Cystopteris bulbifera is usually easy to recognize. Well-developed
leaves tend to have long tapering tips and there are usually some
plants in any population that have the distinctive bulblets. Young
fronds have red petioles and are often sterile, but later leaves
have green petioles and are fertile. Leaves also tend to have glandular hairs, not obvious to the naked eyed, but easily seen through a good hand lens. See steps
60-64 in the key to distinguish the several species of Cystopteris.
The range in North America is from Minnesota through Ontario
to eastern Canada and south to Arkansas and South Carolina. It
is distributed widely in Wisconsin, but is most common in the
areas underlain by limestone, i.e. the southwestern counties,
the Mississippi River area and the eastern counties.
Cystopteris bulbifera commonly grows on calcareous rocks,
but in northern Wisconsin at least, it is not uncommon to find
this species growing on soil in swamps and wet, springy areas
-- more so than is suggested by the Flora of North America for
the broader range.