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 IS BOTRYCHIUM
MORMO (GOBLIN FERN) AT SPIRIT MOUNTAIN?
Gary B. Walton
March 23, 2001
INTRODUCTION
A rare plant survey and other botanically
oriented surveys have been completed at Spirit Mountain
and the developers are busy filing the paperwork on time
for their private project on publicly owned land. However,
I believe that these surveys did not adequately address
the entire flora of Spirit Mountain an area with a steep,
forested terrain covering about 2 square miles. Nor do
I believe that one species in particular, the Goblin Fern,
was searched for properly. The timing of the rare plant
survey was not correct for this species since it began in
May and concluded in June. Eight days were spent searching
in May and one day in June for the following rare species:
Canada Hemlock (Tsuga canadensis, Special Concern
Status), Carolina Spring Beauty (Claytonia caroliniana,
Special Concern Status), and Moschatel (Adoxa moschatellina,
Special Concern Status). These species were targeted for
surveys by the Minnesota Department of Natural Resources.
Other surveys were concerned with documenting the ecological
characteristics of the forests on Spirit Mountain. This
left little time to devote to searching for this very small
and ephemeral plant.
GOBLIN
FERN
Botrychium mormo Wagner, Jr.
(Goblin Fern, listed as a “Special Concern” species in Minnesota)
is a small (4 inches tall maximum, usually around 1.5 inches),
fleshy fern in the moonwort subgenus of the genus Botrychium
(Grapeferns), Family Ophioglossaceae (Adder’s Tongue Ferns).
The illustration to the left (from the University of Wisconsin
Herbarium website) shows just how small this plant is.
There are at least 13 different species
of moonwort ferns from the Great Lakes Region. Nationwide
about 20 or so species have been described. Several moonwort
species are rare endemics known from only a few places although
a few are widely distributed. For some species, habitat
requirements appear to be general and they may be found
in habitats as diverse as grassy meadows and cool shaded
forests. Others are more limited and appear to need specific
soil, light, and moisture conditions.
Goblin Fern is one of the rare endemic moonworts
with very strict habitat requirements. With approximately
60-70 known populations it is sparsely distributed across
northern Michigan, Wisconsin, and Minnesota. It is not
known from anywhere else but these three states. Goblin
Fern has been found exclusively in rich, moist soil of mature
and old growth sugar maple and basswood forests. When it
has been found on unforested sites it turns out that these
sites had been recently logged and that the population extended
into uncut forest. Mature and old growth sugar maple-basswood
forests exist on Spirit Mountain in Duluth, Minnesota including
the areas where a proposed golf course is being sited.
Given habitat and several other factors it is entirely possible
that Goblin Fern occurs on Spirit Mountain.
REASONS
WHY ONE SHOULD EXPECT GOBLIN FERN AT SPIRIT MOUNTAIN
1) Habitat at Spirit Mountain is similar
to habitat in places where Goblin Fern has been found before.
These sites are upland with thick leaf litter and an open
forest floor. The dominant tree species is sugar maple
with basswood. Red oak, yellow and paper birch, and quaking
aspen are also reported as important forest components.
Herbaceous species are also similar and include Spring Beauty
(Claytonia caroliniana), Bloodroot (Sanguinaria
canadensis), Bellwort (Uvularia grandiflora),
Rattlesnake Fern (Botrychium virginianum),
Starflower (Trientalis borealis), Blue Cohosh (Caulophyllum
thalictroides), Baneberry (Actaea pachypoda),
Trillium (Trillium grandiflorum), and seedlings of
sugar maple. In fact, most of the associated species found
with Spring Beauty on Spirit Mountain during the 1998 rare
plant spring survey are the same as those found with Goblin
Fern at sites in Michigan, Minnesota, and Wisconsin.
2) Spirit Mountain is situated between known
populations in Minnesota and Wisconsin. There is a rich
Goblin Fern population center in the Chippewa National Forest.
The predominate forest type is sugar maple with basswood,
aspen, birch. In Crandon, Wisconsin, it occurs in habitat
similar to that found in the Chippewa National Forest.
The one known St. Louis County, Minnesota site is also an
upland sugar maple forest. Several populations have been
found in upland sugar maple forests in Aitkin County near
the town of McGregor.
3) Weather conditions from 1997 to 1999
may not have been ideal for Goblin Fern. Low rainfall seems
to inhibit the fern from sending up shoots. Now that rainfall
has begun to approach normal levels again searches for Goblin
Fern on Spirit Mountain may be successful. In addition,
growth patterns of Goblin Fern are extremely erratic. It
may appear in abundance at a particular site one year and
seem to be completely absent another. This makes the chances
of missing this plant during a one-time-only survey very
good. Repeated surveys over two or more years are needed
to properly document its presence or absence.
More details:
Trophophore stalk 0.2--2.5 cm, usually 0.3--0.6 times length
of trophophore rachis; blade yellow-green to green, shiny,
linear to linear-spatulate, lobed (rarely 1-pinnate), to
5 × 1 cm, very succulent. Pinnae or lobes to 3 pairs, ascending,
mostly widely separated, usually fused together in distal
half of trophophore, distance between 1st and 2d pinnae
not or slightly more than between 2d and 3d pairs, extremely
variable in outline, linear to fan-shaped, undivided to
tip, margins entire to coarsely dentate, proximal pinnae
or blade tip not dentate or with 2--3 shallow, broad teeth,
apex angular, venation like ribs of fan, midrib absent.
Sporophores 1-pinnate, 0.2--3 cm, 0.2--3.5 times length
of trophophore. 2 n =90. The highly seasonal appearance
of Botrychium mormo is more like a fungus carpophore than
a moonwort. In wet years both mature and juvenile plants
are fairly easy to find in known localities; in dry years
they do not appear aboveground. Botrychium mormo may be
eaten and dispersed by animals. The succulent nature of
the whole plant may make it attractive to herbivores, and
because the sporangia do not open, passage through animal
digestive tracts may be required to facilitate the release
of the spores. Another unusual feature of B . mormo is the
tendency for gametophytes to persist on mature sporophytes.
Leaves appearing in late spring to fall. Extremely sporadic,
in rich northern basswood, beech, sugar maple forest; of
conservation concern; 300--600 m; Mich., Minn., Wis.
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