Dichorisandra flesheri Aona

Aona, Lidyanne Y. S., Souza, Everton Hilo De, Bittrich, Volker & Do Amaral, Maria Do Carmo E., 2024, Dichorisandra flesheri (Commelinaceae), a new delicate species from South Bahia, Brazil, Phytotaxa 647 (2), pp. 199-206 : 200-203

Dichorisandra flesheri Aona , sp. nov. ( Fig. 2 )

Type:— BRAZIL. Bahia: Igrapiúna, Reserva Ecológica Michelin, Mata da Vila 5, 13˚49’18”S, 39˚11’54” W, 132 m. a.s.l., 25 November 2022 (fl), E.H.Souza 2500 P.L.Ribeiro; R.R.N.França; S.S. Mota; G.M.D.Ferreira; A.Caetité; G.Q.Nascimento (holotype HURB!) .

Diagnosis: — Dichorisandra flesheri is distinguished from its congeners by the well‒developed indument on stem, sheaths, both sides of the leaf blades, a pendulous inflorescence, inflorescence and flower buds, for presenting six stamens with yellow anthers opening by longitudinal slits, and by the ovoid capsules with a sometimes verrucose epicarp, and apical pubescence.

Description: —Single stemmed erect herbs, to 20‒40 cm tall. Stem densely pilose, with 3‒4 mm long brownish trichomes, internodes 3‒9 cm long at the base, reduced towards the apex. Leaves subrosulate or spirally arranged, sheaths 1.7‒3 cm long, reduced towards the apex, densely pilose, often with pale vinaceous streaks, lower sheaths caducous, distally covered with trichomes, 3‒4 mm long, whitish to brownish, petiole 4‒5 mm long, or inconspicuous; leaf elliptic or orbicular, 14.5‒24.5 × 7‒14.5 cm, discolorous, abaxial surface light green, adaxial surface light green or faintly vinaceous, pilose on both surfaces, trichomes 3‒4 mm long, whitish or brownish, margin ciliate, base attenuate, apex acuminate, primary vein conspicuously sulcate on the adaxial face in vivo. Inflorescence terminal, congested pendulous; basal bract leaf-like, peduncle 5.5‒9.5 cm long, densely pilose; cincinni peduncle 0.5‒1 mm long, pilose, becoming shorter towards the apex, with 6‒10 cincinni, subsessile, congested, with 4–6 flowers each, bracts linear, (6‒)9–30 × 1.5‒4 mm, reduced towards the apex, oriented parallelly to the cincinni rachis, apex curved, pale green, turning scarious over time, abaxial side pilose, trichomes 1.5‒3 mm long, whitish, internally pilose, margin ciliate, bracteoles ca. 10‒12 × 3 mm, scarious, externally villous, margin ciliate. Flowers with densely pilose, ca. 3–7 mm pedicels, buds ovoid or ellipsoid, 18–22 × 3–4 mm, villous; flowers either bisexual or male, petals deliquescent, androecium slightly zygomorphic, 3–3.5 cm diam.; sepals linear to elliptic, 12–15 × 3–4 mm, whitish with purplish margin, hyaline, internally densely pilose, externally glabrous; petals ovate, 1.6–1.7 × 1–1.5 cm, partly blueish and whitish; stamens 6, slightly unequal, directed towards the center and upper part of the flower, filaments 1–1.5 mm long, whitish, erect, anthers 4–5 mm long, oblong, slightly sagittate at base, yellowish, opening introrsely with longitudinal slits, but functionally poricidal; ovary globose,1.5–2 × 1–1.5 mm, glabrous to pubescent; style 7–8 mm long, whitish, purplish in the upper third, erect, apex curved, stigma trilobed; ovules 4–6 per cell, greenish-yellowish. Capsule ovoid, (10-)20–21 × 5–7 mm, greyish when immature, pubescent at the apex, epicarp sometimes verrucose. Seeds not seen.

Etymology: — The specific epithet honors the ecologist Dr. Kevin Michael Flesher, Director of the Reserva Ecológica Michelin (REM) and responsible for the conservation, and research management of the area where this new species was discovered.

Phenology: Collected with flowers from November to June and with fruits in April.

Distribution and habitat: — Dichorisandra flesheri has been collected so far in the southern Bahia state, municipalities of Camamu, Igrapiúna and Ubaitaba ( Fig. 1 ). The species occurs only in the Atlantic Forest, in the phytophysiognomy of the Dense Ombrophilous Forest, occurring mainly on river banks, associated with rocky outcrops in the Reserve.

Additional Specimen Examined (Paratypes): — BRAZIL. Bahia: Acaraó, Rod. lado Sul , 02 June 1971 (fl.), T.S. Santos 1724 ( CEPEC) ; Camamu, Rodovia Travessão / Camamú , Km 33, Ramal à direita para a Fazenda Brahma , 14˚00’S, 39˚13’W, 15 June 1979 (fl.), L.A.M. Silva 499 et al. ( CEPEC) ; ibid., Rod. BA 650 Camamu / Travessão, entrada a 15.7 Km da sede municipal, Fazenda Zumbi dos Palmares (assentamento) ca. 1km da rodovia, ca. 6.3 Km da vicinal para a Fazenda Dandara , 14˚0’54”S, 30˚08’20”W, 22 February 2000 (fl.), J.G. Jardim 2765 et al. ( CEPEC, NY); ibid., Faz. Exílio , entrada no Km 10.7 da BA-650 Camamú/Travessão, ca. 2 Km L da sede da fazenda, 14˚00’7”S, 30˚10’7”W, 21 February 2000 (fl.), J.G.Jardim 2709, A.Aguiar, S.C.S’Antana, F.Junchum & J.Paixão ( CEPEC) ; ibid., trilha a partir da portaria da Faz. Bhrama. 14˚9’5,7”S, 39˚21’4,7”W, 2 February 2006 (fl.), L.Y.S. Aona 987, A.S.B. Gil & E. Meirelles ( ALCB, HURB, UEC) ; Igrapiúna, Reserva Michelin, entrada da Mata da Vila 5, Trilha do Gigó , 13˚49’18”S, 39˚11’54”W, 5 April 2013 (fr.), L.Y.S. Aona 2550 & turma de Biologia floral ( HURB) ; Ubaitaba, Km 8 da BR 101 ao Norte , 16 June 1972 (fl.), T.S. Santos 2309 ( CEPEC) .

IUCN Threat Assessment: — The suggested conservation status for Dichorisandra flesheri is Endangered (EN) B1a(iv)+2ab(i,iii); D. The species was estimated to have an Extent of Occurrence (EOO) of 241,436 km 2 and an Area of Occupancy (AOO) of 32,000 km 2. All specimens of Dichorisandra flesheri were collected from forest remnants, occupying the understory of moist forests in southern Bahia. In the area of occurrence, cocoa ( Theobroma cacao L.) and rubber tree ( Hevea brasiliensis L.) plantations are common, eliminating most of the understory vegetation, for the planting of these crops. Aona-Pinheiro et al. (2012) pointed out that the cocoa and rubber tree cultivation system in the region has been decreasing in recent years, while livestock activity has increased considerably. It is worth noting that the most conserved populations are within the Reserva Ecológica Michelin (REM), a private area maintained by the Michelin company. The REM area was deeply affected by logging between the 1960s and 1970s, however, it was later transformed into a private protected area without logging activities. The known populations within the REM have few individuals (ca. 10), presenting slow growth, flowering only once a year. Recently, Souza et al. (2021) and Souza & Leme (2021) described new species of Bromeliaceae in the REM in the same area of occurrence of Dichorisandra flesheri , reinforcing the importance of floristic studies in southern Bahia.

Notes: — Dichorisandra flesheri can be identified by the well‒developed indument present on stems, sheaths, both sides of the leaf blades, inflorescence, floral buds and the abaxial surface of the sepals, for presenting six stamens with yellow anthers opening by longitudinal slits – a unique character combination within the genus ( Fig. 2 ). Furthermore, the adaxial surface of the young leaf blades presents white longitudinal striations and the secondary and primary veins are adaxially clearly sulcate, abaxially salient.

The inflorescence of this new species is pendulous ( Figs. 2B, F ), an unusual feature in the genus. Only Dichorisandra incurva Martius ex Schultes (1830: 1184) , D. glabrescens ( Seubert 1855: 233) Aona & Amaral (2016: 7) , D. penduliflora Kunth (1843: 114) and D. nutabilis Aona & Amaral (2012: 18) have pendulous inflorescences. However, D. incurva has white flowers (vs. purplish in D. flesheri ) and its fruits are cylindrical, surface smooth (vs. ovoid, surface pubescent at the apex, slightly verrucose in D. flesheri ) ( Fig. 2G ). Dichorisandra glabrescens is a climbing herb up to 2 m high (vs. erect herb up to 40 cm in D. flesheri ) ( Fig. 2A ), petals pale blue to lilac (vs. purplish in D. flesheri , Fig. 2D ), with fruits very similar to those of D. incurva (see above). Dichorisandra penduliflora presents leaves distichally disposed along the stem and the flowers have 5 stamens with whitish anthers, apex and center blue to purplish (vs. rosette or spirally disposed ( Fig. 2A ) arranged and 6 stamens with anthers yellowish ( Fig. 2E ) in D. flesheri . Dichorisandra nutabilis have stamens with purplish anthers, dehiscing by 1 apical pore (vs. stamens with anthers yellowish, opening introrsely with longitudinal slits (functionally poricidal) in D. flesheri ).

Regarding the yellowish stamens, opening introrsely with longitudinal slits (functionally poricidal) in the genus Dichorisandra , the species D. glaziovii Taubert (1890: 2) ( Fig. 4A ), D. saxatilis Aona & Amaral (2016: 68) ( Fig. 4B ), D. sagittata Aona & Amaral (2016: 1) ( Fig. 4C ), D. velutina Aona & Amaral (2012: 15) ( Fig. 4D ) and D. striatula Moraes & Pellegrini (2019: 783) show these same characteristics, but they can be distinguished from D. flesheri according to the characters shown in Table 1 .

Figures

FIGURE 1. Distribution and habitat of Dichorisandra flesherii, endemic to Bahia, Brazil.

FIGURE 2. Dichorisandra flesheri. A. Habit. B. Stem with sheaths (sh) and inflorescence and its peduncle (pd) in detail. C. Detail of inflorescence showing peduncles (pd) and floral buds (fb) with trichomes (tr) and immature fruit (fr). D. Bisexual flower showing the anthers (an) with style (st), gynoecium, petals (pe) and sepals (se). E. Flower with detail of anthers (an) and style. F. Inflorescence with fruits. G. Detail of fruits showing pubescent, slightly verrucose surface. H. Details of roots and rhizomes (rh) and stem (sm).

FIGURE 4. Species of Dichorisandra with yellow anthers, opening introrsely with longitudinal slits (functionally poricidal). Note the inflorescence always erect when compared to Dichorisandra flesheri. A. Dichorisandra glaziovii. Note the leaves with white stripes above. B. Dichorisandra saxatilis. C. Dichorisandra sagittata. D. Dichorisandra nutabilis.