ORCHIDACEAE

 

Greek origin.  Orchis - Testicle

 

One of the most interesting families of flowering plants. The flowers strikingly resemble various forms of animal life,  particularly the insects. The family consists of mostly herbs. The herbs are either terrestrial or epiphytic or saprophytic or lithophytes. The roots are either fibrous or cord like roots or thickened as tubers. The leaf-bearing stem generally thickened or swollen to form pseudobulbs. Inflorescence solitary, a spike or recemose or panicle. Flowers hermaphrodite, irregular often-showy very rarely unisexual,, bractiate. Perianth is of six segments arranged into two series. The inner series of 3 petals with the central petal known as labellum or lip is usually larger brighter in colour highly modified taking different shapes or mimicking insects, animals, moths etc. Labellum frequently projected into a spur or sack. Stamens and style united in a column opposite the lip. And column sometimes produced towards the lip into a beak known as rostellum. Stamen one or two, two celled and introrse. The pollen grains are either granular often in tetrads or usually agglutinated into mealy waxy or bony masses known as pollinia. Ovary inferior,3 carpelled,  one celled usually unilocular with 3 parietal biseriate placentae or in a few genera trilocular with axial placentation. Style stigma and stamens adnate into a single  structure known as column or gynandrium The ovules numerous, fruits, a capsule dehiscing by 3-6 hygroscopically sensitive walls. Seeds numerous without endosperm, minute which remain epically connate.