Title: Untangling New Zealand spider orchids’ web; using DNA fingerprinting techniques to detect hybridisation and species boundaries in members of the Corybas trilobus aggregate.
Applicant: Carlos A. Lehnebach
Institution: Museum of New Zealand Te Papa Tongarewa, Wellington New Zealand
This project focuses on Corybas trilobus, one the most widespread and morphologically variable orchid in New Zealand. This terrestrial orchid is commonly found under beech forest and it flowers during mid-winter to late spring. It is currently believed numerous taxonomically undetermined taxa are included under this name. Many of these ‘forms’ have been given ‘tag names’ which make reference to the colour, size or place where each form was first discovered. Interestingly, many populations across the country consist of two or more different ‘forms’, all flowering at the same time. Whether morphological variation is a result of hybridisation between co-occurring forms is so far unknown.
The main objectives of this project are: 1) Delimit species boundaries among five forms of the Corybas trilobus aggregate; 2) Assess the extent of gene flow between co-occurring forms. 3) Investigate whether morphological variation is linked to hybridisation. DNA fingerprinting (AFLP) and statistical analysis of morphological data (e.g. flower and leaf characters) will be used to address these goals.
The main result of this study was the description of five new species of Corybas endemic to New Zealand. At this side of the Tasman these orchids are known as spider orchids. Two of these new species are very uncommon, each restricted to a single spot of the North and South Island. These are now listed as Threatened species. Our studies showed no evidence of hybridisation between some of these orchids, despite they were growing side by side and flowering at the same time.
Because these orchids are very difficult to study and identify after they have been pressed, several images have been uploaded to the “Collection On line” site of the Museum of New Zealand Te Papa Tongarewa. These images are freely available so anybody can see how these orchids looked like when first collected. Link to the searching engine is here http://collections.tepapa.govt.nz/
Papers arising from this research
Lehnebach CA, Zeller AJ, Frericks J, Ritchie P (2016) Five new species of Corybas (Diurideae, Orchidaceae) endemic to New Zealand and phylogeny of the Nematoceras clade. Phytotaxa 270 (1): 001-024
Five new species of Corybas endemic to New Zealand.
A: C. confusus; B: C. obscurus; C: C. sanctigeorgianus; D: C. vitreus; E: C. walliae