Syagrus guimaraesensis Noblick & Lorenzi, 2014

Noblick, Larry R., Lorenzi, Harri & Souza, Vinicius C., 2014, Four new taxa of acaulescent Syagrus (Arecaceae) from Brazil, Phytotaxa 188 (1), pp. 1-13 : 10-12

Syagrus guimaraesensis Noblick & Lorenzi , sp. nov. (Figs. 5C, 6).

A small palm resembling Syagrus petraea with a short subterranean stem, growing in a similar habitat with narrow leaflets, spike inflorescence and brownish fruit. It differs from S. petraea by its shorter leaf rachis (11–56 vs. 40–125 cm), fewer leaflets (6–16 vs.19–42), thicker leaflets and with a distinctly different leaflet anatomy (Fig. 5C vs. 5D).

Type: — BRAZIL, Mato Grosso: Chapada dos Guimarães, Parque Nacional da Chapada dos Guimarães, near Vieu da Noiva (Bridal Veil) waterfalls, Elevation ca. 611 m, 15°24’21.8’’S, 55°50’3.5’’W (-15.406056, -55.834306), 12 January 2014, L. Noblick & H. Lorenzi

5640. ( holotype ESA!; isotypes HPL!, UFMT!, RB!, SP!, K!, FTG!, NY!, MO!, US!) .

Small, solitary palm to ca. 80 cm. Stem short and subterranean; rhizome 4.5–10 × 3.5–5.5 cm. Leaves number 2–4 (–5) in the crown, sheathing leaf base ca. 4.5–18 cm long; pseudopetiole (true petiole plus part of the sheath) 2.5–11 cm long, true petiole 0.5–6 × 0.4–0.7 cm by 0.2–0.4 cm thick, channeled adaxially and rounded abaxially; rachis 11–56 cm long; leaflets slightly lighter on the abaxial surface, numbering 6–16 along one side, distributed mostly regularly but in clusters of 2–3 along rachis near the base, ramenta scales or tomentum absent where the leaflets are inserted on the rachis and none along the abaxial midvein; basal leaflets 27–48 × 0.1–0.5 cm, middle leaflets 36–75 × 0.4–0.7 cm, apical leaflets 24–38 × 0.1–0.5 cm with an asymmetric tip. Inflorescence interfoliar branching to one order, with prophyll 6.5–8.5 × 1–2 cm, 2-keeled; peduncular bract narrow, woody, sulcate, exterior with scattered thin indument, total length 7.5–23 cm including a 0–1.5 cm beak and with expanded or inflated portion 4.5–11 cm long, 2–3 cm diameter and a 3–6 cm perimeter and a 1–3 mm thickness; peduncle glabrous or with a few scattered scales, ca. 2.5–11 × 0.2–0.6 cm; total inflorescence as measured from the first basal flower to the apex 3–7.5 cm long; rachis none; rachilla, one, glabrous, 3–7.5 cm long; staminate flowers green to yellow, in triads on the lower portion or in staminate diads or singly on the upper portion of the rachillae, 10–11 × 3.8 mm at apex, 12.5–12.8 × 3.5–4.0 mm at the base, sepals and petals 3 in number, sepals 2.3–3.4 × 1.0– 1.7 mm, glabrous, no visible nerves, keeled and connate at the base, petals valvate, 8.7–11 mm × 2.9–3.7 mm with acute tips, nerves indistinct, stamens numbering 6, 3.4–4.4 mm long, anthers 2.2–2.7 mm long, filaments 1.7–2 mm long, pistillode trifid and nearly absent, basal pistillate flowers elongate pyramidal, glabrous, 13.2–16.8 × 6.9–7.9 mm (apical flowers 11.5–11.7 × 6.2–6.6 mm), sepals and petals yellow, 3 in number, sepals 9.5–16.8 × 3.2–7.7 mm, glabrous, no visible venation, imbricate, petals 6.7–15.3 × 2.8–5.5 mm, glabrous, obscurely nerved on the lower portion of the petal, imbricate at the base but valvate at the tips, the valvate portion ½ or more the length of the petals, pistil 6.1–8.0 × 2.5–3.7 mm, glabrous, stigmas 3 in number, and less than 3 mm long, glabrous, staminodial ring ca. 0.5–0.9 mm high and truncate to undulate. Fruit reddish-brown when mature, covered with small stiff appressed brownish hairs, broadly ellipsoid, 2.0 × 1.6 cm, epicarp less than 0.5 mm thick, mesocarp not measured, fleshy-fibrous and endocarp not measured, with 3 visible endocarp pores on the basal end and seed elliptical not measured, endosperm homogeneous. Germination remote tubular. Eophyll simple and entire.

FIGURE. Syagrus guimaraesensis . A. Habit, B. Infructescence with side view of fruit, C. Inflorescence, D. Infructescence with top view of fruit. Scale = ca. 1 cm.

Common name:— None recorded.

Etymology:— The specific epithet “guimaraesensis” refers to the Parque Nacional de Chapada dos Guimãraes from where it was discovered and the type collected with the kind permission and cooperation of the national park service.

Distribution and habitat:— South central Mato Grosso. Grows in very rocky sandy soils both within and outside of the National Park of the Chapada dos Guimarães, near the town of Chapada dos Guimarães. Growing in decomposed sandstone soils, with specimens seen as far south as Rondonópolis and as far north as Diamantino. Also reported to be growing as far as 350 km to the west and at elevations usually above 600 m, but never in large numbers.

Conservation:— This species is well protected within the national park and it usually grows in very rocky soils which are of no agricultural importance, except for pasture, therefore, by IUCN version 3.1 criteria, this palm should be classified as LC, least concern.

Phenology:— Fruiting and flowering in the month of January in exposed areas, but neither flowering nor fruiting in shadier areas at this time of year.

Uses:— None recorded. It may have possible use as an ornamental in rock gardens.

Additional specimens examined:— BRAZIL, Mato Grosso: Chapada dos Guimarães, Mirante do Centro Geodésico, 19 October 1995, Hatschbach , G . et al. 63584 ( FTG!); Chapada dos Guimarães, na estrada para Cuiabá, km 49, próximo ao Parque Nacional da Chapada dos Guimarães, 680 m, 15°23’41.3”S, 55°50’4.2” W (-15.394806, -55.8345), 9 December 2009, Lorenzi , H., R . Campos & K . Soares 6786 ( HPL!); PARNA Chapada dos Guimarães , 19 November 1999, L. A . Neto , M . Aragona , F. T . Paroli 989 ( UFMT!); Chapada dos Guimarães, Parque Nacional da Chapada dos Guimarães, near the Monumento da Pedra in the National Park near km 49, Elevation ca. 601 m, 15°23’40.3’’S, 055°50’05.6’’W (-15.394528, -55.834889), 12 January 2014, L . Noblick & H . Lorenzi 5639 ( ESA!, HPL!, FTG!, NY!); Diamantino, cerca de 20 km após o limite do município de Diamantino. Área de grandes afloramentos rochosos, 23 April 1983, E. C. C . Moraes et al. 278 ( UFMT!) .

Notes:— This species resembles the Bolivian S. petraea , which was formerly the name erroneously given to most acaulescent Syagrus in Brazil with a spike inflorescence. It even grows in a similar environment of decomposed sandstone weathered into “chapada” topography. However, morphologically Syagrus guimaraesensis differs in having a shorter leaf rachis (11–56 vs. 40–125 cm), fewer leaflets (6–16 vs.19–42 leaflets), thicker leaf blades (5C vs. 5D) and different anatomy. Their leaflet anatomy differs by the following characters: S. guimaraesensis has large major veins (vs. small major veins), presence of adaxial minor veins near the leaflet margin (vs. no adaxial minor veins near the leaflet margin) and small fiber bundles between the major veins along the adaxial surface (vs. large fiber bundles between the veins) (Fig. 5C vs. Fig. 5D).