Pereskia bahiensis Gürke subsp. minensis N.P. Taylor & Albuquerque-Lima, 2021

Taylor, Nigel P., Zappi, Daniela C. & Albuquerque-Lima, Sinzinando, 2021, A new Pereskia (Cactaceae) from Minas Gerais, Brazil, Phytotaxa 494 (3), pp. 289-296 : 294-295

Pereskia bahiensis Gürke subsp. minensis N.P. Taylor & Albuquerque-Lima , subsp. nov. ( Fig. 1–3 ).

Type: — Brazil, Minas Gerais, Mun. Ninheira, 15°20’16”S, 41°45’01”W, dry agreste forest south of the town, west of Rua João Rocha Brandão (Ninheira – Berizal), 856 m asl, 23 January 2021, Zappi et al. 5106 (holotype UB!, isotypes UFP, RB) .

Diagnosis:— Pereskia bahiensis subsp. minensis differs from P. bahiensis subsp. bahiensis by its more erect habit (vs. shrubby), much longer and stouter extension shoots (to 6 cm in diameter when still bearing auxoblast leaves) (vs. shorter, more slender extension shoots), leaves to 16 × 11 cm (vs. 5–12 × 2–7 cm), and flowers faintly honey scented (vs. virtually unscented) with 20+ pericarpel bracts (vs. outer and inner bracts respectively only 4–6), c. 15 pale magenta-pink inner perianth-segments (vs. 8–10) and a conspicuous white throat (vs. white throat not noticeable), the stamens held in a more compact mass (vs. stamens looser, less closely arranged) ( Fig 3A–D ).

Description:— Slender shrub or tree to 6 m, with a short trunk to 15 cm diam., bark grey, roughened; 1–2-yearsold extension shoots to 3–4 m × 5–6 cm ( Fig. 1 , B, see arrow), arching towards apex and giving rise to numerous erect parallel lateral branches bearing terminal inflorescences ( Fig. 1C–D ). Areoles when young bearing greybrown trichomes and 3–5 spines 3–4 cm long, reddish to yellowish when in growth ( Fig. 1E ), later brownish black. Auxoblast and brachyblast leaves scarcely differing in shape and size (except the more elongate auxoblast leaves on extension shoots), the brachyblast leaves 1–5 per areole ( Fig. 1F ), obovate to almost orbicular ( Fig. 1G ), conduplicate, retuse to apiculate, (8–)11–14(–16) × (4–)6–10(–11) cm, principal lateral veins 5–7 diverging from each side of the midvein. Flowers 5–6 cm diam., faintly honey-scented, visited by Halictid stingless bees and Apis mellifera ( Fig. 2E–F ); pericarpel bearing 10–14 ± orbicular outer bracts 1.0–1.5 × 0.8–1.1 cm ( Fig. 2A ), inner bracts c. 10, scale-like, orbicular-apiculate, pinkish at apex, adpressed ( Fig. 2B ); outer perianth-segments 6, greenish to pink, 1.5 × 1.2 cm; inner perianth-segments c. 15, 2.5–3.0 × 1.2–1.5 cm, mucronate, pale pinkish magenta, white in lower half; stamens tightly clustered at the centre of the flower, anthers golden yellow; style and 8 erect stigma-lobes white. Fruits and seeds similar to those of subsp. bahiensis , but pericarp bracts larger and more numerous, to 4.0 × 3.5 cm ( Figs. 2G and 3E ). Seeds 5–50 per fruit.

Etymology: —The new taxon is named after the Brazilian state of Minas Gerais (locus classicus).

Vernacular name: — quiabento (according to a local resident).

Habitat and distribution: — Pereskia bahiensis subsp. minensis grows in dense dry forest with a canopy 6–7 metres tall. The total known distribution of the subspecies can be found crossing into Minas Gerais, after passing the highlands of the Serra Geral (Serra da Inhaúma), where the former low-growing campos gerais vegetation has been replaced by extensive plantations of eucalypts. The road then descends into the basin of the Rio Pardo, entering an area of tall dry thorny ecotonal forest including lianas (here referred to as agreste), most of which has been converted for agriculture, at least in the municipal districts of São João do Paraíso and Ninheira, Minas Gerais. In this area the new taxon occurs with other Cactaceae , such as Cereus sp. , Brasilicereus phaeacanthus ( Gürke 1908: 57) Backeberg (1942: 50) and Pilosocereus pentaedrophorus ( Cels 1858: 9) Byles & Rowley (1957: 67) subsp. robustus Zappi (1994: 74) , and typical elements of this vegetation, such as Metternickia princeps Miers (1846: 145), Senegalia tenuifolia ( Linnaeus 1753: 523) Britton & Rose (1928: 118) , Erythroxylum sp. and various lianas. To the east of the locus classicus, including the adjacent part of Bahia south of the Serra Geral (at Lagoa Preta), the plant was seen cultivated as a stock fence, but not observed in the wild state.

Conservation assessment:— Pereskia bahiensis subsp. minensis is currently known from two small wild subpopulations, a total of not more than 30 individuals. The local agreste vegetation has already been largely converted for agriculture and little of this dry forest remains (as can be seen from Google Earth). Our IUCN Red List assessment ( IUCN, 2012) places this taxon into the Critically Endangered (CR) category, based on the very small number of mature individuals, limited area of occurrence (AOO <50 km 2) and advanced and ongoing degree of habitat modification (criteria A3 c, B1 ab+2b, C2 a, D). It is likely that the plant will go extinct if actions to protect this new subspecies, whether in situ or ex situ, are not taken urgently. As a positive note, we observed that the new subspecies is cultivated as a stock fence in various locations east of the type locality, ensuring its survival even in depauperated environments. Also, in March 2021, the authors revisited the population from which the holotype was obtained and collected 40 ripe fruits containing c. 500 seeds for deposition in Brazil’s national seed bank (EMBRAPA, Brasília). These fruits were harvested from the specimen illustrated in Fig. 1C–D .

Additional specimens examined (paratypes): — Minas Gerais, Mun. São João do Paraíso, east of the town towards Ninheira , 15°18’51”S, 41°53’00”W, 863 m asl, 23 January 2021, Zappi et al. 5103 ( UB, RB) ; Mun. Ninheira, east of the town on road from Lagoa Preta ( BA) , 15º15’23.2”S, 41º42’58”W, 926 m asl, cultivated as farm hedge, 10 March 2021, Zappi et al. 5128 ( UB) .

Key to all Pereskia taxa studied: —It follows:

1. Scandent climber with paired retrorse spines on ascending stems; flowers white, strongly geosmin-scented, fruits orange ............. ........................................................................ P. aculeata Miller (1754 : without pagination) (E-South America and the Caribbean)

- Erect plants, paired retrorse spines absent; flowers white, pink, magenta or red, ± unscented, fruit never orange...........................2

2. Small shrubs (sometimes climbing); flowers to 2.5 cm across, leaves <6 cm long; fruit black .......................................................3

- Tall shrubs or treelets; flowers> 3 cm across; leaves> 6 cm long; fruit green to yellow............................... ..................................5

3. Inner perianth-segments 7–8, pericarpel lacking long hairs................................... P. weberiana K. Schumann (1898: 762) ( Bolivia)

- Inner perianth-segments 4–5, pericarpel with long hairs ...................................... P. diaz-romeroana Cárdenas (1950: 15) ( Bolivia)

- Shrub with climbing branches when young .......................................................................... P. horrida Candolle (1828: 475) ( Peru)

5. Flowers red to orange-red, perianth-segments erect............... P. stenantha F. Ritter (1979: 21) (Rio São Francisco valley, E Brazil)

- Flowers rose-like, pink to magenta, perianth-segments spreading.....................................................................................................6

6. Leaves oblong-lanceolate; inflorescences often with>12 flowers.....................................................................................................7

- Leaves orbicular to obovate; inflorescences 2–12-flowered ..............................................................................................................8

7. Inflorescences and bracts purplish ............................... P. violacea (Leuenb.) N.P. Taylor (2017: 5) (Rio Doce drainage, SE Brazil)

- Inflorescences and bracts green .................................................. P. grandifolia (SE & NE Brazil, commonly cultivated elsewhere)

8. Flowers with staminodial hairs between the perianth-segments and stamens ..................................................................................... ............................................................................... P. nemorosa Rojas Acosta (1897: 64) ( Argentina, S Brazil, Uruguay, Paraguay)

- Flowers without staminodial hairs between the perianth-segments and stamens ..............................................................................9

9. Flowers pink; spines of branches reaching 10 cm long, fruit rounded................................................................................................. ............................................................................ P. sacharosa Griseb. (1879: 141) ( Argentina, Bolivia, Paraguay and C-W Brazil)

- Flowers magenta; spines of branches not longer than 5 cm, fruit angular .......................................................................................10

10. Leaves 12 × 7 cm: inner bracts 4–6, flower throat not conspicuously white ........................... P. bahiensis subsp. bahiensis (Bahia)

10’. Leaves to 16 × 11 cm; inner bracts c. 10, flower throat conspicuously white ..................................................................................... ........................................................................................................................ P. bahiensis subsp. minensis (Northern Minas Gerais)

Figures

FIGURE 1. Pereskia bahiensis subsp. minensis (all from population vouchered as Zappi et al. 5106, except A). A, erect shrub habit (Zappi et al. 5103), plant bearing a termite nest. B, habit showing long erect extension shoot (arrowed). C & D, arched apex of extension shoot bearing numerous parallel flowering branches. E, young spines. F & G, areoles bearing brachyblast leaves. Photos by Albuquerque- Lima.

FIGURE 2. Pereskia bahiensis subsp. minensis (all from Zappi et al. 5106, holotype plant, except B & G). A, flower-buds showing outer pericarpel bracts. B, flower-bud with outer pericarpel bracts and numerous adpressed inner scale-like bracts. C, flower half-open after 12 noon. D, inflorescence with flower, young fruit and buds. E & F, flowers with Halictid and honey bee visitors, respectively. G, young fruit (Zappi et al. 5103). Photos by Albuquerque-Lima.

FIGURE 3. Comparison of flowers and fruit of Pereskia bahiensis subsp. minensis (A, C, E, from Zappi et al. 5106) and P. bahiensis subsp. bahiensis (B, D, F, from Bahia, Mun. Brumado, north of Cristalândia, photographed 26 Jan. 2021). Scale marker for A & B = 1 cm. Photos by Albuquerque-Lima.