Equisetum arvense
FIELD HORSETAIL. COMMON HORSETAIL. Perennial. Coconino, Navajo, Apache and Gila counties, 5000-8000 feet [K&P;]. Grand Canyon National Park: Kanabownits Spring, North Rim, 7938 feet (Coconino County) [PP&B;]. Northern Hualapai Mountains, Mohave County; moist soil along drainages [JANAS-24/25]. West Fork of Oak Creek Canyon of Coconino County [DP-21(1)].
Equisetum x ferrissii
(=Equisetum hyemale var. elatum; a hybrid of E. hyemale and E. laevigatum). HORSETAIL. FERRIS’ HORSETAIL. Perennial. Coconino, Navajo and Apache counties, 5000-8000 feet [K&P;]. Grand Canyon National Park: Along Colorado River shoreline and along creeks in side canyons, 2100-5200 feet (Coconino County) [PP&B;]. Northern Hualapai Mountains, Mohave County: at spring in tributary of Sawmill Canyon [JANAS-24/25]. West Fork of Oak Creek Canyon of Coconino County [DP-21(1)].
Equisetum hyemale ssp
affine (also spelled Equisetum hiemale). SCOURING RUSH. COMMON SCOURING RUSH. SCOURINGRUSH HORSETAIL. Perennial. FNA considers the subspecies cited to be the only one present in the US, and range map indicates it may be found throughout the region [FNA-2]. Grand Canyon National Park: Inner Canyon and Fuller Canyon, North Rim, 1300-8100 feet (Coconino County) [PP&B;, E. hiemale]. West Fork of Oak Creek Canyon of Coconino County [DP-21(1), E. hyemale].
Equisetum laevigatum
SMOOTH SCOURING RUSH. Perennial. Coconino and Navajo counties, 5000-8000 feet [K&P;]. Grand Canyon National Park: 1600-8900 feet (Coconino County) [PP&B;]. West Fork of Oak Creek Canyon of Coconino County [DP-21(1)].
