5-5.5 mm long, ca.1.8 mm wide, formed by 2 subclavate, longitudinally cleft, cream-yellow pollinia; viscidium ventral, apical, sheathing the apex of the rostellum, oblong-lanceolate, obtuse, grey, keeled, ca.
Upon removal of whole pollinarium by a pollinator the pollinia may change their angle of orientation as the caudicles and/or stipes dry out and change positions (see also, Darwin, 1877).
Floral architecture and floral dimensions limited the number of visiting animals that functioned as legitimate pollinators as the pollinium or pollinarium was fixed specifically to the part of the vector's body that contacted the receptive stigma when it visited a second flower on a second plant of the same species.
 Barba, GL., and Semir, J., 1999, "Temporal variation in pollinarium
size after its removal in species of Bulbophyllum: a different mechanism preventing selfpollination in Orchidaceae", Plant.
The 1-millimeter-long fragment of a pollen-bearing structure, or pollinarium, rests on the back of a stingless bee that became trapped in amber about 15 million to 20 million years ago.
Because the pollinarium fragment appears to be stuck in the middle of the bee's back, the researchers speculate that the insect had to crawl into the orchid's flower to pollinate it.
The time elapsed before a freshly withdrawn pollinarium
is in the correct position to strike the stigma was found to vary 30-80 s, depending on the orchid species.
Invertebrate House and Pollinarium
, National Zoological Park; Washington, DC.
is removed from the flower when an insect body part catches in the groove of the corpusculum (Wyatt 1978).
As in the Asclepiadoideae, the pollinarium
consists of a corpuscle and pollinia.
For example, among some orchids the precise placement and impressive adherence of pollinaria on visitors' bodies (e.g., van der Pijl and Dodson 1966, Ackerman 1981, Dressler 1981) usually minimize "interspecific pollinarium
transfer" even when pollinators rub against other floral structures.
formed by two ellipsoid, yellow and longitudinally sulcate pollinia; stipe laminar, narrowly triangular, united to an ovoid viscidium.