Lavoisiera quinquenervis Wurdack (1974: 136–137)

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

32. Lavoisiera quinquenervis Wurdack (1974: 136–137) . Type:— BRAZIL. Distrito Federal : Campo slope immediately east of Lagoa Paranoá, elevation 975 m, 11 December 1965, H. S. Irwin 11197, R . Souza & R . Reis dos Santos (holotype: US!; isotype: NY!) .

Erect, much-branched subshrubs to 1 m tall, the upper branchlets dichotomous or frequently 4–5-fastigiate. Branches and branchlets quadrangular to subrounded, frequently leafy to the base but sometimes defoliating with age, furrowed longitudinally on opposite faces, glabrous to inconspicuously and sparsely beset with minute glandular trichomes; internodes 4–7 mm long, with knobby thickenings that persist where a leaf has fallen away, nodes glandular-setulose. Leaves sessile, spreading to laxly imbricate at the ends of branchlets; blade 8–15 × 5–9 mm, rigid-chartaceous, ovate, base rounded to subcordate, apex acute and terminating in a prominent simple trichome, margin serrulate to serrulate-denticulate, glandular-ciliate, the cilia 1–1.5 mm long, rigid, occasionally reddish (especially on young leaves), caducous, adaxial surface glabrous, abaxial surface glabrous or shortly and sparsely glandular-puberulent with a few scattered glandular trichomes, green to grayish-green, flat or occasionally slightly keeled, typically 5-nerved, sometimes 7-nerved (sometimes 5–7-plinerved) with an inconspicuous network of tertiary veins on the abaxial surface. Flowers 5–6-merous, solitary, terminal on principal and secondary branches but overtopped by lateral branches, sessile. Bracts 4–6, shortly subsessile or with a petiole ca. 1.5 mm long, blade 14–16 × 9 mm, ovate, base rounded to subcordate, apex acute and provided with a gland-tipped trichome, 5–9- nerved, margins glandular-ciliate. Hypanthium (at anthesis) 5–7 mm long, ca. 4 mm wide distally, campanulate, glabrous or caducously glandular-puberulent distally. Calyx tube ca. 1 mm long; calyx lobes (at anthesis) 7–9 × 2.5–2.7 mm, chartaceous, oblong-triangular, rounded to acuminate at the apex but shortly acuminate with a gland-tipped trichome 2–2.5 mm long, margin glandular-ciliate, glabrous adaxially, glabrous or minutely and caducously glandular-puberulent abaxially, tardily caducuous in post-anthesis. Petals 20–25 × 12–15 mm, magenta, oblong-obovate, apex rounded and shortly acuminate with a trichome ca. 2.5 mm long, base attenuate, margin minutely and sparsely glandular-ciliolate. Stamens 10 or 12, dimorphic: large (antesepalous) stamens 5–6, filaments 8 mm long, anther thecae 5–5.5 × 1.5 mm, yellow flushed with red, oblong, rostrum 0.5–0.7 mm long, whitish, pedoconnective magenta, 7–7.5 mm long, appendage 1.5 mm long, emarginate, yellow; small (antepetalous) stamens 5–6, filaments 6 mm long, anther thecae 4–4.5 × 1–1.2 mm, yellow, oblong, rostrum ca. 0.5 mm long, pedoconnective 2–2.5 mm long, magenta, appendage 1 mm long, rounded to obscurely bilobed, yellow. Ovary 6- locular, 4/5 inferior, style 13 mm long, straight, glabrous, stigma punctiform. Fruiting hypanthium (including calyx lobes) ca. 13 mm long. C apsule (at maturity) 6–8 × 6 mm, globose, enveloped by the persistent hypanthium, dehiscing from the base to the apex. Seeds 0.99–1.36 × 0.60–0.66 mm, oblong to subreniform, dark grayish-brown, periclinal cell walls of the testa concave (foveolate), the raphal zone about 20% the length of the seed. Chromosome number unknown.

Illustration:— Figure 55 .

Photographic images:— Figures 12E, F .

Phenology:—Flowering in March and December and probably in intervening months: fruiting in March, August, and December.

LAVOISIERA ( MELASTOMATACEAE )

Phytotaxa 315 (1) © 2017 Magnolia Press • 149 150 • Phytotaxa 315 (1) © 2017 Magnolia Press

MARTINS & ALMEDA

Distribution and habitat:—Known only from the Planalto Central in the Distrito Federal and Goiás in cerrado and along lake margins at 975–1000 m elev. Figure 18.

Conservation status:— This species is known from the type and three other collections. Two of these were collected over 100 years ago by Glaziou in Goiás at Guariroba. This locality appears to be in the Distrito Federal as presently delineated. Thus all known collections of this species come from the Distrito Federal which is now heavily modified by the growing city of Brasília. No collections of this species have been made in over 35 years. The EOO is 4 km ² and the AOO is 4 km ². In view of the few known collections, limited geographic and elevational distribution, and extensive habitat modification we assign a classification of Critically Endangered ( CR): B2 ab(iii) .

Discussion:—The diagnostic characters of L. quinquenervis include its uppermost internodes that are glabrous to inconspicuously and sparsely beset with minute glandular trichomes, ovate 5–7-nerved leaf blades with a prominent simple trichome at the apex and subserrulate to serrulate-denticulate margins that are glandular-ciliate, 5–6-merous flowers, yellow antesepalous (large) anther thecae that are flushed with red, glabrous hypanthia and abaxial surfaces of calyx lobes, and 6-locular ovary.

In habit and foliar morphology, L. quinquenervis resembles L. arachnoidea and L. setosa , both of which are also little-collected cerrado species known only from the Distrito Federal and/or Goiás. The former is readily distinguished by its arachnoid indumentum on uppermost internodes, abaxial surfaces of uppermost leaves, and hypanthia. The characters distinguishing the latter from L. quinquenervis are enumerated in the discussion under L. setosa .

Additional specimens examined:— DISTRITO FEDERAL: Mpio. Brasília, Bacia do Rio São Bartolomeu. Quadrícula No. 155, Heringer et al. 4061 (CAS!, K!, MO!, NY!, UEC!, US!); GOIÁS: without exact locality, Glaziou 21310 (BR-2!, C!, G!, K!, LE!, P!); Guariroba, au Morro do Cubatão, Glaziou 21311 (BR-2!, C!, F!, G!, P!, RB!, S!).

Figures

FIGURE 12. SEM images of seeds for representative Lavoisiera species showing lateral symmetrical plane (left) and detail of testa cells and cell wall microrelief (right). A–D. L. pulcherrima (Arbo et al. 4339). E–F. L. quinquenervis (Heringer et al. 4061). Scale bars: A & C=380 µm; B & D=38 µm; E=300 µm, F=75 µm.

FIGURE 55. Lavoisiera quinquenervis. A. Habit. B. Abaxial leaf surface. C. Hypanthium, calyx lobes and bracteoles. D. Ovary cross-section. E. Petal. F. Ventral view of antesepalous stamen (left); lateral view of antepetalous stamen (right). G. Seeds. (Based on: A–G, Heringer et al. 4061, MO, NY, US.)