Lavoisiera cogniauxana Barreto (1936: 63–65)

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

10. Lavoisiera cogniauxana Barreto (1936: 63–65) . Type:— BRAZIL. Minas Gerais: “Habitat in civitate Minas Geraes, ad Serra do Cipó,” 22 April 1892, A. F. M. Glaziou 19270 (holotype: R-9371!; isotypes: BR!, C!, K!, LE!, P!). The BR isotype is mounted on the same sheet with another specimen of this species attributed to Schwacke 7801 from Serra do Cipó (Minas Gerais). Schwacke 7801 is evidently a mixed collection since the collections of this number at RB and W are L. pulcherrima .

Erect shrubs to 2 m tall, copiously glandular-hirsute to glabrate. Branches and branchlets rounded to subrounded distally, glandular-hirsute, dark green or sometimes flushed with red, furrowed longitudinally on opposite faces, defoliating and decorticating basally with age; internodes 7–40 mm long, with glandular and eglandular trichomes 1–3 mm long, nodes with inconspicuous, glandular trichomes and conspicuous leaf scars and knobby thickenings that persist where a leaf has fallen away. Leaves sessile, semi-amplexicaul, spreading, subimbricate and congested distally or sometimes the branchlets leafy to the base; blade 50–75 × 18–35 mm, chartaceous to subcoriaceous, oblong-lanceolate or ovate-lanceolate, base attenuate to subrounded, apex bluntly rounded or obtuse, margins subcallose, entire or sparsely serrulate and glandular-ciliolate, sparsely glandular-setulose on adaxial surface, the trichomes somewhat erect, 1–2 mm long, the glands caducous on old leaves or trichomes totally caducous, obscurely and sparsely glandular-punctate on abaxial surface, flat, green sometimes flushed with red or maroon, 7–9-plinerved, often only the midvein conspicuous, inframarginal pair extending to the apex, the others tenuous. Flowers (7–)8-merous, terminal but becoming central with the elongation of lateral branches, solitary, paired or in simple or reduced pseudodichasia, pedicels ca. 5 mm long; bracteoles subtending the flowers reduced in size (30 × 25 mm) but otherwise similar to the principal leaves. Hypanthium (at anthesis) 9–12 × 5–6 mm, oblong-urceolate and abruptly flaring at the apex, 8–10 mm wide distally, 7–8-lobed (fluted) longitudinally, slightly granulose, copiously covered with spreading glandular trichomes 1–3 mm long with bases that are distinctly pustulate, glabrous at the apex, reddish-green, yellowish when dry. Calyx tube ca. 1 mm long, beset with sessile glands adaxially below the sinus and above the torus; calyx lobes 2–4 × 2 mm, triangular to triangular-ovate and attenuate distally, terminating in a gland-tipped trichome 2 mm long, margins entire or glandular-ciliate, glabrous abaxially or with a few scattered glandular trichomes distally, glabrous adaxially, persistent to tardily caducous in post anthesis. Petals 30–35 × 15–18 mm (adherent basally for a short distance and falling away together with stamens as a unit after anthesis), pink to lavender or reportedly white, obovate, apex obtuse to subtruncate, very sparsely glandular-pilose (fide Barreto's protologue), base attenuate, margins shortly and sparsely glandular-ciliolate, fused at the base and falling away as a unit with attached filaments. Stamens 14 or 16, dimorphic: large (antesepalous) stamens (7–)8, filaments ca. 10 mm long, anther thecae 6–7 × 2 mm, linear-oblong, yellow, rostrum ca. 0.6 mm long, pedoconnective 10–12 mm long, appendage 1.5–2 mm long, obscurely bilobed, yellow; small (antepetalous) stamens (7–)8, filaments 8 mm long, anther thecae 5–6 × 2 mm, linear-oblong, yellow, rostrum ca. 0.6 mm long, pedoconnective 2.5–3 mm long, appendage 1 mm long, subrounded, yellow. Ovary 8-locular, almost completely inferior, style 13–15 mm long, slightly curved at the apex, glabrous, stigma punctiform to truncate. Fruiting hypanthium (including calyx lobes) 15–18 × 10 mm, fluted and constricted distally above the ovary summit but below the calyx lobes. Capsule (at maturity) 10–12 × 9 mm, oblong-urceolate, enveloped by the persistent hypanthium, dehiscing from the base to the apex. Seeds 0.91–1.18 × 0.40–0.50 mm, oblong to reniform, reddish-brown to grayish-brown, periclinal cell walls of the testa at first convex (appearing colliculate or tuberculate) then becoming concave (foveolate), raphal zone about 60–70% the length of the seed. Chromosome number unknown.

Illustration:— Figure 30 .

LAVOISIERA ( MELASTOMATACEAE )

Phytotaxa 315 (1) © 2017 Magnolia Press • 71 72 • Phytotaxa 315 (1) © 2017 Magnolia Press

MARTINS & ALMEDA

Phenology:—Flowering in February and April; fruiting in April based on the few known collections.

Distribution and habitat:—Probably endemic to Minas Gerais where it is known only from Serra do Cipó and Serra da Mangabeira on the Cadeia do Espinhaço along margins of capão where it was reported to be locally common at unspecified elevations. Figure 26 .

Conservation status:—Based on the three known collections of this species we suspect it is endemic to the Cadeia do Espinhaço but we have inadequate data to make an informed assessment of its abundance and distribution. Future research may show that threatened status is justified but until more information is available we regard the status of this species as Data Deficient (DD).

Discussion:—This little-known species has a distinctive suite of diagnostic characters not to be confused with other species of Lavoisiera . Its rounded to subrounded distal internodes are moderately covered with spreading, mostly gland-tipped trichomes. Its large oblong-lanceolate or ovate-lanceolate leaf blades are 7–9-plinerved, sparsely glandular-setulose on the adaxial surface and obscurely and sparsely punctate with a few smooth scattered trichomes 1–2 mm long on the abaxial surface. The (7–)8-merous flowers are on pedicels about 5 mm long. The hypanthia, which are fluted at anthesis and in fruit ( Figures 30H, I ), are covered with spreading gland-tipped trichomes that have distinctly pustulate bases, the adaxial base of the calyx tube is densely glandular-hirtellous ( Figure 30I ), and the ovary is 8-locular.

Among congeners with modally 6–8-merous flowers, acute to cuspidate calyx lobe apices, and pink or magenta petals, L. cogniauxana is probably closest to L. punctata which also has petals that are adherent for a very short distance basally and fall away as a unit along with the stamens. Lavoisiera punctata also has fluted hypanthia, both sets of anther thecae that are yellow in color, and a densely glandular band of indumentum on the adaxial side of the calyx tube. Lavoisiera punctata also differs consistently in its obscurely 3-nerved leaf blades, glabrous cauline internodes and hypanthia (including calyx lobes), and red callose-margined leaf blades that are glabrous adaxially and sparsely punctate with sessile glandular trichomes abaxially.

Additional specimens examine d:— MINAS GERAIS: Mpio. Congonhas do Norte , Serra da Mangabeira , próx. à margem direita do Rio Preto, 18°50'S, 43°49'W, Furlan et al . CFSC 8459 ( SPF!, US!); Mpio. Santana do Riacho , Serra do Cipó, Km 137, estrada de Conceição, Mello Barreto 8943 ( BHCB, BHCB ex BHMH!, F!, NY!, R!) .

Figures

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

FIGURE 30. Lavoisiera cogniauxana. A. Habit. B. Cauline nodes and internodes. C. Abaxial leaf surface. D. Flower. E. Petal and detail of margin (upper left). F. Stamens (ventral view), antepetalous (left) and antesepalous (right). G. Ovary cross-section. H. Hypanthium in fruit. I. Hypanthium at anthesis (petals removed) with enlargement of adaxial calyx lobe sinus (above). J. Seed. (Based on: A, C, E–G, I, J, Mello Barreto 8943, F, US; B, H, Glaziou 19270, LE; D, Furlan et al. CFSC 8459, SPF, US.)