林木贼 lin mu zei

Equisetum capillare Hoffmann; E. sylvaticum var. capillare (Hoffmann) Milde; E. sylvaticum f. multiramosum Fernald; E. sylvaticum var. multiramosum (Fernald) Wherry.

Plants large or medium-sized. Rhizome erect or creeping, blackish brown, nodes and roots with sparse long yellowish brown trichomes or glabrous. Aerial stem annual, dimorphic, fertile and sterile stems appearing simultaneously. Fertile stems reddish brown, sometimes straw-colored, 20-30 cm tall, 2-2.5 mm in diam. at middle, branched eventually, 10-14-ridged; ridges glabrous; internodes 3-4 cm; sheath tubes reddish brown on upper portion, straw-colored in lower portion, 1.1-1.5 cm, with 3 or 4 broad sheath teeth; sheath teeth reddish brown, ovate-deltoid, 0.5-1.1 mm, membranous, with shallow grooves abaxially. Fertile stems remaining alive after spores shed. Sterile stems grayish green, 30-70 cm, 2.5-5.5 mm in diam. at middle, well branched in whorls, unbranched below middle, main stem 10-16-ridged; ridges edged abaxially and with bristlelike protuberances on sides; each ridge often with a row of tubercles; internodes 4.5-6 cm; sheath tubes reddish brown on upper portion, grayish green on lower portion, ca. 6 mm, with 3 or 4 broad sheath teeth; sheath teeth reddish brown, ovate-deltoid, ca. 0.6 cm, membranous, persistent. Lateral branches slender, complanate, 3-8-ridged; ridges with spine-shaped protuberances or glabrous abaxially; sheath teeth open. Strobilus terete, 1.5-2.5 cm, 5-7 mm in diam., apex blunt; stalk prolonged when mature and 3-4.5 cm. 2n = 216.

Forests; 200-1600 m. Heilongjiang, Jilin, Nei Mongol, Shandong, Xinjiang [Japan, Mongolia, Russia; C Asia, Europe, North America (including Greenland)].