Orchid Inflorescence

In terrestrial orchids the inflorescences are either terminal as in the tuberous perennial forms belonging to the Neottieae and Orchideae or lateral as in advanced members like Calanthe , Phaius , Eulophia etc. In epiphytic forms inflorescences are terminal only in a few cases as in Polystachya , the various Eria species with discoid pseudobulbs , Porpax etc. In the majority of cases they are lateral . In Monopodiales they are consistently lateral .

Usually inflorescences are produced from a leafy shoot, but in a few cases like Bulbophyllum fimbriatum, Dendrobium ovatum , Dendrobium heterocarpum , Chiloschista pusilla , etc. , leaves are shed before flowers are produced .

As a rule inflorescences are in simple or compound racemes . In Trias stocksii, one species of Bulbophyllum etc. the inflorescences are single-flowered . In most species of Cirrhopetalum , section of Bulbophyllum , the inflorescence is an umbel . Dendrobium heterocarpum , D. macrostachyum , D. aqueum etc. produce flowers in twos and threes from the nodes of the pseudobulb. Thrixspermum arachnites , Dendrobium haemoglossum , and Ephemerantha species come into bloom periodically as in Dendrobium crumenatum. A curious phenomenon has been observed in Sirhookera . Here inflorescence , is a panicle which persists even after flowers have fallen away. Next year fresh branchlets are produced from the old inflorescence which again produce flowers. In Dendrobium crumenatum also , where under favourable conditions flowering is fairly frequent ,the flowers arise from the old inflorescence stalk which is persistent.