rooted waterhyacinth, saw-petal waterhyacinth.

Habit: rooted, floating-leaved, aquatic perennial with roots typically fixed in mud (Barrett, 1988).

Stems/roots: stems, which can grow up to 8 m in length, form dense stands which can grow to 50 m in width (Agostinho et al., 2007).roots typically vary in length, ranging between 5-100 cm (Padial et al., 2009).

Their leaves can be submerged, emergent, floating, or a combination (Gopal, 1987). Eichhornia azurea’s leaves are alternate on the stem; petiolate leaves are emersed, blade round (7-16 x 2.3-16 cm) with stipule 7-13 cm, and an uninflated petiole (11-25 cm) (Horn, 2002). The leaves of E. azurea grow larger in lotic environments and smaller in lentic environments (Pagioro and Thomaz, 1999).

Flowers are held on erect stems between 8-12cm and bloom for one day (Horn, 2002). Flowering occurs from summer to fall, with 7-50 flowers per stem, some stems carrying over 60 flowers (Gopal, 1987). Eichhornia azurea’s flowers are showy, mauve-blue and white with purple cores and a yellow distal spot (Horn, 2002; Barrett, 1988)., Eichhornia azurea’s style lengths range between 13-15 mm with upper stamen whorls ranging from 17-20 mm in length (Horn 2002; Barrett, 1978). Their proximal stamens range between 15-29 mm with anthers between 1.2-2.3 mm (Horn 2002).Size: Stem length varies and can be shorter than 5 cm in the younger portions of the stems and up to 1 m in the older portions (Padial et al., 2009). The plant can grow to a height of 1 m (Gopal, 1987).

Average seeds per fruit have shown to depend on whether the flowers are mid-styled (40.09 seeds per fruit), or long-styled (27.24 seeds per fruit) (Cunha and Fischer, 2009). The style of a flower is the stalk of the pistil that connects the ovary to the stigma (NCSU, 2021). Each seed is winged, 1.5-2.6 mm long and 0.3-0.9 mm wide (Horn 2002; Sher, 2009). It is primarily pollinated by butterflies and bees (Horn, 2002).

The  roots of E. azurea create underwater shelter in its native range, and provides habitat and a food source (in the form of algae growth) for fishes and invertebrates (Agostinho et al., 2007; Carniatto et al., 2012; Dibble and Pelicice, 2010). Because E. azurea provides structural heterogeneity in its aquatic environments, the rate and efficiency of predation is affected in those environments. An experimental study in its native range to evaluated the effect E. azurea's submerged roots have on predator– prey interactions used Red-eye Tetras (Moenkhausia sanctaefilomenae) as a predator and an ostracod (Cypricercus sp.) and chironomid (Chironomus sp.) as the prey, found that E. azurea roots resulted in increased shelter for both prey types (Padial et al., 2009). A similar conclusion was found in a different study analyzing the predation of Ray-finned fish (Serrapinnus notomelas). It was concluded that the complex structure of E. azurea roots led to the increased density of S. notomelas within the ecosystem, as it provides more protection for the species against predators (Camiatto et al., 2012). Echhornia azurea alters the nutrient concentrations in the water due to high absorption (Castro et al. 2016). A study conducted in the Ivinhema River investigated the fish communities associated with drifting E. azurea macrophyte mats. It was suggested that E. azurea mats provide a dispersal vector for several fish communities as various fish species protect themselves from predators by utilizing the dense macrophyte mats. Fish species' ability to guard themselves against the high risk of predation, along with their reproduction and recruitment of new individuals to their stocks, has resulted in E. azurea acting us an unintentional dispersal vector (Bulla et al., 2011).

Summary of species impacts derived from literature review. Click on an icon to find out more...

Ecological	Economic