Plant Porn - Fern Sperm

At the beginning of the semester, one of the 1st things my students do is sow spores of various ferns and lower vascular plants upon a suitable medium. By the time the course gets to vascular plants the gametophytes, especially ferns, are just about mature. One of their instructions is to select one of the mature looking gametophytes, one a bit like this, and mount it in a drop of water
on a slide for observation. What oftens happens the less observant never even notice, but the sharper objects notice something after a few minutes. What are all those jiggly things swimming around? Then slowly comes the thought: sperm! Of course what stimulates a mature gametophyte to release sperm, water, and there you are watching the whole thing. A couple of enterprising students captured a few seconds of this on video. With literally thousands of sperms being released, any mature archegonia would surely get their eggs fertilized. Pretty darned exciting!