北方阴地蕨 bei fang yin di jue

Rhizomes suberect, shortly cylindrical, annually producing 1 frond 5-10 cm tall. Common stipe 3-8 cm. Sterile lamina sessile or nearly so, lamina 2-pinnate at base, pinnate above, shiny, green, ovate-deltoid, 1-4 × 1-3 cm, fleshy, base cordate; pinnae 3-5 pairs, ascending, mostly overlapping; basal pinnae largest, ovate, up to 2 cm wide, base subtruncate, apex obtuse; upper pinnae and segments of basal pinnae elliptic, up to 5 mm wide; veins free. Sporophore arising at or near top of common stipe, with stalk 1.5-5 cm, 2-pinnate. Spore surface verrucose. 2n = 180.

Forests; ca. 1000 m. Nei Mongol [Japan, Korea; N Europe, North America (Greenland)].

According to reviewer Don Farrar, North American authors recognize three species from within the original concept of Botrychium boreale: B. boreale s.s. in Europe and B. pinnatum H. St. John and B. alaskense W. H. Wagner & J. R. Grant in North America, including Alaska and the Aleutian Islands. The correct placement of Asian material has not yet been critically examined but could prove to belong to one or other of the American species rather than B. boreale s.s.