Microlicia indurata Almeda, R.B.Pacifico & A.B.Martins, 2023

Almeda, Frank, Pacifico, Ricardo, Martins, Angela B. & Medeiros, João Deus, 2023, Microlicia indurata (Melastomataceae: Lavoisiereae), a new narrow endemic from Serra dos Pireneus, Goiás, Brazil, Phytotaxa 619 (4), pp. 285-292 : 286-289

Microlicia indurata Almeda, R.B.Pacifico & A.B.Martins , sp. nov. ( Figs. 1 , 2 )

Type:— BRAZIL. Goiá s: Município de Pirenópolis : Serra dos Pireneus, encosta rupestre próxima a trilha para a Cachoeira do Abade, no entorno do Parque Estadual da Serra dos Pireneus, 15.8397⁰ S, 48.8857⁰ W, elev. 1031 m, 18 February 2017, fl., J. D. Medeiros s.n. (holotype: UEC-184045, digital image!; isotypes: CAS-699605!, FLOR-0029497, digital image!) .

Diagnosis:— Microlicia indurata can be distinguished from M. pohliana by its openly branched shrubby habit to 70 cm tall lacking corky bark (vs. much-branched large shrub or small tree 2–3 m tall with corky bark), internodes 4–9 mm long (vs. 3–5 mm long), adaxial foliar surfaces covered with gland-tipped trichomes 0.5 mm long (vs. glabrous), large calyx lobes 12–13 × 5–6 mm that greatly exceed hypanthia at anthesis (vs. 5–6 × 2.5–3.5 mm that barely exceed hypanthia), uniformly white petals (vs. white petals that are yellow at the base), pedoconnectives on the larger (antesepalous) set of stamens that are 5 mm long (vs. pedoconnectives on larger stamens that are ca. 10 mm long), fruiting hypanthia that rupture and fall away at maturity (vs. fruiting hypanthia that are thick, woody and envelop capsules long after the latter have dehisced), mature capsules are conic apically and often protrude somewhat beyond the hypanthial torus (vs. capsules rounded apically and never protruding beyond hypanthial torus).

Erect, openly branched shrubs to 70 cm tall. Upper branches and branchlets rounded to somewhat compressed, sulcate and longitudinally furrowed on two of the four opposing faces, the angles with prominent green wings ca. 0.5 mm wide, copiously covered with spreading gland-tipped trichomes mostly 0.5 mm long; internodes 4–9 mm long with somewhat thickened scars where leaves have fallen away, the nodes mostly devoid of indumentum on older defoliated branches. Leaves sessile, widely spreading: blades 16–30 × 8–14 mm, chartaceous when dry, elliptic-lanceolate to elliptic-ovate, base broadly rounded to subcordate, apex acuminate, margins entire and beset with glandular trichomes 0.5–0.75 mm long, adaxial surface moderately to sparsely beset with spreading gland-tipped trichomes 0.5 mm long mostly between the impressed primary and secondary veins, abaxial surface moderately to sparsely beset with spreading gland-tipped trichomes 0.5 mm long on and between the elevated primary and secondary veins, conspicuously 5–7- nerved from the base (basal acrodromous), tertiary veins not evident on abaxial surface. Flowers 6-merous, solitary, terminal on primary and secondary branchlets but typically becoming central with elongation of lateral branchlets, sessile, subtended by several sessile bracts 13–17 × 4–9 mm, ovate to elliptic-lanceolate, base obtuse to rounded or subcordate, apex attenuate, margins and abaxial surface with indumentum like the mature leaves, adaxial surface mostly glabrous, 3–7-nerved. Hypanthia (at anthesis) 4–5 mm long, campanulate, 4–5 mm wide at the torus, not constricted above the torus at anthesis, moderately to copiously covered with a mixture of minute, nearly sessile glands and elongate ± appressed white inconspicuously gland-tipped trichomes 0.5–1 mm long. Calyx tube ca. 0.5 mm long; calyx lobes (at anthesis) 12–13 × 5–6 mm, chartaceous, oblong to lanceolate, apex acute and tipped with an eglandular trichome 0.5 mm long, margins glandular-ciliate with abaxial indumentum like the hypanthia, the adaxial surface sparingly covered with identical trichomes distally or essentially glabrous, lobes caducous on mature hypanthia. Petals 26–34.1 × 17–21.1 mm, white, the abaxial surface of petals in bud also completely white on exposed margins, obovate, apex rounded to truncate sometimes varying to shallowly retuse or obtuse, margins eciliate. Stamens 12, dimetric and dimorphic, glabrous; large (antesepalous) stamens 6, filaments 7.5 mm long, white, anther thecae 5 × 1 mm (including 1 mm long rostrum with a ventrally inclined pore), red, oblong, smooth (tetrasporangiate), ± horizontal at anthesis, pedoconnectives 5 mm long, yellow, curved, appendages ca. 1.5 mm long, yellow, blunt, ± rounded-truncate and inconspicuously bilobed; small (antepetalous) stamens 6, filaments ca. 6.5 mm long, white, anther thecae 5 × 1 mm (including 0.75 mm long rostrum with a ventrally inclined pore), at first yellow then becoming orange or brown (with age or following pollination), oblong, smooth (tetrasporangiate), ± erect (at anthesis), pedoconnectives 2 mm long, yellow, curved, appendages ca. 0.75 mm long, ± truncate and bluntly lobed. Ovaries 6-locular, ca. ⅓ inferior, ± ovoid. Styles ca. 9–10 mm long, white, glabrous, declined to one side of flower opposing large red stamens at anthesis, stigmas punctiform. Fruiting hypanthia (excluding deciduous calyx lobes) 10–11 × 9–11 mm, suburceolate, rupturing and flaking away with age. Capsules (at maturity) loculicidal, 11–12 × 10 mm, thick and woody, ovoid, the conic apex often protruding somewhat beyond the torus, dehiscing from the base to the apex with each separating carpel tapering to a sharp acute apex, columella persistent. Seeds 0.50–0.70 × 0.06–0.41 mm, oblong to subreniform, brown, testa foveolate, raphal zone somewhat sinuously oblong, ca. 50–60 % the length of the seed.

Paratypes:― BRAZIL. Goiás: Município de Pirenópolis, haut du Morro do Abade, près de Meia Ponte, 8 September 1894, fr., Glaziou 21307 (BR-550695! BR-550698!, C!, G!, P!); Serra do Arruda , près des Pyreneos, 27 April 1895, fr., Glaziou 21308 (BR-550692! BR-550689!, C!, F-photo!, G!, K!, LE!, P!, R-digital image!) .

Distribution, Habitat, and Phenology:— Microlicia indurata is known only from Serra dos Pireneus, Goiás, Brazil, where it grows on sloping rock outcrops in cerrado rupestre at just over 1000 m elevation ( Fig. 3 ). It was collected in flower in February and in fruit in April and September.

Conservation Status:—Two of the three known gatherings of M. indurata were collected over 120 years ago; one (Glaziou 21308) appears to have been collected within the current boundary of Parque Estadual da Serra dos Pireneus. The type and the other gathering (Glaziou 21307) were collected southwest of the park border. We were not able to calculate AOO or EOO values because none of the known collections of this species were georeferenced. We assign a Data Deficient (DD) status to this species at this time. Since at least one population of this new species occurs in a protected area it is afforded some protection. The other populations represented by the type gathering and Glaziou 21307 are vulnerable since establishing new protected areas or expanding existing ones like Parque Estadual da Serra dos Pireneus is difficult and expensive ( Sax 2023) and agricultural pursuits focused on soybean production are increasingly destroying or degrading the southern cerrado and interdigitating habitats like veredas, gallery forests, rocky fields, and semi-deciduous forests in Goiás state. The park was established on 20 November 1987 by law 10.321/87 to insure the protection of Pico dos Pireneus, the highest point (elevation 1,385 m) in Goiás and to preserve natural ecosystems (especially rocky cerrado) for research, education, and nature tourism. The park encompasses an area of 2,833 hectares in a mountainous region of quartzite and sandstone rock formations dating back to the Precambrian era. It is located between the municipalities of Pirenópolis, Cocalzinho de Goiás, and Corumbá de Goiás in the watershed between the Plata and Tocantins river basins ( Castro et al. 2019).

Etymology: — The specific epithet is derived from the Latin word, induro, which means hardened. It refers to the woody capsules that are thick and hard at maturity unlike the majority of congeners.

Affinities:— Microlicia indurata is readily recognized by its lax openly branched habit ( Fig. 2A ), sessile elliptic-lanceolate to elliptic-ovate leaves that are moderately covered with spreading gland-tipped trichomes on both surfaces, 6-merous sessile flowers, elongate calyx lobes that greatly exceed the hypanthium at anthesis ( Fig. 1E ), uniformly white petals, red antesepalous anthers ( Fig. 2D ), and thick woody capsules that are acutely domed apically ( Fig. 1L ). Among described congeners it appears to be closest to M. pohliana (O.Berg ex Triana 1872: 30) Versiane & R.Romero (2021: 54) of Goiás and Minas Gerais. They share prevailingly 6-merous flowers, 6-locular ovaries, caducous calyx lobes, petals that are largely white on the adaxial surfaces, large (antesepalous) anthers that are red, and capsules that dehisce from the base to the apex. The small (antepetalous) anthers are yellow in both species but in M. indurata this anther series often becomes discolored (brownish) perhaps resulting from bruising following pollination ( Fig. 2D ). Detailed line drawings of M. pohliana are included in Munhoz & Proença (2000: 61) and Martins & Almeda (2017: 138). The only colored flower photo of M. pohliana that we know of appears in Proença et al. (2000: 123) under the taxonomic synonym Lavoisiera fragilis (Cogniaux ex Munhoz & Proença 2000: 60–63) . The photos identified as Lavoisiera fragilis in Medeiros (2011: 346) are in fact Microlicia indurata . Microlicia pohliana was described as having capsules that dehisce from the apex to the base ( Martins & Almeda 2017: 137). The thickened persistent hypanthia that envelop the capsules of M. pohliana make this feature difficult to see. An examination of additional dry material and dissection of several hardened hypanthia reveals that capsule dehiscence in this species is in fact from the base to the apex like M. indurata and the majority of species in the Lavoisiera clade of Microlicia ( Martins & Almeda 2017) . In addition to the differences between M. indurata and M. pohliana enumerated in the diagnosis, the former can be further distinguished by its petals that are uniformly white ( Fig. 2C ) on the abaxial surface (vs. commonly having an asymmetrical red or pink band on the abaxial side of each petal especially evident in bud), leaf blades that are essentially flat when fresh and dry (vs. leaves that are bent and curved downward at the apex), and smaller seeds (0.50–0.70 × 0.06–0.41 mm) that are not tapered on the chalazal side (vs. somewhat larger seeds 1.14–2.04 × 0.70–0.82 mm that are tapered on the chalazal side).

As noted in the introduction, Microlicia indurata was thought to be close to M. nervulosa because of shared foliar morphology, indumentum details, and ovary locule numbers ( Martins & Almeda 2017). The latter, which is endemic to Bahia, differs consistently in having leaf blades that are 6–11(–14)-nerved with only the midvein and inframarginal pair extending to the apex, pedicellate flowers, hypanthia and calyx lobes that are densely covered with spreading glandular trichomes and hypanthia that are markedly constricted at the ovary apex into a cup-like vessel with flaring calyx tube and persistent lobes, petals that are prevailingly yellow but sometimes pink, totally yellow androecium, and completely inferior ovary ( Martins & Almeda 2017). The only other species that is somewhat reminiscent of M. indurata is M. mucorifera (Martius & Schrank ex Candolle 1828: 103) Versiane & R.Romero (2021: 54) , a Minas Gerais endemic that has 5–6-merous flowers, a 6-locular ovary, and a similar indumentum of spreading gland-tipped trichomes. Microlicia mucorifera differs from M. indurata in having smaller leaves (5–17 × 3–8 mm), petals that are prevailing pink with a white base (rarely pale pink or white throughout), a totally yellow androecium, a ⅔ inferior ovary, and smaller mature capsules (5–7 × 3.5–4 mm) with a rounded apex.

Figures

FIGURE 1. Microlicia indurata. A. Habit. B. Representative leaf (adaxial surface). C. Representative leaf (abaxial surface). D. Flower at anthesis (profile view). E. Hypanthium (at anthesis) with petals and androecium removed. F. Enlargement of indumentum details on hypanthium. G. Petal (adaxial surface). H. Antesepalous stamen (profile view) upper right and antepetalous stamen (profile view) lower left. I. Ovary and style. J. Ovary in cross section. K. Mature hypanthium. L. Capsule showing conic apex, dehiscence, and enveloping hypanthium flaking away. M. Seed (profile view). A–J drawn from UEC holotype, K–M from CAS isotype.

FIGURE 2. Field photos of Microlicia indurata. A. Habit showing lax open branching. B. Branch showing leaf posture. C. Flower bud showing petals that are completely white. D. Flower showing horizontal red antesepalous (large anthers) and brownish discolored erect antepetalous anthers. All photos by J.D. Medeiros.

FIGURE 3. Distributions of Microlicia indurata, M. mucorifera, M. nervulosa, and M. pohliana.