There are several species of Grape Ferns in the Northeast, all of which are true ferns, but they are not closely related to the plants we generally think of as ferns. Like other ferns, Grape Ferns do not have flowers; they reproduce with spores, not seeds. A single stalk divides into two blades – one of which is sterile and does the photosynthesizing, and one of which is fertile and bears spores. It is the resemblance of this plant’s clusters of spore-bearing sporangia to miniature clusters of grapes that gives this group of ferns its name.
Cut-leaved Grape Fern, Sceptridium dissectum, is one of the most common species of Grape Ferns in the Northeast. It is often found on disturbed land, is roughly 6” to 8” tall, and has an evergreen sterile frond that appears in July, turns bronze in the fall and dies back in May. The fertile frond has branched clusters of yellow sporangia containing spores which mature at this time of year.
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There is a group of evolutionarily ancient ferns referred to as “Grape Ferns.” Although they are true ferns, they are only distantly related to the ferns growing today. They derive their common name from the resemblance of their (spore-producing) sporangia to a bunch of tiny grapes. Grape Ferns have two blades. One is sterile and does the photosynthesizing; the other is fertile and bears the grape-like sporangia.
Different species of Grape Fern mature at different times during the summer. Leathery Grape Fern (B. multifidum; Sceptridium multifidum) is the largest of the Grape Ferns. Its triangular, sterile blade is very leathery and fleshy. If the fern is growing in full sun, the stalk of the sterile blade is usually quite short, and the branching, fertile blade rises above it. The spores on the fertile blade mature in late summer or early fall.