Menyanthaceae.
The Buckbean family has (5) 6 genera with around 58 (to 70) species including 20 from Australia.
Almost always perennial they grow in water or marshy areas.
They have rhizomes from which the leaves grow.
The almost always alternate leaves can be in, on or above the water.
The base of the petioles sheath the stem.
The petiole is usually attached to the edge of the blade but occasionally to the lower surface (peltate).
Apart from one species the leaves are simple (undivided).
The blades are often heart-shaped with pinnate or palmate veins.
Flowering stems may just break the surface of the water or extend above it.
Inflorescences can be a solitary flower or a number variously arranged and they may be on a leafy stalk or a leafless scape.
Stems can be unbranched with 1, 2 or many flowers at each node.
Others are branched or have a tight cluster or head that may have a whorl of bracts below it (involucre).
The bisexual radially symmetric flowers have parts in 5’s.
The sepals are free or joined at the base.
The petal bases are fused into a tube with spreading lobes.
Petals are yellow, white or white with a yellow center.
There may be a crest or a keel down the centre of the lobes.
The edges can have wings, coarse hairs or a fringe.
The 5 stamens, opposite the sepals are attached to the corolla tube at any level.
The anthers open inwards through longitudinal slits.
The ovary, of 2 fused carpels is superior to half-inferior.
It has 1 locule with 2 parietal placentas each holding numerous ovules.
The single style has 4 stigma lobes.
On a plant the flowers may have styles of different lengths.
The fruit are berries or capsules that open in various ways.
The smooth seeds may have a wings.
J.F.
