Hippeastrum Anthers, a closer look.
Anthers were the sticky-up yellow powdery things that released pollen to insects and the wind. This model worked well through 40 years of science teaching. Biology was a sideshow; chemistry and the wonders of the Periodic Table was my area of expertise.
How pollen emerges from its anther is a wonder to behold. Just a pity it took seventy-plus years before I witnessed it.
I realized there was more to the anther story after watching lilies and Hippeastrum (Amaryllis) flowers. Their anthers go through several different stages. Initially, wine-red coloured grooves line each of the twin lobes that form the anther. There is no pollen visible, to begin with.
Anthers dehisce or split along a built-in line of weakness, the stomium.
Hippeastrum (Amaryllis) anthers pass through several stages as they mature.
They unzip along a line called the stomium. (coloured line)
The growing mass of pollen grains produced in the anther puts pressure on the stomium. During this stage, the anther is drying out and contracting.
The walls of the stomium bend out under pressure and contraction.
The anther lobe turns inside out over about five hours, leaving the yellow pollen grains on the outside.
Anthers are attached to their filament somewhere along their back.
Each wine-coloured groove is a stomium.
The stomium of the middle anther is opening.
Opening under pressure from the packed pollen grains, the outer edges of the anther begins to fold back.
Almost completely folded back on itself.
It takes about 5 hours before the anthers open fully.
The inner surface of the anther is now on the outside with pollen attached.
Filaments curve upwards, presenting their anthers to incoming insects.