Microlicia decumbens Gali, Almeda & Fidanza, 2022

Gali, Lorena, Pacifico, Ricardo, Almeda, Frank & Fidanza, Karina, 2022, Two new species of Microlicia (Melastomataceae) from Chapada Diamantina, Bahia, Northeastern Brazil, Phytotaxa 544 (1), pp. 52-60 : 53-56

Microlicia decumbens Gali, Almeda & Fidanza spec. nov. ( Figs. 1 , 2A .)

Diagnosis: — Microlicia decumbens can be recognized by its decumbent habit, reaching ca. 0.25 m tall, branchlets and leaves densely glandular-punctate, leaves linear, an eglandular trichome between the calyx lobes, and isomorphic stamens with inconspicuous ventral appendages.

Type: — BRAZIL. Bahia: Abaíra, Serra da Tromba, Nascente do Rio de Contas , 13°16’S, 41°47’W, 1500 m, 18 December 1992, W. Ganev 1680 (holotype: HUEFS!, isotypes: HUFU-online image!, SPF!, US-online image!) .

Branched decumbent subshrubs ca. 0.25 m tall. Branchlets rounded, densely glandular-punctate. Leaves on short flattened petioles up to 0.4 mm long; blades 2.1–5.8 × 0.5–0.6 mm, linear, coriaceous, glutinous, green and blackened (when dry), base attenuate, margin entire, apex rounded, both surfaces densely glandular-punctate, 1-nerved from the base, the midvein impressed on the adaxial surface. Flowers 5-merous and solitary, pedicels 0.3–0.5 mm long; hypanthia 2–2.2 mm long, 2.2–2.4 mm wide at the torus, campanulate, externally glandular-punctate; calyx tubes ca. 0.1–0.3 mm long; calyx lobes 1.8–2 mm long, 0.2–0.4 mm wide at the base, lanceolate, margin entire, apex acute with a terminal eglandular trichome 0.1–0.3 mm long, with one eglandular trichome 0.6–0.8 mm long between the calyx lobes; petals ca. 5 × 3 mm, obovate, yellow, margin entire, apex acute, both surfaces glabrous; stamens 10, isomorphic: filaments ca. 1.8 mm long, connectives ventrally prolonged ca. 0.2 mm below the thecae, appendages inconspicuous, yellow, thecae ca. 1.7 mm long (excluding the rostra), oblong, yellow, externally smooth (tetrasporangiate), rostra ca. 0.1 mm long, the circular pores ca. 0.1 mm wide; ovaries ca. 1.2 × 1.0 mm, obovoid, superior, glabrous, 3- locular; styles ca. 5 mm long, linear, glabrous, stigmas punctiform. Capsules ca. 3.8 × 3.8 mm, loculicidal, globose, vinaceous-brownish, enveloped by the hypanthia, the apex not exceeding the torus, dehiscent from the apex to the base, columellas deciduous. Seeds ca. 0.4 mm long, reniform, testa foveolate, brownish, raphal zone nearly circular, ca. 1 / 3 length the overall seed.

Distribution, habitat, and phenology: — Microlicia decumbens is probably endemic to campo rupestre areas with sandy soils in Abaíra municipality, Chapada Diamantina, Brazil ( Fig. 3 ). It was collected with flowers and fruits in December.

Conservation status:— We regard the conservation status of this species as Data Deficient (DD) following IUCN guidelines and criteria ( IUCN 2022), until additional collections are made. The municipality of Abaíra is not part of a protected area and despite some studies in these areas ( Woodgyer & Zappi 2005, Romero & Woodgyer 2018, Pacifico & Almeda 2018) it is still lacks studies for the genus Microlicia .

Etymology: —The specific epithet refers to the decumbent habit of this species, that is, the stem is reclined to the soil but the branches are raised ( Beentje 2010).

Affinities: — Microlicia decumbens is morphologically related to M. abairana , M. intercalycina and M. parvula ( Table 1 ). All these share with M. decumbens a similar glandular-punctate indumentum on branches and leaves and yellow petals. Besides, Microlicia decumbens also resembles M. abairana in having petiolate leaves similar in size (2.1-5.8 × 0.5–0.6 mm M. decumbens vs. 3-4 × 0.6-0.8 mm M. abairana ), petal size (ca. 5 × 3 mm M. decumbens vs. 5-6 × 2-3 mm M. abairana ). It differs from M. abairana by its linear leaf blades (vs. lanceolate), in having an eglandular trichome between the calyx lobes (vs. absent), and isomorphic stamens (vs. dimorphic M. abairana ). Microlicia decumbens bears other similarities with M. parvula as both have a campanulate hypanthium, obovoid ovary and isomorphic stamens. Microlicia decumbens can be distinguished from M. parvula by its linear leaf blades (vs. lanceolate) and in having an eglandular trichome between calyx lobes (vs. absent). Among probable relatives, the presence of an eglandular trichome between the calyx lobes is shared only with M. intercalycina , from which M. decumbens can be recognized by its linear leaves (vs. elliptic) with the margin entire (vs. ciliate), and isomorphic stamens (vs. dimorphic). The code for M. decumbens in the multi-access key for Bahian species of Microlicia (Woodgyer 2005) is CDGJNQTVae.

Notes: — Microlicia decumbens was treated as “ Microlicia sp. 7 (G1680)” in the “Checklist of vascular plants of Catolés” ( Zappi et al. 2003).

Figures

FIGURE 1. Microlicia decumbens. A. habit; B. leaf abaxial (left) and adaxial (right) surfaces; C. details of a leafy branch and flower; D. flowering hypanthium and calyx lobes (androecium and style removed); E. adaxial view of a petal; F. stamen (ventral view); G. gynoecium; H. ovary in cross section; I. detail of the stigma; J. capsule enveloped by hypanthium and calyx lobes. Line drawings by Klei R. Souza.

FIGURE 2. A. Microlicia decumbens, photograph of the isotype at US. B. Microlicia macaubensis, photograph of the holotype at MBM.

FIGURE 3. Distribution of Microlicia decumbens and Microlicia macaubensis in Bahia, northeastern Brazil.