Aponogetonaceae Planch.

Aponogetonaceae, F.N. Hepper. Flora of West Tropical Africa 3:1. 1968

Morphology General Habit

Fresh-water aquatic herbs with submerged or floating leaves; rhizome tuberous, with fibrous roots

Morphology Leaves

Leaves long-petiolate, or sessile, oblong-elliptic to linear, with few principal parallel nerves and numerous transverse secondary nerves

Morphology Reproductive morphology Flowers

Flowers hermaphrodite or rarely unisexual, spicate-scapose, spike simple or usually 2- (rarely up to 8-) forked, without bracts

Morphology Reproductive morphology Flowers Perianth

Perianth-segments 1-3, or absent, sometimes petaloid and bract-like, equal or unequal, usually persistent

Morphology Reproductive morphology Flowers Androecium

Stamens 6 or more, free, hypogynous, persistent; anthers extrorse, 2-locular

Morphology Reproductive morphology Flowers Gynoecium

Carpels free, 3-6, sessile; style short; ovules 2 or more, ascending

Morphology Reproductive morphology Fruits

Fruits opening on the adaxial side

Morphology Reproductive morphology Seeds

Seeds without endosperm

J. R. Timberlake, E. S. Martins (2009). Flora Zambesiaca, Vol 12 (part 2). Royal Botanic Gardens, Kew

Morphology General Habit

Rhizomatous perennial monoecious or dioecious herbs, sometimes apomictic, with tubers, usually growing in fresh water or on wet soil

Morphology Leaves

Leaves all basal, alternate, sessile or long petiolate, with blades elliptic to linear or awl-shaped, entire, submerged or floating

Morphology Reproductive morphology Inflorescences

Inflorescence usually a long petiolate single spike or 2 opposite spikes or rarely digitately divided into 3–4(11) spikes, at first enclosed in a membranous caducous spathe, or the inflorescence much abbreviated and resembling a Ranunculus flower in the South African Aponogeton ranunculiflorus

Morphology Reproductive morphology Flowers

Flowers bisexual or unisexual-Tepals 1–6 or lacking, petal-like, persisting or not in fruit

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 1–6, rarely more, lacking in female or apomictic plants; filaments free, filiform or flattened; anther very small, 2–thecous, extrorse, yellowish, brown, violet, purplish or blackish

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary superior with 3–8 carpels, free or slightly united near their base, each one 1-locular, with 1–14 erect ovules inserted at the base or along the carpel suture

Morphology Reproductive morphology Fruits

Fruit of 3–8 free ovoid or bottle-shaped beaked follicles

Morphology Reproductive morphology Seeds

Seeds 1–14 on each follicle, discoid to fusiform, without endosperm; testa simple or double, the inner brown and close to the embryo, the outer pellucid.

Distribution

A monogeneric family widely distributed in tropical and subtropical regions from Africa and Madagascar to India, SE Asia and Australia, but absent from the Americas.

Aponogetonaceae, K.A. Lye (Agricultural University of Norway). Flora of Tropical East Africa. 1989

Morphology General Habit

Rhizomatous glabrous monoecious or rarely dioecious herbs with tubers, usually growing submerged in fresh water or (after drying up) on wet soil

Morphology Leaves

Leaves all basal and alternate, simple and usually with long petioles; blades oblong to linear

Morphology Reproductive morphology Inflorescences

Inflorescence usually a simple or bifid spike (rarely the spike digitate and divided into 3–4 parts), at first enclosed in a thin caducous spathe, very rarely (in the South African species A. ranunculiflorus) the inflorescence is much abbreviated simulating a >i>Ranunculus flower

Morphology Reproductive morphology Flowers

Flowers bisexual or more rarely unisexual

Morphology Reproductive morphology Flowers Perianth

Tepals 1–6 or absent, petal-like, often persisting in fruit

Morphology Reproductive morphology Flowers Androecium

Stamens 1–6, rarely more; filaments free, filiform or flattened; anthers extrorse, 2-thecous, most often only 0.2–0.5 mm. long

Morphology Reproductive morphology Flowers Gynoecium

Ovaries 3–8, free or slightly united near their base; each ovary superior and 1-locular, with 1–14 erect ovules borne along one side of the locule-wall or at the base of the locule

Morphology Reproductive morphology Fruits

Fruit a 1–14-seeded follicle

Morphology Reproductive morphology Seeds

Seeds discoidal to fusiform, straight or slightly curved, with a simple or double testa; endosperm absent