Cystopteris bulbifera

Bulblet fern
Cystopteris bulbifera in bottomland forest in Shades State Park, Indiana
Scientific classification
Kingdom:	Plantae
Division:	Pteridophyta
Class:	Pteridopsida
Order:	Athyriales
Family:	Cystopteridaceae
Genus:	Cystopteris
Species:	C. bulbifera
Binomial name
Cystopteris bulbifera (L.) Bernh.
Synonyms
Filix bulbifera (L.) Underw.

Cystopteris bulbifera (bulblet bladderfern) is a low-growing rock fern with creeping stems and narrow elongate deltate fronds which grow to 75 cm (30 in), native to eastern North America with two disjunct populations in the west. It is found only on calcareous substrates such as limestone. It commonly festoons limestone cave openings. While most commonly found on vertical rock faces, it also grows in rocky scree. C. bulbifera is unusual among ferns in producing bulblets along the bottom of the fronds. This is one of the easiest Cystopteris species to identify.

Closeup of bulblet

This species is known to hybridize with Cystopteris fragilis, Cystopteris protrusa, Cystopteris reevesiana, and Cystopteris tenuis. Hybrids with C. fragilis have given rise to the allohexaploid species C. laurentiana. Hybrids with C. protrusa have given rise to the allotetraploid species C. tennesseensis. The hybrid with C. reevesiana has given rise to the allotetraploid species C. utahensis. The hybrid with C. tenuis is known as C. Xillinoensis, an allotriploid. Also see Cystopteris hybrid complex.

External links

• Flora of North America — distribution map
• USDA plant profile
• Connecticut Botanical Society

Further reading

Cobb, Boughton. (1984). A Field Guide to Ferns and their Related Families of Northeastern and Central North America. Peterson Field Guides.