Taxonomic Notes on Neotropical Maprounea Aublet (Euphorbiaceae)

Abstract

A key to and some remarks on Maprounea in the Neotropics are presented. Maprounea guianensis var. obtusata is discussed and raised to specific rank with the new name Maprounea amazonica. Maprounea brasiliensis is accepted as distinct from M. guianensis. The taxa are separated mainly by characters of the leaves and by fruit size. Additionally, Maprounia glauca is established as a new synonym of Mabea taquari, and a lectotype is designated for the latter. Maprounea Aublet (Euphorbiaceae, Hippomaneae) is a small genus of shrubs and trees occurring in the Neotropics and in Africa. Although the South American taxa have been treated twice quite recently, their taxonomy is still not fully resolved. Pax and Hoffmann (1912) accepted two neotropical species, Maprounea guianensis Aublet and M. brasiliensis A. Saint-Hilaire, both without infraspecific taxa. Allem (1976), however, considered these two species to be identical and united them under the older name, M. guianensis. Senna (1984) disagreed with him and accepted both species as well as a number of varieties of M. guianensis, with the exception of M. guianensis var. undulata Muller Argoviensis, which she did not consider to be distinct from the typical variety. Allem's (1976) study was based mainly on plants from central Brazil and concentrated on floral characters, neglecting the varieties described from other regions. The revision of Senna (1984) was uncritical, although it included very detailed illustrations of all taxa. From these illustrations it is quite obvious that the leaves of M. guianensis var. obtusata (Muller Argoviensis) Muller Argoviensis are very different from those of all other neotropical taxa of the genus. On further examination of leaf and fruit characters in particular I now conclude that this variety represents a distinct species, and also that M. brasiliensis should be kept separate from M. guianensis. KEY TO THE NEOTROPICAL SPECIES OF MAPROUNEA la. Leaves apically obtuse to rounded to emarginate, abaxially eglandular at base (Fig. 1A); 0-1 pistillate flower per inflorescence; staminate inflorescence at least as wide as long; fruits 8--10 mm long M. amazonica lb. Leaves apically acute to mucronate to acuminate, rarely obtuse, abaxially often with basal glands, rarely without; (0-)2-3 pistillate flowers per inflorescence; staminate inflorescence longer than wide; fruits 4-10 mm long. 2a. Tree up to 25 m tall; leaves distinctly longer than wide, apically acute to acuminate, abaxially with 0-1(-2) pair(s) of base glands (Fig. 1F), often with additional submarginal glands in upper half; fruits 4-6(-8) mm long . M. guianensis 2b. Shrub up to 1.5 m tall; leaves hardly longer than wide, apically mucronate, rarely obtuse, abaxially usually with 2-4 pairs of basal glands (Fig. 1G), eglandular in upper half; fruits 8-10 mm long........ M. brasiliensis Maprounea amazonica Esser, nom. et stat. nov. Replaced name: Maprounea guianensis Aublet var. guianensis forma obtusata MUller Argoviensis, Linnaea 32: 115. 1863. Maprounea guianensis Aublet var. obtusata (MUiller Argoviensis) Muller Argoviensis, in Martius, Fl. Bras. 11.2: 543. 1874. TYPE: Brazil. Amazonas: Barra (= Manaus), igap6 of an igarap6, May 1851, Spruce 1475 (lectotype, selected here, G-DC not seen, microfiche; isolectotypes, BM, BR, E, GH, K, NY, OXF, P, TCD). Figure 1A-E. The name Maprounea obtusa Pax already exists for an African species. A new combination based on the neotropical variety obtusata would be very similar to the African name, and because of the risk of confusion a new name, M. amazonica, was chosen according to Article 53.3 of the International Code of Botanical Nomenclature (Greuter et al., 1994). Shrub or tree up to 12 m tall and 15 cm stem diam. Bark smooth. Totally glabrous. Monoecious. Stipules broadly elliptic, ca. 0.7-0.9 x 0.5-0.9 NovoN 9: 32-35. 1999. This content downloaded from 157.55.39.78 on Mon, 20 Jun 2016 07:31:39 UTC All use subject to http://about.jstor.org/terms Volume 9, Number 1 1999 Esser Neotropical Maprounea 33