The fertile brown leaflets interrupt the green, sterile ones.
This fern takes its common name (Interrupted Fern) from the way that the fertile, brown fronds often "interrupt" the green, sterile ones. This intriguing phenomenon is called frond dimorphism: the brown leaflets are loaded with spore-producing sori on their undersides, while the green leaflets are sterile and act like "normal" leaves to capture sunlight. While other ferns (like the closely related Cinnamon Fern) share this condition, Interrupted fern is unique for the way that the fertile fronds shrivel up after they drop their spores, contracting to hug the stem as a small brown mass. This gives the mature plant an "interrupted" look, with brown collars separating the green fronds.
A native of the northeastern United States, this species is ideally suited to moist, woodland soils. In partly shaded spots with evenly moist, humus-rich soil, it will thrive and naturalize over time to form dazzling drifts. Zones 4 to 8.
|Zone||4 - 8|
|PlantHeight||24 in - 3 ft|
|PlantWidth||12 in - 24 in|
|Foliage Color||Brown, Medium Green|
|Light Requirements||Part Shade|
|Moisture Requirements||Moist, well-drained|
|Soil Tolerance||Normal, loamy|
|Uses||Border, Foliage Interest, Ornamental, Outdoor, Fall Color|
|Restrictions||Canada, Guam, Hawaii, Puerto Rico, Virgin Islands|