Floral Diagram

The details regarding the complex structure of the orchid flower were first clarified by Dr. Robert Brown (1833) and later by Charles Darwin (1862). The orchid flower is basically modeled according to the liliaceous pattern ,each flower being constituted by 15 members -3 sepals +3 petals +6stamens in two whorls of three each+ 3 carpels. In Apostasia only three stamens are fertile ,while in Neuweidia ,the anther member of the tribe Apostasiese, there is a further reduction of stamens to two . In Cypripedieae only the two lateral stamens of the inner whorl are fertile ; the two lateral stamens of the outer whorl is represented by a staminode . In Monandrae , on the other hand , only the odd stamen of the outer whorl, situated opposite the labellum , is fertile . The two lateral stamens of this whorl are supposed to have lateral stamens of the inner whorl from the sides of the clinandrium, protecting the pollinia , while the odd stamen of this whorl forms the front of the column.

All the three stigmas are fertile in the Cypripediae and Apostasieae . But in the Monandrae , only two are fertile , the third being transformed into the rostellum.