Cystopteris laurentiana is similar to C. bulbifera,
but differs in having only sparse glandular hairs on the blades,
bulblets are rare or absent and the stipe is not red in young
fronds. It is believed to have arisen as a hybrid of C. bulbifera
and C. fragilis.
C. laurentiana has a very restricted distrubution in North
America. It occurs chiefly in the western Great lakes area and
in scattered locations in the northeastern U.S. and Canada. It
is most common on limestone cliffs. It is very local in Wisconsin,
known mainly from Door County and the Lake Superior region. It
is listed as a "special concern" species.