Common Name: FRAGILE FERN FAMILY
Habit: Perennial herb in soil on rock crevices; rhizome short- to long-creeping. Leaf: spirally arranged, short-spaced or distant, 5--40 cm, +- alike; stipe firm or fleshy, with 2 vascular strands, often expanded at base ("trophopods"); blade 2--3-pinnate-pinnately lobed, thin-herbaceous, broadest at the base or lanceolate, veins free, extending to leaf margin. Sporangia: sori round, with hood-like indusium arching over sorus [naked (Gymnocarpium)].
Genera In Family: 3 genera, +- 37 species: Cystopteris and Gymnocarpium widespread north-temperate (Cystopteris south through Andes, Africa, Australia, New Zealand); Acystopteris southeast Asia (Rothfels et al. 2013 Syst Bot 38:295--306). Note: Polyploidy, often accompanied by hybridization (allopolyploidy), common; many widespread species represent complexes of allopolyploid lineages (Rothfels et al. 2014 Taxon 63:1026--1036; Rothfels et al. 2016 New Phytol in press). Outlying (sister) family to remainder of the large eupolypods II clade (suborder Aspleniineae; Pteridophyte Phyogeny Group 2016 J Syst Evol in press); only distantly related to Woodsiaceae, where often included (Smith et al. 2016 Taxon 55:705--731).
eFlora Treatment Author: Carl J. Rothfels & Alan R. Smith
Scientific Editor: Bruce G. Baldwin & Thomas J. Rosatti.

Common Name: FRAGILE FERN
Habit: Rhizome generally short-creeping. Leaf: stipe +- fleshy, often with few scales, base ×-section with 2 vascular strands; blade 2--3-pinnate, pinnae sides unequal, acroscopic pinnules more spreading, larger, more incised; veins free and extending to leaf margin. Sporangia: sori round; indusia hood-like, arched over sorus, attached on side away from margin, often obscure in mature sori.
Etymology: (Greek: bladder fern, from indusia) Note: Often confused with Woodsia (pinnae sides equal; more fragmented indusia encircling sorus base; veins ending before leaf margin). Species limits, especially in the Cystopteris fragilis complex (sensu Rothfels et al. 2013 Syst Bot 38:295--306), obscured by hybridization and polyploidy (Rothfels et al. 2014 Taxon 63:1026--1036; Rothfels et al. 2016 New Phytol in press).
eFlora Treatment Author: Carl J. Rothfels & Alan R. Smith