The only horsetail with branched branches.
Sterile stems slightly rough, 10-18 faint ridges. Stem cavity 1/4 to 1/3 of stem diameter. Loose green sheaths with persistent brownish teeth. Fertile stems initially unbranched, branches develop as cones mature. Cones long-stalked, pale pink-green when young.
Most frequent in North, scattered distribution elsewhere in Ireland. Damp woods and streamsides usually in mountainous areas.
Identification confirmed by Paul Green
Wood Horsetail. Ballingeary area, Co.Cork. July 2008