Microlicia prostrata 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 : 60-62

Microlicia prostrata R.B.Pacifico & Almeda , sp. nov. ( Figs. 20–21 ).

Type:— BRAZIL. Bahia: Abaíra, Gerais próximas ao Pico do Elefante , 13°17’07.5”S, 41°54’18.7”W, 1900 m, 18 June 2022, fl.,fr., R. Pacifico 656, V.E. Bressan & E.A. Ramos (holotype: HUEM!, isotypes: CAS!, HUEFS!, RB!) .

Diagnosis:— Differs from Microlicia piatensis by the decumbent habit up to 0.2 m tall (vs. erect habit 0.5–1.5 m tall), leaf blades obovate to elliptic (vs. elliptic) with the bases attenuate (vs cuneate), and isomorphic stamens (vs. dimorphic) with pedoconnectives unappendaged (vs. with appendages 0.2–0.8 mm long).

Decumbent shrubs up to 0.2 m tall, dichotomously branched. Upper cauline internodes 0.5–2 mm long, light green (when fresh) becoming pale green (when dry) and defoliated with age, quadrangular, not sulcate, unwinged, densely glandular-punctate. Leaves decussate, ascending, concealing uppermost internodes (both when fresh and when dry), chartaceous, concolored, light green (when fresh) becoming pale green (when dry); petioles 0.3–0.8 mm long, light green, flattened; blades 2.5–3.5 × 1–1.5 mm, obovate to elliptic, apex rounded, base attenuate, margins entire and glandular-punctate, flat, both surfaces densely glandular-punctate, 1-nerved, venation impressed on both surfaces, secondary venation not evident. Flowers 5-merous on short pedicels 0.2–0.4 mm long (equal in length when in fruit), apical, solitary, ebracteolate. Hypanthia (at anthesis) 2.8–3.2 mm long, 2.5–3 mm wide at the torus, light green (when fresh) becoming pale brown in fruit (and when dry), campanulate, equaling the capsule in length at maturity, densely glandular-punctate. Calyx tubes ca. 0.2–0.3 mm long. Calyx lobes 0.6–1.1 mm long, 0.3–0.5 mm wide at the base, light green (when fresh) becoming pale brown (when dry), triangular to linear, apex acute, margins entire and glandular-punctate, externally glandular-punctate. Petals 4.5–5.5 × 3.5–4.5 mm, obovate, yellow, base attenuate, apex acuminate, both surfaces glabrous, margins entire and glabrous. Stamens 10, entirely yellow, isomorphic, erect and clustered around the base of the style; filaments 1–1.4 mm long, glabrous, thecae (excluding rostra) 1.6–1.9 × 0.4–0.5 mm, oblong, smooth (tetrasporangiate), rostra 0.1–0.2 mm long, the ventrally inclined pores ca. 0.1 mm wide, nearly circular, pedoconnectives 0.2–0.4 mm long, unappendaged. Ovary (at anthesis) ca. 1.5 × 1.1 mm, superior, subglobose, glabrous, 3-locular, not adnate to the hypanthium; style 4–5 mm long, yellow, glabrous, sigmoid, stigma punctiform. Fruit at maturity a globose loculicidal capsule ca. 2–2.5 × 1.5–2 mm, pale brown, ovoid, 3-valvate, enveloping hypanthia and rupturing and flaking away with age, dehiscent from the apex to the base (basipetal), columellas deciduous. Seeds ca. 0.3–0.4 × 0.2 mm, yellow, oblong, testa foveolate, raphal zone nearly circular, ca. 30% the length of the seed.

Additional specimen examined: BRAZIL. Bahia: Abaíra, Gerais próximas ao Pico do Elefante , 13°17’07.5”S, 41°54’18.7”W, 1900 m, 18 June 2022, fl., fr., R. Pacifico et al. 657 (CAS!, HUEM!, HUEFS!, RB!) .

Distribution, habitat and phenology:— Probably restricted to the Serra do Elefante in Abaíra, Bahia , Brazil ( Fig. 15 , Appendix 2). Microlicia prostrata was collected in campo rupestre ( Fig. 4 ) at 1900 m elevation, flowering and fruiting in June.

Etymology:— The epithet refers to the decumbent habit of this species, an atypical feature in the genus.

Notes:— Microlicia parvula ( Fig. 5F ) is another putative relative that shares with M. prostrata the glandularpunctate indumentum on the branches, leaves and hypanthia, triangular calyx lobes, yellow petals, and yellow isomorphic stamens (sometimes subisomorphic in M. parvula ) with pedoconnectives lacking conspicuous appendages. Microlicia prostrata can be differentiated by its decumbent habit up to 0.2 m tall (vs. erect habit, 0.3–1.5 m tall), leaves with petioles 0.3–0.8 mm long (vs. absent or up to 0.2 mm long), blades essentially obovate (vs. essentially ovate), and stamens with tetrasporangiate thecae (vs. polysporangiate). None of the putative relatives has been collected in the Serra do Elefante, where M. prostrata is apparently endemic ( Appendixs 1, 2).

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 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.

FIGURE 20. Microlicia prostrata, photos of living individuals. A. Habit. B. Branches terminating in floral buds. C–D. Flowers. All photos by R.Pacifico. Voucher: R. Pacifico et al. 656.

FIGURE 21. Microlicia prostrata, photos of dry specimens. A. Habit. B. Detail of branchlet C. Leaf adaxial surface. D. Leaf abaxial surface. E. Floral bud. F. Stamen. G. Gynoecium. H. Capsule enveloped by the hypanthium. I. Capsule after the hypanthium fell away. J. Seed in lateral view. Scale bars: A, 2 cm; B, 2 mm; C–I, 1 mm; J, 0.2 mm. Voucher: R. Pacifico et al. 656.