Wahlenbergia congesta (Cheeseman) N.E.Br. subsp. congesta, Wahlenbergia congesta subsp. haastii J.A.Petterson, Wahlenbergia morganii Petrie, Wahlenbergia saxicola var. congesta Cheeseman
Vascular – Native
Dicotyledonous Herbs other than 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.
2n = 36
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2017 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants. Authors: By Peter J. de Lange, Jeremy R. Rolfe, John W. Barkla, Shannel P. Courtney, Paul D. Champion, Leon R. Perrie, Sarah M. Beadel, Kerry A. Ford, Ilse Breitwieser, Ines Schönberger, Rowan Hindmarsh-Walls, Peter B. Heenan and Kate Ladley.
2018 | At Risk – Declining
Previous conservation statuses
2012 | At Risk – Naturally Uncommon | Qualifiers: Sp
2009 | At Risk – Naturally Uncommon | Qualifiers: DP
2004 | Sparse
Endemic. South Island from the north-west Nelson coastline south to northern Fiordland and also along portions of the northern Foveaux Strait coastline.
Coastal on rocky bluffs, cliff faces, ledges, beaches (cobble and sand), sand dunes and in low turf overlying seepages. Usually found in the most exposed sites where constant wind and salt blast reduces competition from taller plants.
Compact, mat-forming, predominantly autogamous perennial herb producing numerous close-set rosulate tufts of glossy glabrous, dark green to yellow-green leaves and subsessile white flowers. Petiole 1.5-2 mm, narrow, rather thin. Leaves 8-25 mm, dark green, yellow-green or reddish-green, orbicular, spathulate, margins shallowly crenate-serrate, undulate or flat, narrowed to petiole. Scape solitary arising from centre of each rosette, 10-20 mm long when flowering, elongating up to 50 mm long in fruit. Flowers solitary, terminal, erect, white or faintly tinged blue, 12-15 mm diameter. Calyx lobes 2 x 1 mm wide at base, triangular. Corolla 9-12 mm long, rotate-campanulate to funnelform, tube bowl-shaped, 4 x 5 mm, lobes 7-8 x 5 mm, ovate, obtuse. Capsule 3-6 mm diameter, globular. Seeds glossy brown, ellipsoid.
None - the coastal habitat, compact, mat forming growth form, and small globose capsule readily distinguish W. congesta from the other rosulate New Zealand species of the genus. Within W. congesta Petterson (1997) recognised two subspecies (subsp. congesta and subsp. haastii). Her subsp. haastii is said to differ from subsp. congesta by having smaller capsules (3 mm cf. up to 6 mm diameter in subsp. congesta) and funnelform rather than rotate-campanulate flowers. These are distinctions which on occasion can be seen in other populations that she had treated as subsp. congesta. Petterson (1997) also argued that there was an ecologicaly distinction, with subsp. haastii only growing on schist sand - however, this geological difference is only apparent because in the range where subsp. haastii happens to grow the beaches are made up primarily of the local rock type - schist. In cultivation the characters she used are soon lost, suggesting that irrespective of substrate there is no genetic or ecological basis to warrant this subspecies continued recognition.
November - February
December - April
Easily grown from rooted pieces - best kept in a pot and frequently repotted with fresh soil to keep it going. use free draining soil mixed with plenty of sand. Does not like to dry out to much and does best in a sunny situation.
A widespread at times locally common, biologically sparse and somewhat disjunct species. It is possible that some populations particularly those within dune fields are at risk, are declining or have gone extinct but there is as yet have no clear evidence for this.
wahlenbergia: Named in honour of Wahlenberg, a Swedish botanist and author of A Botany of Lapland.
Where To Buy
Not commercially available.
Fact sheet prepared for NZPCN by P.J. de Lange (22 October 2006). Description adapted from Petterson (1997).
References and further reading
Petterson, J.A. 1997: Revision of the genus Wahlenbergia (Campanulaceae) in New Zealand. New Zealand Journal of Botanv 35: 9-54.
Please cite as: de Lange, P.J. (Year at time of access): Wahlenbergia congesta Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/wahlenbergia-congesta/ (Date website was queried)