Moonworts (Botrychium)

Eleven species of Moonworts (Botrychium) have been recorded from Michigan. They are small ferns and the distinctions between the species are subtle. This post shows specimens of each species. The specimens with a black background were collected by my wife and I and the identifications were verified by Dr. Warren (Herb) Wagner.  Herb used different names for some of the taxa, but the identifications remain the same. I used these study collections for years and photographed them before I give them to the University of Michigan Herbarium. The specimens with the white backgrounds are collections from the Herbarium. I hope that these will help botanists studying this fascinating group.

Daniel Palmer’s Michigan Ferns & Lycophytes should be consulted by anyone interested in this genus. His charts are fantastic and help explain the characteristics of the species. I cannot improve on his species descriptions. Dr Donald Farrar from the Ada Hayden Herbarium has information on Moonworts including species found outside of Michigan. My earlier post gives more information about Moonwort habitats.

Helpful terms for identification

I seldom use common names for Moonworts. I had to look them up for this blog. In the field we refer to them by their specific names or shortened specific names. For example, “I found Matricary, Simplex, and Campestre.”

Lance-leaved Moonwort

Lance-leaved Moonwort (Botrychium angustisegmentum) has a triangular, deep green, sessile, trophophore (sterile segment). The teeth on its segments are pointed.

Daisy-leaved Moonwort
Daisy-leaved Moonwort
Daisy-leaved Moonwort

Daisy-leaved Moonwort (B. matricariifolium) is a highly variable species and probably still needs to be split into additional species. When I first met Herb in 1975 he shared with me his goal of learning the limits of this species. Its trophophore is always stalked, has blunt teeth, and the basal pinnae are not normally larger than the next pair.

Michigan Moonwort
Michigan Moonwort

Michigan Moonwort (B. michiganense) resembles Daisy-leaved Moonwort except the basal pinnae on the trophophore are elongated. See Palmer’s book for further distinctions.

Dune Moonwort
Dune Moonwort

Dune Moonwort (B. campestre) is our earliest Moonwort. I have found it limp on the ground, its spores shed, while other species are still developing. It is greenish-yellow and the pinna (divisions of the trophophore) have teeth at their tips.

Least Moonwort

In Least Moonwort (B. simplex) the trophophore and sporophore split off near the base of the plant. The trophophore is the least divided of the Moonworts.

New World Moonwort
New World Moonwort

New World Moonwort (B. neolunaria) has crescent shaped pinnae nearly straight across its base and that almost overlap each other.

Mingan Moonwort
Mingan Moonwort
Mingan Moonwort

Mingan Moonwort (B. minganense) has pinna that angle about 120 degrees at their base and are well spaced. We found some large specimens with divided pinna in the eastern Upper Peninsula that we originally thought were a new species.

Pale Moonwort

Pale Moonwort (B. pallidum) is distinct in the field with its blue-green color. It is seldom taller than 5 cm [2 inches] and normally has fewer than 5 pinna pairs. The base of the pinna is angled at about 90 degrees.

Spatulate Moonwort
Spatulate Moonwort

Spatulate Moonwort (B. spathulatum) has pinna that are cupped and not flat. Carelessly pressed specimens often have folded pinna. Normally the pinna have rounded teeth.

Little Goblin

The Little Goblin (B. mormo) is a dense woodland species. It grows in leaf litter and sometimes the plants develop under the leaves. I have found plants by carefully lifting the leaf litter. They are the most succulent of the Moonworts. The first-time I saw the Little Goblin, Bob Preston and I crawled the Sable Falls trail, on our hands and knees, in the pouring rain, looking through the leaf litter. It took us several hours to cover the half-mile trail. We found the plants on the way out.

Shade-loving Moonwort

Shade-loving Moonwort (B. tenebrosum) is similar to the Little Goblin. Shade-loving Moonwort is an open forest species often growing at the edge of a wetland. The trophophore and sporophore split at least half-way up the plant.

I hope this post is helpful to fellow “Botrychiators.” When I first learned Michigan Moonworts there were five highly variable species. I learned the others gradually as we split them off. The group is challenging both to find and then to identify. Good luck and happy botrychiating.

 
Copyright 2020 by Donald Drife

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Moonworts

Botrychium matricariifolium

Moonwort habitat – L                                                             Daisy-leaved Moonwort – R

Moonworts or Grape Ferns are small ferns. Most are less than 10cm [4 inches] tall. Herb Wagner called them “belly plants.” They have a vegetative blade, called a trophophore, and a separate fertile segment, called a sporophore. Sporophores resemble tiny clusters of grapes hence the common name. Characteristics of the vegetative blade help to distinguish the species. As you learn the plants other subtle features become apparent such as the color of the plant, timing of spore dispersal, and branching of the fertile segment. The Michigan Flora website has a workable key and range maps. Another great resource is Dr. Farrar’s work found on the Ada Hayden Herbarium website. This site includes species treatments of all of our Moonworts.

Moonworts grow along stable sand dunes or in fields that have had mild disturbances. I find them growing under Wild Black Cherry (Prunus serotina) or Apple (Malus spp.) trees with Poison Ivy (Toxicodendron spp), Sheep Sorrel (Rumex acetosella), Hawkweed (Hieracium spp.), or Wild Strawberry (Fragaria spp.). These habitats are not where most botanists look for native ferns. They also grow along stream banks and along deer paths and old dirt roads through woods. The plants cannot withstand competition from other vegetation and require some type of minor disturbance in order to survive.

Botrychium-matricariifolium

Daisy-leaved Moonwort             (Botrychium matricariifolium)

When I began studying this genus there were five species known from Michigan. Now there are eleven species and perhaps one more still unnamed.

Botrychium simplex

Least Moonwort   (B. simplex)

I recently visited a colony that once had seven different species but now could only find Daisy-leaved Moonwort (Botrychium matricariifolium) and Least Moonwort (B. simplex). Dense grass moved into this old orchard choking out Moonworts. At one time there were 15,000 individuals in this colony. Now there are no more than 500 plants. The National Guard used this field for helicopter gunship firing which tore up the sod slightly, allowing the plants to flourish. After we discovered two threatened Moonworts species, Michigan Moonwort (B. michiganense), and Prairie Moonwort (B. campestre), the Guard discontinued firing to “protect” the area. Currently the sod is too dense and Moonworts are dying out.

Botrychium minganense

Mingan Moonwort                       (B. minganense)

In the 1990s we discovered a colony of 20,000-30,000 Moonworts along ten miles of forest service road in the Upper Peninsula. We visited the area in 2003 and noticed that the road shoulders were growing up. Last weekend we found about fifty plants of four species, Daisy-leaved Moonwort,  Moonwort (B. neolunaria), Mingan Moonwort (B. minganense), and Spatulate Moonwort (B. spathulatum) along the road. Plants occurred mostly on sandbanks kept a little raw by erosion. Lumbering is not happening in the area so road grading is not disturbing the road shoulders and keeping them open.

Botrychium neolunaria

Moonwort               (B. neolunaria)

Moonworts are more difficult to find now than they were 25-years ago. Tony Reznicek stated that Michigan’s open areas are growing up. I believe he is correct.

For such an inconspicuous plant a great deal of lore surrounds it. If you place a Moonwort into a box and leave it overnight it will produce silver. Herb and I tried it and it did not work. Herb said it would have been easier than getting National Science Foundation grants.  Moonwort opens any lock that its spores are placed into. If a horse walks over a plant it will throw a shoe. It is also an ingredient in several love potions.

June and July are the best months for hunting Moonworts. Most species disperse their spores and  wither away before August. Get out and look for plants. They might be difficult to identify to species but they are still fun to find.

 

Copyright 2017 by Donald Drife

Webpage Michigan Nature Guy
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