Here are a few more flower images from Acton Arboretum. I was equipped with an Olympus E-M1 and 40-150mm F4 zoom.  All photos were taken at F4 and a focal range of 122-150mm (244-300 full frame equivalent). ISO ranged from base ISO 200 to ISO 800. 

Bee Balm
Bee Balm

Flowering Raspberry Flowering Raspberry

Lamb's Ear and Bumble Bee
Bumble Bee on Lambs-Ear Plant

Lamb's Ear and Bumble Bee
Bumble Bee in Flight

Soapweed
Wild Sweet William a.k.a. Soapwort

Round-headed garlic
Round-Headed Garlis

Lathyrusalso known as peavines or vetchlings.
Lathyrus

Flowering Raspberry
Flowering Raspberry and Buds