Common name: water hyacinth, water orchid, Nile lily
Eichhornia crassipes (Mart.) Solms APNI*
Synonyms: Pontederia crassipes Mart. APNI*
Eichhornia speciosa Kunth APNI*
Description: Erect, emergent, free-floating, stoloniferous aquatic perennial to 1 m high; roots black to purple, feathery, to 1 m long. Stolons root at nodes to form daughter plants.
Leaves all basal; stalk spongy, often inflated and buoyant, to 75 cm long, up to 3 cm diam.; blade flat, circular to ovate, to 25 cm diam., apiculate, with numerous longitudinal veins, margins gently incurved and often slightly undulate.
Inflorescence axillary, slightly exceeding the leaves, to 20 cm long. Flowers 3–6 (-7) cm in diam., reportedly tristylous, though only one style-form recorded from Australia and fertile seed readily formed. Perianth lobes 6, blue 3–4 cm long, fused below, upper lobe with a darker blue patch with a yellow centre. Stamens 6, 3 longer almost exerted, 3 shorter.
Fruiting inflorescence recurving, becoming submerged.
Flowering: during warmer months.
Distribution and occurrence: Naturalised on North Coast, Central Coast and North Western Plains; all mainland States. Native of South America.
Grows in stationary or slow-flowing, nutrient-rich water; in freshwater rivers and other watercourses, lakes, swamps, lagoons on river floodplains, reservoirs and farm dams.
NSW subdivisions: *NC, *CC, *ST, *NWP, *SWP
Other Australian states: *Qld *Vic. *N.T. ?S.A. *W.A.
Declared Noxious Weed
Water Hyacinth is a free-floating, aquatic herb distinguished by its broad, glossy green leaves with swollen, spongy leaf stalks, and its showy, blue to mauve flowers with distinctive markings on the petals. It is one of the World's worst weeds, being particularly serious in slow-flowing or stagnant freshwater in tropical and subtropical areas. A declared noxious weed in New South Wales. See also Weeds in Australia profile compiled by P.G. Kodela (2007).
Text by SWL Jacobs (1993); revised by P.G. Kodela (July 2012)
Taxon concept: Flora of NSW vol 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.