Dendrobium macrostachyum

Also known as Dendrobium aphyllum, this is the most common dendrobium found in the lowlands of Kerala. It is native to the Western Ghats and Sri Lanka and blooms from March to June. The flowers measure about an inch across. Shown below are two different variants. The second one has a more rounder form and is fragrant.

Cottonia peduncularis

Also known as the bee orchid, it is found in Peninsular India and Sri Lanka and blooms during February and March with a very long and thin inflorescence that is branched at the apex and carries short lived flowers so much so that only two flowers are open at a time. The petals and sepals are reflexed backwards and the lip resembles a bee. The thin inflorescence bobs under the weight of the flower creating an impression of a flying bee.