely toothed.
Flowers unisexual; female flowers not recorded from N.S.W. Male flowers 1–5 per spathe, 2.5–7.5 cm long, axillary, from upper nodes; spathe 8–12 mm long; perianth white, sepals 3–4 mm long, petals 9–12 mm long. Female flowers 1 per spathe; hypanthium 4–6 cm long; perianth white, sepals c. 3 mm long, petals unequal, 6–8 mm long.
Flowering: during warmer months.
Distribution and occurrence: Grows in stationary or slowly flowing water especially where substrate has been disturbed. Commonly used in ponds and indoor fish aquaria. Native of South America.
NSW subdivisions: *NC, *CC, *SC, *SWS, *SWP
Other Australian states: *Qld *Vic. *Tas. *N.T. ?S.A. *W.A.
Dense foliage (due to the leaf whorls being close together), larger leaves and distinctive showy white flowers help distinguish Egeria densa from related species. See also Weeds in Australia profile compiled by P.G. Kodela (2008).
Text by S. W. L. Jacobs; revised by P.G. Kodela (July 2012)
Taxon concept: Flora of NSW 4 (1993)
APNI* Provides a link to the Australian Plant Name Index (hosted by the Australian National Botanic Gardens) for comprehensive bibliographic data
***The AVH map option provides a detailed interactive Australia wide distribution map drawn from collections held by all major Australian herbaria participating in the Australian Virtual Herbarium project.