Botrychiums (Greek botrys, cluster) are commonly called grape ferns because of the clustered arrangement of their rounded sporangia. These ferns are avidly pursued, but not collected, in the wild by aficionados who enjoy "the find." I have joined with fellow travelers to search along several miles of trail and rejoice in spotting a patch of a dozen or so 4-in. (10-cm) high fronds. (Grazing deer have been known to annually eat the reward.) Part of the challenge is the structure of the fern itself which has one, or occasionally two, sterile fronds usually accompanied by a single fertile spike that may originate as an extension from the stipe or from below ground where it would deceptively appear to be an independent stalk. Field populations are not obvious to the casual passerby, although I will confess to once finding Botrychium multifidum on a sandy ocean side lot strictly because of the timely appearance of bright yellow, spore-laden fertile stalks.
Worldwide there are approximately 60 species primarily in North America and eastern Asia. Fleeting and frequently rare in nature, they are widely admired but not considered ornamental in the traditional fern sense, nor for that matter are they willing in the landscape. (One of their best functions is to provide an excuse for a timely social fern foray.) They are characterized by fleshy underground stems, which are dependent on a mycorrhizal (fungal) relationship to survive. Sterile blades with free veins are once-pinnate to tripinnate or more, erect to horizontal, and often with overlapping pinnae. The vascular bundle is a broad, elongate letter C, resembling a slender crescent moon. Spores germinate underground, requiring darkness and the same fungal connection as the parent. In nature it can take as long as eight years to produce a plant. Obviously they are not a practical option for home gardening unless you buy property where they are already established. (And then beware of deer and slugs.)
Historically botrychiums have a rich association with herbal cures and magical powers. The moonwort, Botrychium lunaria, with its lunate (half-moon-shaped) pinnules and once-abundant nearly worldwide distribution, was a leader in mystical powers. (Harry Potter would love it.) Specific uses included boiling the leaves in red wine to produce a concoction that would curtail bleeding and vomiting, as well as heal both internal and external wounds. More fanciful attributes based on the double "key"-shaped pinnae gave it the ability to undo locks and unshoe horses. My favorite, however, is that the fairy folks used the leaflets as their wee horses.
Botrychium biternatum (two sets of three) is native to the U.S. Southeast. Ten-inch (25-cm) fronds are triangular with two to three pairs of pinnate-pinnatifid pinnae. Fronds emerge in summer with the fertile stalk extending well beyond the tip of the sterile and withering as soon as spores are dispersed. The sterile remains wintergreen. Look for it in swampy habitats.
Botrychium dissectum (cut into deep lobes), synonym B. obliquum, is an evergreen with finely divided triangular, shiny sterile blades growing to 8 in. (20 cm). Fronds appear in the summer and often are bronzy in the fall. The fertile stalk emerges from the base of the stipe or occasionally from below ground. Two botanical forms are recognized with f. dissectum bearing incised-pointed pinnae and f. obliquum carrying smooth-lobed pinnae. They join each other in the wild in the woodlands of eastern North America.
Botrychium lanceolatum (narrow and tapering at each end, lance-shaped) is widespread in nature with deciduous populations in North America, Europe, and Asia. New growth appears in the spring and the plant disappears at the end of summer. The frond is primarily composed of a single slender stipe, usually maturing at 6 to 12 in. (15 to 30 cm), topped with a proportionately small triangular sterile blade and matching slender fertile stalk, both of which branch from the tip of the stipe. In the United States it grows in wet meadows on the northern tiers of both coasts with disjunct populations in the Rocky Mountains.
Botrychium lunaria (lunate), like other botrychiums, cannot be introduced into cultivation, but with its unique silhouette is referenced here in deference to the challenge (and potential reward) of the field search. It is a fleshy dwarf, with an annual spring output of single 2- to 6-in. (5- to 15-cm) fronds and a tendency to be camouflaged in grassy sites making it an adventure to find. Both the fertile and sterile portions of the frond, which dies down in late summer, are rigidly erect, parting near the tip of its proportionately long stipe. The fertile extends beyond the sterile. A ladder of four to seven pairs of little, pale green, moonlike overlapping pinnules on the sterile portion gives the species its name as well as an appearance similar to a double-sided key. In nature this, the most widespread of the world's botrychiums, sweeps from Alaska across Canada and down through most of the Pacific Northwest as well as New England, Eurasia, South America, Australia, and New Zealand.
Botrychium matricariifolium (leaves like Matricaria) demands a sharp-eyed hands-and-knees search to detect the 3-to maybe 6-in. (7.5- to 15-cm) fronds of this little critter of a grape fern. It also requires a timely search as the short-lived fronds usually die down by midsummer. The lanceolate to oblong sterile blade is pinnate-pinnatifid and suspended under an upright fertile stalk. The species is common in the woodlands of Europe and the northern portions of midwestern to eastern North America, with spotty populations elsewhere on the continent.
Botrychium multifidum (much divided) is a stubby winter-green species with succulent bipinnate to tripinnate, rounded sterile foliage reaching 6 to 8 in. (15 to 20 cm) with taller upright fertile stalks. It grows in exposed sandy and well-drained loamy sites in the fields of northern and upper midwestern areas of the United States and Canada with populations extending down the Rockies and the West Coast as well as New England. For assistance in the field, look for the brilliant yellow flags of fertile fronds, which appear in midsummer.
Botrychium oneidense (after the Oneida Nation, in New York) is a rare evergreen from woodlands and damp sites in eastern North America. New growth emerges in summer. The
Botrychium dissectum in the New Jersey woods.
sterile and fertile fronds part company just above the ground with the triangular bipinnate to tripinnate sterile blade extending on an outward plane and the fertile continuing upwards in the typical Botrychium structural configuration. The combined height is usually around 6 in. (15 cm).
Botrychium simplex (simple, undivided), the little grape fern, is unusual in occasionally having the sterile frond with tripartite lower pinnae. The 2- to 6-in. (5- to 15-cm) portions are fleshy, small, and once-pinnate with the lissome fertile stalk extending well beyond the sterile. This is a deciduous, circumpolar species with a quiet and sometimes seemingly hidden presence in moist woodlands. New growth occurs in early spring.
Botrychium virginianum (of Virginia), the rattlesnake fern, has an erect stipe. The horizontal sterile portion of the frond is pointed and tripinnate, or even more finely divided, with elongate lower pinnae. A solitary upright fertile stalk originates at the base of the sterile blade with the whole, sometimes reaching up to 18 in. (45 cm) tall. This is a deciduous species with new growth appearing in spring and dying in late summer. One of the most common botrychiums, it grows in moist woodlands in Canada and all but the most arid areas of the United
Botrychium dissectum in the New Jersey woods.
Botrychium lunaria. Illustration by John E. Sowerby from The Ferns of Great Britain by John E. Sowerby and Charles Johnson, London, 1855.
Fertile Botrychium multifidum stands out among the native scrub in sandy soil on the coast of Washington State.
States as well as Mexico, Central and South America, and Eurasia. Native Americans used mashed roots of the species to treat bites of poisonous snakes, hence the common name.
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