Water hyacinth petioles are either erect (up to 60 cm long and bearing flowers) or horizontal (stolons), about 10 cm long, and produce new plants from terminal buds (Parsons & Cuthbertson, 2001).

2.1.2 Leaves:

There are two types of leaves. Some are up to 60 cm long, narrow, and stand erect; others are almost round, up to 30 cm in diameter, and curved upwards with edges somewhat undulate. Both are smooth, glabrous, glossy, and with semi-parallel veins following the curvature of the leaf. Leaf stalks can be 50 cm long with bladder-like swellings, either bulbous or elongated, consisting of large air cells enabling the plant to float on water (Parsons & Cuthbertson, 2001).

2.1.3 Flowers:

Water hyacinth flowers are attractive mauve with six lobes or petals. The uppermost petal has a yellow dot in the center surrounded by darker purple. Each spike consists of about 8 (ranging from 3 to 35) flowers and individual flowers last only a few days. New plants flower when only 3 or 4 weeks old (Parsons & Cuthbertson, 2001). Under favorable conditions, WH may flower repeatedly throughout the year; although the intensity of flowering may vary with seasonal variation in growth rate.

2.1.4 Fruits and seeds:

The fruit consists of a narrow 3-celled capsule about 1 to 1.5 cm long, containing up to 300 seeds. Seeds are about 1 to 1.5 mm long with many longitudinal ribs. The seeds can germinate in a few days. In cool temperature areas, they remain dormant for 15 to 20 years in dry mud, germinating when moistened. A temperature of 20 to 35^oC usually enhances germination. In other words, rapid growth occurs with increasing summer temperature (Parsons & Cuthbertson, 2001).

2.1.5 Roots:

The root morphology is highly plastic, fibrous and has one single main root with many laterals, forming colossal root system. Because each lateral root has a root tip, WH may exploit nutrient in a low-nutrient water body (Xie & Yu, 2003). Lateral roots are generally longer and denser at low phosphorus levels than at high phosphorus levels (Xie & Yu, 2003). In shallow water, the roots may become attached to the bottom for several weeks when the water level drops (Parsons & Cuthbertson, 2001). The root-shoot ratio varies inversely with nutrient level, particularly with respect to nitrogen. Purple roots are characteristic of plants when nutrient levels are low in the water. (Xie & Yu, 2003)

2.1.1 Petioles:

2.1.2 Leaves:

2.1.3 Flowers:

2.1.4 Fruits and seeds:

2.1.5 Roots: