I made what I thought to be an interesting discovery on the water on Dec 4 from my kayak. I found this floating fragment of Najas minor in my cove, and picked it up to take a closer look. It appears to have seeds in the leaf axils, something I have observed frequently up until now. What caught my eye though, was the translucent appearance of the seeds.
It looks as if the seeds have been released from the seed case, which has remained intact and attached to the fragment. All prior fragments examined were not observed to be translucent.
I used needles and tweezers, with a magnifying light, to open the seed case, and found both to be empty, as suspected.
It seems that the seeds remain intact on the floating fragments for quite some time. These plant fragments are not so tiny that they necessitate using a fine mesh net for the harvesting season (Aug/Sept/Oct). It seems that the seeds are only released from their casings later in the season.