Scientific Name: Nymphaea mexicana
Synonyms: Castalia flava, Nymphaea flava
Common Names: Yellow Waterlily, Banana Waterlily
Growth Habit: Herb/Forb
Arizona Native Status: Introduced. This naturalized and cultivated ornamental water plant is native to Mexico and the southern United States.
Habitat: Riparian. This aquatic plant grows in sunlit ponds, shallow lakes, and slow stream bends in riparian areas. These particular Yellow Waterlilies were observed growing wild in a pond along Arivaca Creek.
Flower Color: Yellow
Flowering Season: Spring, Summer
Height: Up to 1 foot (30 cm) above the surface of the water, but usually less
Description: The flowers open in the afternoon, close at night, and have 12 to 30 yellow, lanceolate to narrowly elliptic petals, numerous yellow stamens, and yellowish green to red-tinged sepals. The flowers are followed by up to 1 inch (2.5 cm) long, egg-shaped fruits that ripen underwater. The leaves have smooth or sinuate (rippled) margins, radial veins, and are solid bright green or spotted with brown above, hairless, and egg-shaped to almost perfectly round with nearly touching to overlapping basal lobes. The aerial leaves are green to reddish green below, while the leaves floating on the surface of the water are reddish purple below. The leaves emerge from erect, unbranched, cylindrical rhizomes. The plants spread asexually by stolons (horizontal shoots), forming numerous clones. During the winter, the dormant plants have clusters of fleshy, tuberous, banana-shaped roots.
The similar American White Waterlily (Nymphaea odorata) has fragrant, white or pink flowers and leaves with non-sinuate margins.
Kingdom: Plantae – Plants
Subkingdom: Tracheobionta – Vascular plants
Superdivision: Spermatophyta – Seed plants
Division: Magnoliophyta – Flowering plants
Class: Magnoliopsida – Dicotyledons
Family: Nymphaeaceae – Water-lily family
Genus: Nymphaea L. – waterlily
Species: Nymphaea mexicana Zucc. – yellow waterlily
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