tropical and subtropical Africa, Madagascar, Asia, Australia
Numerous species, with the taxonomy updated fequently. Some are:
Aponogeton boivinianus Baill. ex Jum.
A. capuronii H. Bruggen
A. crispus Thunb.
A. distachyos L. f.
A. elongatus F. Muell. ex Benth.
A. euryspermus Hellq. & S.W.L. Jacobs
A. longiplumulosus H. Bruggen
A. madagascariensis (Mirb.) H. Bruggen [also offered under the synonyms A. fenestralis (Pers.) Hook.f.) and A. henkelianus Baum]
A. natans (L.) Engl. & K.Krause
A. rigidifolius H. Bruggen
A. tofus S.W.L. Jacobs
A. ulvaceus Baker
A. undulatus Roxb. (A. stachyosporus de Wit)
A. vanbruggenii Hellq. & S.W.L. Jacobs
Aponogeton distachyos is introduced into parts of eastern Australia and the United States.
A. madagascariensis is established in Mauritius.
submerged bulb plant with floating and rarely erect leaves (in at least one species)
Stem tuberous or rhizomatous. Leaves submerged and/or floating, rarely emersed, in a rosette, with or without petiole; leaf blade usually very long, linear to oblong or elliptic, sometimes wavy, bullate or fenestrate. Flowers borne on elongate, single or forked spike above water level; immature spike enveloped by a sheath-like spathe which falls off as inflorescence opens. Flowers few to numerous, unisexual or bisexual, small, white, yellow, pink or purple, with 2 petals and no sepals.
typically found in still or running waters, mostly riverine
This distinctive genus of obligate aquatic plants is represented by 57 species in the Old World and is the only member of the family Aponogetonaceae. About a dozen species are commonly cultivated or harvested from the wild for sale in the aquarium hobby, although numerous other species are occasionally traded. Species of Aponogeton naturally undergo an annual resting cycle in which the leaves die back in the cool season, only to be replaced by fresh growth in the warm season. In Madagascar, Australia, and Sri Lanka some species are threatened by over-collecting for the aquarium trade.