Pleroma goyazense A.I.M.R. Machado, R.Romero & P.J.F.Guim., 2023

Machado, Ana Isa Marquez Rocha, Romero, Rosana & Guimarães, Paulo José Fernandes, 2023, Pleroma goyazense (Melastomataceae), a new species from Goiás state, Brazil, and a new synonym in Pleroma, Phytotaxa 622 (3), pp. 215-226 : 216-221

Pleroma goyazense A.I.M.R. Machado, R.Romero & P.J.F.Guim. , sp. nov. ( Figs. 1−3 )

Diagnosis: — Pleroma is morphologically similar to P. crassirame (Cogniaux in Taubert 1896: 446) P.J.F.Guimar ã es & Michelangeli (in Guimar ã es et al. 2019: 977), but differs in having sparsely leaves arranged on the upper branches (vs. densely in P. crassirame ) and pedoconnective stamens with dorsal appendage (vs. absent). It is also similar to P. robustum ( Cogniaux 1885: 394) Guimar ã es & Michelangeli (in Guimar ã es et al. 2019: 988), but differs in having lanceolate and non-involucral bracteoles (vs. orbicular and involucral) and sepals acuminate at the apex (vs. obtuse).

Type: — BRAZIL. Goiás: Mossâmedes, Parque Estadual da Serra Dourada, próximo ao Mirante 16°04’0.03” S 50°10’17.5” W, 975 m, 28 May 2011, (fl), A.I.M.R. Machado et al. 15 (holotype HUFU!; isotypes RB!, UFG!) .

Description:—Shrub, 0.5‒1 (‒2) m tall, branched. Branches terete, non-decorticant, older branches brownish-cream, glabrescent, aphyllous, younger branches greenish-cream, villous, trichomes short and eglandular. Leaves opposite, isomorphic in size at each node, sparsely arranged on the upper branches, internodes 0.9‒2.9 cm long, petioles 4‒7.5 mm long, villous, eglandular trichomes, leaf blades 3‒4.5 × 1.5‒2 cm, chartaceous, elliptic to lanceolate, discolorous, 5-veined from the base, adaxial surface light bright green (when fresh) or dark green (when dry), abaxial surface greygreen (when fresh) or dull yellow-brown (when dry), apex obtuse to rounded, base attenuate, margin entire, covered with trichomes on both leaf surfaces, adaxial surface bullate-strigose, with the conical base of trichomes surrounded by tiny trichomes, abaxial surface foveolate, villous-setose, with an indumentum that mixes straight trichomes with other curly ones, and setose indumentum over main veins. Inflorescences in thyrsoids glomerulate, terminal, 4.5‒5 cm long, 4‒8 flowers, branches villous, trichomes eglandular. Flowers 5-merous, pedicellate, diplostemonous; bracts and bracteoles caducous after anthesis, bracts 2, petiolate, the petioles 5‒6 mm long, blades 12‒15 × 6‒7 mm, lanceolate, 3-veined, apex acute, the indumentum similar to that of the leaves; bracteoles 2, non-involucral, sessile, blades 11‒13 × 3‒4.5 mm, lanceolate, 1-veined, apex acute, adaxial surface sericeous, eglandular, abaxial surface glabrous, margin entire, ciliate, egladular; pedicels 4.5‒5 mm long; hypanthium 7‒10 × 4.5‒5.5 mm, cylindrical, sericeous, trichomes setose, eglandular, white (either fresh or dry); sepals 4.5‒10 × 1.5‒2 mm, triangular-lanceolate, apex acuminate, densely sericeous at the middle, trichomes setose eglandular, white (when fresh or dry), with an eglandular trichome between the sepals, 1.2‒1.5 mm long; petals ca. 15 × 10 mm, purple, obovate, apex obtuse, margin entire, eciliate or ciliate; stamens 10, subisomorphic, filaments filiform, erect, light purple, moderately to densely glandular at the ventral side, pedoconnectives short, light purple, ventral appendages present, purple, glabrous, bilobed, dorsal appengades present, bilobed, flattened, light purple, glabrous, anthers oblong, purple, slightly curved, rostrate, ventral surface corrugated, pore distal, ventrally inclined; filaments 6‒8 mm long, pedoconnectives 0.5‒1 mm long, ventral appendages 0.3‒ 0.6 mm long, dorsal appendages 0.4‒0.5 mm, anthers 7.5‒10 mm long; ovary superior, 5-locular, pluriovulate, apex velutinous, trichomes setose, eglandular, whitish; style ca. 20 mm long, filiform, lilac, densely pilose, trichomes setose, eglandular, white to light lilac, present to the lower half of the stylus, stigma truncate. Capsules 0.6‒0.9 × 0.4‒0.6 mm, whitish, covered by the persistent hypanthium, sepals deciduous. Seeds not seen.

Distribution, Habitat and Ecology:— Pleroma goyazense is endemic to Parque Estadual da Serra Dourada, in Goiás state, Brazil ( Fig. 4 ), occurring in cerrado rupestre (rupestrine savanna) on rocky outcrops or crevices, at approximately 975 m elevation, where it is uncommon (see Machado & Romero 2020).

Conservation status:—Following the categories and criteria proposed by the IUCN (IUCN 2012, 2022), P. goyazense should be preliminarily considered Critically Endangered (CR) due to its restricted area of occupancy (AOO = 8.00km 2) (criterion B2) and the extent of occurrence (EOO = 0.142 km 2) (criterion B1), occurrence in a single locality (criterion B2a), and populations estimated at less than 50 individuals (criterion D). Although a state conservation unit protects this species, so far, only one population with less than 30 individuals is known (D.O. Diniz, pers. comm.).

Phenology:—Materials with flowers were collected in April and May, and with fruits in May and October.

Etymology: —The specific epithet “ goyazense ” refers to the restricted occurrence of the new species in the state of Goiás, Brazil. The name “ Goiás ” originates from the name of the indigenous tribe “guaiás”, which means “equal individual, similar people, of the same race” (see IBGE 2023). This indigenous tribe may have lived in Goiás state in the 17 th century ( Quintela 2003). We apply the original spelling Goyaz, which was replaced by Goiás in 1943 (see Quintela 2003).

Paratypes: — BRAZIL. Goiás: Mossâmedes. Parque Estadual da Serra Dourada , 4 May 1969 (bud), J. A . Rizzo 4160 ( HUFU!, RB!); Serra Dourada, 1969 (fl), J. A . Rizzo 4061 ( RB!); ibidem, 19 April 1988 (bud, fl.), Ana & Wesley 6530 ( HUFU!); Serra Dourada, na cabeceira do rio dos índios, 13 May 1994 (fl), J. A . Rizzo 11355 ( HUFU!); Parque Estadual da Serra Dourada , 16°04’40.2”S 50°11’25.6”W, 989 m, 27 May 2021 (fl., fr.) D. O . Diniz et al. 1403 ( UFG!); Reserva Biológica Prof. José Ângelo Rizzo, Serra Dourada , 27 October 1997 (fr.), V. L . Gomes-Klein et al. 3333 ( UFG!); without a municipality specified, ca. 15 km (straight line) S of Goiás Velho, quartzite rock outcrops and soil, with cerrado, [approx. - 16.066667°S, - 50.171389°W], 10 May 1973 (fl.), W. R . Anderson et al. 10016 ( F [online image!], K [online image!], NY [online image!], RB!, US!) .

Figures

FIGURE 1. Pleroma goyazense A.I.M.R. Machado, R.Romero & P.J.F.Guim. A. Flowering branch. B. Detail of the leaf abaxial surface. C. Detail of the leaf adaxial surface. D. Hypanthium and sepals. E. Antepetalous stamen. F. Antesepalous stamen. G. Ovary apex, style and stigma. Drawn by Natanael Nascimento dos Santos from A.I.M.R. Machado et al. 15 (HUFU).

FIGURE 2. A‒F. Pleroma goyazense A.I.M.R. Machado, R.Romero & P.J.F.Guim. A. Cerrado rupestre in the Parque Estadual da Serra Dourada, Goiás state, Brazil. B. Shrub near a rocky outcrop. C. Upper vegetative branches. D. Inflorescence. E. Flower in frontal view. F. Floral bud, and flower after pollination without petals. Photos: Danielle de Oliveira Diniz.

FIGURE 3. A‒C. Pleroma goyazense A.I.M.R. Machado, R.Romero & P.J.F.Guim. A. Branch with villous indumentum. B. Leaf blade: bullate-strigose on the adaxial surface. C. Leaf blade:villous-setose on the abaxial surface.D‒F. Pleroma crassirrame (Cogn.) P.J.F.Guim. & Michelang. D. Branch with villous indumentum. E. Leaf blade: bullate on the adaxial surface. F. Leaf blade: villous on the abaxial surface. G‒I. Pleroma robustum (Cogn.) P.J.F.Guim. & Michelang. G. Branch with indumentum setose. H. Leaf blade: bullate on the adaxial surface. I. Leaf blade: villous and reticulate on the abaxial surface. Photos: A‒C. W.R. Anderson 10016 (RB); D‒F. P.G. Delprete 8965 (RB) and G‒I. A. Rizzo 4067 (RB).

FIGURE 4. Geographic distribution of Pleroma goyazense A.I.M.R. Machado, R.Romero & P.J.F.Guim. in Goiás state, Brazil.