Merianthera Kuhlm.

Goldenberg, Renato, Bochorny, Thuane, Amorim, André Márcio, Ziemmer, Juliana Klostermann & Fraga, Claudio Nicoletti de, 2023, Merianthera calyptrata sp. nov. (Melastomataceae, Myrtales), a new candelabriform species from Minas Gerais, Brazil, European Journal of Taxonomy 888, pp. 64-76 : 66-67

Genus Merianthera Kuhlm.

Arquivos do Instituto de Biologia Vegetal do Rio do Janeiro 1 (3): 231–233 ( Kuhlmann 1935), here amended.

Type species

Merianthera pulchra Kuhlm., Arquivos do Instituto de Biologia Vegetal do Rio do Janeiro 1 (3): 231–233 ( Kuhlmann 1935).

Description (modified from Goldenberg et al. 2012)

Shrubs to treelets, sparsely to moderately glandulose-granulose. Leaves opposite, entire, acrodromous, caducous. Inflorescences terminal short panicles, depauperate few-flowered cymes or reduced to solitary flowers; bracts absent, bracteoles absent or small, caducous. Flowers pedicellate, 5(–6)-merous; hypanthium sometimes with a constriction above the ovary; calyx regularly or irregularly lobed, seldom calyptrate and dehiscing through a transversal, circumscissile slit; petals free, obovate to elliptic; stamens 10(–12), glabrous, strongly zygomorphic and dimorphic, filament strongly flattened, connective with one basal (descending) and one apical, erect (ascending) portion, ascending portion always 2-lobed, lobes curved backwards in the antesepalous stamens and not curved backwards in the antepetalous stamens, anthers slightly dorsally arched, with a dorsal or apical pore in the antepetalous stamens and an apical to slightly ventrally located pore in the antesepalous stamens. Ovary completely inferior, with a sterile, apical stylar column, (3–)4–5-celled, the protruding placentae axillary; style curved at the apex, glabrous or puberulous, stigma punctiform. Fruits costate, apically constricted or not, rupturing along the costae when mature or seldom through (3–)4 regular, longitudinal slits; seeds many, pyramidal, testa rugulose.

Key to the species of Merianthera (modified from Goldenberg et al. 2012)

1. Stems hollow, fistulose when dry; flowers solitary, either on top of a short peduncle (then a 1-flowered strongly reduced cyme) or not .......................................................................................................... 2

– Stems solid when dry; flowers in panicles or seldom in depauperate cymes with two or more flowers ............................................................................................................................................... 3

2. Leaves with an acuminate to abruptly acuminate apex; flowers bibracteolate, borne on a short peduncle; calyx not calyptrate, dehiscing through regular lobes ................ M. burlemarxii Wurdack

– Leaves with a rounded or obtuse apex; flowers ebracteolate, not borne on a peduncle; calyx calyptrate, dehiscing through a transversal, circumscissile slit ............................................................................ ...................................................................... M. calyptrata R.Goldenb., Bochorny & Fraga sp. nov.

3. Calyx regularly lobed; style basally puberulous or granulose-glandulose ....................................... 4

– Calyx irregularly lobed; style glabrous ............................................................................................. 7

4. Leaves glabrous on abaxial surface; petals purple ........................................................................... 5

– Leaves with dense indumentum on abaxial surface; petals pink ...................................................... 6

5. Hypanthium weakly costate and smooth; calyx lobes lacking external teeth; style glandular-puberulous on its basal half ........................................................... M. bullata R.Goldenb., Fraga & A.P.Fontana

– Hypanthium strongly costate and rugose; calyx lobes with distinct, thick external teeth; style granulose-glandulose at the base ............................................. M. verrucosa R.Goldenb., Fraga & A.P.Fontana

6. Leaves with strigulose abaxial surface, with curled, discrete trichomes ............................................ .............................................................................................................. M. sipolisii (Cogn.) Wurdack

– Leaves with lanate abaxial surface, with arachnoid-amorphous, matted trichomes ........................... ......................................................................................................... M. eburnea R.Goldenb. & Fraga

7. Leaves with petioles 12–29 mm long; panicles with more than 8 flowers .......... M. pulchra Kuhlm.

– Leaves sessile or with petioles up to 9 mm long; depauperate racemes with up to 4(–5) flowers, reduced to triads, diads or sometimes single flowers .......................................................................... ................................................................................ M. parvifolia R.Goldenb., Fraga & A.P.Fontana