Mionandra Griseb. (Grisebach 1874: 101)

de Almeida, Rafael F., de Morais, Isa L., Pellegrini, Marco O. O. & van den Berg, Cassio, 2023, Molecular phylogeny and character-mapping support the synonymy of Cordobia and Gallardoa in Mionandra (Malpighiaceae), Plant Ecology and Evolution 156 (3), pp. 352-364 : 352

Mionandra Griseb. (Grisebach 1874: 101)

Figs 2 , 3 , 4 , 5

Brittonella Rusby ( Rusby 1893: 429) - Type species: Brittonella pilosa Rusby [= M. camareoides Griseb.]

Cordobia Nied. ( Niedenzu 1912: 41), syn. nov. - Type species: Cordobia argentea (Griseb.) Nied. [= M. argentea Griseb.]

Gallardoa Hicken ( Hicken 1916: 102), syn. nov. - Type species: Gallardoa fischeri Hicken [= M. fischeri (Hicken) R.F.Almeida]

Type species.

Mionandra camareoides Griseb.

Diagnosis.

Distinguished from Peixotoa by its stipules connate at the base or up to the middle (i.e. bifid), leaves short-petiolate, hirsute-sericeous; umbels 1-flowered, peduncles absent; sepals free, chartaceous, completely revolute or involute along margins; petals narrowly elliptic, margin glandular-fimbriate; fertile stamens 5, staminodes 3-5, antherodes filiform, minute; style apex truncate to slightly expanded; mericarps with wings reduced, rarely dorsal wing well-developed (Table 1 ).

Description.

Erect or scandent to prostrate subshrubs; xylopodium present; indumentum throughout the plant ranging from sericeous to glabrescent; stipules expanded, connate at base or up to the middle (i.e. bifid), triangular, interpetiolar, persistent or deciduous. Leaves opposite, never reduced in the inflorescences; petioles cylindric, short-petiolate (up to 2 mm long), eglandular; blade narrowly elliptic, elliptic, lanceolate to ovate, base cuneate to obtuse, margin entire, apex acute to acuminate, abaxially 0-2-glandular near the base. Umbels solitary, terminal; cincinni 1-flowered; bracts absent; peduncles absent; bracteoles absent. Flowers bisexual, zygomorphic, chasmogamous; pedicels short to elongate; sepals concealing petals during enlargement of bud, completely revolute or involute along margins at anthesis, lateral sepals abaxially 2-glandular, the anterior usually eglandular; petals clawed, yellow, sometimes turning orange at age, both sides glabrous, limb narrowly elliptic to oblanceolate or obovate to widely obovate, base cuneate, margin glandular-fimbriate, apex round, claw plane, posterior petal erect, glandular along margins, lateral petals patent to erect. Androecium 8-10, fertile stamens 5, staminodes 3-5; filaments connate at base, straight, rarely curved, stamen filaments longer than staminode filaments, glabrous or pubescent; connective minute, inconspicuous; fertile anthers monomorphic or dimorphic, erect at apex, glabrous; antherodes absent to present, filiform, reduced to a glandular tissue, glabrous. Gynoecium with carpels connate their whole length in flower, separating during fruit development, styles thick, cylindric, erect, equal, divergent, apex of styles truncate to slightly expanded, stigma terminal to lateral, crateriform or discoid. Schizocarp breaking apart into 3 winged mericarps, separating from a short torus; mericarps with dorsal wing reduced, sometimes well-developed; lateral wings always reduced, free or fused; wings coriaceous, margin sinuate; nut ridged near areole; areole ovate to elliptic. Seeds smooth or rugose; embryos ovoid, cotyledons bent, equal or unequal.

Distribution, habitat, and ecology.

Mionandra s.l. comprises four species confined to dry forests (Chaco), savannas, and temperate steppes (Patagonian steppes) from Argentina, southern Bolivia, and western Paraguay in South America (Fig. 2 ).

Notes.

A comprehensive treatment for the genera comprising Mionandra s.l. (including Cordobia and Gallardoa ) and three of their four species are presented by Aliscioni and Torretta (2017) within the Flora of Argentina project, with M. paraguariensis (which does not occur in Argentina) not included in the treatment. Thus, we provide an updated key to all species of Mionandra s.l., plus comments on the recognition of M. paraguariensis .

Figures

Figure 2. Distribution map of Mionandra (grey circles) and Peixotoa (white circles) in South America. Dark green: rainforests; Light green: dry forests; Orange: savannas; Lilac: Tundra / Puna; Yellow: temperate steppes; Light red: temperate forests.

Figure 3. Mionandra argentea. A. Shrubby habit. B. Detail of a floral shoot showing the partially connate stipules in the node and the sessile 1 - flowered cincinnus with a long-pedicellate floral bud. C. Flower in frontal view. D. Flower in lateral view showing the sepals involute along margins. Photographs A-B by Etienne Lacroix-Carignan; C-D by Andrea Cocucci.

Figure 4. Mionandra camareoides. A. Shrubby habit. B. Detail of floral branches. C. Detail of flowers. D. Flower in frontal view. Photographs A-C by Eduardo Alfredo; D by William Anderson.

Figure 5. Mionandra fischeri. A. Shrubby habit. B. Detail of a flower in frontal view. C. Detail of a flower in lateral view. D. Detail of floral branches. Photographs A-B by Anival Prina; C by Michelle Delaloye; D by Ivan Federico Ebrecht.