Calotropis commonly called as Ak in native language is a milkweed because of the milky latex produced. Calotropis is a common weed found abundantly in North India. The peculiar thing about its pollen grains is the formation of Pollinia.
Using a foldscope I could easily observe and understand the structure of a pollinium. From a Calotropis flower, I firstly removed its Gynostegium (the stigmatic disc) and then gently separatedthe pollinia from the edges of the pentangular disc and mounted them on a slide to observe though a foldscope.
A pollinium is a hard sac-like definite structure formed from a mass of pollen grains agglutinated within one anther. These are transferred during pollination as a single unit. This is commonly referred to as –Translator. In Calotropis it is seen that each translator consists of two parts:
- A pair of arms – Caudicles
The corpusculum attaches to the margins of stigma disc between the anthers and the pair of arms is attached to the pollinia of the adjacent anther