Rhynchospora serrana 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 : 118-119

Rhynchospora serrana Silva Filho, W. W. Thomas & Boldrini , sp. nov. ( Fig. 1B , 2C )

Similar to Rhynchospora boeckeleriana Silva Filho, Trevisan & Boldrini (2017:181 ; Fig. 2D ), it differs in being shorter, having inconspicuous rhizomes, larger spikelets, basal glumes with an acute-aristate apex, and a finely rugulose achene surface with 12-15 transverse ridges.

Type:— BRAZIL. Santa Catarina: Campo Alegre, Serra do Iquererim , campo de altitude, 1700m, 19 November 1992, J. Cordeiro & C. B. Poliquesi 915 (holotype MBM156361 !, isotype US3682025 , image no. 2255048!) .

Perennial, rhizomes inconspicuous. Culms 17–32 × 0.06–0.3 cm. Leaves sheath 1.2–5.7 cm long; leaves blade flat, 13–42 × 0.15–0.4 cm, concentrated at base forming a rosette. Synflorescence comprising a terminal paniculodium and 3–4 axillary paniculodia, each of these contracted and composed of partial paniculodia, and these comprised of fascicles of spikelets; apical paniculodium 1.1–1.8 × 0.9–1.6 cm; axillary paniculodia 0.8–1.2 × 0.4–1.1 cm. Spikelets 4–5 mm long, lanceoloid. Glumes vinaceous, membranaceous, not caducous in mature spikelets; basal glumes ovate-lanceolate, the apex acute-aristate; upper glumes lanceolate, the apex acute-mucronate. Stamens 3, anthers 1.7–2 mm long. Achene body 1–1.1 × 0.7–0.9 mm, elliptic-obovoid, pale stramineous with occasional darker streaks, the surface finely rugulose, with 12–15 transverse ridges. Stylopodium 0.4–0.6 × 0.6–0.9 mm, triangular, confluent with achene, brown.

Distribution and Habitat:— Known only from the Campos de Cima da Serra, in the states of Paraná and Santa Catarina, Brazil. These natural grasslands are found at elevations above 900 m in southern Brazil and have high levels of endemism ( Stam 2016).

Conservation status: — Data Deficient (DD). There are only two collections of this species, and nothing is known about the size of populations. The absence of other collections, however, suggests that this species is rare.

Etymology: —The name refers to the distribution of this species in the mountain ranges of southern Brazil.

Paratypes: — BRAZIL. Paraná: Piraquara, Torre da Vigia , 29 September 2004, E. F. Costa & E. Barbosa 13 ( MBM!, US!). Santa Catarina: Campo Alegre, Serra do Iquererim , campo de altitude 1700m, 19 November 1992, J. M. Silva & C. B. Poliquesi 915 ( MBM!, US 3454854 , image no. 2255049!) [probably the same collection as the type, but the first collector is different] .

Notes: —The holotype at MBM was originally determined as R. riparia (Nees) Boeckeler and the isotype at US as R. aff. luzuliformis Boeckeler. Although section Luzuliformes was recently revised by Silva Filho et al. (2013), and specimens from many herbaria studied, we did not become aware of this new species at the time.

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.