9b. Equisetum variegatum subsp. alaskanum (A. A. Eaton) Hultén, Acta Univ. Lund. 2. 37(1): 59. 1941.
阿拉斯加木贼 a la si jia mu zei
Equisetum variegatum var. alaskanum A. A. Eaton in Merriam, Harriman Alaska Exped. 5: 390. 1904; E. alaskanum (A. A. Eaton) J. P. Anderson; Hippochaete hyemalis (Linnaeus) Milde ex Bruhin var. alaskana (A. A. Eaton) Farwell; H. variegata subsp. alaskana (A. A. Eaton) koda.
Plants small to medium-sized. Rhizome erect and creeping, blackish brown, nodes and roots with long yellowish brown trichomes. Aerial stem perennial, monomorphic, green, 15-20 cm tall, 1.2-1.5 mm in diam. at middle, not branched; internodes 2-4 cm. Aerial stem 6-8-ridged, ridge abaxially nearly rectangular or arc-shaped, middle portion with or without shallow grooves, with 1 row of tubercles on each side; sheath ca. 0.2 cm, green but distal and middle portion with a blackish brown band; sheath teeth 6-8, recurved, deltoid, ca. 0.1 cm, teeth of middle portion blackish brown, black at margin, membranous, abaxially with 4 longitudinal ridges at base, apex acute and shortly aristate, persistent. Strobilus ellipsoid, 0.6-0.8 cm, 0.2-0.4 cm in diam., apex with acute tip, sessile.
Meadows; ca. 100 m. Liaoning [NW North America (including Aleutian Islands)].