Syagrus santosii Soares & Guimarães. (2013a: 420)

Noblick, Larry R., 2017, A revision of the genus Syagrus (Arecaceae), Phytotaxa 294 (1), pp. 448-450 : 448-450

56. Syagrus santosii Soares & Guimarães. (2013a: 420) . Type:— BRAZIL. Bahia: lateral direta [south side] da barragem do Rio Jequitinhonha , –15.97, –39.59, 28 July 2011, L.A. Mattos Silva, C.A. Guimarães & J.L. Paixão 5243 (holotype HUESC [HUESC-10000], isotypes ALCB, CEPEC, RB, R)

Figure 78 plate, Figure 77 map.

Short to moderately-sized, solitary palm. Stem ca. 1.6–4.4 m × 15–21 cm; 47–67 cm in circumference, generally inclined for 0.6–3.5 m with persistent spiny leaf bases. Leaves 12–20; sheathing leaf base ca. 85 cm long, covered with a sparse indument, armed with spines along their margins; pseudopetiole 64–75 cm long; petiole 0–2 long; rachis 160–194 cm long; leaflets green to yellow-green slightly lighter on the abaxial surface, 71–90 along one side, regularly arrange, lying in one plane, ramenta scales or tomentum frequently present where the leaflets are

A REVISION OF THE GENUS SYAGRUS

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NOBLICK A REVISION OF THE GENUS SYAGRUS

Phytotaxa 294 (1) © 2017 Magnolia Press • 197 inserted on the rachis and along the abaxial midvein; basal leaflets 50–58 × 1.2–2.0 cm, middle leaflets 46–54 × 2.0–3.0 cm, apical leaflets 20–27 × 1.0– 1.5 cm with an asymmetric tip. Inflorescence erect to pendulous, spirally branched; prophyll 26–41 × 4.0– 5.2 cm, fibrous, lanceolate; peduncular bract 130–156 cm long, expanded portion 51–70 cm long, including a beak to 3.5 cm, perimeter 7.0– 8.4 cm, 1–2 mm thickness, narrow, woody, sulcate, exterior covered with a rusty tomentum; peduncle ca. 85–120 × 1.2–1.3 cm, elliptical in cross-section, covered with a sparse chestnut-colored indument when young; inflorescence axis 50–70 cm long; rachis 38–48 cm long, initially whitish yellow then turning green in fruit; rachillae 43–62, glabrous, 22–24 cm long at the apex, 26–34 cm long at the base; staminate flowers 7–10 mm long, some with a short pedicel up to 1 mm long near the base of the inflorescence, green to yellow, sepals 1.5 mm long, glabrous, petals 6–8 × 1.5–2 mm with acute tips, coriaceous, nerves indistinct, stamens 5–6 mm long, anthers 2.5–4 mm long, filaments 3.5–4 mm long, pistillode less than 1 mm long; pistillate flowers conical, 7–10 × 6–7 mm, yellow, glabrous, sepals 7–9 × 7–10 mm, petals 6–9 × 7–9 mm, glabrous, pistil 5–7 × 3–4 mm, stigmas not measured, glabrous, staminodal ring not measured. Fruit ellipsoid or ovoid, 2.9–4.6 × 2.6–3.8 cm, which frequently split at its tip, yellow or greenish yellow when mature covered with a rusty tomentum, epicarp is less than 0.5 mm thick, mesocarp 2–4 mm thick, yellow, sweet-tasting, succulent and fibrous; endocarp ovoid, 2.7–4.2 × 2.4–3 cm, 2.5–3 mm thick on its sides; seed more or less ellipsoid, not measured, endosperm homogeneous. Germination remote-tubular.

Common name:— None known.

Etymology:— The specific epithet, santosii , honors João Eduardo Santos of Itapebi, Bahia, Brazil, known locally as “Joãozinho das Orquídeas,” a well-known local expert of orchids and bromeliads and also the discoverer of this species, as well as Syagrus itapebiensis .

Distribution and habitat:— At the moment only one population of this species has been found on the margins of the Rio Jequitinonha, in the Municipio of Itapebi, Bahia, Brazil, where it grows for a distance of 4 km along the southern margin of the river at an elevation of 111–119 m above sea level on rocky 80° slopes in areas of heavy brush in sandy clay soils. It grows next to other Arecaceae , like Allagoptera caudescens (Mart.) Kuntze , Attalea burretiana Bondar and naturalized Elaeis guineensis Jacq.

Conservation:— A large portion of the population was drowned by the construction of the hydroelectric dam of Itapebi. It is estimated that the current population of this species is ca. 5,000 individuals at this location. The area is not under any protection, but it is a very steep, slope that is unsuitable for agriculture or pasture. Since there is only one population of ca. 5,000 individuals, this species is classified as vulnerable, VU B1+2ab(i,v); C2a(ii).

Phenology:— This species flowers and fruits throughout the year, especially in the months of April–May and September–October.

Uses:— This is a potential landscape palm with edible fruits.

Notes:— According to the authors, this species is similar to S. schizophylla with its spiny petioles, but Syagrus santosii differs from S. schizophylla by its larger fruits (2.9–4.6 × 2.6–3.8 cm vs. 2–3.5 × 1.5–2.5 cm), larger endocarps (2.7–4.2 × 2.4–3 vs. 1.8–2.5 × 1.3–2.2 cm), and homogeneous endosperm. The S. santosii inflorescence has many more rachillae (43–62 vs. 14–38). Its leaf rachis is only slightly curved with 71–90 leaflets, while S. schizophylla is more curved with 18–50 leaflets. Syagrus schizophylla grows only a short distance from the coast in the restinga region, while S. santosii grows more than 70 km from the coast along the Rio Jequitinhonha in the rainforest region.

Representative specimens:— BRAZIL. Bahia: Itapebi, Represa da UHE do Rio Jequitinonha , –15.97, – 39.62, 28 August 2012, K.P. Soares et al. (paratype HDCF [HDCF-6276]) .

Figures

FIGURE 77. Distribution maps of Syagrus sancona, S. santosii, S. schizophylla, S. smithii, S. stenopetala, S. stratincola and S. vagans.

FIGURE 78. Syagrus santosii. A. Habitat near Itapebi, Bahia, steep banks of a new reservoir on the Rio Jequitinhonha. B. Habit of several palms. C. Habit. D. Inflorescence. E. Infructescence. Note petioles near top of image are heavily armed with spines. F. Newly opened inflorescence with staminate flower. G. Flowers. H. Fruits with cross-section of fruit showing homogeneous endosperm with no internal cavity on top left and endocarp on top right. Also note splitting apices. Grids are in centimeters.