Aponogeton is the only genus of 45-50 species of flowering plants in the family Aponogetonaceae. The species are fully aquatic plants, native to tropical and warm temperate regions of Africa, Asia, and Australasia. Many species grow in temporarily still or flowing waters and live through the dry period as a dormant tuber. Most Asian species remain submerged all year round, whereas the tubers of the African species are able to survive the dry season by shedding their leaves and undergoing a dormant period.
Aponogeton boivianus Baill. ex Jum. is native to Madagascar, it inhabits fast flowing rivers. The plant grows from a tuber, which looks like a spherical cap. It is easy to distinguish from other members of the genus. The unfolding leaves are light or yellowish green, purplish or brownish green if exposed to ultra violet light, later turning to dark green. The plant itself can grow quite large, leaves ranging from 15-80 cm in length and 0.5-8 cm width. The leaf veins run parallel, the lamina is wavy. The inflorescence is whitish or soft pink, not showy. The plant has a dormant period, which can be induced by drought, or it may occur spontaneously in an aquarium. Plant the tubers half buried to eliminate rot. The first picture taken by Janos Agoston shows 3 or 4 year old tubers on a 1×1 cm grid, the second shows the foliage.
Aponogeton crispus Thunb. is native to Sri Lanka in southeastern Asia, where it usually occurs in seasonal ponds, becoming dormant in the dry season. It is also found in still and running waters. It is a submerged aquatic plant with a round rhizome 2–3 cm in diameter. Leaves are 15-50 cm long 1-3 cm wide, mid green, the tips can be brownish on newly emerging ones. The first picture taken by Janos Agoston shows 3 or 4 year old tubers on a 1×1 cm grid, the second shows the new growth.
Aponogeton crispus 'Red' is an aquacultural (horticulture under water) variety found by Tropica Aquarium Plants. It is the same as the common variety, but it grows only to 40 cm tall, and has burgundy leaves. It is only propagated by tissue culture. If you want nice rich color use an additional UV lamp or fluorescent light specially designed for fresh water plants.
Aponogeton distachyos L.f. is a fresh water aquatic perennial with tuberous roots and floating oval leaves native to South Africa. It has sweetly scented white flowers used in cooking. This species is now invasive in s. Australia, w. South America and w. Europe. Photo 1 was taken by Alan Horstmann and photo 2 was taken by Nhu Nguyen at the UC Botanical Garden. Photos 3 & 4 were taken by Janos Agoston, showing 2 new leaves and the tuber on a grid.
Aponogeton longiplumulosus H.Bruggen is native to Magadascar. The tuber is black, or dark brown, slightly conical, and the bottom is more or less flat. Leaves are slender wavy, 15-60 cm long, green. It is similar to Aponogeton crispus, but the leaves are thinner and less fluted. It is not a demanding plant. The picture taken by Janos Agoston shows 3 or 4 year old tubers on a 1×1 cm grid.
Aponogeton madagascariensis (Mirb.) H.Bruggen (common name 'Madagascar lace plant'), is native to Madagascar (hence the name). This plant is very distinct from all other species regarding the tuber, which is brown, about as thick as a pencil and branching. At first glance it looks like a rhizome, but rhizomes have roots even when dormant, while tubers lose their roots totally when entering dormancy. Foliage is similar to Aponogeton henkelianus, but the leaves are much wider (3-6 cm). This plant is studied by plant physiologists - just like Monstera deliciosa - to have a better understanding of programmed cell death. In bud stage the lamina is intact as any other leaf in general. But as the leaf expands and ages the cells between the veins start to collapse, making a fine netting. Most of the time the leaves are light to mid green, sometimes dark green maybe with a purplish flush on the young ones. This plant can be propagated vegetatively by dividing carefully the tuber, or by seed as all other Aponogeton species. It has the same inflorescence and needs as Aponogeton henkelianus. It is very susceptible to rot! The picture taken by Janos Agoston shows 3 or 4 year old tubers on a 1×1 cm grid.
In 2023 Aponogeton henkelianus Baum and Aponogeton madagascariensis var. henkelianus (Baum) H.Bruggen (common name 'Henkel lace plant') are considered to be synonyms of A. madagascariensis. Also native to Madagascar, the tuber looks like a piece of black clay, very similar to Aponogeton longiplumulosus. The new leaves are purplish green when exposed to UV light, older ones are light green, 15-50 cm long and 1-3 cm wide. The inflorescence is soft pink, it divides into 2 or 3 panicles. It also has a dormant period. In the aquarium it needs clean water, free from algae which can damage the leaf and is visually unattractive. The first picture taken by Janos Agoston shows 3 or 4 year old tubers on a 1×1 cm grid.
Aponogeton ulvaceus Baker is native to Madagascar. The tuber resembles an acorn, but the dead leaf bases are hard and fibrous, firmly attached to it, protecting the bud. Leaves are very wavy, lamina is undivided, light green, from 15-60 cm long and 4-10 cm wide. The inflorescence is sometimes two panicles with a small green spathe, white or greenish; it flowers freely. This is the fastest growing and most undemanding species available to aquarists. Photos by [[Janos Agoston. The first shows the inflorescence. The second shows 3 or 4 year old tubers on a 1×1 cm grid.