I'm collecting cones of mountain pine (P. uncinata) for propagation. These are young trees, ranging from 4 to 10 feet tall. Some of the cones are quite small, about 2 cm long. The largest are about 6 cm long. I expect there to be substantial size variation in the seeds, once the cones open. Both smaller seeds, and more seeds that aren't filled. In general will the seeds from smaller cones not work as well for propagation? At this point I have about 8 liters of cones -- probably about 400 cones total. So I expect to get a few thousand seeds. So my options at this point: * Ignore the differences. Treat the cones as one batch. Smaller seeds will tend be separated out with the sir sorter and float test. * presort the cones by size into 3-4 groups. Process each grouop separately. See what happens. Do it well, and report back here. This involves a bunch of extra book keeping. Intent at this point is to plant this fall N seeds per cell into 412 styroblocks, protect from rodents, but otherwise leave outside.
I'd be inclined to discard all the small cones, under about 3.5 or 4 cm long, it's not likely you'll get any viable seed from them.
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I'd be interested in anything size-related you can find out. Last year I bought seeds of P. coulteri, which were two distinct sizes. All the larger germinated, and the smaller did not. However, I did muddy the waters by stratifying them differently. Not sure why I did that! Didn't write anything down. Ha. Also, if anyone knows anything about viability of "sinkers" vs. "floaters" I'd like to know. I have some pine and hickory seeds soaking right now.
Can you remember the sizes of them? Wondering if perhaps the two sizes could have actually been two different species? But note I was referring to the sizes of the cones the seeds came from, not the seeds themselves (which generally don't vary significantly within a species).
I actually still have the smaller ones, I dug them back out of the pots after I gave up on them sprouting. I was going to dissect a couple but never got around to it. The viable seeds were the same colour and finish, but about double in mass. The OP mentioned smaller seeds being sorted out. The one I just crudely dissected looks fine inside, so I'll give them another try.
In general the floaters are either hollow shells either becasue the embryo never filled it, or some critter hollowed it out for you. This is botany. I'm sure there are eceptions. You can test this by trying to sprout the floaters. Caution: SOME seeds have bristly coats that trap air bubbles. You get false floaters from these. a few drops of Dawn dish soap or Jet Dry may help. All bets are off on seeds that use water dispersal. e.g. they float to their new home. Seeds need to be dewinged, and de-fluffed first. One of the tricks you find in seed sorting books is various solution mixes to change the density of the liquid. Alcohol is a common one (About 20% lighter than water) There are lots of potential solutions. Lot of them are poisonous to you, flamable, explosive, toxic to the plant, or all 4
I will get out the camera and take some pics of seeds. Seeds vary a LOT even from the same tree. Overall, a variation of about 3:1 in seedwing size. Even within a single cone, there is substanial variation. On P. ponderosa as a rule the seeds from near the distal end (farthest from the root) of the cone tend to be larger than from the proximal (stem) end.
Thanks! Not sure what those are, but they're definitely not pine seeds of any species! Pine seeds are perfectly oval, without any of the "lumpy" outline those seeds have. Pic of some (with their wings still on) here: https://www.flickr.com/photos/vanaspati/6320566326 Can you post a photo of the seedlings you have got from the larger seeds?
That's not been my experience, as long as you exclude obvious unpollinated (undeveloped) seeds - the small individual in the link photo in the previous post, with the 5 good seeds all the same size. It'll be interesting to see your pics!
