Piriqueta pampeana Cabreira & Miotto, 2015

Cabreira, Thaíssa N., Facco, Marlon G. & Miotto, Silvia T. S., 2015, Piriqueta pampeana, a new species of Turneraceae (Passifloraceae s. l.) from Rio Grande do Sul, Brazil, Phytotaxa 234 (1), pp. 75-82 : 76-80

Piriqueta pampeana Cabreira & Miotto , sp. nov. ( Figs 1 and 2 )

Piriqueta pampeana resembles P. suborbicularis (A. St.-Hil. & Naudin) Arbo and P. taubatensis (Urb.) Arbo , but differs by a pair of discoid basilaminar nectaries (0.5–1.5 × 0.5–1 mm), a pair of petiolar nectaries (1–2 × 0.5–1 mm) and nectaries (0.5–2 × 0.5–1.3 mm) distributed along the leaf margin (vs. a pair of discoid nectaries (0.4–2 × 0.5–1 mm), located at the junction of the petiole with the blade and nectaries (0.5–1.5 × 0.2–0.8 mm) arranged along the basal blade or basal to half of the blade, in P. suborbicularis , and only discoid nectaries (0.3–1.2 × 0.2–0.6 mm), located in the leaf margin, in P. taubatensis ), acute apex of the sepals (vs. mucronate) and yellow spot at the base of the petals (vs. orange, reddish, violaceous and vinaceous).

Type: — BRAZIL. Rio Grande do Sul: Alegrete, na margem da BR-377, a 10 km de Manoel Viana, 174 m, 29°41’14.3’’S, 55°29’58.4’’W, 19 December 2013, T. N. Cabreira & M. G. Facco 232 (holotype ICN!, isotypes CTES!, K!).

Hemicryptophyte herb, perennial, erect to decumbent, 21–44 cm high; generally vertical rhizomes, simple or branched, 2–7 mm diam., whitish; cylindrical stem, simple or branched, indumentum sparsely tomentose, with dull brownish yellow porrect-stellate tector trichomes and whitish simple tector trichomes. Leaves papery, discolored, 12–63 × 5–43 mm, elliptic to largely-elliptic, base cuneate, apex obtuse, cuneate or rounded, serrated to crenate margins, rarely entired; upper surface sparsely-tomentose, porrect-stellate trichomes, 5–10 rays, dull brownish yellow, lower surface densely-tomentose, porrect-stellate trichomes, whitish; a pair of basilaminar discoid nectaries, 0.5–1.5 × 0.5–1 mm, a pair of petiolar nectaries, 1–2 × 0.5–1 mm, oriented to the upper surface and nectaries, 0.5–2 × 0.5–1.3 mm, distributed along the leaf margin; presence of acrolaminar colleters, oriented laterally or to the upper surface. Stipules absent or reduced to subulate prominences, 1.4–2.1 mm long; petiole 1–6 mm long, indument like that to the stems. Flowers axillary, solitary, heterostylous. Peduncle 1–6 × 0.7–1.3 mm, with dense porrect-stellate trichomes. Bracteoles green, 1.4–2.0 mm long, located at the apex of the peduncle. Pedicel 4–13 × 0.7–1.6 mm, with porrect-stellate trichomes less dense than the peduncle. Calyx dull brownish yellow, the calyx tube 2–3 mm long, internally glabrous and externally tomentose, dull brownish yellow porrect-stellate trichomes; sepals 7–13 × 2–5 mm, lanceolate, base truncate, apex acute, with approx. 6–7 parallel veins, usually with hyaline membranous edge. Corolla white, petals 13–18 × 6–14 mm, obovate, cuneate base, with a yellow spot at the base of the petals, apex obtuse, with a short mucron, yellow veins. Corona yellow, 0.7–1.3 mm long, glabrous, lacerate in the apex. Cylindrical fillets, 1.1–3.5 mm long in long-styled flowers, 4.2–5.3 mm long in short-styled flowers, inserted in a basidorsal cavity of the anther, glabrous, whitish to dull brownish yellow, the base welded in the calyx tube, sometimes with semilunar nectary in the insertion of the fillets; anthers 2–4 mm long, basifixed, narrow-ovoid to sagittate, sometimes falcate, yellow, base emarginate, recurved apex. Ovary ovoid, 2.2–3.4 × 2.3–2.8 mm, densely covered with porrect-stellate trichomes, 48–56 ovules; three cylindrical styles, 2.5–4 × 0.3–0.7 mm in long-styled flowers, 0.9–2 × 0.2–0.4 mm in short-styled flowers, erects, dull brownish yellow, generally darker and pilose at the base; stigmas brush-like, 0.5–1.9 × 0.7–2.4 mm, with 5–25 branches, yellow. Fruit a loculicidal capsule, 3–9 × 3–8 mm, subglobose, externally verrucose and densely pilose, with porrect-stellate tector trichomes, three valves, valves ovate, dull brownish yellow; seeds 2–4 × 1–2 mm, obovate, curved; exostome conical; raphe linear; chalaza rounded, sometimes slightly prominent; upper surface reticulate, glossy, blackened when ripe, light brown to reddish-brown when immature; areoles concave, rectangular to hexagonal; epidermis glabrous; aril 1–3 mm long, laciniate, membranous when dry, involving almost all the seed.

Paratypes:— BRAZIL. Rio Grande do Sul: Alegrete, Arroio Lageado, rodovia para São Francisco de Assis , 25 January 1986 (fl.), J. Mattos & N. Mattos 29732 ( HAS!) ; Alegrete, cerca de 6 km de Alegrete, na rodovia para Manoel Viana, 26 January 1986 (fr.), J. Mattos & N. Mattos 29721 ( HAS!) ; Alegrete, na margem da BR-377, a 10 km de Manoel Viana, 163 m, 29°44’28.6’’S, 55°33’43.4’’W, 17 December 2014 (fl.; fr.), T. N. Cabreira & K. A. Freitas 292 ( ICN!) ; Maçambará, estrada para Serrinha do Iguariaçá , a mais ou menos 500 m da BR-287, km 456, 22 February 2015 (fl.), S. Bordignon & R. Singer s.n. ( ICN 181059 !) ; Manoel Viana, a 8 km de Manoel Viana, 7 December 1982 (fl.; fr.), J. Mattos & N. Mattos 23789 ( HAS!) ; São Francisco de Assis, a 10 km de Manoel Viana, na rodovia para São Francisco de Assis , 7 December 1982 (fl.; fr.), J. Mattos & N. Mattos 25022 ( HAS!) ; São Francisco de Assis , a 10 km de Manoel Viana, 20 October 1984 (fl.; fr.), J. Mattos & N. Mattos 30642 ( HAS!) .

Distribution and habitat:— Piriqueta pampeana is only known from the western region of Rio Grande do Sul state, Brazil. The specimens were collected in four municipalities, Alegrete, Maçambará, Manoel Viana and São Francisco de Assis ( Fig. 3 ), and belong to small populations in grasslands of sandy soils on roadsides. This region belongs to Pampa biome and is characterized by fields of shallow soils from basalt, stony and associated with drought in summer ( Boldrini 2009).

Conservation status:— Following the IUCN Red List guidelines ( IUCN 2014), the species is ranked as Endangered (EN) under criteria B1ab(iii) + B2ab(iii), because of the low extent of occurrence (<5,000 km 2) and low area of occupancy (<500 km 2); number of locations (four municipalities); and decline of quality of habitat, due to the presence of environmental degradation, mainly garbage and replacement of natural vegetation by monoculture of Zea mays Linnaeus (1753: 971–972) and Pinus spp. Cordeiro & Hasenack 2009 also verified that anthropic occupation in the state of Rio Grande do Sul produced a landscape dominated by anthropic physiognomy, remaining only 31.38% of its coverage with natural or semi-natural features.

Etymology:— the species is named in reference to its occurrence in the Pampa biome, in Rio Grande do Sul state, Brazil.

Phenology:— flowering and fruiting occur simultaneously from October–February.

Figures

FIGURE 1. Piriqueta pampeana Cabreira & Miotto. A. Habit.B. Part of the calyx, showing the outer sepals. C. Short-styled flower detail, with the inner sepals, petals, corona and stamens. D. Gynoecium. E. Fruit, showing the inner and outer surfaces. F. Seed with aril, rapheal view. G. Leaf detail, showing the nectaries. (A–D and G from T.N. Cabreira & M.G. Facco 232, ICN; E–F from J. Mattos & N. Mattos 29721, HAS). Drawings by Anelise Scherer.

FIGURE 2. Piriqueta pampeana Cabreira & Miotto. A. Habit. B. Part of the leaf; the arrows indicate pairs of petiolar, basilaminar and marginal nectaries. C. Long-styled flower showing the petals, yellow spot, sepals, androecium and gynoecium. D. Immature fruit. E. Mature fruit with seeds wrapped by aril.

FIGURE 3. Map showing the occurrence area of Piriqueta pampeana in Rio Grande do Sul, Brazil. *The dashed line shows the boundary between the Pampa biome and the Brazilian Atlantic Forest biome. **The abbreviations of the countries are according to ISO 3166. SC: Santa Catarina state. PR: Paraná state.