Flora of New Zealand Series

field horsetail

Rhizomes pubescent. Aerial stems dimorphic. Sterile stems green, 10-80 cm × 1-5 mm, usually regularly branched with lateral branches simple; ridges nearly smooth; grooves (4)-6-14; sheaths green, up to 10 mm long, teeth as many as grooves; central hollow < 1/2 diam. of main stem; main stem occasionally bearing terminal cones in mid-summer. Fertile stems normally appearing in spring before the sterile stems and dying after shedding spores, pale brown, usually smaller than sterile stems, not branched; sheaths pale brown with darker teeth, up to 14 mm long. Cones (4)-10-40 mm long.

N.: S. Auckland (Kawhia), Hawke's Bay (Havelock North), New Plymouth, Wellington (Wanganui, lower Rangitikei R.); S.: Marlborough (Awatere R., Woodside Creek), Nelson (Mokihinui R., Matiri R., Murchison and lower Buller R.), Canterbury (Christchurch), Otago (Dunedin).

N. temperate 1922

Damp ground, river banks and lake margins.

This is an agressive weed which is becoming well established in some areas, particularly where rainfall is moderate to high or where it can grow in riparian sites. Once established it is extremely difficult to eliminate because of its extensive underground rhizomes and resistance to herbicides. The sp. in the N. Hemisphere has been monographed by Hauke, R.L., Nova Hedwigia 13 : 81-109 (1967); 30 : 435 (1978), and its coning behaviour in N.Z. described by Brownsey, P. J., Moss, T. C. and Sneddon, B. V., Wellington Bot. Soc. Bull. 42 : 16-21 (1985).