Vascular – Exotic
Herbs - Dicotyledonous composites
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
Prickly thistle with cobwebby hairs over most parts, small magenta flowerheads in clusters of up to 10 at the tip of a thin ± leafless prickly flower stem, up to 1.5 m tall, easy to break.
Scattered throughout both islands, absent from drier areas, common in Westland
Wet pasture and swampy waste places.
Wetland plant indicator status rating
Information derived from the revised national wetland plant list prepared to assist councils in delineating and monitoring wetlands (Clarkson et al., 2021 Manaaki Whenua – Landcare Research Contract Report LC3975 for Hawke’s Bay Regional Council). The national plant list categorises plants by the extent to which they are found in wetlands and not ‘drylands’. The indicator status ratings are OBL (obligate wetland), FACW (facultative wetland), FAC (facultative), FACU (facultative upland), and UPL (obligate upland).
FACW: Facultative Wetland
Usually is a hydrophyte but occasionally found in uplands (non-wetlands).
Fibrous rooted biennial. Stems not branched, or branched above, with soft scattered multicellular and fine cobwebby hairs, (20)-80-150-(200) cm tall, ribbed, with coarsely spiny wings between leaf bases; branches slender. Leaves oblanceolate to narrowly elliptic, shallowly to deeply pinnatifid, green above, paler beneath, (5)-10-25-(35) X (1.5)-3-8-(15) cm, with sparse soft multicellular hairs above and beneath, often also with sparse to dense cobwebby tomentum beneath; Leaf lobes narrowly deltoid to linear; prickles pale, 2-10 mm long; uppermost leaves becoming smaller. Capitula cylindric to narrowly ovoid at flowering, erect, 1.2-1.5X 1 cm, in clusters of up to 10; peduncles 0-1 cm long. Outer involucral bracts linear, ciliate; apex acute, not spinous, suberect. Carolla magenta, 11-12 mm long; lobes 3.5-4-(5) mm long. Style slightly exserted beyond carolla lobes. Achenes pale, narrowly obovoid, 3-3.5 X c. 1 mm; pappus 8-12 mm long; cilia on pappus bristles 1-2 mm long.
No other thistle has the combination of magenta flowerheads and slender, winged, brittle stems.
November - to February
Biennial. Seed dispersed by wind or contaminated machinery.
Reason for introduction
Unknown, seed or soil contaminant
Can be controlled manually, or herbicidally depending on situation.
cirsium: A kind of thistle
palustre: From the Latin palus ‘swamp’, meaning growing in swamps
Factsheet prepared by Paul Champion and Deborah Hofstra (NIWA). Features description from Webb et al., (1988).
References and further reading
Webb, C.J.; Sykes, W.R.; Garnock-Jones, P.J. (1988). Flora of New Zealand Volume 4: Naturalised pteridophytes, gymnosperms, dicotyledons. Botany Division, DSIR, Christchurch.
Popay et al (2010). An illustrated guide to common weeds of New Zealand, third edition. NZ Plant Protection Society Inc, 416pp.
Johnson PN, Brooke PA (1989). Wetland plants in New Zealand. DSIR Field Guide, DSIR Publishing, Wellington. 319pp.