Flora Pittsburghensis makes an important original contribution to the botanical literature. Brunnera macrophylla is recorded as naturalized in Ohio and New York, but not in Pennsylvania. We have found it, however, deep in the woods in Bird Park in Mount Lebanon, some distance from any cultivated planting.
Siberian Bugloss looks very much like a species of Forget-Me-Not (Myosotis spp.), but is easily distinguished by its large heart-shaped leaves (thus the specific name macrophylla, which means “large-leaved”). These plants grew in Bird Park in Mount Lebanon, where they were blooming at the beginning of May.
Gray does not describe this species, but the quick description above should make identification straightforward.