Dyssochroma caatingae G.B.Silva & T.R.S.Silva, 2025

Silva, Gabriel Barros Da, Jesus, Rodrigo José Araújo De, Giacomin, Leandro Lacerda, Stehmann, João Renato, Cardoso, Pedro Henrique & Silva, Tânia Regina Dos Santos, 2025, Two new species of Dyssochroma (Solandreae, Solanaceae) and an updated identification key to the genus, Phytotaxa 706 (1), pp. 91-100 : 92-96

1. Dyssochroma caatingae G.B.Silva & T.R.S.Silva sp. nov. ( Figs. 1 , 2A–D ).

Type:— BRAZIL. Pernambuco, Floresta, Serra do Periquito , 8º36’15”S, 37º54’5”W, 9 February 2017 (fl), V. M. Cotarelli et al. 2717 (holotype HUEFS-248273; isotype HRSN-4392) .

Diagnosis:— A species similar to Dyssochroma viridiflorum , but differs by its pubescent young stems, calyces and corollas (vs. glabrous or glabrescent), shorter leaves with (0.8–) 1.2–3.4 cm (vs. 7.3–12.4 cm long), and ovary 5–6 × 6 mm (vs. 3 × 3.5 mm in D. viridiflorum ).

Lianas, stems to ca. 2 cm in diam., subterete, bark brownish, young stems pubescent, with simple, 4–12-celled non-glandular trichomes, white, turning yellow to ferruginous when dry, 2–3 mm long, older stems glabrescent. Leaves chartaceous, petioles 2.5–7 mm long, blades (0.8–)1.2–3.4 × (0.3–) 1.6–1.8 cm, ovate, base cuneate, apex acute or attenuate, adaxial surface sparsely pubescent, abaxial surface pubescent, with simple, 4–5-celled non-glandular trichomes, falcate, 0.2–0.3 mm long, absent along the veins, margins slightly sinuous, ciliate. Flowers solitary, terminal, pedicel 1–1.5 cm long, enlarged distally, hirsute, with simple or branched, 5–7-celled non-glandular trichomes, 1–4 mm long, also with few crooked trichomes 0.3–0.5 mm long. Bracts 1–2 mm long, subulate. Calyx green, ovate, regularly deeply 5-lobed, lobes 1.7–2 × 0.7–0.9 cm, apex acute, outer surface pubescent, the trichomes like those on the stems, leaves and pedicels, inner surface glabrous. Corolla with valvate aestivation, campanulate, green, tube 3–5.2 cm long, pubescent on outer and inner surfaces, with simple, crooked, non-glandular, ca. 0.3 mm long, lobes shorter than the tube, ca. 1 cm long, with few crooked and slender trichomes 0.2–0.3 mm long, apex obtuse, revolute at anthesis; stamens exserted ca. 1 cm from the corolla tube, equal length reaching the same level, the filaments adnate ca. 1 mm to the base of the corolla tube, enlarged and glabrous at the base, attenuate at apex, the free part 2.5–4 cm long, anthers basifixed, linear, opening by longitudinal slits, 7–8 × 2 mm, shortly lobed at base (ca. 1 mm long), brown, not connivent, thecae not confluent at the apex; ovary glabrous, conical, 5–6 × 6 mm, with a nectariferous disk around, style 6–8 cm long, filiform, stigma saddle-shaped, placed ca. 1 mm above the anthers. Fruits not seen.

Distribution and ecology:— Dyssochroma caatingae was collected in a region known as Serra do Periquito in the municipality of Floresta, located in the center of Pernambuco state, within the Caatinga domain, Brazil ( Fig. 3 ). This distribution represents the first recorded occurrence of the genus outside the Atlantic Forest domain ( Orejuela et al. 2017; Stehmann & Giacomin 2025). The Serra do Periquito is characterized by different vegetation types, with a predominance of hyper- and hypoxerophilous caatinga on the slopes, and seasonal forest at higher elevations ( Araújo Filho et al. 2001). The new species occurs in seasonal forest above 880 m and was collected with flowers in February.

Preliminary conservation assessment:— Dyssochroma caatingae is only known from the type specimen, collected outside of protected areas, having an AOO of less than 10 km 2. At present, no detailed information is available regarding its population size or the potential threats to its survival. Therefore, it should be classified as (DD) Data Deficient ( IUCN 2012, 2024). Future field expeditions in the Serra do Periquito and seasonal forests of the Caatinga domain in Pernambuco state are essential to provide more information about its distribution and ecology.

Etymology:— The epithet is a reference to the first record of Dyssochroma in the Caatinga domain. Until now, the genus was considered restricted to the Atlantic Forest domain in Brazil.

Taxonomic notes:— Dyssochroma caatingae can be distinguished from the three previously described Dyssochroma species mainly by its pubescent indumentum. It has a variety of types of non-glandular trichomes covering its vegetative and reproductive organs, which are multicellular, either simple or branched on the pedicels and calyces, whereas D. atlanticum , D. longipes and D. viridiflorum are characterized as glabrous or glabrescent plants, rarely with sparse, minute unicellular simple trichomes ( Stehmann & Giacomin 2025). Among these three species, D. caatingae is most similar to D. viridiflorum , both sharing green calyces and corollas. Notably, the type specimens of D. caatingae were previously identified in herbarium collections as D. viridiflorum . However, these species differ in the characteristics detailed in the diagnosis above. Additionally, although both species occur in Pernambuco state, D. caatingae is found in the Caatinga domain, while D. viridiflorum has been recorded in the Atlantic Forest domain and has a wider distribution, also recorded in the states of Bahia, Ceará, Espírito Santo, Minas Gerais, Rio de Janeiro, São Paulo, and Paraná ( Stehmann & Giacomin 2025).

Figures

FIGURE 1. Dyssochroma caatingae. A—Habit. B—Young branch with inflorescence.C—Detail of the leaf margin and venation, adaxial surface. D—Leaf base and part of petiole. E—Flower pedicel and calyx. F—Detail of the pedicel indumentum. G—Different types of pedicel trichomes. H—Flower. I—Different types of calyx and corolla trichomes. J—Anthers and part of gynoecium. K—Stigma. L—Ovary. (V.M. Cotarelli 2717, illustrated by Pétala G. Ribeiro).

FIGURE 2. Field photos of the two new species of Dyssochroma. A–D. Dyssochroma caatingae; A—Flower and leaves overview. B— Stem and flower overview. C—Floral bud, showing the small leaves from the young branch. D—Corolla seen from below, showing the stamens and stigma. E-G. Dyssochroma jardimii; E—Habit, detailing the leaves margins. F—Stem with floral bud and flowers, detailing the stamens and stigma. G—Corolla seen from below. Photos: A-D, Vinícius Messas Cotarelli; E-G, Jomar Gomes Jardim.

FIGURE 3. Distribution map of Dyssochroma caatingae and D. jardimii in Brazil. The highlighted area includes all or part of the following states:AL (Alagoas), BA (Bahia), CE (Ceará), MA (Maranhão), MG (Minas Gerais), PB (Paraíba), PE (Pernambuco), PI (Piauí), RN (Rio Grande do Norte), SE (Sergipe). Phytogeographic domains are depicted for the states of Bahia and Pernambuco, where the new species occur.