Hi, I had found an Acer palmatum dissectum red with strange samaras. Indeed, the wings form an angle >180°, like a butterfly. I also observed that the cultivar Asahi zuru have rounded samaras with a wing very short. Shishigashira have tiny samaras. So I wonder to know if the form and the size of samaras is a criterium when you name a cultivar? And if not, could this criterium be use, in addition with the leaves form, the shape, the color... And can my strange samaras be the result of an open pollination with other species of the section palmata? Maybe nobody have the answer but I'm a curious guy. I always want to know everything :)
That is an interesting question. I don't think the size and form of the samaras is generally used as a criterion when naming cultivars, but I believe the same developmental abnormalities affecting the leaves and growth habit that make the cultivar worth naming can also affect the development of the samaras. For example you mentioned Shishigashira has tiny samaras; this is most likely a side-effect of the same deletions or additions to the genetic code that cause the small crinkled leaves and short internodes of this cultivar. My take on this is no. The samara is part of the fruit and the genetic code of the male pollen donor only affects the seed which resides within the fruit. I can see how the genetic quality of the pollen could affect the number of seeds set, and maybe even the weight of the individual seeds, but it is hard to see how this would affect the shape and size of the samaras. I give the example of the tomato and sweetcorn. When considering tomato plants the fruit characteristics such as flesh colour, size, shape are not affected by the pollen donor, and you will only know if your tomato is crossed when you grow out the seeds and see what results. Sweetcorn on the other hand displays the actual seeds within the ear of corn, and the colour, flavour and sweetness of the corn will depend on the pollen donor because you are eating the seed rather than the fruit. If an ear of corn is pollinated by multiple donors of different characteristics it can display kernels of multiple colours in the same ear. Also, I suspect environmental conditions at time of early development of the fruits can have an effect on eventual samara size and shape. I would be interested to hear other people's take on these questions too.
@maf thank you for your answer. When I was talking about an open pollination I was thinking about the parents of the cultivar I've seen with strange samaras.
Ah yes, of course the pollen parent could affect the shape in that case. I mistakenly thought you were talking about possible open pollination that made the seed with the strange samaras. Again I think changes in the samara shape or size would be linked to mutations that affect leaf shape/size/lobes/dissection or internode length.
Unfertilised samaras (samaras where the seed has not developed: thin, lightweight, flexible seed that on cutting open show no embryo or cotyledons) are frequently mis-shapen. Quite possible that some cultivars are always sterile, others may only develop occasional viable seeds. Oddly-shaped samaras with viable (plump, filled) seeds are more worthy of investigation though.
