Abstract
Morphological characters support the description of two new species of Orchidaceae from New Caledonia: Dendrobium butinii M.Pignal & Munzinger sp. nov. and Dendrobium letocartiorum Munzinger & M.Pignal sp. nov. The lectotypes of Dendrobium camaridiorum Rchb.f. and D. crassifolium Schltr. are designated here. A leaf anatomical study was conducted and provided useful characters to distinguish the five New Caledonian graminoid Dendrobiineae species. Two identification tools are provided: an anatomical key for sterile material of grass-like Dendrobiineae and a morphological key for the New Caledonian graminoid Dendrobium. We propose preliminary conservation assessments with IUCN criteria for the new taxa.
Highlights
The New Caledonian flora is remarkable, both for its endemism, estimated at ca 75% (Morat et al 2012), and for the presence of numerous primitive angiosperm groups (Lowry II 1998; Pouteau et al 2015). Morat (1993) estimated that 5–10% of the flora remained undescribed, an interpretation supported by the ongoing description of one new endemic plant species on average per month (Gâteblé et al 2018), including some in the Orchidaceae (Pignal & Munzinger 2011; Faria 2016)
The fruits were observed in the field and in cultivation during the months of January, May, July, October, November and December and flowering specimens are from May and November
The group of graminoid Dendrobium is taxonomically artificial, because it includes species of two sections, Grastidium and Biloba, which do not seem to be phylogenetically related. Species in this group are characterized by a morphological resemblance and share ecological constants
Summary
The New Caledonian flora is remarkable, both for its endemism, estimated at ca 75% (Morat et al 2012), and for the presence of numerous primitive angiosperm groups (Lowry II 1998; Pouteau et al 2015). Morat (1993) estimated that 5–10% of the flora remained undescribed, an interpretation supported by the ongoing description of one new endemic plant species on average per month (Gâteblé et al 2018), including some in the Orchidaceae (Pignal & Munzinger 2011; Faria 2016). Our colleague and friend Jean-Pierre Butin (Forest Service, Northern Province) brought to our attention some potentially new species of Orchidaceae. These belong to the genus Dendrobium Sw. and are characterized by long thin stems, and narrowly elliptical leaf blades evoking the Poaceae Barnhart, that we call ‘graminoid’ species. Two New Caledonian species were known at that time to have this strange habit: D. camaridiorum Rchb.f. and D. crassifolium Schltr. Another graminoid Dendrobium, D. unicarinatum Kores (1989: 97) is known to occur on the island. Monanthos Schltr. (Schlechter 1912: 251)
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