(Mingan moonwort)
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Photo of Botrychium minganense by Mary Stensvold
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Botrychium minganense is a small moonwort fern with fan-shaped leaflets found in meadows and open soil in mountainous regions of Denali on both sides of the Alaska Range crest. The genus
Botrychium in the Ophioglossaceae family includes small perennial ferns that are divided into two parts: the
sporophore, a modified leaf bearing grape-like
sporangia, and the
trophophore, which bears the single frond. Members of this genus have undergone significant recent taxonomic revision (splitting into new species) and proper identification usually requires expertise. The
trophophore of
B. minganense is
linear to
oblong in outline, once- pinnately divided into up to 10 pairs of
pinnae.
Pinnae are cuneate to fan-shaped, and do not overlap as they do with
B. lunaria. The margins are
entire or
crenate (wavy). The basal pair of
pinnae is of equal size to the adjacent pair. The
sporophore is once-
pinnate, shorter to taller than the
trophophore, and distinctly stalked. Plants are a dull yellowish green (unlike
B. lunaria's deep green). Other
Botrychium species in Denali have
pinnatifid leaves.
Botrychium minganense is perennial yet ephemeral, usually emerging in early to mid-summer and withering soon after spore release.
Moonworts have two generations: an underground haploid lifestage (
gametophyte) and an aboveground diploid phase (
sporophyte). The underground stage is much longer-lived and is entirely dependent on
mycorrhizae for its survival. The
gametophyte typically self-fertilizes and the movement of sperm underground is highly limited. The fertilized plant produces diploid tissues, several years later this will produce an aboveground, diploid plant. The aboveground plant is a single frond, with a sterile, photosynthetic leaf and a fertile leaf, bearing spores. The single-celled spores produced are dispersed by wind, becoming buried underground and developing into new
gametophytes. Moonworts also spread asexually through propagules called gemmae which are borne typically on the underground
rhizomes.
Botrychium minganense occurs only in North America, ranging from Alaska, into all Canadian provinces, and southward into the all of the western U.S. states, the Great Lakes region and New England. In Alaska this species is most commonly found south of the Yukon River but also occurs in isolated stations in the northern Brooks Range and in Cape Krusenstern. In Denali, B. minganense occurs in the mountains and valleys on both sides of the Alaska Range.
Details are shown in the Plots & Charts found at right, depicting recent Denali data.
B. minganense is found in the park growing at elevations from 399 m to 1203 m with an average plot elevation of 919 m. It occurs more commonly on south facing slopes. It preferred moderately angled sites with an average slope angle of 17 degrees. It is generally found on steeper north-facing slopes.
Details are shown in the Plots & Charts found at right. For more on how to interpret these figures, visit Understanding Data Presented.
This species can be found in sandy to gravelly soils and was found over a relatively narrow range of pH values (4.6-6.7) that averaged 5.8.
Occurs in well drained to moist sites.
