The pollen spores are usually aggregated into two or four waxy masses ( "pollinia," sing. pollinium), which usually can only be removed by the agency of insects upon which all but a very few orchids are absolutely dependent for the pollination of the flowers.    From Wordnik.com.  [Elements of Structural and Systematic Botany For High Schools and Elementary College Courses] Reference

In this latter case we have a pollinium in its most highly developed and perfect condition.    From Wordnik.com.  [VII. Miscellaneous Objections to the Theory of Natural Selection] Reference

Each pollinium consists of two leaves of pollen united for about half their length in the middle with elastic threads.    From Wordnik.com.  [Wild Flowers Worth Knowing] Reference

A pollinium when highly developed consists of a mass of pollen-grains, affixed to an elastic footstalk or caudicle, and this to a little mass of extremely viscid matter.    From Wordnik.com.  [VII. Miscellaneous Objections to the Theory of Natural Selection] Reference

These I attempted to fertilise, but with two only of the six have I been successful: I succeeded in forcing a single pollen-mass into the stigmatic chamber of one of the latter, but I failed to do this on the other; however, by inserting a portion of a pedicel with a pollinium attached, I caused the latter to adhere, with a gentle press, to the mouth of the stigmatic chamber.    From Wordnik.com.  [More Letters of Charles Darwin — Volume 2] Reference

He who will carefully examine the flowers of orchids for himself will not deny the existence of the above series of gradations—from a mass of pollen-grains merely tied together by threads, with the stigma differing but little from that of an ordinary flower, to a highly complex pollinium, admirably adapted for transportal by insects; nor will he deny that all the gradations in the several species are admirably adapted in relation to the general structure of each flower for its fertilisation by different insects.    From Wordnik.com.  [VII. Miscellaneous Objections to the Theory of Natural Selection] Reference