What are the factors affecting acorn size and shape? Can a single tree make varied sizes/shapes? If so, why

The size and shape of the acorn depends on the specie. Since each acorn tree is one single specie each acorn on that tree will be relatively the same shape and size.

Acorns vary from 1 – 6 cm long and 0.8 – 4 cm broad. Acorns take between about 6 or 24 months (depending on the species) to mature.

For example, the acorns on a Quercus Alba are between 12-25 mm long. Click on the link below to see the different acorn specie and find the characteristics you need for your acorn.

http://en.wikipedia.org/wiki/List_of_Quercus_speci...