This weeks microscopy features Grevillea barklyana (Proteaceae), aka the gully grevillea. Endemic to Victoria, this species is critically endangered (these flowers came from a horticultural plant). Its florets are quite large- almost too big to fully capture under my microscope. They also have a really neat little surprise I wanna share with you guys…..
When you get a close look at them you may notice their pollen is bright pink, not the yellow colour that we typically think of for pollen! Pink pollen! That’s pretty dang cool, guys.
Also, if you’re like “what part of the flower is this pollen on, this isn’t an anther” you’d be right! Proteaceae has secondary pollen preseantion. Bascially, pollen dehisces from anthers onto the pollen presenter (tip of the style). So that photo above is the pollen dehisced onto the pollen presenter, waiting for a pollinator to come and grab it and carry it off to the next plant. The stigma will become receptive to pollen donation once its own pollen leaves. Anyway, back to pink pollen.
From my own dissections the pollen starts out as yellow and turns pink as the florets mature and open. This is a dissected unopened (immature) flower and the pollen is briiight yellow here. Here’s a series kind of showing the colour change from bright yellow to pink:
I’ve been meaning to capture more species with a variety of pollen colours, so it was nice finding out we had this species on campus to look at!
