Lavoisiera punctata Martius & Schrank ex Candolle (1828: 104)

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

31. Lavoisiera punctata Martius & Schrank ex Candolle (1828: 104) . Type :— BRAZIL. Minas Gerais: “Habitat in campis frigidiusculis altis supra saxa arenaria inter Villam Riccam et Tejuco,” C. F . P. Martius s.n. (holotype: M-0174603-n.v., online image!, photos of holotype: CAS!, F!, NY!, UEC!; isotypes: BM!, BR!) .

Erect, openly and dichotomously branched glabrous shrubs or small trees 1–3 m tall, with rough fissured bark. Branches and branchlets at first quadrangular, deeply furrowed longitudinally on opposite faces, the outer epidermal layer cracking and falling away with age and then the branches becoming rounded and pale brown; internodes 4–15 mm long, with knobby thickenings that persist where a leaf has fallen away, nodes with short vinaceous glandular trichomes. Leaves sessile or subsessile, almost semi-amplexicaul, spreading to antrorsely spreading, subimbricate and congested on the branchlets distally; blade 25–40 × 10–15 mm, subcoriaceous to coriaceous, oblong-lanceolate to elliptic, somewhat conduplicate, base subrounded and obscurely subauriculate, apex broadly acute to subrounded, margins callose-thickened and red when fresh, sparsely and minutely toothed for the distal third of the blade, proximally entire, green to pale green, conspicuously and sparsely punctate with sessile dark brown glandular trichomes abaxially along distal portion of the blade, dark green and glabrous adaxially, flat, obscurely 3-nerved, the midrib elevated and enlarged at the base. Flowers (6–)8-merous, solitary, terminal, becoming central with elongation of lateral shoots, shortly pedicellate, pedicel ca. 1 mm long. Bracts subtending the flowers somewhat larger than (45 × 28 mm) but otherwise similar to the principal leaves. Hypanthium (at anthesis) 7–10 × 4–5 mm, campanulate, constricted distally above the ovary, longitudinally 8- ribbed and fluted, green, slightly granulose. Calyx tube inconspicuous to ca. 0.3 mm long, adaxially densely granulose; calyx lobes (at anthesis) 2–3 × 1.5–2.5 mm, chartaceous, triangular to cuspidate, shortly apiculate, pungent and tapering to a trichome ca. 1 mm long, glabrous on both surfaces, persistent to tardily caducuous in post-anthesis. Petals 25–30 × 12–14 mm (adherent at the very base and falling away together with stamens as a unit after anthesis), pink to pink-magenta with darker venation and a yellowish-green or white base, obovate-oblong, apex subrounded to oblique-truncate or slightly emarginate, base attenuate, margin entire or shortly glandular-ciliate, fused at the very base. Stamens 12–16, dimorphic: large (antesepalous) stamens 6–8, filaments 9–10 mm long, greenish-yellow or yellowish-orange, anther thecae 5 × 1.5–2 mm, linear oblong, yellow, often turning brown at least distally following pollination, rostrum ca. 0.5 mm long, pedoconnective 5–7 mm long, yellowish-orange, appendage 1.5 mm long, emarginate to obscurely bilobed, yellow; small (antepetalous) stamens 6–8, filaments 6–7 mm long, greenish-yellow or yellowish-orange, anther thecae 4 × 1.2–1.5 mm, linear-oblong, yellow on abaxial surface but brown on adaxial surface, rostrum 0.5 mm long, pedoconnective ca. 2 mm long,

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MARTINS & ALMEDA yellowish, appendage 0.7 mm long, rounded to inconspicuously lobed, yellow. Ovary 6–8-locular, 3/4 inferior, style 8–10 mm long, slightly curved at the apex, glabrous, stigma punctiform. Fruiting hypanthium (including calyx lobes) ca. 15 mm long, fluted, strongly constricted above the ovary. Capsule (at maturity) 8 mm long, oblong to urceolate, enveloped by the persistent hypanthium and calyx lobes, dehiscing from the base to the apex. Seeds 0.86–1.16 × 0.44–0.57 mm, oblong to reniform, sometimes somewhat L-shaped, orangish-red, periclinal cell walls of the testa concave (foveolate), raphal zone about 66% the length of the seed. Chromosome number unknown.

Illustrations:— Figure 54 ; Martius (1831: t. 270).

Photographic images:— Figures 4H, I .

Phenology:—Flowering in February, March, June, October, and November; fruiting in February, October, and November.

Distribution and habitat:—Endemic to Minas Gerais where it is known from small populations on the Serra do Cipó and the Serra do Caraça in campo rupestre, sandy fields, and stream banks at 1200–1300 m elev. Figure 20 .

Conservation status:—This rare and little-collected species is known from the type and 10 other collections representing three populations. Two of these occur adjacent to one another on the Serra do Cipó and the third occurs on the Serra do Caraça. Only two old collections are known from the latter locality. Based on our field work, the populations on Serra do Cipó consist of fewer than five individuals and appear not to occur within the confines of the National Park. Botanically, the Serra do Caraça is still little-collected so the persistence of this species at that locality seems likely, as the vegetation is largely intact and protected in a Private National Heritage Reserve that was established in early 1990. The EOO is 366 km ² and the AOO is 12 km ². In view of its few known localities, limited elevational distribution and small populations we assign a classification of Endangered (EN): B2ab(iii).

Discussion:— Lavoisiera punctata has a combination of distinctive features that readily separates it from congeners. Its uppermost branchlets are distinctly quadrangular and deeply furrowed longitudinally on opposite faces. Its upper leaf blades are conduplicate with a bright red subcallose margin and conspicuously but sparsely punctate with sessile dark brown glandular trichomes abaxially. It has modally 8-merous flowers and a 6–8-locular ovary, pink to pink-magenta petals with darker venation and a yellowish-green or white base adaxially. It is unlike almost all other congeners in having a prominently fluted hypanthium ( Figures 4I ; 54C ) with a conspicuous granulose ring-like band at the adaxial base of the calyx lobes above the torus ( Figure 54C ). Like some of the other large-flowered species of Lavoisiera its petals appear to adhere together for about 0.25 mm at the base and fall away as a unit with attached staminal filaments.

Among congeners with modally 8-merous flowers, acute to cuspidate calyx lobe apices, and pink-magenta petals, L. punctata is probably closest to L. belinelloi , L. macrocarpa , and L. pulcherrima , all of which have petals that are also adherent for a very short distance basally and fall away as a unit along with the staminal filaments following anthesis. Of these species, only L. belinelloi has anther thecae of both antesepalous and antepetalous stamens that are yellow in color like L. punctata but it differs in lacking the red subcallose foliar margins and glandular-punctate abaxial foliar surfaces. It also has calyx lobes that are beset with inconspicuous slender glands adaxially, its fruiting hypanthia are sessile, and it is restricted to Serra do Cabral in Minas Gerais. Both L. macrocarpa and L. pulcherrima differ from L. punctata in having the large antesepalous set of anther thecae that are pink-orange or reddish in color. Lavoisiera macrocarpa is readily separated from all of the taxa in this species group by its open, divaricately branched habit ( Figure 4A ) and its leaves that dry with an irregular mottled pattern of lighter and darker green or brown bands on both surfaces. This mottled pattern occurs on the leaf surfaces of some but not all dried specimens. It also does not occur on all leaves on any one specimen.

Although L. pulcherrima can become a small tree with leaves that are commonly crowded on branchlets distally like L. punctata , its leaf blades are glabrous and glaucous on both surfaces, its hypanthia are terete, and it lacks the granulose ring-like band at the adaxial base of the calyx lobes above the torus. Another feature that readily separates L. pulcherrima from L. punctata is the persistent fruiting pedicel with attached columella and vascular ribs of post-mature capsules that creates a broom-like effect ( Figure 53H ).

LAVOISIERA ( MELASTOMATACEAE )

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MARTINS & ALMEDA

Additional specimens examined:— MINAS GERAIS: Mpio. Santana do Riacho , Serra do Cipó , between Kms 111 and 112 along the road from Lagoa Santa to Conceição do Mato Dentro , 19°17'S, 43°34'W, Almeda et al. 8561 ( CAS!, MO!, NY!, UEC!); Mpio. Santana do Riacho , Serra do Cipó , Km 126 along the road from Lagoa Santa to Conceição do Mato Dentro , 19°14'S, 43°30'W, Almeda et al. 8610 ( CAS!, UEC!); Mpio. Santana do Riacho , Serra do Cipó , 32 km beyond the bridge over the Rio Cipó enroute to Conceição do Mato Dentro , - 19.23376, -43.51021, Almeda et al. 9709 ( BHCB!, CAS!, K!, NY!, RB!, UEC!); Mpio. Santa Bárbara, Serra do Caraça , Morro da Carapuça , Glaziou 14759 ( BR!, C!, F!, G!, K!, LE!, P-2!, R!); Mpio. Santana do Riacho , Serra do Cipó , Km 137-estrada de Conceição, Mello Barreto 8775 ( BHCB ex BHMH!, F!); Mpio. Santana do Riacho , Serra do Cipó , Km 149-estrada do Pilar, Mello Barreto 8880 ( F!, NY!); Mpio. Santana do Riacho , Serra do Cipó , Km 126 along the road from Lagoa Santa to Conceição do Mato Dentro , 19°14'S, 43°30'W, Semir 5617 ( UEC!); Mpio. Santana do Riacho , Serra do Cipó , Km 136, Semir 8661 ( UEC!); Mpio. Santana do Riacho , Serra do Cipó, Km 135, 19°14’22”S, 43°30’58”W, Semir 28670 ( UEC!); Mpio. Santa Bárbara, Serra do Caraça, Ule 2534 ( BR!, R!, US!) .

Figures

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 20. Distributions of Lavoisiera angustifolia, L. belinelloi, L. bradeana, L. punctata, L. sampaioana, L. scaberula, and L. tetragona.

FIGURE 53. Lavoisiera pulcherrima. A. Habit. B. Adaxial leaf surface. C. Flower. D. Hypanthium and calyx lobes. E. Ovary crosssection. F. Ventral view of antesepalous stamen. G. Ventral view of antepetalous stamen. H. Old disintegrating hypanthia and capsule with persisting vascular strands. I. Seed. J. Petal with enlarged detail of apical margin (upper left) and lateral margin detail (lower right). (Based on: A, Romero & Nakajima 5948, UEC; B–J, Pirani et al. CFSC 10270, UEC.)

FIGURE 54. Lavoisiera punctata. A. Habit. B. Abaxial leaf surface with enlarged surface detail (upper left). C. Hypanthium, calyx lobes, and style with enlarged detail of calyx lobe base and intercalycine sinus (above). D. Ovary cross-section. E. Petal with enlarged detail of margin (right). F. Ventral view of antesepalous stamen (left), lateral view of antesepalous stamen (right). G. Ventral view of antepetalous stamen (left), lateral view of antepetalous stamen (right). H. Disintegrating mature hypanthium and enclosed capsule. I. Seed. (Based on: A, B, H, I, Semir 28670, UEC; C–G, Almeda et al. 9709, CAS, UEC.)