Manihot confertiflora M. J. Silva, 2015

Silva, Marcos José Da, 2015, Two new wild cassava species (Manihot, Euphorbiaceae) from the Brazilian Cerrado, Phytotaxa 213 (2), pp. 131-139 : 133-135

Manihot confertiflora M. J. Silva , sp. nov. ( Figs. 1 , 2 )

A new species characterized by 3-lobed leaves with the lower surface green opaque, subspicate racemes with congested flowers, pistillate bracts on the base of the pedicel, subsessile staminate flowers, gamosepalous pistillate calyx and the fruits not winged.

Type: — BRAZIL. Goiás: Alto Paraíso de Goiás, Chapada dos Veadeiros, área lateral à Fazenda Felicidades, 1,5 km a partir da GO 239, 100 m acima do rio das Cobras, 2 November 2013, (fl), M. J. Silva, P. H. B. Santos & R. C. Sodré 5572 (holotype UFG!, isotypes NY!, UB!).

Shrubs 0.60 × 2.2 m, growing from a xylopodium, monoecious, erect; vegetative and reproductive parts glabrous; stems unbranched or dichotomously branched near the apex, cinereous, smooth, waxy; latex yellow. Stipules almost caducous. Leaves in alternate spiral arrangement, distributed especially at the apex of branches; lamina chartaceous to slightly coriaceous, glabrous on both surfaces, base cordate, 3-lobed or more rarely unlobed near the inflorescence, lobes overlapping at sinus, each one 6–8 × 3.8–6 cm, ovate, ovate-oblong, or oblong-obovate, margin entire, apex acuminate, sometimes oblique or cuspidate; venation camptodromous-brochidodromous, triplinerved, primary and secondary veins pinkish, purplish, or yellowish, the primary ones prominent on both surfaces, the secondary ones 11–12 diagonally arranged in relation to the midrib and impressed on both surfaces, upper surface green-vinaceous to green, glossy, lower surface glaucous to green-cinereous, with a smooth wax pattern; petiole 4–9.5 cm long, angular, canaliculate above, greenish to vinaceous or purplish. Racemes 6–13 cm long, subspicate, glabrous, terminal or in the axil of dichotomous branches, erect, solitary or in clusters of 4, robust, bisexual, with two pistillate flowers at the base and 8 to 13 terminal staminate flowers, axis cylindrical, waxy. Staminate flowers: buds 12.0–12.2 × 8.3–8.4 mm, orbicular to ovoid, yellowish without purplish pigmentation, waxy externally; bracts (at the base of the pedicels) 7.9–8.0 × 1.0– 1.1 mm, oblong to oblong-elliptic or lanceolate, acuminate to acute at the apex, persistent, bracteoles 5–5.2 × 0.6–0.7 mm, lanceolate, glabrous on both surfaces, acute to acuminate at apex, margin shortly denticulate near the apex, subopposite, persistent; pedicel 1.9–2.1 mm long, cylindrical, green-vinaceous, waxy; calyx 7.6–8 × 8.1–8.3 mm, widely campanulate, yellowish to greenish with purplish pigmentation, shortly tomentose internally, near the apex in the central portion and near the margin, lobes widely triangular to ovate, apex obtuse, sometimes shortly apiculate dorsally; disc 10-lobed, dark yellow, lobes rounded; stamens 10, in two whorls of five; filaments 6.2–9 mm long; anthers 2.2–2.6 mm long, oblongoid to ellipsoid, yellowish. Pistillate flowers: buds 7.3–8 × 8–8.1 mm, widely ovate to triangular, green-yellowish to green-purplish; bracts (at the base of the pedicels) 7–7.2 × 1–1.2 mm, lanceolate to oblong-elliptic, glabrous on both surfaces, acute to acuminate at the apex, margin shortly denticulate near the apex, persistent; bracteoles 5.2–5.3× 0.7–0.8 mm, lanceolate, similar to those of staminate flowers; pedicel 12–14 mm long, obconical, glabrous, pinkish to yellow-vinaceous; calyx 8–10 × 6–8 mm, widely campanulate, yellowish with vinaceous blots, pubescent internally, lobes triangular to widely triangular, apex acute to obtuse, sometimes shortly apiculate dorsally, margins involute; disc discretely lobed, yellowish; ovary 2.9–3.1 × 2.4–2.5 mm, oblongoid, glabrous, not winged, green, styles 3, conspicuously united at the base, free portion 2.1–2.3 mm long, with papillose apex. Capsules 10.0–11.0 × 9.0– 9.1 mm, subglobose, smooth, glossy, wingless, with septicidal and loculicidal dehiscence, green, slightly glossy. Seeds 6.0–6.3 × 4.9–5.0 mm, widely oblong, maculate; caruncle 1.8–1.9 mm, hat-shaped, cream to whitish.

Additional specimens examined (paratypes): — Goiás: Alto Paraíso de Goiás, Chapada dos Veadeiros, GO 118 , km 156, nas imediações da Fazenda Primavera, 3 November 2013, (fl), M. J. Silva, P. H. B. Santos & R. C. Sodré 5576 ( UFG), M. J. Silva, P. H. B. Santos & R. C. Sodré 5578 ( UFG) ; GO 239 , cerca de 10 km a partir da estrada que sai de Alto Paraíso de Goiás em direção à entrada para o alojamento do PNVC, 14º8’40,2”S, 47º33’53,3”W, 1,402 m elevation, 12 October 2013, (fl), M. J. Silva et al. 5459 ( UFG), M. J. Silva et al. 5461 ( UFG) ; Cerrado rupestre da Fazenda Felicidades, 12 October 2013, (fl), M. J. Silva et al. 5464 ( UFG) ; Chapada dos Veadeiros, 7 km antes de chegar ao município de Alto Paraíso de Goiás, 4 April 2013, (fr), M. J. Silva et al. 4790 ( UFG) ; 14º3’15,2”S, 47º32’33,3”W, 1,466 m elevation, 11 May 2013, (fl), M. J. Silva et al. 4916 ( UFG), M. J. Silva et al. 4917 ( UFG), M. J. Silva et al. 4918 ( UFG) ; 1,5 km da estrada de terra que leva ao rio dos Couros, 14º3’15,2”S, 47º32’33,3”W, 1,466 m elevation, 6 September 2014, (fl, fr), M. J. Silva et al. 4918 ( UFG) ; Teresina de Goiás, 4,1 km a NW de Teresina de Goiás, ao longo da GO 241 , rumo a Cavalcante, 13º49’S 47º35’S, January 1995, (fl), A. C. Allem & V. S. Silva 4385 ( CEN) .

Distribution and ecology: —This species is probably endemic to the Chapada dos Veadeiros, where, so far, it has been found in a range of 35 km 2 in the municipality of Alto Paraíso de Goiás. It grows in the Cerrado region on rocky outcrops or rocky crevices, wet grasslands, and near the margin of streams, between 1.402 and 1.466 m elevation. The specimens stand out in the landscape due to the virgate, cespitose habit, and its young leaves vinaceous or purplish. According to the IUCN criteria ( IUCN 2014), the species can be recognized as Critically Endangered CR [B2 ab (ii)], because it occurs in an area of occurrence smaller than 100 km 2 not protected by law and generally disturbed by human occupancy since it is a touristic destination.

Phenology: —Collected with flowers and fruits from September to May, but with intense fruiting in the last month.

Etymology: —The specific epithet “ confertiflora ” alludes to the groups of congested flowers in the upper third of the inflorescence.

Relationships: — Manihot confertiflora morphologically resembles M. irwinii Rogers & Appan (1973: 137) in its shrubby habit, yellow latex, usually 3-lobed leaves with the lobes overlapping at base, and bracts and flowers of both sexes lanceolate in shape. However, in M. irwinii the inflorescence is a raceme or a panicle with laxly distributed flowers (vs. subspicate racemes with congested flowers in M. confertiflora ), leaves are whitish on their lower surface (vs. green opaque), both male and female flowers have a vinaceous calyx with yellowish margin (vs. greenish to slightly vinaceous), staminate flowers are pedicellate (vs. subsessile, pedicels up to 1.2 mm long), pistillate bracts are 8–12 mm long and found in the lower third of the pedicels (vs. 7–7.2 mm long and found at the base of the pedicels), a dialysepalous pistillate calyx (vs. gamosepalous), and the fruits are winged (vs. not winged).

Figures

FIGURE 1. Manihot confertiflora. A. Flowering branch. B. Staminate bract. C. Staminate bracteole. D. Staminate bud. E. Staminate flower. F. Staminate flower with calyx split and open. G. Pistillate bract. H. Pistillate bracteole. I. Pistillate bud. J. Pistillate flower. K. Fruit. L. Seed, ventral side. Drawn by Cristiano Gualberto from the holotype.

FIGURE 2. Manihot confertiflora. A. Flowering branch. B. Inflorescence; note the staminate flower with campanulate and yellowish calyx. C. Staminate flower, ventral view. D. Pistillate flower, ventral view.E. Pistillate flowers, lateral view. F.Wingless fruit.Photographs by the author.