Botrychium lineare

The close relationship of Botrychium lineare to B. campestre has been suggested since its original description (Wagner & Wagner, 1994). Genetic studies indicate that 'lineare' is best treated as an infraspecific taxon of B. campestre and the published name by Farrar and Gilman (2017) is Botrychium campestre var. lineare. The Colorado Flora (2012) refer to this taxon as Botrychium campestre ssp. lineare.

Botrychium lineare or B. campestre var. lineare var. ined. is one of several moonworts with a large range, but with sporadically occurring, widely separated, and extremely small populations. The total number of individuals so far observed throughout North America is very low, several hundred at most. However, the species is difficult to survey for, and can exist below ground for most of its life cycle. Botrychium lineare is currently known from about 50 widely disjunct sites, primarily in the mountains of western North America, including Alaska, Yukon Territory, British Columbia, Alberta, Washington, Oregon, Montana, California, Wyoming, South Dakota, Colorado, and Utah; possibly found in Nevada; historical in Idaho. In addition, a site has recently been found in Minnesota and western Quebec, and historical collections are known from eastern Quebec and New Brunswick.

Widely spread but very spotty distribution, primarily in the mountains of western North America. It has apparently not been confirmed extant in eastern North America since 1947, when it was last collected in Quebec (also historically known from New Brunswick) (Farrar 2006). A site in Minnesota has recently (2005) been documented as well as a site in western Quebec (Farrar 2011). Believed extant in Alaska, Yukon Territory, British Columbia, Alberta, Washington, Oregon, Montana, California, Wyoming, South Dakota, and Colorado; likely extant in Utah; possibly found in Nevada; historical in Idaho. Farrar (2006) believes that there may be "additional occurrences throughout the mountains of western Canada where it has not heretofore been sought" and that "recent documentation in SD and WY along with other eastern species supports possible continued existence of the species in other eastern sites." These same comments were supported in Farrar (2011), and overall that undetected populations probably exist in these places.

Historically known from 34 sites; only 16-19 of these are thought to be extant (Farrar 2006). Limited monitoring and survey efforts continue to locate some new populations (USFWS 2003); for example, sites in Wyoming and the Black Hills of South Dakota are among those recently documented (Farrar 2006). Further, intensive survey efforts since 2006, have resulted in documentation of over 51 sites and 17 metapopulations. Undoubtedly more sites are present, but the taxon remains relatively uncommon compared to the five most common moonworts (Popovich pers comm. 2014).

Some threats to Botrychium lineare may exist from road maintenance activities and other disturbances at several sites, by invasive exotic plants at three sites, and possibly by livestock grazing at some sites; however, the species may tolerate some disturbance since it appears to be a habitat generalist and is found in disturbed habitats (USFWS 2003, 2004). Also, this fern's small, highly disjunct populations leave it vulnerable to loss due to stochastic natural phenomena.