Luehea divaricata Mart., 2025

Gerace, Samuele, Peruzzi, Lorenzo, Baumgratz, José Fernando A. & Bovini, Massimo G., 2025, Flora of Rio de Janeiro: the genus Luehea (Malvaceae: Grewioideae), Rodriguesia (e 00512024) 76, pp. 1-13 : 8

3. Luehea divaricata Mart. , Nov. Gen. Sp. Pl. 1(4): 101. tab. 63. 1826. Figs. 1 ; 2 e-f; 3b-c

Sh r ubs to t rees, 2–15 m h ight. Pet iole 0.5–1.5 cm long. Leaves 7.5–14 × 3.5 –6.5 cm, membranaceous, elliptic, base rounded, adaxial surface green, with sparse stellate trichomes to glabrous, abaxial surface white, with only dense arachnoid trichomes or also sparse stellate trichomes. Inflorescence with 10–20 flowers, ca. 10 cm long, terminal; pedicel 0.6–1 cm long. Flowers 4–6 cm wide. Epicalyx with 7–8 bracteoles, 1.1–1.9 × 0.3–0.4 cm, lanceolate to narrow-lanceolate. Sepals 1.9–2.6 × 0.5–0.8 cm, ovate, 1/2-basal revolute. Petals 1.9–2.3 × 0.9–1.3 cm, pinkish with base yellow, obovate, margin repand. Androecium with phalanges connate in a basal ring; staminodes 0.6–1.1 cm long; stamens 1.3–1.8 cm long, the innermost connate almost to the apex forming a tube around the style. Ovary 0.3–0.5 × 0.25–0.35 cm, ovate, circular in transversal section; style 1–1.5 cm long, 2/3-basal pubescent, stigma 0.09–0.18 cm wide, 0.03–0.1 cm long. Capsule 1.7–2.2 × 0.9–1.2 cm, ovate, base rounded to truncate, apex acute, villose, valve with dorsal surface slightly convex, circular cross section, margins plane, not crest-like. Seeds 0.7–0.8 × 0.25–0.3 cm.

Selected examined material: Areal, condomÍnio Fazenda das Roseiras , 22.IV.2019, fr., M.G. Bovini & K. De Toni 4497 ( RB). Italva, localidade Boa Sorte , estrada RJ-204, bem próximo a BR-356, 24.V.2022, fl. and fr., J.F.A. Baumgratz et al.1724 ( RB). Itatiaia, Passa Quatro , 9.VI.1941, fr., W.D. Barros 296 ( RB). Maricá, Parque Estadual da Serra da Tiririca, Morro da Serrinha , 28.IV.2014, fl., D.N.S. Machado et al. 427 ( RB). Nova Friburgo, Lumiar , Flor das Andorinhas, 20.III.2001, fl. and fr., A. Quinet ( RB00437055 ). Rio de Janeiro, Jardim Botanico Rio de Janeiro, canteiro 8D, 14.I.2015, fl., M. Nadruz 2938 ( RB). Sapucaia, Fazenda Pilatos , 20.IX.2000, fr., F.M.B. Pereira ( RB00437056 ).

Luehea divaricata is widely distributed from Brazil, Uruguay, and Paraguay to northern Argentina ( Souza & Esteves 2002). In Brazil, it is widespread, particularly in the phytogeographic domains Atlantic Forest, Cerrado, Pampa and Caatinga. In Rio de Janeiro state, Luehea divaricata occurs at elevations that range from 50 to 700 m in submontane to montane ombrophilous forests and in riparian or gallery forests, showing a preference for areas with high brightness ( Fig. 1 ). This species is only present in the Parque Estadual da Serra da Tiririca (Maricá). Flowering was recorded from January to May, and fruiting from April to July.

Luehea divaricata is the only species showing the innermost stamens connate almost to the apex, forming a tubular structure around the style. This species can be easily recognized by its inflorescences with numerous flowers and pink petals, with yellow base ( Fig. 3c ). However, a pink corolla is also observed in L. paniculata Mart. , a species morphologically similar to L. divaricata and easily confused, especially when no fruit is available. The fruit is, indeed, the main diagnostic feature that separates these two species, showing ovate shape and circular cross section in L. divaricata ( Figs. 2f ; 3b ), but elliptic shape and pentagonal cross section in L. paniculata ( Fig. 2l ). These two species can be distinguished by other morphological features, in particular obovate petals and connate stamens in L. divaricata vs. orbicular petals and free stamens in L. paniculata .

Figures

Figure 1 – Geographical distributions of Luehea candicans var. candicans, L. candicans var. gracilis, L. conwentzii and L. divaricata in the state of Rio de Janeiro.

Figure 2 – a-b.Luehea candicans – a. leaf; b. capsule.c-d.L. conwentzii – c. leaf; d. capsule. e-f.L. divaricata – e. leaf; f. capsule. g-h. L. macrophylla – g. leaf; h. capsule. i-j. L. ochrophylla – i. leaf; j. capsule. k-l. L. paniculata – k. leaf; l. capsule. m-p. L. speciosa – m. leaf; n-p. capsules. (a-b. S. Lima 406; c-d. C. Farney et al. 3578; e-f. J.F.A. Baumgratz et al. 1724; g-h. S. Gerace 128; i-j. T.M. Scarponi; k-l. D.N.S. Machado & L.A. Ribas 285; m-o. G.A. de Queiroz 408; n. B.N. Riguetti 18; p. D. Costantino). Photos by Samuele Gerace.

Figure 3 – a. Luehea conwentzii – fruiting branchlet. b-c. L. divaricata – b. fruiting branchlet; c. flower. d-e. L. macrophylla – d. fertile branchlet; e. detail of the fertile branchlet. f. L. speciosa – fruiting branchlet. Photos: a. Massimo Bovini; b-c. Marcus Coelho; d-e. Samuele Gerace; f. Carlos Ferreira.