Let's compare their autumn colors between shirasawanum & tenuifolium.

The followings are leaves of Acer tenuifolium.

Leaves in the center began to change color.

UL : New leaves, UR : Leaves in summer, LL : Autumn color
LR : Autumn color at Mt. Chausu Nagano Pref.

The new young leaves with soft hairs not so much as those of japonicum & sieboldianum

New leaves

Pretty flowers

Comparison of flowers between shirasawanum & tenuifolium

Upper : Shirasawanum having upright flowers, Lower : tenuifolium carrying flowers

Samaras and leaves, Mt. Chausu Highlands Nagano Pref.
(Carrying flowers, but having upright samaras)

Let me show you recent images.

Firstly, autumn colors of Acer tenuifolium !

Let's show you Flowers at Chausu-yama Highlands in 2012.

Flowers and new leaves, Mt. Chausu Highlands Nagano Pref.

Flowers and new leaves, Chausu-yama Highlands Nagano Pref.

Comparison of young leaves of "Fan-like leaf maples"

Upper L : Acer japonicum, Upper R : Acer sieboldianum
Lower L : Acer shirasawanum, Lower R : Acer tenuifolium
(Conspicuous soft hairs of japonicum & sieboldianum)