Turnera spicata L.Rocha & Arbo, 2018

Rocha, Lamarck, Arbo, Maria Mercedes & Ribeiro, Patrícia Luz, 2018, Turnera spicata: a new species of Turneraceae (Passifloraceae s. l.) from the Brazilian Atlantic Forest, Phytotaxa 343 (2), pp. 167-174 : 168-170

Turnera spicata L.Rocha & Arbo , sp. nov. ( Figures 1–3 )

Type:— Brazil. Espírito Santo: Linhares, Reserva da Companhia Vale do Rio Doce, estrada Juerana Vermelha , Barra seca, próximo à casa do guarda, 19°04’56’’S, 39°53’12’’W, 11 April 2006 (fl., fr.), J. Paula-Souza, M. Paciência, D. Sampaio, A.C.P. Oliveira, V.C. Souza & V.R. Scalon 5733 (holotype: RB!; isotypes: CTES!, CVRD, ESA!, ICN!, SPF!, VIES) .

Turnera spicata resembles T. albicans Urb. , but differs from it by the indument with microcapitate glandular trichomes (vs. glandular trichomes absent), leaves with secondary veins with a divergence angle of 40–60° (vs. 57–80°), the inflorescence, a spike-like abbreviated raceme (vs. globular capitulum), bracts 3.5–4.8 × 1.5–2 mm, obovate to lanceolate (vs. 2.5–3.5 × 2–2.3 mm, subcircular or widely ovate), flowers shortly pedunculate 0.4–1 mm long (vs. sessile), bracteoles 2.7–3.5 mm long, lanceolate (vs. 1.9–2.8 mm, obovate or spatulate) and petal blades pilose only at the base (vs. pilose up to the middle).

Shrubs, ca. 50 cm tall, old branches whitish, striated longitudinally, glabrescent or sparse-pilose, young branches pilose, with microcapitate glandular trichomes, simple patent microtrichomes (<0.1 mm), simple tector trichomes smooth or wavy, and some thicker, golden; internodes 0.7–2.7 cm long, sometimes developing a brachyblast, slightly wider; leaf scars prominent. Leaves chartaceous, slightly discolored; stipules 2, lateral, triangular, 0.5–1.2 mm long, persistent, tomentose, reddish-brown; petiole 3–10 mm long, indument like that of the young stems; nectaries basilaminar, 1– 2(–3) pairs, 1–1.4(–2) mm diam., elliptic, opposite, oriented laterally or downward, dark brown, margins glabrous or with some microtrichomes; blade 3.9–12 × 1.4–5 cm (length: width = 2.4–2.8:1), elliptic to obovate, base attenuate, apex acute, sometimes obtuse, margins plane, serrated to slightly serrated, teeth terminated in colleters; upper surface olive-green, glossy, with sparse microcapitate glandular trichomes and simple tector curved to adpressed, concentrated on the main vein and margins; lower surface whitish olive-green, with sparse microcapitate glandular trichomes and simple tector appressed trichomes, concentrated on veins and along the margins; venation eucamptodromous, secondary veins 6–10 pairs, curved, slightly sunken in the upper face, somewhat prominent in the lower surface, 40–60° divergent from the main vein, forming arcs which end in the next vein before the blade edge, tertiary veins visible; minor venation sometimes visible. Inflorescences spike-like abbreviated racemes, elongated, terminal, rarely axillary; basal bracts ovate to lanceolate, 2.5–7.5 mm long, with stipules up to 1 mm long, breafly petiolate, with 1–2 pairs of nectaries, the following ones obovate to lanceolate, 3.5–4.8 × 1.5–2 mm, apex generally acute, with an apicule 0.2–0.4 mm long, margins entire, upper surface glabrescent, with some simple tector trichomes, lower surface sparse-strigose, with microcapitate glandular trichomes and simple tector trichomes, thin or thick, smooth, sometimes wavy, concentrated on the main vein and margins, 3 or 5 veins, reddish-brown. Flowers heterostylous; peduncle 0.4–1 mm long, free or up to 0.7 mm adnate to bract petiole; pedicel absent or almost; bracteoles (prophylls) 1 pair, 2.7–3.5 × 0.7–1.3 mm, inserted below the calyx, lanceolate, margins entire, apex acute, strigose outside, glabrous inside. Calyx 4–5 mm long, campanulate, calyx tube 2–2.5 mm long, strigose outside, with simple tector trichomes, thin and wavy, pilose inside only at the throat, lobes 1.5–2.5 × 0.9–1.1 mm, triangular, 3–nervate, with thick and smooth trichomes ca. 0.6 mm long, the inner ones with membranaceous margins, apex acute, with an apical mucron ca. 0.3 mm long. Corolla 5–6 mm long, petals’ claw glabrous, pilose at the throat of the floral tube, petals’ blade 2.8–3.5 mm long, narrow-obovate, white, yellow and pilose at the base, apex obtuse. Staminal filaments subulate, free from each other, 2.2–2.5 mm long in long-styled flowers, ca. 3.5 mm long in short-styled flowers, hirsute mainly at the mid-distal portion, flattened dorsiventrally at the proximal portion, 0.3–0.5 mm adnate to floral tube; anthers 0.7–1.1 × 0.5–0.7 mm, glabrous, dorsifixed, ovoid, base emarginate, apex apiculate, not recurved after dehiscence, apicule 0.2– 0.3 mm long. Ovary 0.7–1 mm long, ovoid, tomentose-hirsute outside, placentas 2–3-ovulate; styles 2.2–4.5 mm long in long-styled flowers, ca. 1 mm long in short-styled flowers, tomentose-hirsute mainly at the mid-proximal portion, slightly arched; stigmas brush-like. Fruit a loculicidal capsule, 4–4.5 mm diam., broadly ovoid; epicarp verrucose, with microcapitate glandular trichomes and simple short tector trichomes, some thick long hairs concentrated on valves apex which show a horny-like pilose appendix; internal surface glabrous, glossy, placental vein prominent. Seeds 2.2–2.4 × 1–1.2 mm, obovoid, slightly curved; exostome 0.2–0.3 mm long, conical; raphe whitish, linear, rapheal side sigmoid; chalaza prominent, concave, narrowed at the base; episperm reticulate, reticule nodes not prominent, areoles concave, quadrangular, rectangular or hexagonal, with a point-shaped depression; epidermis papillose; aril 1.2–1.5 mm long, lobed, whitish.

Paratypes:— BRAZIL. Espírito Santo: Linhares, Reserva Companhia Vale do Rio Doce, estrada paraju, Km 1.9, aprox. 19°08’33”S, 39°53’18”W, 2 December 2006 (fl., fr.), E.J. Lucas, V.C. Souza, N.A. Brummit, O.R. Campos, T.B. Flores, L.V.S. Jennings & D. Sampaio 958 (CTES!, RB!, SPF!) ; São Mateus, mata do distrito Pedra D’Água, sentido São Mateus-Guriri , 18°42’57’’S, 39°51’32’’W, 19 March 2017 (fl., fr.), J.L. Costa-Lima & R.B. Silva 2810 (CTES!, HUEFS!, MAC!, UFRN!) .

Etymology:—The species epithet refers to the inflorescence, a spike-like abbreviated raceme.

Distribution and habitat:— Turnera spicata is currently known by three collections at Linhares and São Mateus, state of Espírito Santo, Brazil. Occurs in an area of arboreal restinga, a subtype of Atlantic Forest vegetation known commonly as mussununga.

Conservation Status:—The collections of Turnera spicata , probably belong to three different populations, two of these from a particular conservation area, the Reserva Natural da Companhia Vale do Rio Doce, one of the largest protected areas of Brazilian Atlantic Forest, ca. 23,000 hectares. It is difficult to evaluate the conservation status of this species due to the limited sampling, more field surveys in promising areas are required. Since the new species occurs in a protected area and the impact on its population cannot be properly assessed, we tentatively classify T. spicata as Deficient Data (DD) ( IUCN 2017).

Phenology:—Flowering and fruiting specimens were collected in December, March and April.

Additional comments:— Turnera spicata belongs to the ser. Capitatae due to the indument with microcapitate glandular trichomes, well developed stipules, leaves with nectaries, small flowers gathered in racemose inflorescences, staminal filaments adnate to the floral tube only at the base, anthers dorsifixed not curved at dehiscence, styles densely pilose and seeds reticulate, obovoid with chalaza prominent and slightly concave, sigmoid rapheal side and papillose epidermis.

Within Turnera ser. Capitatae , T. spicata seems to be closely related with T. albicans Urban (1883: 135) . Both species are shrubs, with leaves usually large, adaxially glossy, almost glabrous, flowers with white petals and yellow throat gathered in congested inflorescences, fruit valves with a horn-like pilose appendix at the apex and small seeds with a punctiform cavity in each reticule areole. The new species shows restricted occurrence in the state of Espírito Santo, while T. albicans is known from restingas (a vegetation type associated with mangroves and white sand) in southern Bahia, and differs from the new species by the sessile flowers congested in a globular capitulum, and the indument composed only of simple tector trichomes ( Table 1).

Turnera spicata brings to mind T. annularis Urban (1883: 124) , ser. Annulares , because of the small flowers, with white petals and yellow throat, gathered in abbreviated racemes. However, T. spicata can be distinguished from it by the indument with microcapitate glandular trichomes (vs. with sessile-capitate glandular trichomes) stipules 0.5–1.2 mm long. (vs. 1.5–5 mm long), leaves bearing 1–2(–3) pairs of extrafloral basilaminar nectaries (vs. 3–4 pairs), bracteoles lanceolate (vs. spatulate) epicarp verrucose (vs. smooth). Furthermore, in contrast to the restricted occurrence of the new species, T. annularis is widely distributed in Brazil, occurring in the states of Minas Gerais, Bahia, Pernambuco, Paraíba and Rio de Janeiro, but has not yet been registered in the state of Espírito Santo ( Table 1).

With T. spicata , Turnera ser. Capitatae comprises eleven species: T. schomburgkiana Urban (1883: 132) and T. waltherioides Urban (1914: 158) , are distributed from southeastern Venezuela, Guiana to the far north of Brazil (Roraima). The other species are endemic to the Atlantic Forest, and except for T. capitata Cambessèdes (1829: 215) which occurs from Minas Gerais to Santa Catarina, the others present restricted occurrence: e.g. T. dasystyla Urban (1898: 10) is endemic to the semidecidual seasonal forest in the state Minas Gerais; T. hatschbachii Arbo (2000: 27) is endemic to the state of Espírito Santo; T. albicans ( Urban 1883: 135) and T. marmorata Urban (1898: 9) are endemic to the Southern Bahian restinga; T. maracasana Arbo (2000: 29) is endemic to the “mata de cipó”, Bahia and T. pernambucensis Urban (1883: 133) is endemic to the montane and submontane semideciduous seasonal forest in the state of Pernambuco.

Figures

FIGURE 1. Turnera spicata. A. Part of a reproductive branch. B. Detail of leaf, upper surface, showing the margin with simple microtrichomes and teeth ending in colleters. C. Part of stem showing leaf base and stipule. D. Leaf, proximal portion, upper surface, showing extrafloral nectaries. E. Inflorescence with floral buds and floral scars below. F. Inflorescence with floral scars and persistent stipules. G–H: Bract: G. Upper surface, H. Lower surface. I. Part of a long-style flower, showing the inner face of the floral tube, with detail of sepal apex and two stamens. J. Pistil of a long-style flower, with two bracteoles. K. Fruit with bracteoles. L–M. Seed with aril: L. Rapheal view, M. Lateral view (Drawing from E.J. Lucas 958—RB, by Natanael Nascimento).

FIGURE 2. Distribution map of Turnera spicata in the Espírito Santo state (ES).

FIGURE 3. Turnera spicata. A. Habit. B. Inflorescence showing long-styled flowers. C. Detail of inflorescences, showing flowers, floral buds and floral scars. D. Part of a leaf, proximal portion, upper surface, showing pairs of extrafloral nectaries (white arrows) (Photographed by James Lucas Costa-Lima).