Corybas wallii Lehnebach, 2016

Lehnebach, Carlos A., Zeller, Andreas J., Frericks, Jonathan & Ritchie, Peter, 2016, Five new species of Corybas (Diurideae, Orchidaceae) endemic to New Zealand and phylogeny of the Nematoceras clade, Phytotaxa 270 (1), pp. 1-24 : 13-14

5. Corybas wallii Lehnebach , sp. nov. ( Fig. 10A–C)

Type:— NEW ZEALAND. North Island: Tongariro National Park, Whakapapa, along Whakapapanui stream, 21 October 2011, McGlynn SP104210 (holotype: WELT!)

Diagnosis:— C. wallii resembles C. vitreus in the pale colour of its flower but it differs by its conspicuously yellow to pale green labellum lamina and margins, the presence of numerous glandular trichomes on the internal and external surface of the labellum and larger leaves. It differs from C. trilobus by its overall pale green to yellow flower.

Terrestrial herbs, 13–34 mm tall at flowering. Leaf distinctly petiolate, petiole (5.5)9.3–15.1(28.8) mm long; lamina cordiform to sub-oblong or sub-hastate, (6.4)8.8–11.2(14) × (9.3)12.6–17.0(23.5) mm; margin entire; apex mucronate with mucro (0.2)1.5–2.0(2.6) mm long. Flower solitary, held erect on a peduncle (2.7)4.4–6.2(11.6) mm long, floral bract narrowly triangular to deltate when flattened, (2.6)4.2–5.5(10) × (1.4)2.2–2.8(3.7) mm, dorsal sepal pale yellowgreen, arching over the labellum, concave to cucullate, narrow at the base and widely spathulate towards the tip and at times bearing trichomes on the upper surface, apex emarginated or rounded; lateral sepal linear-filiform, pale yellowgreen, at times pale pink, (9.4)13.3–17.8(25) mm long; petals are similar to the dorsal sepals but longer, (24.5)39.5– 51.2(62.2) mm long; labellum pale green or yellowish, less often with a few blotches of pink near the upper section, auriculate at base, aperture (1.2)1.8–2.1(2.6) mm in diameter; lamina deflexed, ca. 7 mm wide, with a central groove formed by the inwards folding of the lamina, extending downwards to the lower margin and sunken pit formed at the point where the lamina bends, margin incurve, mostly entire but erose at the lower margin, inner surface of the labellum covered with glandular trichomes, some also present in the outer surface. Ovary (3.0)4.7–6.5(9.0) mm long. Column 2.3 mm long, straight with deltate to shallowly deltate wings flanking the stigma.

Specimens examined:— NORTH ISLAND: Boundary Stream Main Island, Tumunako loop track, 19 October 2012, Lusk SP104188 ( WELT) ; Tongariro National Park, Whakapapa, sites along Whakapapanui river , 21 October 2011, McGlynn SP104175 ( WELT) ; Egmont / Taranaki National Park, about 75 m up Nature Loop track, behind camphouse, 14 November 2011, McGlynn SP104179 ( WELT) ; Egmont National Park, North Egmont visitor centre, Ngatoro loop walk, 14 November 2011, McGlynn SP104409 ( WELT) ; Egmont National Park, North Egmont Visitor Centre, Ngatoro loop walk, 29 October 2012, McGlynn SP104410 ( WELT) ; Egmont National Park, Stratford Plateau to ski field, 30 October 2012, McGlynn SP104411 ( WELT) ; Ruahine Forest Park, track to Rangiwahia hut, 24 September 2012, McGlynn SP104178 ( WELT) ; Eastern Ruahine Ranges, Sunrise trackt to Sunrise hut, 26 September 2011, Lehnebach, Zeller & Lusk SP104406 ( WELT) ; Eastern Ruahine Ranges, Swamp track, 26 September 2011, Lehnebach, Zeller & Lusk SP104407 ( WELT) ; Eastern Ruahine Ranges, Swamp track, 26 September 2011, Lehnebach, Zeller & Lusk SP104408 ( WELT) ; Tararua Forest Park, Otaki Forks, Pukeatua track, near the summit of Pukeatua , 25 October 2014, Lehnebach & Zeller SP104164 ( WELT) ; Rimutaka Range, Mount Climie, under scrub by the roadside, 02 Nov 2014, Lehnebach & Zeller SP104169 ( WELT). SOUTH ISLAND: Kahurangi National Park , track to Salisbury lodge, 15 November 2011, Lehnebach, Frericks & Moorhouse SP104124 ( WELT) ; Kahurangi National Park, Gordons Pyramid route, close to Potholes track, 16 November 2011, Lehnebach, Frericks & Moorhouse SP104393 ( WELT) ; Nelson Lakes National Park, Mt Robert road, 9 November 2012, Lehnebach, Moorhouse & Upson SP104151 ( WELT) .

Etymology:— This species is named after Walli (Walburga) Zeller, mother of the second author of this article.

Distribution:— Endemic to New Zealand. North and South Islands ( Fig. 10D).

Habitat:— In leaf litter under southern beech ( Fuscospora or Lophozonia Nothofagaceae ] or kamahi (Weinmania racemosa Linnaeus (1782: 227), Cunnoniaceae) forest, mossy seepages or gravelly soils, between 600 to 1150 m.

Phenology:— Flowering October to mid November, fruiting September to early January.

Conservation status: — Corybas wallii is common montane and sub-alpine areas of the North and South Islands. It is, therefore, regarded as ‘Not Threatened’ using the criteria of Townsend et al. (2008).