(This is a follow-up to this identification question).
How can one distinguish between Elaeagnus umbellata and E. multiflora?
I see some minor differences in the descriptions e.g. on Wikipedia, but I'm not sure which differences are definitive.
I was convinced by the first answer that I have an umbellata, but when the second answer arrived I realized that I have no clue how to be sure which is which.
I usually distinguish between them by the drupes. There is some overlap here, but less than there is on leaf size, width, color etc. The fruits (drupes) are usually more consistent. Elaeagnus umbellata has darker, rounder fruit on a shorter stem. Elaeagnus multiflora has slightly elongated, slightly more orangish fruits hanging from longer stems. Fruit size is variable. See comparison pictures below.
Left: Berries of Elaeagnus umbellata. Right: Berries of Elaeagnus multiflora.
From this picture on your previous question, I believe the plant you have is Elaeagnus umbellata, as suggested in this accepted answer (vote given).
