The Genus Polystachya is in Family Orchidaceae > Subfamily Epidendroideae > Tribe Vandeae > Subtribe Polystachyinae.
(ausgenebank.agriculture.vic.gov.au says Tribe Vandeae holds ‘unidentified or unnamed plants of Neobenthamia’.)
Neobenthamia is a synonym of Polystachya.
Plants of the World Online (Kew) accepts 243 Polystachya species.
They are from tropical and subtropical areas around the world but especially Africa.
Many are very small clumping plants.
They are epiphytic on other plants but may grow on leaf litter among rocks or in soil.
The grow from the nodes along a rhizome (underground stem).
There are usually a number of stems from each node forming clumps.
The thin stems may have small ovoid pseudobulbs at the base.
The pseudobulbs remain covered by the lower leaf bases.
Each stem has 1 leaf or a few often arranged in 2 ranks (distichous).
Leaves along a stem may be folded up lengthwise.
Erect or spreading leaves are linear, lance-shaped, elliptic or oblong.
Terminal inflorescences are a solitary flower or a number in a raceme or panicle.
(Racemes have a midrib with flowers, on a pedicel, with the lower flower opening first. Panicles are branched.)
The erect or pendulous inflorescences often have bracts on the peduncle.
Flowers are mostly upright (non-resupinate) with the lip at the top.
Flower size varies greatly from minute to a few that are large.
Flowers have 3 sepals with the single ovate, elliptic or lance shaped one being free.
The 2 larger lateral sepals are joined at the base and to the foot of the column.
The 2 ovate to linear lateral petals are smaller than the sepals.
The third petal is the usually 3-lobed labellum or lip.
The base is attached to the foot of the column (with the lateral sepals).
There may be a callus at the lip base and/or some hairs along it.
The column, usually short and thick projects forward from the base of the flower.
Fusion of the bases of the foot, lip and column forms a prominent projection.
The anther is at the top of the column.
It consists of 4 waxy clumps of pollen (pollinia) under an anther cap.
Sometimes there are 2 deeply lobed pollinia.
Pollinia are attached to the floor of the anther by a stalk (stipe) or a viscidium.
The viscidium is a large or small sticky area on the pollinia.
The joined stigmas lie on the column below the anther.
Fruit are a capsule.
J.F.
