Microlicia bicolor R. B. Pacifico, Almeda & Gali 2022, sp. nov.
Creators: name: Pacifico, Ricardo
name: Almeda, Frank
name: Gali, Lorena
name: Fidanza, Karina
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Myrtales
Melastomataceae
Microlicia
Microlicia bicolor

description: Microlicia bicolor R.B.Pacifico, Almeda & Gali, sp. nov. (Figs. 1–2)
Type:— BRAZIL. Bahia: Mucugê, Distrito of Guiné, Parque Nacional Chapada Diamantina, Beco do Guiné trail upslope to the Vale do Pati, 12°45’25.7”S, 41°30’43.8”W, 1,187 m, 21 May 2019, fl., fr., F. Almeda 10748, R.B. Pacifico, L. Daneu & L.C. Gomes (holotype: HUEM!, isotypes: CAS!, CEPEC!).
Diagnosis:— Microlicia bicolor differs from M. torrendii by its 1-nerved leaves (vs. 1-3-nerved in M. torrendii), the midvein slightly impressed on the abaxial surface (vs. prominent), calyx lobes terminating in a longer eglandular trichome ca. 0.5 mm long (vs. no apical trichome or a short one ca. 0.2 mm long), petals basally overlapping during anthesis (vs. non-overlapping) that are pale pink with a yellow base, or white faintly flushed with pink and a yellow base (vs. entirely magenta), and staminal filaments, pedoconnectives, and appendages that are yellow (vs. reddish or magenta).
Copiously branched divaricate erect shrubs ca. 0.5 m tall, xylopodiferous. Branchlets light green (when fresh), subquadrangular, glandular-punctate, the stem angles unwinged or with narrow wings ca. 0.1 mm wide. Leaves spreading, flat, decussate, sessile, imbricate, ca. 2–3 times longer than the internodes; blades 5–8.5 × 1.5–6 mm, ovate to lanceolate, chartaceous, both surfaces vivid green when fresh, pale green when dry, base rounded, margin entire and glandular-punctate, the apex acute or rounded, eventually terminating in a rigid eglandular trichome up to 0.5 mm long (caducous), 1-nerved, the vein ca. 1 mm wide at the leaf base becoming faint towards the apex, impressed on the adaxial surface and slightly impressed on the abaxial surface, both surfaces densely glandular-punctate, tertiary veins absent. Flowers 5-merous on pedicels ca. 0.5 mm long, solitary, clustered at the apex of the branchlets, terminal or axillary. Hypanthia (at anthesis) 4.5–5.3 mm long, 3.8–4 mm wide at the torus, green when fresh turning pale-brown when dry, campanulate, densely glandular-punctate. Calyx tubes inconspicuous up to 0.2 mm long. Calyx lobes (at anthesis) 2.5– 3.5 mm long, 1.5–2 mm wide (at the base), narrowly triangular, margin entire and glandular-punctate, apex rounded to acute, terminating in an eglandular trichome ca. 0.5 mm long (caducous), externally glandular-punctate. Petals 9.5–11 × 6.5–7.5 mm, obovate, pale pink with a yellow base, or white faintly flushed with pink and a yellow base, margins entire, apex rounded to bluntly acute or obtuse, both surfaces glabrous. Stamens 10, dimorphic; larger (antesepalous) stamens 5, filaments 3.9–4.1 mm long, yellow, pedoconnectives 4.1–4.4 mm long, yellow, appendages 1.4–1.6 mm long, yellow, apex truncate to slightly emarginate, thecae 3–3.2 mm long (excluding the rostrum), linear-oblong, yellow becoming brownish in post-anthesis, externally slightly corrugated, polysporangiate, rostra 0.7–0.9 mm long, white, the circular pores ca. 0.2–0.3 mm wide, ventrally inclined; smaller (antepetalous) stamens 5, filaments 2.6–2.9 mm long, yellow, pedoconnectives 2.4–2.6 mm long, yellow, appendages 0.9–1.1 mm long, apex truncate, thecae 2.4–2.8 mm long (excluding the rostra), linear-oblong, yellow becoming brownish in post-anthesis, externally slightly corrugated, polysporangiate, rostra 0.4–0.6 mm long, the circular pores ca. 0.1–0.2 mm wide, ventrally inclined. Ovaries ca. 2.5 × 2 mm, ovoid, superior, glabrous, 3-locular; style ca. 8.5 mm long, declinate, linear, yellow, stigma punctiform. Loculicidal capsules 4–5 × 2.8–4 mm (when mature), ovoid, brownish (when dry), initially enveloped by the hypanthium that is constricted at the apex (forming a tube 1–2 mm long), then tardily rupturing and flaking away with age, the apex not exceeding the torus when mature, dehiscent from the apex to the base, columellas caducous. Seeds ca. 0.7–0.9 × 0.5–0.7 mm long, yellow, oblong-reniform, the testa reticulate.
Distribution, habitat and phenology:— Apparently endemic to Serra do Esbarrancado, along the trail to Vale do Pati, District of Guiné, Mucugê, Bahia (Fig. 3). It grows on rocky outcrops exposed to full sun, at elevations between 1,096 -1,187 m (Fig. 4E). Collected flowering and fruiting in January, February, May and June.
Recognition:— Microlicia bicolor can be recognized by its ovate to lanceolate 1-nerved leaves that are glandularpunctate on both surfaces, flowers on pedicels ca. 0.25–1 mm long, hypanthia glandular-punctate, calyx lobes tipped with an eglandular caducous trichome ca. 0.5 mm long, petals pale pink with a yellow base, or white faintly flushed with pink and a yellow base, uniformly yellow anther thecae, and antepetalous stamens with stout appendages ca. 0.9–1.1 mm long.
Besides Microlicia torrendii (see diagnosis), M. bicolor is somewhat similar in morphology to M. candolleana, M. obtusifolia, M. amplexicaulis, and M. sincorensis, all of which share leaves that are ovate to lanceolate, imbricate, and glandular-punctate on both surfaces. Microlicia bicolor differs from M. candolleana by its 1-nerved leaves (vs. 3–7-nerved in M. candolleana), shorter calyx tubes up to 0.2 mm long (vs. 0.5–0.8 mm long), calyx lobes narrowly triangular (vs. subulate), petals pink with a yellow base, or white faintly flushed with pink and a yellow base (vs. uniformly pink), yellow polysporangiate anthers (vs. bicolored, tetrasporangiate), and antepetalous stamens with stout connective appendages ca. 0.9–1.1 mm long (vs. ca. 0.2 mm long). Microlicia bicolor is readily distinguished from M. obtusifolia by its glandular-punctate hypanthia (vs. covered with pedicellate glandular trichomes in M. obtusifolia), and from M. amplexicaulis by the short pedicels ca. 1 mm long. (vs. 2.5–6 mm long); it also differs from both species by its polysporangiate anthers (vs. tetrasporangiate) and petals pink with a yellow base, or white faintly flushed with pink and a yellow base (vs. uniformly magenta). Vegetatively, M. sincorensis is also reminiscent of M. bicolor but its leaves are modally longer, 7–11 mm long (vs. 5–8.5 mm long in M. sincorensis) and its petals are larger, 14–17 × 11–18 mm (vs. 9.5–11 × 6.5–7.5 mm). The anthers of M. sincorensis also have distinctive elongate apical pores (vs. circular pores in M. bicolor) and its mature hypanthia greatly exceed the enveloped ovary to form a distinct neck (vs. apex not exceeding the torus when mature).
Except for M. torrendii and M. sincorensis (both Bahia endemics), all other compared species are known only from Minas Gerais state and grow more than 1,000 km distant from Guiné, Mucugê (Bahia).
Note:— Microlicia bicolor was treated as Microlicia sp. 3 in the treatment of Lavoisiereae (as Microlicieae) from Mucugê, Bahia (Pataro et al. 2017).
Etymology:— The epithet refers to the variation in petal color among individuals of this species, i.e. pale pink with a yellow base, or white faintly flushed with pink and a yellow base (Fig. 2. A–D).
Conservation:— The estimated EOO and AOO of M. bicolor are 1,231 km 2 and 12 km 2. These values would support an Endangered (EN) conservation status if criterion B of IUCN (2019) is applied. All collections apparently came from Chapada Diamantina National Park, where populations of M. bicolor are protected.
Additional specimens examined (paratypes):— BRAZIL. Bahia: Mucugê. Distrito of Guiné, Parque Nacional Chapada Diamantina, Beco do Guiné trail upslope to the Vale do Pati, 12°45’25.7”S, 41°30’43.8”W, 1,187 m, 21 May 2019, fl., fr., F. Almeda et al. 10747 (CAS!, CEPEC!, HUEM!, RB!); ibidem, 21 May 2019, fl., fr., F. Almeda et al. 10750 (CAS!, CEPEC!, HUEM!); Guiné, 1,096 m, 5 May 2000, fl. fr., A.A. Conceição 871 (UEC-online image!, SPF!); Serra do Esbarrancado, 12º44”S, 41º30”W, 24 February 2005, fl., fr., A.A. Conceição 1177 (HUEFS!); Beco do Guiné no acesso ao Vale do Pati, Parque Nacional da Chapada Diamantina, 12°45’19.7”S, 41°30’37.4”W, 1,156 m, 25 June 2022, fl., fr., R. Pacifico et al. 705 (CAS!, HUEFS!, HUEM!, RB!); Beco do Pati, 12 o 45’24”S, 41 o 30’43”W, 1,205 m, 24 June 2011, fl., fr., L. Pataro et al. 120 (HUEFS!); Guiné, subida para o Beco do Pati – Serra do Esbarrancado – Chapada Diamantina, 12º45’S, 41º30’W, 1,186 m, 27 January 2015, fl., fr., A. Queiroz-Lima et al. 135 (ALCB!); ibidem, 27 January 2015, fl., fr., A. Queiroz-Lima et al. 138 (ALCB!, CEPEC!).
description: Published as part of Pacifico, Ricardo, Almeda, Frank, Gali, Lorena & Fidanza, Karina, 2022, Novelties in Microlicia (Melastomataceae, Lavoisiereae) endemic to the campo rupestre of Guiné, Chapada Diamantina, Bahia, Brazil, pp. 290-300 in Phytotaxa 566 (3) on pages 291-295, DOI: 10.11646/phytotaxa.566.3.4, http://zenodo.org/record/7137850