The study explores established ideas about the orchid flower Architecture that may or may not be spurred . The report discusses that the appendage of the lip is meant for storing nectar and is possessed by quite a number of species . It may vary in shape and length in the different species. In the African Angraecum sesquipedale, it reaches a length of one foot. In many Peristylus species , it is scroriform or globular , whereas in Gastrochilus , it is wide and cup-shaped . There are two spurs instead of one in satyrium and diplocentrum.
Situated in the centre of the flower opposite the lip and facing it is the unique structure ,the column or the gynostegium ,which is peculiar to the orchids and their chief identifying character. The gynostegium is formed by the fusion of the filaments ,styles and stigmas of the flower . The only fertile anther of the flower is borne on top of the column. In diandrae , where two anthers are fertile , they are borne subteminally on the two sides of the column . In orchideae and Neottieae ,the anther is persistent ,whereas in the advanced Epidendreae they are deciduous . The anther cap which is easily removable in the deciduous forms , provides a protective covering over the pollen grains, which are collocted in masses called the pollinia . The pollinia are contained in a cavity called the clinandrium (Allen, 2004, 12) .
There is a great amount of variation in the construction of the pollen apparatus in the various species. In the primitive Diandrae pollinia are not formed ; instead pollen grains adhere together by a viscous substance. In Neottieae and Orchideae pollinia are organized but are of soft consistency. In the former they separate easily into a powdery mass and are termed granular of mealy pollinia are organized but are of soft consistency . In the former they separate easily into a powdery mass and are termed granular or mealy pollinia while in the latter they cohere in packets and are termed sectile pollinia . In the advanced Epidendreae the pollinia are hard and waxy .
The pollinia may or may not have appendages . In Neottieae and Orchideae and advanced subtribes of Epidendreae , like Oncidiinae and Sarcanthinae , these appendages are present and the whole structure is called the pollen apparatus , being consistuted by the pollinia , the stipe and viscidium to caudicle , which is a tail-like prolongation of the pollinia . The stipe is of columnar derivation and is often hygrophilous . The caudicle and disc are part of the pollinial apparatus in Orchideae also . But here they are derived from the pollinium itself and are thereby morphologically distinct from the stipe and disc of the ...