Botrychium is a genus of ferns, seedless vascular plants in the family Ophioglossaceae. Botrychium species are known as moonworts. They are small, with fleshy roots, and reproduce by spores shed into the air. One part of the leaf, the trophophore, is sterile and fernlike; the other, the sporophore, is fertile and carries the clusters of sporangia or spore cases. Some species only occasionally emerge above ground and gain most of their nourishment from an association with mycorrhizal fungi.

<!-- left|frame|Moonwort (Botrychium lunaria) [messes up layout real bad. Not in Commons, so it is left here for species article] -->

Taxonomy

The Smith et al. classification of 2006, based on molecular phylogeny, placed Botrychium in Ophioglossaceae. Subsequent classifications have maintained this placement. Circumscriptions of the genus vary. The Christenhusz and Chase classification of 2014 recognizes a broadly circumscribed Botrychium.

Unassigned species:

  • (thin-leaved moonwort)
  • Botrychium farrarii <small>Legler & Popovich 2024</small>
  • Botrychium onondagense <small>Underw. 1903</small>
  • Botrychium rubellum <small>Stensvold & Farrar 2024</small>
  • Botrychium socorrense (Isla Socorro moonwort)
  • Botrychium sutchuanense <small>Chien & Chun 1959</small>
  • †Botrychium ternatopsis <small>Kuzitchkina 1960</small>
  • Botrychium tolucaense <small>Wagner & Mickel 2004</small>

Conservation

Moonworts can be found in many environments, including prairies, forests, and mountains. While some Botrychium species are quite rare, conservation efforts can be difficult. Determining the rarity of a species is complicated by the plants' small leaves, which stand only 2-10 centimeters (1 to 4 inches) above the soil. Even more of a challenge in obtaining an accurate population count is the genus's largely subterranean life cycle. The vast majority of any one population of moonworts actually exists below ground in banks consisting of several types of propagules. One type of propagule is the ungerminated spores, which must percolate through the soil beyond the reach of light in order to germinate. This presumably increases the probability that the spore will be in range of a mycorrhizal symbiont before it produces the tiny, roughly heart-shaped gametophyte, which also exists entirely below ground. Finally, some species produce gemmae, a form of asexual propagation achieved by budding of the root.

This mycorrhizal dependence has also made lab cultivation of moonworts difficult. Thus far, only germination of the gametophyte has been successful.

<!--

The only British species is the Botrychium lunaria ('moonwort'), a little plant pretty frequent in dry mountain pastures. About a dozen species occur in the United States, Botrychium lunaria ranges from Colorado to New England, Lake Superior, and sparingly northward. Botrychium simplex, a rare species, with small fronds, is found from California and Yellowstone Park to Lake Superior and eastward. Botrychium lanceolatum ranges from Colorado to Lake Superior, Ohio, New Jersey, and New England. Botrychium lunarioides is found from Massachusetts to Florida in dry, rich woods and shady pastures. Botrychium ternatum occurs throughout North America.

[this is pretty useless information, as it deals with Botrychium sensu lato, and only from a USUK perspective.]

-->

References

  • USDA Plants Profile for Botrychium (grapefern)
  • Efloras.org: Flora of North America, treatment of genus Botrychium
  • ITIS.gov: List of Botrychium species — with species links.