Microlicia barbata R.B.Pacifico & Almeda, 2022

Pacifico, Ricardo & Almeda, Frank, 2022, New species of Marcetia and Microlicia (Melastomataceae) endemic to the campo rupestre of Chapada Diamantina, Bahia, Brazil, Phytotaxa 573 (1), pp. 39-69 : 52-54

Microlicia barbata R.B.Pacifico & Almeda , sp. nov. ( Figs. 13–14 ).

Type:— BRAZIL. Bahia : Rio de Contas , Trilha para o Pico do Itobira , 13°22’35.4”S, 41°52’57.7”W, 1613 m, 16 June 2022, fl., fr., R. Pacifico 619, V.E. Bressan & E.A. Ramos (holotype: HUEM!, isotypes: CAS!, HUEFS!, RB!) .

Diagnosis:— Differs from Microlicia cryptandra Naudin (1845: 175) by the nodes of branches covered with shorter eglandular trichomes 0.5–1.2 mm long (vs. 2–3.5 mm long), shorter triangular calyx lobes 1.6–2 mm long (vs. 2.6–6.5 mm long) that are only glandular-punctate (vs. glandular-punctate and covered with glandular trichomes 0.5–1.5 mm long), petals glabrous on both surfaces (vs. glandular-punctate and/or with trichomes on both surfaces), and by the strongly dimorphic stamens with polysporangiate anthers (vs. subisomorphic stamens, tetrasporangiate anthers).

Erect shrubs 0.5–1 m tall, much-branched. Upper cauline internodes 2–4 mm long, light green (when fresh) becoming pale green (when dry) and defoliated with age, quadrangular, not sulcate, unwinged, densely glandularpunctate and covered with eglandular trichomes 0.5–1.2 mm long. Leaves decussate, ascending, concealing uppermost internodes (both when fresh and when dry), papyraceous, concolored, light green (when fresh) becoming pale green (when dry), sessile or on inconspicuous petioles up to 0.2 mm long; blades 2.5–4.5 × 1.5–2.5 mm, ovate, apex acute, base rounded to slightly cordate, margins slightly serrulate and ciliate with eglandular trichomes 0.5–1.2 mm long, marginal regions recurved, both surfaces densely glandular-punctate and covered with eglandular trichomes 0.5–1.2 mm long, 1-nerved, venation prominent on the abaxial surface and impressed on the adaxial surface, secondary venation not evident. Flowers 5-merous, sessile or on inconspicuous pedicels up to 0.2 mm long, apical, solitary, ebracteolate. Hypanthia (at anthesis) 3.3–3.8 mm long, 2.9–3.2 mm wide at the torus, light green (when fresh) becoming brownish (when dry), campanulate, ± equaling the capsule in length at maturity, densely glandular-punctate covered with vinaceous eglandular trichomes 0.5–1.2 mm long. Calyx tubes 0.2–0.3 mm long. Calyx lobes 1.6–2 mm long (excluding apical trichome), 1.5–1.8 mm wide at the base, light green (when fresh) becoming brownish (when dry), patent at anthesis, triangular, apex acuminate terminating in a vinaceous eglandular trichome 0.4–0.7 mm long, margins entire, eciliate, externally densely glandular-punctate. Petals 8–11 × 6–8 mm, obovate, magenta with a yellow base, the base attenuate, apex acute terminating in an inconspicuous eglandular trichome ca. 0.3 mm long, both surfaces glabrous, margins entire and glabrous to inconspicuously ciliate with minute eglandular trichomes up to 0.3 mm long. Stamens 10, entirely yellow, dimorphic, antesepalous anthers ± horizontal (at anthesis), subparallel and clustered, antepetalous anthers ± erect and clustered near the floral axis; antesepalous (larger) stamens with filaments 4.7–5.1 mm long, glabrous, thecae (excluding rostra) 4.2–4.7 × 0.5–0.8 mm, linear to oblong, corrugate (polysporangiate), rostra 0.3–0.5 mm long, the ventrally inclined pores ca. 0.2 mm wide, nearly circular, pedoconnectives 3–3.5 mm long, the short appendages 0.2–0.3 mm long, apex truncate; antepetalous (smaller) stamens with filaments 2.5–3.5 mm long, glabrous, thecae (excluding rostra) 2.7–3 × 0.5–0.8 mm, oblong, corrugate (polysporangiate), rostra 0.3–0.4 mm long, the ventrally inclined pores ca. 0.2 mm wide, nearly circular, pedoconnectives 1.5–1.9 mm long, the short appendages 0.1–0.3 mm long, apex truncate. Ovary (at anthesis) ca. 2.5 × 1.3 mm, superior, globose, glabrous, 3-locular, not adnate to the hypanthium; style 8–9 mm long, magenta with a yellow base, glabrous, sigmoid, stigma punctiform. Fruit at maturity a subglobose loculicidal capsule ca. 4–4.5 × 2–3 mm, pale brown, ovoid, 3-valvate, enveloping hypanthia, rupturing and flaking away with age, dehiscent from the apex to the base (basipetal), columellas deciduous. Seeds ca. 0.6–0.7 × 0.3 mm, yellow, oblong, testa foveolate, raphal zone nearly circular, ca. 20–30% the length of the seed.

Additional specimens examined:— BRAZIL. Bahia: Rio de Contas . Trilha para o Pico do Itobira , 13°22’35.4”S, 41°52’57.7”W, 1613 m, 16 June 2022, fl., fr., R. Pacifico et al. 620 ( CAS!, HUEM!, HUEFS!, RB!) ; Borda da Mata do Pico Itobira [“ Itoibira ”], 14 February 2006, fl., fr., A.K.A. Santos et al. 927 ( HUEFS!) .

Distribution, habitat and phenology:— Probably endemic to the Serra do Itobira region in Rio de Contas, Bahia , Brazil ( Fig 15 , Appendix 2). It was collected in campo rupestre ( Fig. 4 ) at 1613 m, exposed to full sun, flowering and fruiting in February and June.

Etymology:— The epithet refers to the beard-like indumentum on the hypanthia, which is absent on the calyx lobes, and makes this species easily distinguishable from its congeners.

Notes:— Microlicia barbata differs from Microlicia fasciculata Martius ex Naudin (1845: 180) by the hypanthia that are covered with red eglandular trichomes (vs. white), which are absent on the calyx tube and calyx lobes (vs. present), and linear anthers (vs. oblong) that are longer than those of M. fasciculata in both antesepalous (4.2–4.7 mm long vs. ca. 2.5 mm long, respectively) and antepetalous stamens (2.7–3 mm long vs. ca. 2 mm long). Microlicia comparilis Wurdack (1984: 136) is another putative relative and shares with M. barbata a dense indumentum of glandular trichomes on the branches and both leaf surfaces, ascending 1-nerved leaves, and magenta petals. Microlicia barbata differs by its indumentum composed of longer trichomes 0.5–1.2 mm long (vs. 0.3–0.4 mm long), ovate leaf blades (vs. lanceolate), calyx lobes only glandular-punctate (vs. glandular-punctate and covered with eglandular trichomes), and dimorphic stamens (vs. isomorphic). Microlicia barbata , M. comparilis , and M. fasciculata probably grow together at Rio de Contas. In turn, M. cryptandra ( Fig. 5D ) is endemic to Goiás ( Versiane et al. 2016, Diniz & Silva 2020). We suspect that the distribution of M. cryptandra in Minas Gerais reported by Romero et al. (2022b) was based on H.S. Irwin et al. 24643 (NY). That record is erroneous as this specimen was collected in Chapada dos Veadeiros (Goiás), although it was mistakenly assigned to Minas Gerais state on the label.

Nomenclatural note:— Romero et al. (2022a) recently proposed the name Microlicia hirsuta ( Candolle 1828: 119) R. Romero, Versiane & Woodgyer (2022a: 113) as a new combination based on Microlicia variolosa var. hirsuta Candolle (1828: 119) [= M. fasciculata ]. This name is superfluous because “ hirsuta ” is a varietal name and does not have priority outside of its rank. Therefore, here we recognize M. fasciculata as the valid name for this species.

Suggested conservation status:— Data Deficient (DD; see Appendix 2).

Figures

FIGURE 4. Landscapes with campo rupestre vegetation in Chapada Diamantina, Bahia, Brazil. A. Serra da Batávia, Mucugê – type locality of Marcetia auricularia and Microlicia daneui. B. Serra do Barbado,Abaíra – type locality of Marcetia santosiae. C. Pico do Elefante,Abaíra – type locality of Microlicia prostrata (in the background, Serra do Barbado). D. Serra do Porco Gordo, Arapiranga (Rio de Contas) – type locality of Microlicia tetramera. E. Serra do Esbarrancado, Guiné (Mucugê) – type locality of Marcetia unguiculata. F. Serra do Gobira, Mucugê. Photos:A, by U. Marques; B–F, by R. Pacifico.

FIGURE 5. Selected photos of species compared to new taxa described in this study. A–B. Marcetia nummularia. A. Habit. B. Flower close up. C. Microlicia obovatifolia, flower close up. D. Microlicia cryptandra, flowering branch. E. Microlicia noblickii, flower close up. F. Microlicia parvula, flowering branch. G. Microlicia sulfurea, flowering branch. H. Microlicia juniperina, flowering branches. Photos: A–B, E, H, by R. Pacifico; C–D, F, by F. Almeda; G, by J.A. Siqueira Filho (HVASF herbarium).

FIGURE 13. Microlicia barbata, photos of living plants.A. Flower close up. B. Branches terminating in floral buds. Photos by R.Pacifico. Voucher: R. Pacifico et al. 619.

FIGURE 14. Microlicia barbata, photos of dry specimens. A. Habit. B. Detail of branchlet. C. Leaf abaxial surface. D. Leaf adaxial surface. E. Floral bud. F. Petal adaxial surface. G. Antesepalous stamen. H. Antepetalous stamen. I. Gynoecium. J. Capsule enveloped by the hypanthium. Scale bars:A, 2 cm; B, E–J, 2 mm; C–D, 1 mm. Vouchers:A, A.K.A. Santos et al. 927; B–J, R. Pacifico et al. 619.

FIGURE 15. A. Brazil with Bahia state highlighted. B. Bahia with the study area outlined (dashed line). C. Distributions of Microlicia barbata, Microlicia prostrata, and Microlicia tetramera in the Chapada Diamantina, Bahia, Brazil.