Microlicia schwackeana Glaziou ex Versiane & R.Romero, 2022

Versiane, Ana Flávia Alves & Romero, Rosana, 2022, Microlicia schwackeana (Melastomataceae), a new species from campo rupestre in Minas Gerais, Brazil, Phytotaxa 539 (2), pp. 186-194 : 187-191

Microlicia schwackeana Glaziou ex Versiane & R.Romero , spec. nov. ( Figs. 1−2 )

Diagnosis: —The scandent habit, petiolate and horizontal leaves, membranaceous leaf blade, with both surfaces, pedicel, hypanthium, and sepals densely covered with glandular trichomes mixed with spherical glands, and flowers with a long pedicel (4.5−5 mm long) are remarkable features and distinguish this species from all others Microlicia .

Type: — BRAZIL. Minas Gerais: Diamantina, Parque Estadual do Biribiri , alto da Mãe Rita, fundo da casa de ventos, 18°10’58.5”S, 43°37’14.8”W, 1342 m, 27 April 2012 (fl, fr), I.M. Araújo et al. 319 (holotype: HUFU!; isotypes: DIAM!, RB!) .

Subshrub, scandent, multi-branched. Younger branches terete, green or reddish, with glandular trichomes mixed with spherical glands, older branches terete, brownish, without leaves at the base, peeling off with age; nodes not thickened, internodes 6–13.5 mm long. Leaves petiolate, petiole 0.3−0.4 mm long, terete, with glandular trichomes mixed with spherical glands, horizontal, not imbricate, not amplexicaul; blade 3–8.5 × 1.5–6 mm, membranaceous, discolorous (when dry), abaxial surface light green, adaxial surface dark green to brownish, rarely reddish, ovate or cordate, apex acuminate, base rounded or cordate, margin entire, glandular-ciliate, both surfaces densely covered with glandular trichomes mixed with spherical glands, 3−5-veined, visible on both surfaces, sometimes lighter than the abaxial surface, secondary and tertiary veins present, visible on both surfaces. Inflorescence in dichasia, becoming solitary with elongation of the branches, lateral or at the apex of the branches, bracts 4.5–5 × 3−3.5 mm, elliptic, bracteoles 2–3 × 1–2 mm, elliptic. Flower 5-merous, perianth actinomorphic, pedicel 5–7 mm long, terete, densely covered with glandular trichomes mixed with spherical glands, green-brownish; hypanthium 1.5–2.5 × 1–1.5 mm, campanulate, brownish, covered with long glandular trichomes (ca. 1 mm long) mixed with spherical glands; calyx tube ca. 0.1 mm long, sepals ca. 4 × 0.3 mm, narrow-triangular, apex acute, shorter than the hypanthium length, brownish, with long glandular trichomes (ca. 1 mm long) mixed with spherical glands; petals ca. 8.5 × 4.5 mm, lilac, oblong, apex rounded, margins glabrous; stamens 10, dimorphic, bicolored, anthers tetrasporangiate; larger (antesepalous) stamens 5, filaments ca. 3 mm long, lilac, anthers ca. 1.5 mm long including beaks, light pink, ovate, beaks ca. 0.2 mm long, lilac, pedoconnectives ca. 3 mm long, lilac, ventral appendages ca. 1 mm long, yellow, apices retuse; smaller (antepetalous) stamens 5, filaments ca. 2.5 mm long, lilac, anthers ca. 1.5 mm long including beaks, yellow, ovate, beaks ca. 0.2 mm long, white, pedoconnectives ca. 1 mm long, yellow, ventral appendages ca. 0.2 mm long, yellow, apices rounded; ovary ca. 1.5 × 1 mm, 3-locular, globose, superior, glabrous; style ca. 8 mm long, lilac, slightly curved at apex, stigma punctiform, cream. Capsule ca. 2.5 × 2.3 mm, ovate-cylindrical, smooth, brownish, basipetal dehiscence, hypanthium covering the entire capsule and peeling off as the fruit mature, columella deciduous; seeds ca. 0.4 × 0.2 mm, pale brown, slightly curved, testa foveolate.

Paratypes:— BRAZIL. Minas Gerais: Conceição do Serro [Conceição do Mato Dentro], Ponte de Joaquim José, May 1892 (fr), J.C.C. Sena s.n. (OUPR5935!). Diamantina , Parque Estadual do Biribiri , trilha no fundo da Casa dos Ventos, 18°10’57”S, 43°37’15”W, 1376 m, 5 December 2012 (fr), A.F.A. Versiane & K.R. Silva 365 (HUFU!); idem, trilha atrás da Casa dos Ventos, 1 August 2013 (fl), I.M. Franco et al. 1261 (HUFU!). Serra do Cipó , 22 April 1892 (fr), A.F.M. Glaziou 19290 (K!, C!, P05316160!, P05316161!, P05316162!, R000009166!) .

Distribution, Habitat, and Conservation: — Microlicia schwackeana is endemic to Minas Gerais, occurring at Biribiri State Park (BSP) and Serra do Cipó, in Diamantina and Conceição do Mato Dentro municipalities, respectively ( Fig. 3 ). In the Serra do Cipó, M. schwackeana is known by two collections made 130 years ago by Auguste François Marie Glaziou (1828–1906) and Joaquim Candido da Costa Sena (1852–1919). In the Diamantina Plateau, the M. schwackeana population occurs inside a protected area (the BSP) and it is found in campo rupestre on shaded areas near by quartzitic rock outcrops. Thus, since M. schwackeana is known only from a single locality in the BSP, there is no appropriate data on the abundance, and data on distribution are lacking to the Serra do Cipó we consider that M. schwackeana is a Data Deficient (DD) taxon.

Etymology: —The specific epithet “schwackeana” was proposed by Glaziou (1908) in his work “Liste des Plantes du Brésil Central recueillies en 1861–1895”. However, all new taxa in this catalog were included in the Suppressed Works list of the International Code of Nomenclature for algae, fungi, and plants – ICN ( Turland et al. 2018; see also Mansano & Pederneiras 2016). Glaziou (1908) chose this epithet to honor the German botanist, explorer, and naturalist Carl August Wilhelm Schwacke (1848–1904). Schwacke emigrated to Brazil in 1872, where he lived until his death. He worked as a professor of botany and director at the School of Pharmacy in Ouro Preto, Minas Gerais, Brazil. In 1892, he founded the herbarium of the School of Pharmacy of Ouro Preto, which was incorporated into the Professor José Badini herbarium (OUPR) at the Federal University of Ouro Preto in 1986 [( Stafleu & Cowan (1985); see also https://debio.ufop.br/breve-histórico-e-principais-coleções)]. Here we opted to maintain the tribute since this epithet is not occupied in Microlicia [Article 6.9 of the ICN] ( Turland et al. 2018).

Taxonomic Notes: — Microlicia schwackeana bears some resemblance to M. pabstii Brade (1962: 251) and M. sciophylla Pacifico & Fidanza (2017: 1) , which also occur in the Diamantina Plateau s.l. on shaded areas. The three species have membranaceous leaf blades with secondary and tertiary veins, campanulate hypanthium with narrowtriangular sepals, dimorphic and bicolored stamens with tetrasporangiate anthers [also see Brade (1962) and Pacifico & Fidanza (2017)]. However, M. pabstii has branches, leaf blade, hypanthium, and sepals covered only with spherical glands (vs. glandular trichomes mixed with spherical glands in M. schwackeana ), sessile leaves (vs. petiolate), elliptic leaf blade (vs. ovate or cordate), and crenulate margin (vs. entire). Microlicia schwackeana and M. sciophylla also share branches, hypanthium, and sepals covered with long glandular trichomes mixed with spherical glands [see Pacifico & Fidanza (2017)], but M. sciophylla differs by its leaf blade covered only with spherical glands (vs. glandular trichomes mixed with spherical glands in M. schwackeana ).

Some collections (Araújo et al. 319, Franco et al. 1261, Glaziou 19290, Sena s.n., Versiane & Silva 365) have been previously identified as M. edmundoi . However, when analyzing the type collection of M. edmundoi (E. Pereira 1385 at HB), we concluded they are different species. Microlicia edmundoi and M. schwackeana share branches, leaf blade, hypanthium, and sepals covered with glandular trichomes mixed with spherical glands, discolorous leaf blade with secondary and tertiary veins, campanulate hypanthium, dimorphic and bicolored stamens with tetrasporangiate anthers. However, M. edmundoi differs in having a chartaceous leaf blade with serrate margin (vs. membranaceous and entire in M. schwackeana ), short pedicellate flowers [0.7−1.5 mm long] (vs. long pedicellate [4.5−5 mm long]), triangular sepals (vs. narrow-triangular), and leaf blade with the adaxial surface blackish when dry (vs. dark green to brownish, rarely reddish). So far, M. edmundoi is known only by its type collection from Diamantina, where it seems to be endemic. Table 1 includes the features comparing M. edmundoi , M. pabstii , and M. sciophylla with M. schwackeana .

Figures

FIGURE 1. Microlicia schwackeana Glaziou ex Versiane & R.Romero. A. Branches. B. Flowering branch with a long pedicellate flower. C. Leaf blade: adaxial surface above, abaxial surface bellow. D. Hypanthium and sepals. E. Petal. F. Smaller stamen (antepetalous) on the left, larger stamen (antesepalous) on the right. G. Ovary and style. H. Mature fruit dehiscing into 3 valves from the apex with remaining hypanthium covering the base. (Drawn by Klei Sousa from I.M. Araújo et al. 319).

FIGURE 2. Microlicia schwackeana Glaziou ex Versiane & R.Romero.Photos of living specimens. A. Population with scandent branches near a rocky outcrop in Diamantina Plateau, Minas Gerais, Brazil. B. Branch with horizontal leaves. C. Detail of a reddish branch with petiolate and cordate leaves. D. Post-mature capsule. E. Flower. Photos: A−D: A.F.A. Versiane (A.F.A. Versiane & K.R. Silva 365); E: I.M. Araújo (I.M. Araújo 319).

FIGURE 3. Occurrence map of Microlicia schwackeana Glaziou ex Versiane & R.Romero in Minas Gerais state, Brazil.