Orchidaceae
Vanilla
Kingdom: Plantae Rank: Genus Parent: Orchidaceae Status: Valid
Morphological Description
Diagnosis:
Plants of Vanilla are the only true orchid lianas (vines) in the flora. The succulent plants sparsely root at the nodes. Typically ascending stems of Vanilla grow up a support without flowering and only flower on descending segments that are suspended from the canopy. Flowering appears to be combined function of a hormone shift based on orientation and brighter light conditions. All species produce short, fleshy-succulent, congested racemes that produce the flowers singly in succession or just a few at one time. The individual flowers are short-lived and in most species last a single day.
Vegetative Morphology
Habit: Hemiepiphytic succulent lianas rooting at the nodes.
Leaves: Leaves linear to broadly ovate, sessile, sometimes absent.
Reproductive Morphology
Inflorescence: Inflorescences axillary racemes, two-ranked or spiral.
Flowers: Flowers showy, ephemeral, fragrant, usually sequentially produced over long periods of time. Sepals and petals free, spreading. usually subsimilar, subequal. Lip unlobed or three-lobed, tubular, +/- callus keels, scales or tricvhomes in various combinations. Column elongate, bent below the apex; pollinia not distinctly divided, soft and paste-like.
Fruit: Fruits fleshy, indehiscent.
Seeds: Tiny, many per fruit.
Other
Notes: Vanilla species are rarely encountered in flower in the wild. When plants are found in flower every effort should be made to take photographs of the flowers including the lip ornamentation. In addition, because the short-lived flowers tend to degrade before drying for traditional herbarium specimens, at least one flower per collection should be preserved in alcohol if practical.