Utricularia gibba (humped, "Obanaitotanukimo")

Japanese name: オオバナイトタヌキモ （大花糸狸藻）
Scientific name: Utricularia gibba

[Overview]
A perennial found in nutrient-poor waters and wetlands.
A carnivorous plant.
It has no roots and is free-floating, but in wetlands it extends stems underground and grows in a mat.
The stems are very thin, about 0.2–1 mm, branch freely, and grow to 20 cm or more.
The leaves are alternate, fork in two, and become thread-like, 0.5–1.5 cm long.
The leaves bear a small number of bladders.
The bladders are ovate, about 1–2.5 mm in diameter, with a valve that opens inward; when small animals such as water fleas approach, the valve opens and sucks them in.
A raceme is borne on a flower stalk standing erect above the water.
The flowers are yellow and lipped, about 0.6–1.2 cm in diameter, with the base of the lower lip swollen and often with reddish brown markings.
There is a spur behind the flower.
The fruit is a capsule.

[History]
It was brought in with ornamental fish in the 1930s; since then, plants introduced for ornamental use have escaped, and others brought in along with other aquatic plants have become naturalized.

[Cultivation]
Propagate by division.
Grow it floating in a container with a water depth of 10 cm or more, or put paddy soil in a water-lily bowl or similar and let it grow in a mat.
It prefers a sunny place, but if the water temperature rises or the color fades in direct summer sunlight, move it to partial shade.
Fertilizer is not particularly necessary.
There are no particular pests or diseases.

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