1) What is the difference between bursicles and viscidium ?
2) What is the singular of 'Theca' that pouch-like structure covering the pollinia
3) Does the rostellum have any function in pollination or it is just a structural platform
4) Are the stigma usually located at the back of the flower, behind the stamenoid column in Orchis and the floor of the labellum (stigmatic cavity) in Ophrys?
Thanks