Myoxanthus parahybunensis (Barb.Rodr.) Luer (1982a: 47)

Rojas-Alvarado, Gustavo, Blanco, Mario A. & Karremans, Adam P., 2021, A taxonomic synopsis and morphological characterization of Myoxanthus (Orchidaceae: Pleurothallidinae), Phytotaxa 507 (3), pp. 211-258 : 244

36. Myoxanthus parahybunensis (Barb.Rodr.) Luer (1982a: 47) . (Fig. 17B,C)

Basionym: Anathallis parahybunensis Barbosa Rodrigues (1882: 76) .

TYPE:— BRAZIL. Minas Gerais: in trees along the River Parahybuna, 680 m, Barbosa Rodrigues s.n. (holotype: lost, lectotype selected in Rojas-Alvarado & Karremans 2020, tab. 150, in Iconogr. Orchid. Bresil, vol. 3, at the Library of Rio de Janeiro Botanical Garden, cited as tab. 789 [(unpublished) in Barbosa Rodrigues (1882: 76); copied and reproduced in black and white in Cogniaux [1896: tab. 111, fig. II, 1896]; reproduced in colour in Sprunger et al. (1996, vol. 1: 208).

Heterotypic synonoyms: Pleurothallis peduncularis Lindley (1843: 47) , nom. illeg. hom. non Hook. 1841. Humboltia peduncularis Kuntze (1891: 668) , as “ Humboldtia ”, replacement name. Specklinia peduncularis Barros (1983 [1984]: 110), nom. illeg. TYPE:— BRAZIL. Without locality, imported from Rio de Janeiro by Messrs. Loddiges (holotype, K!).

Pleurothallis macropus Schlechter (1915: 130) .

TYPE:— ECUADOR. San Nicolas : Río Pilaton, flowered in June 1886, Sodiro 30 [actually Luis Sodiro] (holotype: BR!; isotype, P!).

Distribution:— Costa Rica, Venezuela, Colombia, Ecuador, Peru and Brazil.

Notes:— Myoxanthus parahybunensis is the oldest available name for the taxon commonly referred to as M. exasperatus , a name that has been misapplied ( Rojas-Alvarado & Karremans 2020, see Myoxanthus exasperatus discussion). Since Pleurothallis peduncularis Lindl. is illegitimate (according to Art. 58.1, Ex. 1 of the International Code of Nomenclature, Turland et al. 2018), the name must be cited as Humboltia peduncularis Kuntze.

Myoxanthus parahybunensis is recognized by its caespitose habit, ramicauls with few trichomes covering only the basal sheath of the ramicaul, other ramicaul sheaths smooth without trichomes or scars, flowers yellowish and whitish with sepals and petals narrowly elongate, the column not toothed but with purple wings and lip subpandurate with purple margins. Myoxanthus parahybunensis is similar to M. neilli but distinguished by flowers up to 10 mm in diameter vs. 5 mm and purple margins of the lip vs. greenish.