Syagrus yungasensis M.Moraes, Novon 6: 89 (1996)

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Distribution

Map uses TDWG level 3 distributions (http://www.nhm.ac.uk/hosted_sites/tdwg/geogrphy.html)
Boliviapresent (World Checklist of Arecaceae)B
Restricted to narrow dry valleys and steep rocky slopes in the semideciduous foresta of the eastern slope of the Andes, between 700 and 1000 m elevation. (M. Moraes, Novelties of the Genera Parajubaea and Syagrus (Palmae) from Interandean Valleys of Bolivia. 1996)A

Discussion

  • Syagrus yungasensis was found on the stretch of road between Chulumani and La Asunta growing on rocky soils and cliff faces in steep ravines. These dry interandean valleys are very different from the humid forests found in much of the Yungas, and are a result of orographie conditions. The linear distance from the collection sites to peaks of ca. 6500 m in elevation in the Cordillera is ca. 55 kilometers. The population is found within rainshadowed valleys, and the vegetation is characterized by the presence of semideciduous and xerophytic species that withstand extended periods without rain. Small species of Syagrus often turn out to be local endemics, such as in the northeast of Brazil (Larry Noblick, pers. comrn.). Some acaulescent endemic species were reported from Brazil: .S'. duartci Glassman, S. harleyi Glassman, S. mendanhensis Glassman, S. microphylla Burret, and S. werdermannii Burret (Glassman, 1987). This new small species may have evolved in recent geologic periods: it has survived in a restricted habitat that is biogeographically related to the ChaqueƱan flora further south, but separated by the more humid forests of the Yungas and Chapare. (M. Moraes, Novelties of the Genera Parajubaea and Syagrus (Palmae) from Interandean Valleys of Bolivia. 1996)A

Diagnosis

  • Caudex solitarius 4-5 m. Pinnae utroque latere 98- 120, irrregulariter dispositae vel 4-10 aggregatae ad medium usque foliato. Rhachilla 32-46 appressus ad rhachim, flores feminei congesti ad rhachillae basim. (M. Moraes, Novelties of the Genera Parajubaea and Syagrus (Palmae) from Interandean Valleys of Bolivia. 1996)A

Conservation

  • This species is only known from narrow valleys. Due to an increasing Dumber of vehicles and road construction in the ana ill population OOuld be endangered. However. most populations are found on inaccessible, Steep slopes and are not thought to be in any immediate danger. (M. Moraes, Novelties of the Genera Parajubaea and Syagrus (Palmae) from Interandean Valleys of Bolivia. 1996)A

Etymology

  • The specific epithet refers to the geographical region known locally as the Yungas, an area that comprises much of the east slope of the Andes in northern and central Bolivia. (M. Moraes, Novelties of the Genera Parajubaea and Syagrus (Palmae) from Interandean Valleys of Bolivia. 1996)A

Uses

  • None recorded. (M. Moraes, Novelties of the Genera Parajubaea and Syagrus (Palmae) from Interandean Valleys of Bolivia. 1996)A

Description

  • Stem solitary 4-5 m tall, 7-9 cm diam., smooth surface with overlapping internodes without foliar bases. Leaves 13-18, ca. 2.2 m long; sheath 12- 25 cm long, fibrous; pseudopetiole 80-100 cm long, fibrous, channeled with slightly raised midridge, margins with fibers 6-8 cm long; rachis 1.2-1.4 m long, triangular in cross section at apex; pinnae 98-120 per side, lanceolate, irregularly inserted in groups of 4-10, 4-6 cm apart, open, nearly perpendicular to rachis, plicate at base, green and lustrous adaxially, glabrous with ramenta on central nerve abaxially, in each group the apical pinnae erect to apex; basal pinnae 39-68 X 0.4-0.5 cm; middle pinnae 45-63 X 1-1.2 cm; apical pinnae 4-15 X 0.1-0.2 cm. Inflorescences up to 8 per plant, 40-95 cm long; prophyll 16 cm long, fibrous; peduncular bract 80-92 cm long, apiculate, inflated above, woody, sulcate, brown externally, glabrous and dark brown internally; peduncle 56 cm long, glabrous; rachis 10-13 cm long, glabrous; rachillae 32-46, appressed to rachis, 11-15 bearing 2-4 pistillate flowers, the remaining rachillae with only staminate flowers, basal ca. 8-26 cm long and apical 2.5-10 cm long; sometimes one single rachilla inserted 40 cm from the base of peduncle, with 5-6 pistillate flowers. Staminate flowers sessile, to 6 mm long; sepals and petals apiculate; stamens 6, 2-3 mm long; filaments to 1 mm long; anthers to 2 mm long. Pistillate flowers 9-10 mm; sepals and petals apiculate; ovary glabrous with trifid stigmas; staminodial ring to 2 mm high, undulate. Fruit 3.5- 4 X 2.5-3 cm; epicarp smooth, green with brown scales at apex; mesocarp fibrous; endocarp 5 mm thick covered with persistent coarse fibers, rough surface, beaked at the base and with lightly prominent ridges that stop short of apex; seed 1, endosperm homogenous. (M. Moraes, Novelties of the Genera Parajubaea and Syagrus (Palmae) from Interandean Valleys of Bolivia. 1996)A

Materials Examined

  • BOLIVIA. La Paz: Sud Yungas. 82 km from Chulumani on road to La Asunta. 7(H) m. M) May 1986, Beck 12636 (LPB). (M. Moraes, Novelties of the Genera Parajubaea and Syagrus (Palmae) from Interandean Valleys of Bolivia. 1996)A

Bibliography

A. M. Moraes, Novelties of the Genera Parajubaea and Syagrus (Palmae) from Interandean Valleys of Bolivia. 1996
B. World Checklist of Arecaceae