Lavoisiera canastrensis Almeda & A. B. Martins, 2017

Martins, Angela B. & Almeda, Frank, 2017, A Monograph of the Brazilian endemic genus Lavoisiera (Melastomataceae: Microlicieae), Phytotaxa 315 (1), pp. 448-450 : 448-450

7. Lavoisiera canastrensis Almeda & A. B. Martins , sp. nov.

Cespitose or sparingly branched subshrubs 30–40 cm tall, perennating from a lignotuber. Branches glabrous, defoliating basally with age. Leaves subsessile, subcoriaceous, flat or slightly keeled, margins subcallose to conspicuously callose-thickened, serrulate, ciliate, apex pungent, glabrous on both surfaces, 1-nerved. Flower 5–6-merous, in simple or compound dichasia or solitary. Hypanthium narrowly campanulate, green-reddish, mostly glabrous or with a few glandular trichomes. Petals deep pink with a white or greenish-white inverted V-shaped patch at the adaxial base. Ovary 5–6-locular, 2/3 inferior.

Type :— BRAZIL. Minas Gerais: “Mpio. São Roque de Minas, Parque Nacional da Serra da Canastra , morro próximo ao alojamento, 20°00’S, 46°15’W,” 22 June 1998, F . Almeda 7878, R. Romero, O. Robinson & D. Robinson (holotype: UEC!; isotype: CAS!) .

Erect, cespitose or sparingly branched subshrubs (20–)30–40(–50) cm tall, perennating from a thick woody lignotuber. Branches and branchlets quadrangular or subrounded, longitudinally furrowed on opposite faces, defoliating with age basally; internodes glabrous, 2–9(–20) mm long, with knobby thickenings that persist where a leaf has fallen away, nodes with yellowish to vinaceous glandular-hirtellous trichomes. Leaves subsessile, petiole ca. 1 mm long, spreading to subimbricate distally; blade 7–22 × 3–10 mm, subcoriaceous, rigid, flat or slightly keeled, oblong-elliptic, ovate-oblong to ovate, base subrounded to broadly cuneate, apex acute-acuminate and terminating in a pungent persistent trichome, margins serrulate and subcallose to conspicuously callose-thickened, ciliate, the cilia 0.5–1 mm long, glabrous on both surfaces, greenish-gray to yellowish-green, 1-nerved, sparsely setose (the trichomes eglandular) along the midvein on abaxial surface, sometimes absent. Flowers 5–6-merous, typically in aggregated simple or compound dichasia or variously reduced to solitary flowers, terminal in principal and lateral branchlets but sometimes becoming central or pseudolateral with elongation of lateral shoots, sessile. Bracts subtending the flowers slightly modified, 8–9 × 4 mm, ovate, very similar to the principal leaves, bracteoles 6–9 × 1.5–2 mm, oblong-lanceolate, margins with red glandular trichomes. Hypanthium (at anthesis) 4–6 × 2–4.5 mm, narrowly campanulate, striolate, totally glabrous or with a few scattered red glandular trichomes at the apex, the trichomes 0.8–1 mm long, green-reddish. Calyx tube 1–1.5 mm long; calyx lobes (at anthesis) 4–5 × 1.5–2 mm, membranaceous, triangular, apiculate at the apex tapering to a glandular trichome, margins glandular-ciliate, very sparsely glandular-hirtellous abaxially, essentially glabrous adaxially but with scattered sessile trichomes along the adaxial base of the intercalycine sinuses, tardily caducous in post-anthesis. Petals 10–18 × 5–6 mm, deep pink with a white or greenish-white inverted V-shaped patch at the adaxial base, obovate, apex subrounded to obtuse, base broadly attenuate, margins eciliate but tipped with a glandular trichome. Stamens 10 or 12, dimorphic: large (antesepalous) stamens 5–6, filaments 7–8 mm long, yellow, anther thecae 2.5–3 × 1–1.5 mm, intense red, ovate-oblong, rostrum 0.4 mm long, red, pedoconnective 4–6 mm long, yellow, appendage 1–2 mm long, conspicuously bilobed, yellow; small (antepetalous) stamens 5–6, filaments 5–6 mm long, yellow, anther thecae 2–3 × 0.8–1 mm, yellow, ovate-oblong, rostrum 0.3 mm long, pedoconnective 1.5–2 mm long, yellow, appendage 0.3 mm long, inconspicuously rounded, yellow. Ovary 5–6-locular, 2/3 inferior, style ca. 7 mm long, slightly sigmoid, glabrous, stigma punctiform. Fruiting hypanthium (including calyx lobes) 10–14 × 4–5 mm, ovoid-oblong to globose, glabrous or with a few scattered trichomes, constricted above the ovary, gray. Capsule (at maturity) 5–7 mm long,

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MARTINS & ALMEDA globose, coriaceous, frequently enveloped by the persistent hypanthium, dehiscing from the base to the apex, pale maroon to gray. Seeds 0.81–1.13 × 0.40–0.57 mm long, oblong to subreniform, dark brown, periclinal cell walls of the testa concave (foveolate), the raphal zone about 60–70% the length of the seed. Chromosome number unknown.

Illustration:— Figure 25 .

Photographic image:— Figure 1H .

Phenology:—Flowering January through July; fruiting in March through June, and September through November.

Distribution and habitat:—Endemic to Serra da Canastra, Parque Nacional da Serra da Canastra , Minas Gerais, where it can be locally common in campo rupestre, campo limpo, and sandy soils at 1200–1340 m elev. Figure 26 .

Conservation status:— All of the fewer than 20 collections of this species were made in the last 25 years but coordinate data were available for only the collections made for this study. The AOO is 8 km ² and all known populations of this species occur within the boundaries of Parque Nacional da Serra da Canastra. Thus the species is afforded some protection but periodic fires remain a threat to this species like those of other campo rupestre habitats in the region. This species appears to be able to regenerate from lignotubers after a fire but the intensity and recurrence of fires present an ongoing threat. In view of its restricted geographic and elevational distribution we recommend a classification of Critically Endangered (CR): B2ab(iii).

Discussion:— Lavoisiera canastrensis and the widespread L. imbricata are the only species in the genus that grow on Serra da Canastra. Lavoisiera canastrensis is a sparingly branched subshrub with narrowly callose-thickened ciliate-serrulate leaf margins, sessile 5–6-merous flowers, and fruiting hypanthia that are essentially glabrous for the better part of their length. All of its foliar trichomes, including those along the prominent midvein abaxially are eglandular ( Figure 25B ). Its calyx lobes, however, are sparsely glandular-hirtellous abaxially and along the margins, and the intercalycine sinuses are beset with scattered gland-like trichomes adaxially ( Figure 25E ). Floral features provide some of the most important diagnostic characters of this species. The petals are deep pink with a well-defined inverted V-shaped patch at the base that is greenish-yellow but white distally. The large set of anther thecae are intense carmine red (including the rostra) and the bright yellow appendages are prominently bilobed ( Figure 1H ). The anther thecae of the smaller staminal whorl are yellow, the common character state for the majority of Lavoisiera species.

The collections of Lavoisiera canastrensis have routinely been identified as L. pulchella , a more southerly species that is largely centered in the Brazilian states of São Paulo and Paraná. There is little doubt that these two taxa are sister species. They share 5–6-merous flowers, 5–6-locular ovaries, and the distinctive androecial color dimorphism ( Figures 1H ; 4E ). Lavoisiera pulchella can consistently be separated, however, by its pedicellate flowers and fruiting hypanthia that are moderately covered with gland-tipped trichomes like those of the noncallose thickened leaf blade margins and elevated abaxial midvein ( Figures 52C, E ). In addition, the petal color of L. pulchella is a paler pink with a diffuse obovate patch of white at the base and the larger anther thecae are red but the rostra are white to pink and the paler yellow appendages are essentially unlobed ( Figure 4E ).

Lavoisiera canastrensis and L. pulchella also grow in different Brazilian biomes. The former is restricted to habitats within the Cerrado biome and the latter presently grows in areas that were once covered by the interior Atlantic rain forest before the geographic extent of this biome was severely constricted and modified by anthropogenic activity.

Etymology:—The epithet for this species is derived from Serra da Canastra , a trunk-like rolling plateau at about 990–1500 m in southwestern Minas Gerais where it appears to be endemic. The Canastra range is home to an important assemblage of plants and animals of the Cerrado biome, including endemic and threatened species ( Romero & Nakajima 1999; Silva & Silveira 2006; Vasconcelos et al. 2015).

Additional specimens examined:— MINAS GERAIS: Mpio. São Roque de Minas, Parque Nacional da Serra da Canastra , 22 km beyond visitor center off of road to Cachoeira Casca d’Anta parte alta, 20°16.266’S, 46°32.289’W, Almeda et al. 9040 (BHCB!, CAS!, UEC!); Mpio. São Roque de Minas, PARNA Serra da Canastra. Estrada para a Cachoeira da Casca d’Anta, Nakajima et al. 943 (HUFU, US!); Mpio. São Roque de Minas, base do morro próximo à sede administrativa, Nakajima et al. 1464 (HUFU, US!); Mpio. São Roque de Minas, Parque Nacional da Serra da Canastra, Nakajima et al. 2567 (CAS!, HUFU); Mpio. São Roque de Minas, estrada para Sacramento, 3 km da sede administrativa, colina do vale do rio São Francisco, PARNA Serra da Canastra ,

LAVOISIERA ( MELASTOMATACEAE )

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MARTINS & ALMEDA LAVOISIERA ( MELASTOMATACEAE )

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Nakajima & Romero 191 (HUFU!, US!); Mpio. São Roque de Minas, base da colina, próximo á sede administrativa, PARNA Serra da Canastra, Romero & Nakajima 644 (HUFU, US!); Mpio. São Roque de Minas, estrada para a cachoeira da Casca d’Anta, PARNA Serra da Canastra, Romero & Nakajima 715 (HUFU, US!); Mpio. São Roque de Minas, estrada para a cachoeira da Casca D’Anta, PARNA Serra da Canastra, Romero & Nakajima 1074 (HUFU, US!); Mpio. São Roque de Minas, Nascente do rio São Francisco, Romero & Nakajima 3512 (CAS!, HUFU); Mpio. São Roque de Minas, PARNA Serra da Canastra. Morro próximo á sede administrativa, Romero et al. 864 (HUFU, US!); Mpio. São Roque de Minas, Morro próximo á sede administrativa, PARNA Serra da Canastra, Romero et al. 1673 (CAS!, HUFU, US!); Mpio. São Roque de Minas, após a Torre de Observação, estrada para Sacramento, PARNA Serra da Canastra, Romero et al. 1797 (HUFU, US!); Mpio. São Roque de Minas, nascente do Rio São Francisco, PARNA Serra da Canastra, Romero et al. 1995 (CAS!, HUFU, US!); Mpio. São Roque de Minas, nascente do Rio São Francisco, PARNA Serra da Canastra, Romero et al. 2416 (HUFU, US!); Mpio. Piumhi, Parque Nacional da Serra da Canastra , entre Piumhi e Araxá, ca. de 80 km de Piumhi, Shepherd et al. 7159 (SP!, UEC!); Mpio. São Roque de Minas, P.N. Serra da Canastra , Sousa 17960 (BHCB!).

Figures

FIGURE 1. Images of Lavoisiera species. A. L. adamantium (Almeda et al. 8504). B–C. L. alba (Almeda et al. 9624). D–E. L. arachnoidea (unvouchered image). F. L. belinelloi (Almeda et al. 8532). G. L. bradeana (Almeda et al. 9718). H. L. canastrensis (Almeda et al. 7878). I. L. caryophyllea (Almeda et al. 9172). J–K. L. chamaepitys (Almeda et al. 8500). L. L. confertiflora (Almeda et al. 9725). Image credits: A–C, F–L. Frank Almeda; D–E. Karina Fidanza.

FIGURE 4. Images of Lavoisiera species. A−C. L. macrocarpa (Almeda et al. 9173). D. L. mucorifera (Almeda et al. 9607). E. L. pulchella (Almeda et al. 9830). F−G. L. pulcherrima (Almeda et al. 9666). H−I. L. punctata (Almeda 9709). J. L. rigida (Almeda et al. 9089). K. L. rigida (Almeda et al. 9604). L. L. rigida (Almeda et al. 9635). Image credits: A−L. Frank Almeda.

FIGURE 25. Lavoisiera canastrensis. A. Habit. B. Abaxial leaf surface. C. Abaxial bract surface. D. Flower. E. Hypanthium, calyx lobes and style with enlarged detail of intercalycine sinus (above). F. Ovary cross-section. G. Petal with enlarged detail of apex (above). H. Ventral view of antesepalous stamen. I. Ventral view of antepetalous stamen. J. Fruiting hypanthium. K. Capsule, dehiscing from the base. L. Seed. (Based on: A–L, Almeda et al. 7878, CAS, UEC.)

FIGURE 26. Distributions of Lavoisiera canastrensis, L. cogniauxana, L. crassifolia, L. pulchella, and L. rigida.

FIGURE 52. Lavoisiera pulchella. A. Habit. B. Abaxial leaf surface. C. Abaxial bract surface. D. Flower. E. Hypanthium and calyx lobes. F. Ovary cross-section. G. Petal with apex detail (above) and margin detail (lower left). H. Ventral view of antesepalous stamen. I. Ventral view of antepetalous stamen. J. Seed. (Based on: A–J, Shepherd & Andrade 6158, UEC.)