New Zealand Pigmyweed

First published 2013 Invasive: High impact Invasive: Documenting Ireland’s Wildlife Ireland’s Documenting New Zealand pigmyweed showing its dense mat like like its dense mat showing pigmyweed Zealand New 2009 © Crown - GBNNSS structure New Zealand pigmyweed in flower with succulent leaves leaves with succulent in flower pigmyweed Zealand New © 2009 Crown - GBNNSS on the stem. a collar form that

Please report your sightings of this species at: this species of sightings your report Please http://invasives.biodiversityireland.ie Freshwater. but with many in the wild localised distribution Very waterbodies. in artificial occurrences Established. Crassulaceae. usually takes but reproduction Seeds can be produced are nodes individual plant tiny fragments, through place viable individual. a new producing capable of C. Hurley

Green. dense mats. Singular plants form Rigid and round. joined bases Leaf pairs. linear 2cm long and in opposite Up to when emergent fleshy Leaves a collar. form to the stem around when permanently submerged. and flatter absent.often are flowers small with 4 whitish petals, Very

Crassula helmsii Crassula

New Zealand pigmyweed Zealand New

The National Biodiversity Data Centre Data Biodiversity National The Colour: Mat forming: Stem: Leaves: Identifying features Identifying

Habitat: in Ireland: Distribution Status: name: Family : Reproduction Species profile Species

New Zealand pigmyweed in flower - in flower pigmyweed Zealand New Flower: New Zealand pigmyweed Invasive: High impact

Threats Forms thick dense mats which can float or be submerged.

The thick mats cause shading of existing water plants and the depletion of oxygen in the water, which leads to a reduction of native flora and fauna.

Possible health hazard, as the thick mats can be mistaken for dry land.

The species can move onto a terrestrial habitat after it colonises an aquatic area. New Zealand pigmyweed invading and matting the sur- Can obstruct boats and reduce the opportunities where fishing can take place, face on the edges of a pond in Ireland -C.Hurley which may impact upon local economies.

Similar species

Most similar to native water-starwort (Callictriche) species. However, the water- New Zealand pigmyweed may be confused with Callitriche species which have notched leaf tips.- starwors do not have fleshy leaves and they are typically notched at the leaf tip. © www.aphotoflora.com Notching may not be visible to the naked eye but should be with a hand lens.

Showing the variation in the plants structure and form based on its habitat. Far left - terrestrial, middle - emergent, far right - submerged - © GBNNSS

View Ireland’s distribution of this species on http://maps.biodiversityireland.ie Biodiversity

National Biodiversity Data Centre fact sheet. Produced with funding from The Heritage Council Maps and the EPA STRIVE Programme 2007-2013 Text: Colette O' Flynn & Oisín Duffy (Version 1) November 2013.