Rhynchospora reitzii Silva Filho, W. W. Thomas & Boldrini, 2018

Filho, Pedro Joel Silva Da Silva, Thomas, William Wayt & Boldrini, Ilsi Iob, 2018, Two new species of Rhynchospora (Cyperaceae) from southern Brazil, Phytotaxa 383 (1), pp. 117-120 : 117-118

Rhynchospora reitzii Silva Filho, W. W. Thomas & Boldrini , sp. nov. ( Fig. 1A , 2A )

Related to Rhynchospora emaciata ( Nees 1842:121) Boeckeler (1869:149 ; Fig. 2 B ), it differs in having a shorter and narrowly ellipsoid spikelet, a stramineous to brown achene, a rugulose achene surface with 9–12 transverse ridges, and a triangular stylopodium tapering to a subulate tip and confluent with achene.

Type:— BRAZIL. Santa Catarina: Palhoça, Pilões , mata, erva, 23 February 1956, R. Reitz & R. Klein 2754 (holotype MBM175273 !, isotypes HBR!, NY612820 !, US2281953 !) .

Perennial, rhizomes inconspicuous. Culms 38–53 × 0.04–0.2 cm. Leaves mostly basal, forming a rosette; sheathes 0.5–4.8 cm long; blades flat, 13–34 × 0.06–0.19 cm. Synflorescence comprising an apical corymbodium and 2–-3 axillary corymbodia, each of them loose and composed of partial corymbodia, and these comprised of single spikelets or fascicles of spikelets; apical corymbodium 2–5.5 × 3.2–6 cm, the axillary ones 1.3–4.4 × 2–5.4 cm. Spikelets 3–3.5 mm long, narrowly ellipsoid; glumes caducous in mature spikelets; basal glumes stramineous, ovate-lanceolate, membranaceous, acute-mucronate at apex; distal glumes stramineous, lanceolate, membranaceous, apically acute. Stamens 3, the anthers 0.9-2 mm long. Achene body 0.8–1 × 0.8–0.9 mm, broadly-obovate, stramineous to brown, the surface transversely rugulose, with 9–12 transverse ridges. Stylopodium 0.5–0.8 × 0.4–0.8 mm, triangular, tapering to a subulate tip, concave at base, stramineous to brown, confluent with achene.

Distribution and Habitat:— Known only from the municipality of Palhoça in the state of Santa Catarina, Brazil. Found in subtropical moist forests. The nearby Parque Estadual Serra do Tabuleiro is forested with elevations ranging from near sea level to over 1000 m.

Conservation status: — Data Deficient (DD). There are only two collections of this species, and nothing is known about the size of populations. Nevertheless, the absence of other collections in this relatively well-collected area suggests that this species is rare.

Etymology: —The name honors Padre Antônio Carlos Raulino Reitz, one of the collectors of this species and also one of the most important botanists and collectors in southern Brazil during the past century, and especially in Santa Catarina.

Paratypes:— BRAZIL. Santa Catarina: Palhoça, Pilões , rain forest, 29 November 1956, L. B. Smith & R. Klein 7984 ( HBR, NY612805 !, US!, image no. 2257448!) .

Notes: —The holotype was first identified by Manuel Barros as Rhynchospora emaciata and later cited in Las Ciperaceas del Estado de Santa Catalina ( Barros 1960) as R. tenuis . The paratype was identified as R. tenuis and not cited in that work. The area of Pilões, where the two specimens were collected, seems to be situated very close to the Serra do Tabuleiro State Park in Santa Catarina.

Figures

FIGURE 1. Synflorescences with respective spikelets. A. Rhynchospora reitzii. B. Rhynchospora serrana. Illustrations by Bobbi Angell, A from Smith & R. Klein 7984 (NY) and B from J. Cordeiro & C. B. Poliquesi 915 (US).

FIGURE 2. Spikelets and achenes. A. Rhynchospora reitzii (R. Reitz & R. Klein 2754, NY). B. Rhynchospora emaciata (G. Hatschbach 24011, NY). C. Rhynchospora serrana (J. Cordeiro & C. B. Poliquesi 915, US). D. Rhynchospora boeckeleriana (A. C. Araújo 1664, NY). The scale is the same for all spikelets and achenes.