There are 126 species of Vanilla in Family Orchidaceae > Subfamily Vanilloideae > Tribe Vanilleae.
Subfamily Vanilloideae is characterised by having flowers with 1 stamen and parietal placentation.
Vanilla are evergreen mostly epiphytic orchids that grow as a vine.
With no support they can grow along the ground rooting at the nodes.
The branched or unbranched stems, up to 30 m long are smooth and fleshy.
Aerial roots attach them to trees or any support.
There may be no leaves, small scale-like ones or larger ones with no petiole or a very short one.
Alternate leaves attach to the nodes and any aerial roots attach on the other side of the node.
Blades can be oblong, elliptic or linear.
Axillary or occasionally terminal inflorescences are racemes with or without a peduncle.
Occasional racemes are branched (panicles) and all can have a few to many (100) flowers on pedicels.
There are ovate bracts at the base of the peduncle.
Flowers, around 3 cm long open first at the bottom of the racemes.
The 3 sepals and 2 lateral petals are free and spreading.
The lateral petals often have a keel on the outer surface.
The petals are slightly larger than the sepals.
They are white, cream, yellow-green to a deeper green.
Flowers are resupinate (upside down) so the larger medial petal, the lip is at the bottom.
The lip or labellum may be in one section or have 3 deep or shallow lobes each side.
At the base of the lip its sides, and any claw are usually fused to the column.
The lateral lobes on the middle section usually fold up around the column.
The larger end of the lip is curled back.
The lip may be coloured mainly with yellow or purple.
There may be calli which are variously shaped outgrowths or hairs.
The long column, with no foot may have wings on the sides or hairs at the base.
The anther at the top of the column has 2 or 4 pollinia (waxy bundles of pollen).
Pollinia may be free, directly attached to the rostellum or on a stalk but there is no viscidium.
The transverse stigma, sometimes bi-lobed is below the anther but eparated by the narrow rostellum.
The fertilised inferior ovary develops into a long cylindrical dehiscent capsule.
The single chamber can have up to thousands of small black seeds.
J.F.
