Macropsychanthus Harms ex Schumann & Lauterbach (1900: 366)

Fonseca-Cortés, Andrés, Snak, Cristiane & Queiroz, Luciano Paganucci De, 2023, Macropsychanthus nitidus: a new rank and combination for dioclea rostrata var. nitida (leguminosae, papilionoideae), Phytotaxa 619 (4), pp. 293-298 : 293-294

Macropsychanthus Harms ex Schumann & Lauterbach (1900: 366)

originally comprised four species confined to Southeastern Asia to New Guinea (Adema, 1998). Recently, Queiroz & Snak (2020) has demonstrated that Dioclea Kunth (1824: 437) is a non-monophyletic genus, with its species falling into three different positions: (1) the puzzling species, Dioclea paniculata Killip ex R.H. Maxwell (1978: 243) , was highly supported as a member of the Galactia clade; (2) Dioclea subg. Dioclea appeared as sister to a clade composed of Cleobulia Bentham (1837: 67) and Cymbosema Bentham (1840: 61) ; and (3) the species of Dioclea subgenera Pachylobium and Platylobium composed a paraphyletic grade, nesting the genera Luzonia Elmer (1907: 220) and Macropsychanthus . Therefore, they proposed that the circumscription of Dioclea should be restricted to Dioclea subg. Dioclea , with 13 species and that the limits of Macropsychanthus should be widened to include the genus Luzonia , as well as the Dioclea subgenera Pachylobium and Platylobium . Under the current circumscription, Macropsychanthus Harms ex K. Schumann & Lauterbach (1900: 366) comprises ca. 50 species, with a pantropical distribution, mainly confined to the Neotropics ( Queiroz & Snak 2020). The genus is characterized by its lianescent habit, erect pseudoracemose inflorescences composed of secundiflorous brachyblasts, bicallosal standard petals and turgid or laterally compressed fruits ( Queiroz & Snak 2020). Phylogenetic studies on the genus supported the presence of two clades, recognized as subgenera by Queiroz & Snak (2020): subgenus Macropsychanthus and subgenus Platylobium .

The subgenus Platylobium is restricted to South America and is characterized by basifixed triangular stipules, leaves lacking stipels, laterally compressed fruits and elastically dehiscent, and seeds with circular hilum.This subgenus includes nine species: Macropsychanthus bicolor (Benth.) L.P. Queiroz & Snak, (2020:105) M. coriaceus (Benth.) L.P. Queiroz & Snak (2020:106) , M. duckei L.P. Queiroz & Snak (2020:106) , M. erectus (Hoehne) L.P. Queiroz & Snak (2020:106) , M. hispidimarginatus (R.H. Maxwell) L.P. Queiroz & Snak (2020:106) , M. macrocarpus (Huber) L.P. Queiroz & Snak (2020:107) , M. rigidus (R.S. Cowan) L.P. Queiroz & Snak (2020:107) , M. ruddiae (R.H. Maxwell) L.P. Queiroz & Snak (2020:107) , and M. scabrus (Rich.) L.P. Queiroz & Snak (2020:107) ( Queiroz & Snak, 2020).

Bentham described Dioclea rostrata Benth. (1837:69) . Later, in the Flora Brasiliensis, Bentham (1859) introduced a new variety: D. rostrata var. “β” nitida , only known from the type collection. A detailed morphological analysis of type collections and the specimens of this subgenus revealed the presence of more collections of this taxon, mainly identified as Dioclea bicolor . Here we propose a new combination and a new rank for D. rostrata var. nitida , including complete description, illustration, distribution, and comparison within the morphologically similar species.