Mamedea R. F. Almeida & M. Pell., 2024

de Almeida, Rafael F., de Morais, Isa L., Alves-Silva, Thais, Antonio-Domingues, Higor & Pellegrini, Marco O. O., 2024, A new classification system and taxonomic synopsis for Malpighiaceae (Malpighiales, Rosids) based on molecular phylogenetics, morphology, palynology, and chemistry, PhytoKeys 242, pp. 69-138 : 69-138

2.9. 8. Mamedea R. F. Almeida & M. Pell. gen. nov.

Fig. 4 U

Type species.

Mamedea pulchella (Griseb.) R. F. Almeida & M. Pell.

Diagnosis.

Mamedea can be recognised by its erect shrub to subshrub habit, present xylopodium, leaves entire at base, umbels, 1–4 - flowered, peduncle usually absent or reduced, not bearing reduced leaves, sepals bent inwards between the petals at anthesis, petals fimbriate, androecium with 3 fertile stamens, anthers glabrous to pubescent, staminodes 2, antherodes present or not, when present larger than the fertile anthers, glabrous to pubescent, usually red to orange at post-anthesis, 2 posterior carpels rotated so that all face the posterior petal, mericarps with dorsal and lateral wings reduced to ribs or teeth, and with a rugose nut, chromosome number n = (20 –) 40.

Description.

Shrubs to subshrubs. Roots fibrous, woody near the xylopodium. Xylopodium present, small to large. Branches erect, slender, woody to herbaceous, sometimes brittle, sericeous to glabrescent; internodes inconspicuous to elongated. Stipules interpetiolar, minute, free to connate, sericeous or distally glabrous, deciduous or persistent. Leaves opposite or decussate; petioles short, sericeous, tomentose, lanate or glabrescent, eglandular; lamina entire, elliptical, lanceolate to ovate, velutinous, sericeous, lanate or tomentose, base cuneate or rounded, margin entire, apex acute, obtuse, rounded or mucronate; venation eucamptodromous or brochidodromous, secondary veins strongly ascending and subparallel. Umbels solitary, axillary, (1 –) 2–4 - flowered, sessile to pedunculate; inflorescence leaves not reduced; bract alternate, minute, plane, persistent, sericeous to glabrous, eglandular, persistent; cincinni (1 –) 2–4, alternate, 1 - flowered, pedunculate; bracteoles opposite, minute, plane, persistent, sericeous to glabrous, eglandular, persistent. Flowers chasmogamous or cleistogamous, bisexual, zygomorphic, hypogynous; pedicel elongated, longer or shorter than the peduncle, sparsely sericeous, tomentose, velutinous or glabrescent; sepals 5, free valvate in bud, erect in bud, bent inwards between the petals at anthesis, triangular to broadly ovate, sericeous or tomentose, apex acute, the anterior eglandular and narrower, the lateral 4 biglandular, the glands green, yellowish-green, dark red, or reddish-purple, secreting oil, in fruit persistent, somewhat accrescent, enclosing nutlets until maturity; petals 5, imbricate in bud, yellow to orange-yellow at anthesis, glabrous or abaxially sparsely tomentose, limb plane, margin short-fimbriate, basal fimbriae mostly tipped with tiny glands, posterior petal with claw slightly thicker, sometimes with a pair of glands near the limb, limb slightly broader than the 4 lateral ones; androecium with 5 stamens, filaments free or connate at base with adjacent filaments, fertile stamens 3, opposite anterior and posterior-lateral sepals, heteromorphic, filaments stout, glabrous, anthers rimose, glabrous or locules tomentose at apex, connective glandular; staminodes 2, opposite anterior-lateral sepals, homomorphic, filaments slender, antherode equalling or larger than anthers (reduced to an apical swelling in M. harleyi and M. lanata ), glandular, pubescent (glabrous in M. harleyi ); ovary superior, 3 - carpellate, carpels syncarpic, the posterior 2 rotated so that all face the posterior petal, minutely puberulent, style 1, basal, straight, glabrous, borne low on inner face of anterior carpel, stigma terminal, truncate, held above anthers or at the same level at anthesis. Schizocarp with 3 mericarps, dorsal and lateral wings reduced to ribs or teeth, glabrous to velutine; carpophore absent. Chromosome number n = (20 –) 40.

Etymology.

The genus name honours the Brazilian botanist Dra Maria Candida Henrique Mamede (b. 1956), friend, colleague, and long-time contributor to the Brazilian Malpighiaceae .

Notes.

Mamedea currently comprises seven accepted species (one threatened species; Suppl. material 1) of shrubs or subshrubs endemic to altitudinal grasslands, savannas, campos rupestres, and seasonally dry tropical forests of Argentina, Bolivia, Brazil, Paraguay, and Uruguay, South America. For partial identification keys, see Almeida et al. (2020) for Brazil and Aliscioni and Torretta (2018, under Aspicarpa ) for Argentina.

Figures

Figure 4. Leaf blades of Malpighiaceae A leaf with sagittate base of Stigmaphyllon ciliatum B leaf with rounded base of Banisteriopsis adenopoda C leaf with cordate base of Stigmaphyllon blanchetii D leaf with cuneate base of Banisteriopsis vernoniifolia E leaf with obtuse base of Stigmaphyllon paralias F leaf with truncate base of Stigmaphyllon gayanum G leaf with oblique base of Stigmaphyllon lanceolatum H leaf with attenuate base of Acmanthera minima I leaf with entire margin of Stigmaphyllon caatingicola J leaf with 3 - lobed margin of Stigmaphyllon caatingicola K leaf with 5 - lobed margin of Stigmaphyllon angustilobum L leaf with crenate margin of Stigmaphyllon crenatum M leaf with ciliate margin of Stigmaphyllon ciliatum N leaf with dentate margin of Stigmaphyllon vitifolium O leaf with plane blade margin of Banisteriopsis membranifolia P leaf with revolute blade margin of Verrucularina glaucophylla Q rounded leaf apex of Tetrapterys phlomoides R mucronate leaf apex of Banisteriopsis magdalenensis S emarginate leaf apex of Hiraea cuiabensis T cuspidate leaf apex of Banisteriopsis adenopoda U acuminate leaf apex of Mamedea harleyi V acute leaf apex of Banisteriopsis membranifolia (photographs A – D, F, G, I, L, O, P, T – V by R. F. Almeida; E, M by M. O. O. Pellegrini; H by F. Farronay, Q by G. A. Dettke, N by A. C. Dal Col, R by C. Baez, S by I. L. Morais).