Macrolobium duckeanum R.S.Cowan

  • Authority

    Cowan, Richard S. 1953. A taxonomic revision of the genus Macrolobium (Leguminosae-Caesalpinioideae). Mem. New York Bot. Gard. 8 (1): 257-342.

  • Family

    Caesalpiniaceae

  • Scientific Name

    Macrolobium duckeanum R.S.Cowan

  • Description

    Latin Diagnosis - Arbor( ?), ramulis foliisque glabris. Petiolus 10-15 mm. longus, canaliculatus, glaber. Foliola 8.5-11.5 cm. longa, 4-6 cm. lata, valdissime inaequilateralia, arcuata, elliptica, basis inferiore latere auriculato, superiore acuto, ad apicem acuta et extremitate acuta vel obtusa, saepe inaequilaterali; costa saliens, venuli conspicui. Inflorescentiae 3.5-7 cm. longae, axe dense puberulo, pedunculo 2-5 mm. longo; bracteis 2.5 mm. longis, 1.5 mm. latis, caducis, oblongo-ovatis, intus glabris, extus dense puberulis; pedicelli 2.5 mm. longi, dense puberuli; bracteolis 6 mm. longis, 3-4.5 mm. latis, oblongis vel ovalibus, concavis, apiculatis, intus glabris, extus dense puberulis. Hypanthium 2 mm. longum, sessile, glabrum. Sepala quinque, duobus adaxilibus fere omnino conjugentibus, 4.5-5 mm. longa, 1.5-2.5 mm. lata, oblonga, vel ovalia, acuta, concava, irregulariter ciliolata. Petali lamina 5.5 mm. longa, 8 mm. lata, transverse ovalis, unguicilo late alato, petala ad basim ciliolata et extus pilosula, intus pilosa in unguicilo. Filamenta 11.5-15.5 mm. longa, ad basim villosa. Stigma capitellatum. Stylus 17.5 mm. longus, ad basim puberulus. Ovarium 2 mm. longum, 1 mm. latum, oblongum, puberulum, 2-ovulatum, gynophoro 2 mm. longo, puberulo. Fructus (senes valvae solum) circa 10.5 cm. longus, 4 cm. latus, oblongus, alis angustis, carpophorum 8 mm. longum, minute puberulum. Semina 2.5 cm. longa, 2 cm. lata, ovalia, plana, testa teniiicoriacea, plus minusve venosa.

  • Discussion

    Type Collection: A. Ducke 15605, "chemin de fer d'Alcobaca, Tocantins, Campina d'Arumateua," State of Para, Brazil, Jan. 1915 (HOLOTYPE US, isotype G). Known only by the type collection.

    It is with the greatest pleasure that this species is named for Dr. Adolpho Ducke, who has contributed so richly to the knowledge of the flora of northeastern South America by his extensive collections and voluminous writings. He has described a large number of species of Macrolobium and his synopsis of the genus in the Amazonian Hyalea was quite well done. It is fitting, then, that his name be perpetuated in a species of a genus to which he has given so much of his time and energy.

    The collection cited was identified as M. bifolium when received for this study. While this is the closest relative of the new species, the latter is readily recognizable by the rotund-auriculate lower side of the leaflet base, its puberulous rather than papillate-puberulous ovary, its transversely oval petal blade, and its minutely puberulous rather than papillate-puberulous fruit.