Euploca decorticans M.J. Silva & J.I.M. Melo, 2022

Silva, Marcos José Da & Melo, José Iranildo Miranda De, 2022, A new species of “ rooster coomb ”, Euploca decorticans (Heliotropiaceae), from the highlands of the state of Goiás, Brazil, Phytotaxa 530 (2), pp. 245-250 : 245-250

Euploca decorticans M.J. Silva & J.I.M. Melo , sp. nov. ( Figs. 1 , 2 and 3 ).

Subshrubs or shrubs 0.9–1.85 m tall, always erect; stem exfoliating by cinereous longitudinal plates; leaves held horizontally, petiolate, with base obtuse, apex obtuse or acute, velutinous-whitish on both surfaces; venation brochidodromous; inflorescence 9–23 cm long, opposite to the leaves, solitary; flowers 8.4–8.9 mm long, always pedicellate, the calyx 3.7–3.8 mm long, velutinous externally, with lobes triangular or oblong-triangular, the corolla 7.4–7.8 mm long, salverform, entirely yellow.

Type:— BRAZIL. Goiás: Niquelândia, Reserva Particular de Desenvolvimento Sustentável Legado Verdes do Cerrado, Núcleo Engenho , Área do Coimbra , crescendo sobre solo areno-pedregoso, em topo de morro a 100 m da lateral direita da Caverna Timbó, Cerrado Denso, 14º33’08”S, 48º30’04”W, 644 m a.s.l., 28 January 2021, fl., fr., M. J. Silva 11899 (holotype UFG!; isotypes CEN!, HACAM!, NY!, to be distributed) .

Subshrubs or shrubs 0.9–1.85 m tall, erect or suberect when greater than 1.5 m tall; adult stems glabrous, cinereous, flaking off in thin longitudinal plates, young stems densely velutinous-canescent or whitish; xylopodium absent. Leaves alternate spiral, held horizontally with Kranz anatomy, petiole 1.8–2 mm long, villous, non decurrent; leaf blades 3–3.8 × 1.2–1.6 cm, membranaceous, discolored, abaxial surface light green, abaxial surface opaque green or green-whitish, elliptic or ovate-elliptic, apex acute or obtuse, base obtuse, margin flat or slightly revolute, ciliated, velutinous on both surfaces, the trichomes shorter on abaxial surface, whitish; venation brochidodromous, midrib impressed on adaxial surface and prominent on abaxial surface, secondary veins 4–6 pairs, impressed on both surfaces, Inflorescence (9) 10–23 cm long, 1.1–15 cm, terminal, sometimes axillary and opposite to the leaves, always solitary, congested, many flowered; peduncle 1–1.2 cm long, similar to the branches and leaves in relation to the trichomes; bracts 3–3.2 × 0.8–1 mm, membranaceous, elliptic or oblong-spatulate, persistent, flat, velutinous externally, ciliate, barbelate internally. Flowers 8.4–8.9 mm long; pedicel 1.7–1.8 mm long; calyx 3.7–3.8 × 0.9–1.1 mm, lobes triangular to oblong-triangular, velutinous externally, glabrous internally; corolla 7.4–7.8 mm long, salverform, always entirely yellow, velutinous externally along its length and in the central portion of the lobes, tube 4–4.1 mm long, lobes 2–2.1 × 2.5–2.6 mm, widely oval, apex obtuse or rounded, shortly mucronate; stamens subsessile, filaments inserted 2–2.1 mm above the base of the tube; anthers 1.8–2 mm long, cordate, pubescent and slightly coherent at the apex; ovary 0.4–0.5 mm long, style ca. 0.7 mm long, cylindrical; stigma 0.6–0.7 mm long, bifid at the apex. Schizocarp 1.1–1.2 × 1.8–1.9 mm, globose, shortly pubescent, styles and stigma persistent, nutlets 4, ca. 0.9 mm long, angulate, brownish, with a cavity (pit) in each ventral surface.

Distribution and habitat:— The species has so far been found in the municipality of Niquelândia, state of Goiás ( Fig. 3 ), where it grows on hilltops in open areas of “cerrado denso” on sandy-clay and stony soil close to rock outcrops between 644 and 1000 meters of elevation. It draws attention in the landscape for its erect aspect and the slender stems with rhytidome conspicuously flaking off in plates. Among the species of the genus occurring in Brazil, this reaches up to 1.85 m tall, which probably makes its stem topple and be parallel to the ground, when then its inflorescences up to 25 cm in length and in an ascending aspect.

Phenology:— Collected with flowers and fruits between January and March.

Etymology:— The specific epithet “ decorticans ” alludes to the species presenting a stem with rhytidome flaking off in grayish longitudinal plates.

Preliminary conservation status:— Euploca decortica ns has an Extent of Occurrence and Area of Occupancy calculate as 179.9 km 2 and 12.000 km 2, respectively so it is considered Endangered [EN B2 ab (iii)]. Despite this, we emphasize that the new species was found in a Permanent Biodiversity protection unit that is the Private Reserve of Sustainable Development Legado Verdes do Cerrado, which ensures its full protection, and that it grows in a very common type of vegetation in the highlands of the state of Goiás , “cerrado denso”, so it might be found in other locations in the state of Goiás, Brazil .

Affinities and morphological characterization:— Euploca decortica ns is morphologically most similar to E. salicoides ( Fig. 4 ) shown especially by the color of the branches, leaves and corolla and, partly by the habit and appearance of growth. However, E. decorticans is a subshrub or shrub with slender stems presenting 0.9–1.85 m tall, always erect (vs. subshrub with 0.2–0.9 m tall, erect, prostrate or decumbent in E. salicoides ), has an adult stem flaking off in longitudinal plates (vs. striated with fissures, but never flaking off), young branches velutinous (vs. strigose or villous); leaves petiolate, held horizontally, the leaf blades 3–3.8 × 1.2–1.6 cm, elliptical or oval-elliptical, velutinous on both surfaces, with base obtuse and margin flat or slightly revolute (vs. sessile or subsessile, ascending, the leaf blade 0.7–5 × 0.15–1.4 cm, lanceolate, oblong-lanceolate, oval-lanceolate or broadly ovate, hirsute or villous on the adaxial surface and strigose or tomentose on the abaxial surface, with base truncated or cordate, and margin conspicuously revolute), venation brochidodromous (vs. apparently hyphodromous), inflorescences 9–23 cm long, showing the same trichomes as the branches (vs. 1.1–15 cm long, strigose or tomentose); bracts 3–3.2 × 0.8–1 mm, elliptical or oblong-spatulate, flat (vs. 2–5 × 0.5–3 mm, lanceolate or oval, revolute); flowers with 8.4–8.9 mm long, the pedicel 1.7–1.8 mm long (vs. flowers 4–5 mm long, sessile or with pedicel up to 1 mm long), calyx 3.7–3.8 mm long, lobes triangular or oblong-triangular (vs. calyx 2–3 mm long, the lobes elliptical or widely elliptical); corolla 7.4–7.8 mm long, entirely yellow, salverform, velutinous externally (vs. corolla 3–5 mm long, tubular, yellow or white, strigose externally); anthers 1.8–2 mm long, cordate (vs. ca. 1 mm long, ovate); style ca. 0.7 mm long (vs. style 1–1.1 mm long), as well as schizocarp with 1.8–1.9 mm diameter (vs. ca. 1.5 mm).

Additional specimens examined (Paratypes):— BRAZIL. Goiás: Niquelândia , Macedo, ca. 15 km N of Niquelândia, 14º18’S, 48º24’W, 1000 m a.s.l., 22 April 1988, fl., fr., R. E . Brooks et al. 192 ( NY); ibd., Reserva Particular de Desenvolvimento Sustentável Legado Verdes do Cerrado, Núcleo Engenho, Área do Coimbra , crescendo sobre solo areno-pedregoso em topo de morro cerca de 100 m da lateral direita da Caverna Timbó, cerrado denso, 14º33’08”S, 48º30’04”W, 644 m a.s.l., 28 January 2021, fl., fr., M. J . Silva 11718 ( UFG), M. J . Silva 11719 ( UFG), M. J . Silva 11720 ( UFG), M. J . Silva 11721 ( UFG), M. J . Silva 11722 ( UFG), M. J . Silva 11723 ( UFG), M. J . Silva 11724 ( UFG), M. J . Silva 11725 ( UFG), M. J . Silva 11726 ( UFG); ibd., topo de morro, 14º33’07”S, 48º30’03”W, 673 m a.s.l., 19 February 2021, fl., fr., M. J . Silva 11896 ( UFG), 11897 ( UFG), 11898 ( UFG); ibd., após o cordão rochoso do topo de morro cerca de 300 m na lateral da Caverna do Timbó , 14°18’04”S, 48°40’14”W, 656 m a.s.l., 27 March 2021, fl., fr., M. J . Silva, A. A . Alonso & I. S . Santos 12142 ( UFG); Área do Zé Gordo , primeiro afloramento de rochas da estrada principal, cerca de 1,1 km a partir da entrada lateral de acesso a casa abandonada, 14°34’12”S, 48°23’30”W, 687 m a.s.l., 20 February 2021, fl., fr., M. J . Silva, I. S . Santos & B. R . Pereira 12015 ( UFG), 12016 ( UFG), 12017 ( UFG), 12018 ( UFG) .

Figures

FIGURE 1. Euploca decorticans. A. Fertile branch; B. Detail of the stems, note the rhytidome flaking off in longitudinal plates; C. Leaf; D. and E. Detail of the adaxial surface of the leaf blade showing the trichomes; F. and G. Detail of the abaxial surface of the leaf blade showing the prominent secondary veins and the trichomes, respectively; H. and I. Variation in shape of bracts; J. Portion of the inflorescence; K. Flower, note the conspicuous pedicel; L. Corolla split open showing androecium and gynoecium; stigmatic ring is widest structure at top of style under the receptive stigma; M. Detail of the external surface of the corolla showing arrangement of the trichomes; N. Detail of the trichomes of the corolla; O. Stamen with a bit of corolla tube that bears it; note prolonged apex of anther; P. Calyx split open showing gynoecium; Q. Young fruit, note the accrescent and persistent calyx; R. Adult fruit, note the calyx and style persistent view; S. Nutlet, dorsal view; T. Nutlet, lateral view. Drawn by Cristiano Gualberto from holotype.

FIGURE 2. Euploca decorticans. A. and B. Habit, note in A the pendant stem and long inflorescences, in B the erect growth, and in b1 the long inflorescences seem to be lateral, because the axillary renewal shoots are nearly collinear with the shoot below; C. Highlighting the vegetative branch, note held horizontally leaves; D. Base of the stems, note the rhytidome flaking off; E. Terminal portion of the inflorescence, showing yellow flowers. Photographs by M.J. Silva.

FIGURE 3. Distribution currently known of E. decorticans.

FIGURE 4. Euploca salicoides. A. Habit; B. Fertile branch, note the ascending leaves and short inflorescences with white flowers with yellow centers; C. Vegetative branch, note ascending leaves with revolute margin and large trichomes; D. and E. Terminal portion of the inflorescence, showing in D the corolla white with yellow center, and in E. corolla uniformly yellow. Photographs by M.J. Silva (A) and H.J.C. Moreira (B–E).