Acer palmatum
Koshimino has a sessilifolium leaf structure, meaning the leaves attach directly to the stem with little to no petiole. In addition, each lobe is split to the vestigial petiole, giving a feathery look. Koshimino is typically regarded as more vigorous than Hagoromo, and I would say that is relatively true. Both make beautiful small trees, with Hagoromo being shrubbier.