Acianthera nikoleae A.Doucette & J.Portilla, 2016

Doucette, Alfonso, Portilla, Jose & Cameron, Kenneth M., 2016, Ten new taxa in the orchid subtribe Pleurothallidinae (Epidendroideae, Epidendreae) from Ecuador, Phytotaxa 257 (3), pp. 230-248 : 231

Acianthera nikoleae A.Doucette & J.Portilla , sp. nov. ( Figs. 1 , 11D )

Type:— ECUADOR. Zamora-Chinchipe: Pangui, reported to grow on coffee trees around 1,200 m, flowered in cultivation at Ecuagenera Orchid Nursery, Gualaceo, Ecuador, 4 September 2015, Doucette 0319 (holotype: HA).

Diagnosis: The new species is most similar to Acianthera melanochthoda (Luer & Hirtz in Luer 1996: 169) Pridgeon & M. W.Chase (2001: 244) but differs in the hispid sepals that are larger and expanded/fused into lamina.

Epiphytic, repent herbs, roots 0.6 mm in diam. Stems 3.2–5.9 5 0.8–1.4 mm, enveloped by 2–3 papery sheaths, 5.0 5 3.0 mm. Leaves elliptical, verrucose, 26–48 5 14–24 mm. Inflorescence with a single flower; peduncle 1.4 5 0.4 mm; bracts 2.3 5 1.2 mm; pedicel 2.7 5 1.0 mm; ovary pubescent, 0.9 5 1.0 mm; dorsal sepal lanceolate, rose and orange, hispid, 11.0 5 2.9 mm; synsepalum oblong with a triangular recess, similar in colour to the dorsal sepal, 16.0 5 5.0 mm; petals spathulate with a toothed margin towards the acute apex, orange, 4.0 5 1.0 mm; lip lanceolate with a toothed margin, orange, 3.4 5 1.0 mm; column 3.2 5 0.6 mm.

Etymology:— Named to honour Nikole Portilla, daughter of Jose Portilla, president of Ecuagenera.

Notes:— This species belongs to a group of about eight (The Plant List 2015) attributable to Apoda-prorepentia ( Luer 1986: 31) Luer (2004: 255) , characterized by repent habit, single-flowered inflorescences and a papery bract. Acianthera nikoleae is most similar to A. melanochthoda , but differs in the larger flower size (e.g. synsepalum 11 mm vs. 7 mm long) and longer pubescence on the sepals and margin of the petals (toothed vs. entire). The sepalar morphology of A. nikoleae is unique in the group because the lateral sepals are expanded and fused into a thin layer extended beyond a triangular cavity formed in the centre of the synsepalum.

The group of species similar in morphology to Acianthera nikoleae was originally attributed to Pleurothallis subgen. Apoda-prorepentia Luer (1986: 31) . The species were transferred to Acianthera after molecular phylogenetic analyses (Pridgeon et al. 2001) indicated that Acianthera melanochthoda rendered Pleurothallis non-monophyletic (Pridgeon & Chase 2001, Solano et al. 2011, Karremans & Rincon-Gonzalez 2015). The International Plant Names Index (2016) indicated that A. nikoleae represents one of at least two species described since the key to the species ( Luer 2007) was published. The second species recently described, Apoda-prorepentia hirtzii Luer in Luer & Thorele (2013: 174), appears to be referable to Acianthera dodsonii , which is also reported to have purple spots on the leaves that are not raised ( Luer 2007), and otherwise matches the latter in distribution and morphology of plant and flowers. We treat this a synonym of Acianthera dodsonii .

Figures

FIGURE 1. Acianthera nikoleana. A. Habit, drawn to 5cm scale. B. Flower. C. Dorsal sepal. D. Lateral sepals. E. Petal. F. Lip. G. Flower with petals and sepals removed. All drawn to 1 mm scale.

FIGURE 11. A. Masdevallia constricta f. glabra. B. Masdevallia pachyura f. pardinella. C. Masdevallia posadae f. rugosepala. D. Acianthera nikoleana. E. Pleurothallis papillingua. F. Pleurothallis gigiportillae. G. Pleurothallis cardiostola f. magnidraba. H. Zootrophion machaqway. I. Stelis glaucus. J. Trisetella portillae.