Rhynchospora caduciglumis P. Weber & R. Trevis., 2017

Rhynchospora caduciglumis P. Weber & R. Trevis. View in CoL , sp. nov. ( Figure 1 View FIGURE 1 , A–F)

Type: — BRAZIL. Santa Catarina: Florianópolis, Parque Municipal da Lagoinha do Leste, Pântano do Sul. Trilha que leva a Lagoinha do Leste , na trilha, solo arenoso, ambiente aberto, 9 March 2012, R. Ardissone, R. Affonso & Th. Greco 128 (Holotype FLOR , Isotypes, ICN , MO , NY , K , RB )

Figure 1 View FIGURE 1 , A–F.

Diagnosis: —Differs from R. polyantha by having shorter spikelets (2.8–4.0 vs. 4.0–5.0 mm), fascicles with fewer spikelets, deciduous scales when the achenes are mature, and narrower leaves (1.6–2.0 (–3) vs. 2.0–4.0 (–4.5) mm).

Perennial, caespitose, rhizomes short. Culm erect, smooth, obtusely trigonous, up to 63 cm long and 1.5–2.5 mm wide. Leaves flattened, erect, linear, shorter than the culm, 1.6–2 (–3) mm wide, smooth to slightly scabrous distally along margins and abaxially along the midvein. Inflorescence comprising a terminal and 1–4 lateral coflorescences, the peduncles 1–17 cm long, the subtending bracts 5–29 cm long and 1.0-2.0 mm wide; terminal coflorescence with 1–10 fascicles, the bracts longer than or equaling the anthelae; fascicles of 3–15 spikelets. Spikelets lanceolate, 2.8– 4 × 0.7–1.4 mm, maturing 1 to 3 achenes, comprising 6–9 scales, the proximal 2 sterile, the next 3–5 subtending fertile flowers; scales brown, mucronate, cymbiform, ovate, 2.3–3.3 × 1–1.4 mm. Perianth bristles 6, shorter than or equaling the stylopodium, 1–2.4 mm long, antrorsely scabrous. Stigma bilobate. Stamen 1. Achene biconvex to almost plano-convex, obovoid to ellipsoid, 1–1.4 × 0.7–0.9 mm, pale to dark brown or greenish pale brown while immature, transversely rugulose, with 12–14 transverse rugae; stylopodium light brown, rarely blackish, triangular, 0.7–1.3 mm long, 0.4–0.5 mm wide in the base, with apex acute to acuminate; stipe 0.1–0.2 mm long.

Geographical distribution: —The species has only been recorded so far in the states of Rio Grande do Sul and Santa Catarina, southern Brazil, in the Atlantic Forest biome.

Habitat:—Open, dry or humid areas from the coast to the high fields at elev. 1400 m. Found in environments such as damp or drained fields, marshes, bogs, river banks, forest edges and hillside forest clearings.

Phenology: —Collected in fruit throughout the year.

IUCN Classification: —Near Threatened (NT) [Extent of occurrence: (NT); Area of occupancy: (LC)].

The categorization IUCN as Near Threatened (NT) is due to the scarcity of data, since the species is relatively common and occurs in different environments, from the coast to high fields.

Etymology: —The specific epithet refers to the glumes that are deciduous as soon as the fruit matures, a striking feature in this species.

Note: —This species has enough variation in the attributes of achenes, which appear to be close to R. polyantha and R. marisculus . It differs from R. polyantha in the usually narrower leaves (1.6–2 (–3) vs. 2–4 (–4.5) mm), scattered fascicles with fewer spikelets, shorter spikelets (2.8–4.0 vs. 4.0–5.0mm) and deciduous scales when the achenes are mature. It differs from R. marisculus mainly in the shorter spikelets (2.8–4.0 vs. 4.5–6.5 mm) and bristles shorter than or equaling the stylopodium (vs. widely surpassing the stylopodium apex). (see Table 1 View TABLE 1 ).

Additional Collections (paratypes):— BRAZIL. Rio Grande do Sul: São Francisco de Paula, CPCN Pró Mata , 23 Oct 2004, P.M.A. Ferreira 35 ( MPUC) ; São Francisco de Paula, CPCN Pró Mata , Apr 2004, P.M.A. Ferreira 94 ( MPUC) ; São Francisco de Paula, 29°23’27,48”S 50°23’0,85”W, elev. 894m, 4 March 2012, P.J.S. Silva Filho 1516 ( ICN) GoogleMaps ; Santa Catarina: Águas Mornas elev. 350m 27 March 1973, R. Klein & Bresolin 10960 ( HBR) ; Blumenau, 27°01’19,26”S 49°06’52,97”W, elev. 423m, 25 Feb 2013, L.A. Funez 1798 ( FURB) GoogleMaps ;