Bogs and Acidic Peatlands of Southern New England by Marsha C. Salett
Taxonomy
Osmunda claytoniana L.
OSMUNDACEAE (Royal Fern Family)
EtymologyOsmunda, possibly after the Saxon god, Osmunder, the Waterman; claytoniana is named for the American botanist, John Clayton (1686-1773), a contemporary of Linnaeus.
DescriptionInterrupted fern is a twice-cut -- or bipinnate -- fern that gets its name from the growth pattern of its fertile leaflets. They occur in the middle of the fertile frond between rows of sterile leaflets. Interrupted fern's sterile fronds and growth habit are similar to those of cinnamon fern. Interrupted fern is large, often growing in dense clusters to 4' tall.
Wetland indicator statusFACU
Plant Height1-5 feet
LeavesSterile and fertile fronds different; both twice-cut, lanceolate. Sterile frond: arching, shorter than fertile fronds, dull green; with 18-20 pairs of pinnate leaflets (pinnae) that are alternate or not quite opposite; base of mature leaflets and stem are smooth. Fertile frond: 2-4' tall, dull green; both sterile and fertile parts on same frond; 4 or more pairs of fertile, sporangia-bearing pinnae in middle of blade with several pairs of sterile pinnae above and below; dark green, turning brown.
Fruiting PeriodMay-July.
HabitatMoist woods, margins and hummocks of swamps.
RangeNewfoundland to Ontario and Minnesota; south to Georgia, Tennessee, and Arkansas.
(c) 1998-2006 Marsha C. Salett