Hello,

I have found that the floater method to determine seed viabilty to be unreliable, because although many seeds that hydate will usually(!) sink after taking in water,there are some healthy seeds with hard coats that may not hydrate completely or otherwise remain floating due to membrane-like air chambers built into the seeds...

The floater test may cause the lightest/emptiest and most unviable seed to float along with some delayed hydrating viable seed...it does not reliably filter out viable seed(s) from unviable and I disreccomend it,especially for rare/valuable seeds due to the inaccuracies of the test...

Although it is true that seeds that are extremely underdeveloped,mouldy or otherwise dead will usually float,I have found many viable seeds containing air trapped inside of the seed someplace which will cause the seed(s) to float...in point of fact,many Convolvulaceae seeds are known to be labyrinth type seeds that develop air chambers to cause the seeds to float on the surface of water(s) to facilitate the wider dispersal of the seed(s) from rain,flood or other water sources...

There are many species in Convolvulaceae that are not officially classified as labyrinth seeds,but sometimes a portion of a population will produce some healthy 'floaters' as an extra insurance policy to insure seed dispersal over a wider geographic area via any possible available water transport...

Additionally,some seeds that are in a deeper state of dormancy may not initially fully hydrate and a portion of these dormant seeds may continue to float,until they are ready to more fully hydrate and sprout at a later time...

TTY,...

Ron

Thanks, Ron! I'll remember this for the future.
:0) Phyl