Acianthera amsleri Rykacz., Driessen & Kolan., 2018

Rykaczewski, Max, Driessen, Wiel & Kolanowska, Marta, 2018, A new species of Acianthera (Pleurothallidinae, Orchidaceae) from Brazil, Phytotaxa 372 (4), pp. 291-295 : 292

Acianthera amsleri Rykacz., Driessen & Kolan. sp. nov. ( Fig 1 & 2)

Type:— BRAZIL. Flowered in cultivation at Panningen, Netherlands, June 2017, obtained from Roland Amsler (Switzerland), W. Driessen s.n. ( UGDA p-3958!).

Diagnosis:—Species similar to Acianthera hystrix ( Kränzlin 1921: 7) Barros (2004: 10) and A. portilloi (Luer & Escobar: 1982: 144) Karremans & Rincón-González (2015: 178) but it differs by elliptic (vs. ovate), obtuse leaves (vs. acute), pubescent ovary (vs glabrous), oblanceolate, pubescent dorsal sepal (vs glabrous), lip with trapeziform lateral lobes, and lip disc ornamented with three lamellae (vs ciliate or ecallous).

Plant small in size, epiphytic, repent, the rhizome stout, branching, up to 15 cm long, 6 mm between ramicauls. Ramicaul stout, 12-28 mm long, enclosed by single inflated sheath. Leaf 50-70 mm long including the petiole, 15 mm wide, prostrate, thickly coriaceous, elliptical to ovate cuneate into petiole, apex obtuse, incised. Inflorescence a single flower, borne at the base of the leaf behind the inflated, loose, 8 mm long spathe. Pedicel 6 mm long, incurved, glabrous. Ovary 2 mm long, carinate, pubescent. Dorsal sepal 18 mm long, 5 mm wide oblong-oblanceolate, fleshy, densely pubescent, apex acute, 3-veined. Lateral sepals 17 mm long, 6.5 mm wide, connate together near to the apex into bifid, oblong-ovate, concave at the base, fleshy, densely pubescent, 6-veined synsepal. Petals 4.5 mm long, 1.5 mm wide, spathulate, glabrous, apex acute, 1-veined. Lip elliptic in outline, trilobed, glabrous, 3.6 mm long, 1.5 mm wide unexpanded, the apex rounded; basal half with incurved, subtruncate, lateral lobes with subacute apices; disc with three parallel, erect, thick, glabrous lamellae running from the lip base; the blade with a transverse callus above the claw; claw short, less than 1 mm long, biauriculate, hinged to the column foot base. Column 3.5 mm long, terete, straight with prominent clinandrium; anther, rostellum and stigma ventral. Column foot 2 mm long. Pollinia 2.

Etymology:—Named in honour of Roland Amsler from Switzerland, co-discoverer of this species.

Figures

FIGURE 1. Dissected flower of Acianthera amsleri A. Dorsal sepal; B. Petal; C. Synsepal; D–E.Various views of the lip. Draw by P. Baranow. Scale bars 1 mm.