Dichorisandra pulcherrima M.J.Silva & Aona, 2023

Silva, Marcos José Da & Aona, Lidyanne Yuriko Saleme, 2023, A beautiful new species of Dichorisandra (Commelinaceae) from the mountains of northeastern Goiás, Brazil, Phytotaxa 620 (3), pp. 216-224 : 217-222

Dichorisandra pulcherrima M.J.Silva & Aona , sp. nov. ( Figures 1 , 2 )

Type:— BRAZIL. Goiás: Niquelândia, Reserva Particular de Desenvolvimento Sustentável Legado Verdes do Cerrado, Núcleo Engenho, Área da Divisa entre a Ponte Nova e o Coimbra, Borda de Floresta Estacional, solo argiloso, 14º32’34”S, 48º31’15”W, 574 m. a.s.l., 28 January 2021 (fl), M . J . Silva, I. S . Santos, B. S . Pereira & B. G . Costa 11763 (holotype UFG!; isotypes CEN!, HURB!) .

Diagnosis:—This species can be recongnizes among its congeners mainly those of the Dichorisandra hexandra group ( D. hexandra , D. pubecens , and D. rigidifolia ) by the erect habit; stems, outer surface of the sheaths velutinous, petiole, abaxial surface of the leaves, cincinnus bracts, bracteoles, buds, and outer surfaces of the sepals are shortly velutinous; leaves with apex conspicuously caudate and margin ciliated; bracts of the cincinnus caducous, petals lilac to purple with basal third white; pollen sacs purple, and capsules verrucose at apex.

Description:— Herbs 1.6–1.8 m tall, terrestrial, perennial, erect, without pendulous branches. Roots tubers fascicled, ovoid, ellipsoid to widely fusiform; stems 1.8–2.5 cm diam. at base, erect, branching in the upper third, shortly velutinous, including the outer surface of the sheaths at the base of the branches, subpetiole, the abaxial surface of the leaves; internodes 4–4.5 cm long, cylindrical, densely and shortly velutinous, trichomes brown in mature organs, light brown in immature ones. Leaves distichously-alternate and spiral-alternate near to the inflorescences; sheaths (1.6–) 2–2.6 cm long, the ones at the base of the branches, 2.9–3 cm long, the ones at the apex of the branches up to 3.5 cm long, densely and shortly velutinous, margin ciliated, trichomes brown in mature organs and light brown in immature ones; petiole inconspicuous or up to 2 mm long, dark green; leaf blade 10–17 × 3.8–5 cm, elliptic to oblong-elliptic, glabrous or glabrescent on the adaxial surface, densely and shortly velutinous on the abaxial surface, base conspicuously asymmetric, margins entire, shortly ciliate, apex conspicuously caudate. Inflorescences 10.5–11.5 cm long, terminal, erect; basal leaf not differentiated from the others; peduncle and rachis of inflorescences, outer surfaces of the sepals, cincinnus bracts, foliaceous bracts, bracteoles and buds velutinous; peduncle 2.8–4.2 cm long, light green; cincinnus bract (7–)10–10.8 × (2.3–) 2.9–3 mm, ovate or lanceolate, decreasing in size towards the apex of the inflorescence, parallel to the cincinnus peduncles, foliaceous, caducous, light green, margin ciliated, apex acute to acuminate; cincinnus peduncle 4–10 mm long, decreasing in length towards the apex, light green; cincinni (10–)11–14, alternate, laxly arranged, 3–5-flowered, light green; bracteoles 2.1–2.2 × 1.9–2 mm, deltoid, green, scarious, margin ciliated, apex obtuse. Flowers 1.8–1.9 × 1.2–1.4 cm, bisexual or staminate, zygomorphic due to the position of the stamens and sepals; pedicel 2.5–2.6 mm long, villous, becoming 3.5–5 mm long when in fruit; floral buds 8.6– 8.8 × 4.75–4.8 mm, oblongoid or ovoid, densely tomentose; sepals 8.9–9 × 4.8–4.9 mm, oblong-elliptic to ovate, cymbiform, pale green in the lower third, pinkish-purple to violet distally, externally tomentose, internally glabrous, margin entire, glabrous, obtuse; petals 12.9–13 × 8–8.1 mm, widely obtrullate or obovate, lilac to purple with lower third white, margin entire, apex obtuse; stamens 6, subequal, suberect, filaments 1.4–3.3 mm long, twisted, pale lavender near the connective, anthers 4.6–5.1 mm long, connective whitish, glabrous, pollen sacs purple, dehiscent through 2 apical pores, base sagittate; ovary 1.8–1.82 × 1.4–1.5 mm, globose, glabrous, smooth, style 6.5–6.6 mm long, whitish, stigma capitate, densely papillose. Capsule 9–12 × 6.9–8 mm, loculicidal, depressed, subglobose and globose, vinaceous to atro-vinaceous at mature, glabrous, verrucose at apex. Seeds 2–3 per locule, 4.3–4.5 × 2.9–3.1 mm, ovoid, dorsiventrally compressed, black, testa smooth; hilum C-shaped, as long as the seed; embryotega semilateral; aril orange, spongy, thick.

Paratypes:— Brazil. Goiás: Niquelândia, Reserva Particular de Desenvolvimento Sustentável Legado Verdes do Cerrado, Núcleo Engenho, Área da Divisa entre a Ponte Nova e o Coimbra, Borda de Floresta Estacional, solo argiloso, 14º32’34”S, 48º31’15”W, 574 m. a.s.l., 28 January 2021 (fl), M. J. Silva, I. S. Santos, B. R. Pereira & B. G. Gosta 11765 ( UFG), 11766 ( UFG), 11767 ( UFG); ibd., 14º34’40”S, 48º31’51”W, 588 m. a.s.l., 18 February 2021 (fl., fr.), M. J. Silva, I. S. Santos & B. R. Pereira 11870 ( UFG), 11871 ( UFG), 11872 ( UFG), 11873 ( UFG), 11874 UFG); ibd., 18 February 2021 (fl.), I. S. Santos, M. J. Silva & B. R. Pereira 851 ( UFG); ibd., 14º32’33”S, 48º31’15”W, 583 m. a.s.l., 25 March 2021, fr, M. J. Silva, A. A. Alonso & I. S. Santos 12063 ( UFG); Final do Coimbra 1, próximo a divisa com o Coimbra, lado esquerdo da estrada sentido Vila, borda sombreada da vegetaç„o, 25 March 2021, fr, M. J. Silva, A. A. Alonso & I. S. Santos 12066 ( UFG), 12068 ( UFG), 12070 ( UFG); Início da Área do Coimbra 1, lado direito da estrada, após plantio de soja em floresta estacional, 14º32’32”S, 48º31’39”W, 578 m. a.s.l., 27 March 2021, fl, fr, M. J. Silva, A. A. Alonso & I. S. Santos 12190 ( UFG), 12191 ( UFG), 12192 ( UFG) .

Distribution and habitat:— Dichorisandra pulcherrima is currently known from the Reserva Particular de Desenvolvimento Sustentável Legado Verdes do Cerrado, municipality of Niquelândia, state of Goiás ( Figure 3 ). It grows in shaded environments at the edge and inside seasonal dry forests and “cerrad„o” formations on clayey soils between 574 and 588 m. a.s.l., forming populations with over 40 mature individuals.

Flowering and fruiting: — January to March.

Etymology:— The specific epithet “ pulcherrima ”, derived from the Latin “ pulcher ”, which means beautiful, was applied because it has a slender, tall build, with flowers and fruits that stand out and bring beauty to the landscape where it grows.

Preliminary Conservation Assessment:—Species with an Extent of Occurrence Area estimated at 5, 076 km 2, which allows us to classify it as Vulnerable (VU) B1b, B2ab(i,iv,v). Despite this, the species was found in a Permanent Conservation Unit, which ensures its preservation.

Diagnostic morphology and relationships:— Dichorisandra pulcherrima resembles D. villosula due to its indumented stem, sterile branches with distichous-alternate leaves with asymmetrical base and hairy on both surfaces; externally hairy and ciliated sheaths; inflorescences terminal, erect with hairy axis; cincinnus bracts parallel to peduncles, scarious bracteoles, anthers with sagittate base with two apical pores, and glabrous ovary. However, it differs in that D. pulcherrima always has an erect habit, without pendulous branches, leaf blade elliptical or oblong-elliptic, with 10–17 × 3.8–5 cm, caudate at apex, inflorescence measuring 10.5–11.5 cm long, with (10–)11–14 laxly distributed cincinni, cincinnus bracts (7–) 10–10.8 mm long, oval-acuminate or lanceolate, bisexual flowers with 1.8–1.9 cm diam., sepals 8.9–9 × 4.8– 4.9 mm, oblong-elliptic to ovate-oblong, pink or violet distally, petals largely obtruded or obovate, lilac to purple from the middle third, stamens with filaments 1.4–3.3 mm long and anthers 4.6–5.1 mm long, pollen sacs purple, and ovary with 1.8–1.82 × 1.4–1.5 mm. Paradoxically, D. villosula is usually a climbing plant up to 5 m tall, with pendulous branches, has leaf blade ovate, lanceolate or linear with 12–16.5(–19) × 2.5–5 cm, acuminate at apex, inflorescence measuring 7–8.5 cm long. with (8–)11–20 congested, cincinni, cincinnus bracts 20–25 mm long, linear, bisexual flowers with ca. 1.5 cm long, sepals with 7–9 × 4 mm, ovate or elliptical, white-blue distally, petals ovate or obovate, blue from the middle third, stamens with filaments ca. 1 mm long and anthers ca. 6 mm long, the pollen sacs bluish, as well as ovary with ca. 1 × 1 mm. Associated with this, Dichorisandra villosula occurs in the regions Noth (Acre, Amazonas, Pará, Rodônia, Roraima and Tocantis states) and Southeast (Minas Gerais) of Brazil, while the new species has so far been found in the Midwest region (Goiás state).

Collections from the state of Goiás were erroneously identified by Aona (2008) as D. hexandra or D. pubescens due to limited and/or poorly preserved reproductive organs, with little information about the habit. This was due to the scarce number of samples of Dichorisandra in the herbaria from Central-Western Brazil, reinforcing the collection effort made and the partnership of projects, such as the project “Biodiversity and Endemism in the Reserva Particular de Desenvolvimento Sustentável Legado erdes do Cerrado”.

Other species of the genus, such as D. hexandra and D. pubescens , also occur in the state of Goiás, according to Aona &Amaral (2022), and can be confused with D. pulcherrima , due to their erect habit, sterile branches, distichously-alternate leaves, pollen dehiscence through 2 apical pores, and by the color of the floral organs. However, the characters listed in Table 1 help to differentiate them.

Considering the recent discoveries of Dichorisandra in the state of Goiás (See Silva & Aona 2022 and this manuscript), associated with the fact that there are collections in some Herbaria (e.g., CEN, HUEG, IBGE, UB and UFG) from Goiás state without identification or misidentified, we provide an identification key to the Dichorisandra species occurring in the state of Goiás.

Figures

FIGURE 1. Dichorisandra pulcherrima M.J.Silva & Aona. A. Fertile branch. B. Leaf. C. Detail of the leaf base. D. Sheath, note the dense trichomes. E. Trichomes on the adaxial surface of the leaf. F. Trichomes on the abaxial surface of the leaf. G. Inflorescence detail. H. Floral bud. I. Cincinnus bracts. J. Detail of trichomes on the adaxial side of the cincinnus bract. K. Bracteole. L. Detail of the trichomes on the adaxial side of the bracteole. M. Flower in ventral view. N. Sepals. O. Sepal trichomes, adaxial view. P. Petals, adaxial view. Q. Androecium and gynoecium. R. Gynoecium with two stamens removed. S. Stamens. T. Detail of the stigma. U. Fruit. (From holotype, Illustrated by Cristiano Gualberto).

FIGURE 2. Dichorisandra pulcherrima M.J.Silva & Aona. A. Habit. B. Portion of the stem densely hairy. C. Sheath, note the tomentose ferrugineous trichomes. D. Underground system, note the fascicled roots tubers. E. Inflorescence. F. Flower in frontal view. G. Fruit, note surface verrucose. G. Open fruit, note the orange aril (Images by M.J. Silva).

FIGURE 3. Distribution map of Dichorisandra pulcherrima M.J.Silva & Aona in Goiás state, Midwestern region of Brazil. A. Map of Brazil, highlighting Goiás State in gray; B. Map for the state of Goiás, showing its political boundaries and variation in elevation. C. Municipality of Niquelândia (dotted area) with the species distribution points. Abbreviations for the Brazilian states (BA, Bahia; GO, Goiás; MG, Minas Gerais; MS, Mato Grosso do Sul; MT, Mato Grosso; TO, Tocantins) and the Distrito Federal (DF).