Syagrus petraea (Mart.) Beccari (1916: 467)

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

44. Syagrus petraea (Mart.) Beccari (1916: 467) . Cocos petraea Mart. in Orbigny (1844: 100). Calappa petraea (Mart.) Kuntze (1891: 982) . Type:— BOLIVIA. Chiquitos: Sierra de Santiago, without date, A.D. d'Orbigny 21 (holotype P!)

Figure 62 plate, Figure 60 map.

Small, solitary to clustering palms, clustering by way of stolons. Stem short, subterranean, appearing acaulescent, 20–30 cm long, entire plant 30–80 (120) cm tall. Leaves 3–6 in crown, spirally arranged, spreading to ascending; sheathing leaf base 8–20 × 3 cm with fibrous margins; pseudopetiole 10–20 cm long with fibrous and/or smooth margins; petiole 2.4–12 × 0.3 cm; rachis 40–99(–125) cm long, with deciduous tomentum; leaflets lanceolate, silvery green, glabrous to white-waxy on both sides, but especially on the abaxial surface, with acute, bifid apiculate, symmetrical apex, 19–42 along one side, regularly or irregularly distributed in usually loose clusters of 2 or 3 in slightly divergent planes; no ramenta scales present where the leaflets are inserted on the rachis nor on the basal portion of the leaflet along the abaxial midvein, transverse veins inconspicuous; basal leaflets not measured, middle leaflets 18–43 × 0.6–1.1(–1.9) cm, apical leaflets not measured, mostly with acute, acuminate, asymmetric tips. Inflorescence spicate (rarely branched), prophyll 3.5–9(–12) × 2–3 cm, lanceolate, rounded abaxially, glabrous; peduncular bract ca. 9–33 cm long, expanded portion 5–15 × 3.7–6.0 cm, woody, thin, deeply sulcate, often with whitish-gray tomentum becoming glabrescent with age; peduncle 9–16 × (0.3–) 0.4–0.8 cm; inflorescence axis 6–13 cm long; rachis absent; rachilla 1, 6–13 cm long; staminate flowers 9–12 mm long at the

A REVISION OF THE GENUS SYAGRUS

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NOBLICK apex, 12–14 × 4–5 mm at the base, pale yellow, sepals 2 × less than 1 mm, coriaceous, petals 3–4 × 1.2 mm, light yellow, coriaceous, with acuminate tips, stamens 5.5–7 mm long, anthers 4–6 mm long with sagittate bases, filaments short, less than 2 mm, pistillode ca. 1 mm; pistillate flowers ca. 15 × 6 mm, yellow becoming light green, sepals 8–15 × 4–5 mm, petals ca. 13 × (2–) 3 mm, pistil 5 × 2–3 mm with a furfuraceous lower half, stigmas not measured, staminodal ring ca. 1 mm high, undulate. Fruit ellipsoid to ovoid, 2.0–2.5 × 1.6–1.8 cm, orangishbrown or yellowish green or light yellow in younger fruits with a rusty integument, epicarp smooth to a slightly rough fibrous, less than 0.5 mm thick, mesocarp 1–2 mm thick, sweet, succulent and fibrous; endocarp ellipsoid, 1.7 × 1.2 cm, 1.5–2 mm thick on the sides, bony, light brown color, trivittate, cavity smooth, dark brown; seed ellipsoid, 1.3 × 0.7 cm, endosperm homogeneous. Germination remote-tubular.

Common name:— coquillo, motacú-chí, itacuchi, palma-de-los-rocas ( Bolivia); ariri, coco-de-vassoura, tucum-de-indio.

Etymology:— The specific epithet, petraea , refers to the rocky habitat of the original type collection of Cocos petraea collected from Bolivia by d'Orbigny. However, this species is certainly not restricted to this type of habitat.

Distribution and habitat:— Grows in eastern Bolivia (Santiago de Chiquitos), in rocky cerrados, in poor, rocky to sandy soils, often in the sand filled cracks between rocks. Seen only in the Serrania de Santiago, in Santiago de Chiqitos, Santa Cruz on slopes south of the cerros El Banquete and San Miserato and in zones of exposed rocky slabs between Santiago and Roboré, at 550–850 m with little vegetation.

Conservation:— This species is currently considered a Bolivian endemic that grows in the Santiago de Chiquitos region in the province of Santa Cruz. It is found in fairly large populations in the rocks of the Chapada, in soils of little agricultural value, although it will grow in deeper soils as well. Other than fires, which it can survive, no other threat exist, and therefore it is classified as least concern, LC.

Phenology:— Appears to flower and fruit year around, most specimens collected in flower in September and October, but few with mature fruits.

Uses:— Its fruits are avidly consumed by animals. It has a potential for landscaping.

Notes:— Several palm species, especially those with short subterranean stems and a spicate inflorescence, have long been thought to belong to one very variable and widely distributed species, S. petraea . However, on a trip to Bolivia to find S. petraea in its type locality I discovered that S. petraea is strictly a Bolivian endemic, which grows in one pre-Cambrian rock formation that terminates near the Brazilian frontier close to the pantanal and the Rio Paraguay. However, this same geological formation may continue in the Serra da Bodoquena in Brazil. Since that discovery, two species formerly synonymized under S. petraea were resurrected in Lorenzi et al. (2010) (i.e. S. glazioviana , S. loefgrenii ), and several species of similar habit have been discovered and named (i.e. S. allagopteroides , S. caerulescens , S. emasensis , S. evansiana , S. guimaraesensis , S. longipedunculata , S. minor , S. pleiocladoides , S. pompeoi , S. procumbens ). The distinctive leaflet anatomy of S. petraea distinguishes it from anything else in South America with one exception. More recent work on an anatomical key by the author suggests that S. petraea is most closely related to the S. glazioviana complex, although morphologically they are different.

Representative specimens:— BOLIVIA. Santa Cruz: Chiquitos, Cerro de Santiago, 4 km NE of Santiago [Santiago de Chiquitos], Transects 2–4, 800 m, –18.33, –59.50, 17 May 1991, A.H. Gentry et al. 74016 ( MO, USZ) ; Chiquitos 15 km al Este de Roboré yendo hacia Santiago de Chiquitos , 200 m, –18.41, –59.63, 12 November 1996, Jardim & Mamani 3677 ( AAU, MO, NY, USZ) ; Chiquitos, Santiago, Sierranía Santiago , 800 m, –18.35, –59.56, 29 December 2000, L. R. Moreno et al. 245 ( JBSC) ; Chiquitos, Santiago, Sierranía Santiago , 850 m, –18.34, –59.54, 29 December 2000, L. R. Moreno et al. 246 ( JBSC) ; Chiquitos, a 12 km de Roboré a Santiago , 500 m, –18.34, –59.66, 7 March 2010, L.R. Moreno et al. 357 ( JBSC!) ; Chiquitos, Santiago de Chiquitos , March 2010, H. Lorenzi et al. 6835 ( HPL!) ; Chiquitos , 3 km E de Santiago de Chiquitos, 700 m, –18.33, –59.57, 22 November 1989, M. Saldias et al. 953 ( MO, NY, USZ) ; Chiquitos, Santiago de Chiquitos, 800 m, –18.38, –59.56, 24 October 2010, J.R.I. Wood & D. Villarroel 26931 ( UB!, USZ!); Velasco , without locality, 250 m, July 1892, Kuntze s.n. ( NY!) ;.

Figures

FIGURE 60. Distribution maps of Syagrus oleracea, S. orinocensis, S. petraea, and S. picrophylla.

FIGURE 62. Syagrus petraea. A. Rocky habitat of palm near Santiago de Chiquitos, Santa Cruz, Bolivia (Lorenzi et al. 6835). B. Habit sometimes appearing clustered. C. Solitary plant with infructescence. D. Whole plants showing horizontal underground stem. E. Inflorescence. F. Infructescence. G. Infructescence with mature fruits, which are often green. Scale in centimeters and inches.