Microlicia flavistyla R. B. Pacifico, Almeda & R. Goldenb., 2025

Pacifico, Ricardo, Almeda, Frank, Engels, Mathias Erich & Goldenberg, Renato, 2025, Two new species of Microlicia (Melastomataceae) from unprotected campo rupestre in the western Chapada Diamantina, Bahia, Brazil, PhytoKeys 266, pp. 253-265 : 253-265

Microlicia flavistyla R. B. Pacifico, Almeda & R. Goldenb. sp. nov.

Figs 2 D – F , 4

Type.

Brazil • Bahia: Ibitiara. Cadeia do Espinhaço, Chapada Diamantina , 12°31'46"S, 42°03'43"W, 1,238 m, 15 Jan 2025, fl., M. E. Engels & D. Liebsch 12720 ( holotype: UPCB barcode UPCB 0095340 !, isotypes: CAS!, RB!) .

Diagnosis.

Differs from M. oligochaeta Wurdack by the modally shorter leaves, 2.7–4.6 × 1.2–3.3 mm (vs. 4 – (5–7) × 3–5 mm in M. oligochaeta ), that are imbricate to subimbricate (vs. not imbricate), with both surfaces only glandular-punctate (vs. with sparse eglandular trichomes on both surfaces), 1 - nerved (vs. 3 - nerved), and flowers with shorter calyx lobes, 1.5–1.9 mm long (vs. 2.7–3.2 mm long), and a yellow style (vs. pink or white).

Description.

Copiously branched erect shrubs ca. 0.5 m tall. Branchlets light green (when fresh), quadrangular, glandular-punctate, and sparsely covered with eglandular trichomes 0.5–1.2 mm long, the stem angles unwinged. Leaves ascending (when fresh), flat, decussate, ca. 2 times longer than the internodes, on flattened petioles 0.5–0.8 mm long; blades 2.7–4.6 × 1.2–3.3 mm, elliptic to narrowly elliptic, papyraceous, both surfaces vivid green when fresh, pale green when dry, base cuneate to attenuate, margin entire and ciliate with eglandular trichomes 0.5–1.2 mm long, the apex acute to rounded, 1 - nerved from the base, venation slightly impressed on the abaxial surface and inconspicuous on the adaxial surface, both surfaces densely glandular-punctate. Flowers (4 -) 5 - merous on inconspicuous pedicels 0.3–0.4 mm long, solitary, terminal, sometimes clustered at the apex of the branchlets. Hypanthia (at anthesis) 2.6–2.8 mm long, 2.0– 2.5 mm wide at the torus, yellowish green when fresh, turning brown when dry, campanulate, densely glandular-punctate. Calyx tubes 0.2–0.4 mm long; calyx lobes (at anthesis) 1.5–1.9 mm long (excluding apical trichome), 0.9–1.1 mm wide at the base, triangular, apex acute terminating in an eglandular, persistent trichome ca. 1.0– 1.2 mm long, externally glandular-punctate, the margin entire and ciliate with eglandular trichomes ca. 1.8–2.8 mm long, each calyx lobe also alternating with one or a few eglandular, persistent trichomes ca. 1.8–2.8 mm long. Petals 9–11 × 5–7 mm, widely obovate, pink, margin entire, apex bluntly acute to obtuse or emarginate, both surfaces glabrous. Stamens (8) 10, dimorphic, entirely yellow; larger (antesepalous) stamens (4) 5, filaments 4.2–4.4 mm long, pedoconnectives 6.6–6.9 mm long, appendages 1.3–1.5 mm long, apex truncate, thecae 2.0– 2.4 mm long (excluding the rostrum), oblong, yellow, externally corrugated (polysporangiate), rostra 0.3–0.5 mm long, white, the circular pores 0.1–0.3 mm wide, ventrally inclined; smaller (antepetalous) stamens (4) 5, filaments 3.2–3.6 mm long, pedoconnectives 2.7–2.9 mm long, appendages 0.9–1.0 mm long, apex truncate, thecae 1.8–2.0 mm long (excluding rostra), oblong, yellow becoming brownish in post-anthesis, externally corrugated (polysporangiate), rostra 0.3–0.5 mm long, the circular pores 0.1–0.2 mm wide, ventrally inclined. Ovaries ca. 2.1 × 1.4 mm, ovoid, superior, glabrous, 3 - locular; styles 6.6–7.1 mm long, linear, yellow, stigma punctiform. Loculicidal capsules 3.6–3.8 × 2.5–2.9 mm when mature, ovoid, brownish when dry, initially enveloped by the constricted hypanthium at the apex (neck ca. 0.6 mm long), then tardily rupturing and flaking away with age, the apex not exceeding the torus, dehiscent from the apex to the base, columellas caducous. Seeds not seen.

Distribution, habitat, and phenology.

Like M. integra , M. flavistyla is known only from the Serra de Ibitiara (western Bahia; Fig. 5 ), where it has been found on campo rupestre at 1,238 m elevation (Fig. 2 A ). Collected flowering and fruiting in January.

Recognition.

Microlicia flavistyla can be recognized by its 1 - nerved, petiolate leaves, measuring 2.7–4.6 × 1.2–3.3 mm, with eglandular trichomes 0.5–1.2 mm long restricted to the margins; flowers with pink petals and yellow stamens and style; and polysporangiate anthers.

In addition to its similarities with M. oligochaeta (see diagnosis), it also resembles M. wurdackiana but differs in that its leaf blades are narrowly elliptic (vs. orbicular-elliptic), glandular-punctate on both surfaces (vs. covered with eglandular trichomes ca. 0.3 mm long on both surfaces), hypanthia only glandular-punctate (vs. densely covered with eglandular trichomes), and calyx lobes ciliate with trichomes 1.8–2.8 mm long (vs. margin of calyx lobes fringed and glandular-punctate). Like M. integra , M. flavistyla is also evidently allopatric with its morphologically closest relatives (Fig. 5 ). For a comparison with M. integra , see comments under that species.

Etymology.

The specific epithet flavistyla is derived from the Latin flavus (“ yellow ”) and stylus (“ style ”), referring to the species’ distinctive yellow styles. This contrasts with its closest relatives, in which the styles are pink or white.

Additional specimen examined ( paratype).

Brazil • Bahia: Ibitiara. Cadeia do Espinhaço, Chapada Diamantina , 12°31'46"S, 42°03'43"W, 1,238 m, 15 January 2025, fr., M. E. Engels 12717 & D. Liebsch ( CAS!, RB!, UPCB!) .

Figures

Figure 2. A. Landscape at the Serra de Ibitiara, Bahia, Brazil; B, C. Microlicia integra; B. Habit; C. Flowering branches; D – F. Microlicia flavistyla; D. Habit; E. Branchlet terminating in a flower at anthesis, view from behind; F. Branchlet terminating in a flower at anthesis, in lateral view; Photos: A – C, by R. Pacifico; D – F, by M. E. Engels.

Figure 4. Microlicia flavistyla. A. Habit; B. Branchlet terminating in a flower; C. Leaf adaxial (left) and abaxial (right) surfaces; D. Detail of leaf margin trichome; E. Petal in adaxial view; F. Floral bud; G. Detail of a calyx lobe; H. Flower in lateral view; I. Antepetalous (left) and antesepalous (right) stamens; J. Gynoecium and enveloping hypanthium at anthesis; K. Capsule enveloped by the hypanthium. Drawn from M. E. Engels 12720 & D. Liebsch.

Figure 5. Distribution of Microlicia flavistyla and probable relatives. A. Brazil with Bahia state highlighted; B. Bahia; C. Distribution of M. flavistyla, M. oligochaeta, and M. wurdackiana on the Chapada Diamantina.