Begonia microinduta M.D.Miranda, 2021

Miranda, Marcelo Dias, 2021, Begonia microinduta (Begoniaceae) a new species from the Atlantic Coastal Forest in the state of São Paulo, Brazil, Phytotaxa 497 (1), pp. 49-53 : 49-53

Begonia microinduta M.D.Miranda , sp. nov. ( Figs. 1 , 2 , 3 )

Begonia microinduta is most similar to Begonia windischii L.B.Sm. ex S.F.Sm. & Wassh. (1999: 27) both species have a rupiculous habit, tardily deciduous stipules, short peduncled inflorescences, very short inflorescence ramification, persistent floral bracts, staminate flowers with dorsal surface with simple and 2-branched trichomes in the center, pistillate flowers with 3 tepals with serrulate and ciliate margin. But the new species differs in its petiole covering with short microscopic trichomes throughout (vs. sparsely pilose in the upper third with villous trichomes, with a trichome necklace at the base of the petiole and in the apex), leaf veins on the abaxial surface pubescent with microscopic trichomes (vs. glabrous), narrower ca. 15–19 × 6–8 cm (vs. broader ca. 15–22 × 10.5–12.5 cm) leaf blade, cuspidate (vs. acute) apex, greenish-white (vs. vinaceus) abaxial leaf surface, white (vs. white to reddish-white) flowers, peduncles covered with microscopic trichomes (vs. sparsely pilose with villous trichomes) and pistillate flowers with 2 to 3 trichomes in the center (vs. glabrous).

Type: — BRAZIL. São Paulo: Caraguatatuba, Bairro Jaraguazinho, face leste do Morro do Jaraguá , vivendo sobre a rocha no interior da floresta. 23°36’45.49” S, 45°26’36.16” W, ca. 250 m elevation, 16 January 2020, M . D. Miranda 3 (holotype: RBR!) .

Description: —Erect herbs, rhizomatous, rupicolous, 19–60 cm tall. Stem cylindrical, internodes 1.5–4 cm long, ca. 8 mm wide, lenticellate, greenish-red, pubescent with glandular trichomes sparsely distributed along the stem, better seen on young shoots. Cystoliths absent. Stipules tardily deciduous, 12–20 × 11– 10 mm, ovate-lanceolate, apex acute, aristate in one of the stipules, margins entire, pubescent on dorsal surface along the principal vein, with microscopic trichomes, green, papyraceous when mature. Leaves simple, petioles 6.5–9.5 cm long, 4 mm wide, cylindrical, lenticellate, greenish-red, reddish distally, densely pubescent throughout entire length with short microscopic trichomes, hairs hyaline, leaf blades basifixed, 15–19 × 6–8 cm, entire, transversely obovate, asymmetrical, apex acuminate, base cordate, basal lobes not overlapping, margins dentate-serrulate, wavy, membranaceous, adaxial surface glabrous, dark green, shiny, abaxial surface glabrous, except by being pubescent on the veins with short microscopic trichomes, light green to whitish-green, venation actinodromous, veins 8–10. Inflorescence in 2-branched cymes, 4.5–5.5 cm long, fasciculated, rachis very short, ca. 1–2 mm long, peduncle pubescent, microscopic trichomes, green. Bracts persistent, primary bracts ca. 10 × 11 mm, ovate, apex acute, margin entire, glabrous, green. Staminate flower: pedicels 12–13 mm long, glabrous to sparsely pilose at the apex, trichomes microscopic, tepals 4, outer two white, 15 × 15 mm, ovate, apex rounded, margins entire, membranaceous, pubescent on the dorsal surface in the center, simple and 2- branched trichomes, hairs whitish-red, ca. 2 mm long, inner two white, 12–13 × 3–4 mm, oblanceolate, apex obtuse, base acute, margins entire, glabrous, stamens 25 to 30, 2– 3 mm long, filaments 0.5–1 mm long, free, anthers 2 mm long (including connective), oblong, yellow, laterally rimose. Pistillate flower: pedicels green, 12 mm long, glabrous; bracteole absent; tepals 3, white, equal, 15–18 × 12–13 mm, ovate, apex acute, margin ciliate, serrated, dorsal surface scarcely pilose on the center close to the base, with 2 to 3 simple trichomes; ovary whitish-green, 3-locular, ca. 8–9 × 9–10 mm, with sparsely distributed glandular trichomes, wing’s margins slightly serrated; placentae entire; stigmas yellow, 3, ca. 3 mm long, bifurcate, branches spiraled, with stigmatic papillae distributed along the branches. Capsule glabrous, green, ca. 19 × 16 mm (including the wings), transversely ovate, dehiscent on basal portion, light brown when mature, wings 3, unequal, the largest one 8–10 mm wide, the smallest one 3–5 mm wide, locular region 10–11 × 5 mm, elliptic, margins glabrous, slightly serrated, pinkish-green when fresh; peduncles 1–2.5 cm long, glabrous; seeds oblong.

Phenology:—Flowering and fruiting from August to January.

Distribution and ecology:— Begonia microinduta is endemic to São Paulo state, found in two localities in the Microregion of Caraguatatuba municipality, those localities are associated with the hill known as Pico do Jaraguá or Pico do Tinga. It grows close to the steep slopes and valleys, in places with rocky outcrops, in submontane ombrophilous forest, at elevations around 250 m. This species is rupicolous, ombrophilous and hygrophilous, living in humid localities, next to the watercourse. Until the present moment, only two populations are known, their habitats are 800 meters apart from each other. Due to being known from only two localities, Begonia microinduta is provisionally assessed as Vulnerable (VUD2) under IUCN Red List criteria ( IUCN Standards and Petitions Committee, 2019).

Additional specimen examined (paratype):— BRAZIL. São Paulo: Caraguatatuba, Bairro Jaraguazinho , vertente úmida e íngreme, em afloramentos rochosos ao lado do curso d’água. 23°36’22” S, 45°26'19" W, elevação 230 m, 26 August 2020, M . D. Miranda 11 ( RBR!) .

Taxonomic notes: — Begonia microinduta can be easily recognized by its narrow leaves with cuspidate leaf apex, pubescent petiole, leaf veins on the abaxial surface and peduncles covered with short microscopic trichomes, thin petioles, ca. 4 mm wide, besides having greenish-white abaxial leaf surface and white flowers. Apart from resembling B. windischii , B. microinduta is also related to B. lorenzii E.L. Jacques (2020: 39) , differing by having trichomes with less than 1 mm (vs. trichomes with ca. 1–2 mm), glabrous (vs. pubescent) adaxial leaf surface, abaxial leaf surface pubescent in the veins (vs. pubescent throughout), narrower ca. 15–19 × 6–8 cm (vs. broader ca. 15–22 × 10.5–12.5 cm) leaves, thinner petioles, ca. 4 mm (vs. ca. 6 mm) wide, staminate flowers abaxially pilose in the center, glabrous close to the margin (vs. pilose throughout the tepal), pistillate flowers scarcely pilose in the dorsal surface with 2 to 3 trichomes (vs. densely pilose throughout the tepal) and glabrous (vs. pubescent) fruit.

Etymology:—The specific epithet refers to the microscopic size of trichomes composing the indumentum of the petiole.

Figures

FIGURE 1. A–L. Begonia microinduta M.D.Miranda. A, Adaxial leaf surface; B, Abaxial leaf surface; C, Inflorescence showing staminate flowers; D, Inflorescence showing pistillate flowers; E, Staminate flower, anterior view; F, Staminate flower, posterior view; G, Staminate flower, lateral view; H, Pistillate flower, anterior view; I, Pistillate flower, posterior view; J, Pistillate flower, lateral view; K, Ovary, cross section; L, Dried fruit. (Scale Bars:A–B= 19 cm; C= 3 cm; D= 1.2 cm; E–F= 3 cm; G= 1.5 cm; H–I= 3.2 cm; J= 1.6 cm; K= 1 cm; L= 1.8 cm). (A–L from M.D. Miranda 11).

FIGURE 2. A–E. Begonia microinduta M.D.Miranda. A, Habit; B, Apical bud, showing stipule indumentum; C, Immature flower buds; D, Seedlings on rock in the natural habitat; E, Upper portion of the petiole, showing microscopic trichomes. (Scale Bars:A= 7 cm; B= 2.5 cm; C= 5 mm; D= 10 mm; E= 15 mm) (A–E from M.D. Miranda 11).

FIGURE 3. Distribution map of Begonia microinduta M.D.Miranda (red dot) in the Microregion of Caraguatatuba municipality.