Eriocaulon itapevense Alff & Stützel, 2019

Alff, Carolina Costa, Stützel, Thomas & Miotto, Silvia Teresinha Sfoggia, 2019, A new species of Eriocaulon and an annotated checklist of Eriocaulaceae from the Coastal Plain grasslands of Southern Brazil, Phytotaxa 403 (3), pp. 199-209 : 200-205

Eriocaulon itapevense Alff & Stützel sp. nov. ( Figs. 1–5 )

Type: — BRAZIL. Rio Grande do Sul: Torres, Parque Estadual de Itapeva, Lagoa do Simão, 29°22’38”S 49°46’21”W, 30 June 2018, C.C.Alff & C.Rabuske 132 (holotype ICN!, isotypes FLOR!, K!, MBM!, NY!, RB!, SPF!).

Eriocaulon itapevense is morphologically similar to E. magnificum . The new species differs from E. magnificum mainly by height up to 120 cm (vs. up to 80 cm), leaves, spathes and scapes opaque green to greyish, with pubescent indument (vs. bright-green, glabrous), apex of the leaves strongly cucullate and pungent to touch (vs. slightly cucullate, not pungent to touch), spathe lateral slit 40–180 mm length (vs. 22–30 mm), capitulum up to 15 mm diameter (vs. up to 12 mm), capitulum receptacle up to 7 mm diameter (vs. up to 4 mm), involucral bracts 4.5–5 (5.5) × 2.5–4 mm (vs. 2–4.1 × 1–2.5 mm), pistillate flowers with median petals rhombic-spathulate (vs. spathulate), and epipetalous glands up to 0.5 mm long, frequently reaching the median third of the petals (vs. up to 0.2 mm long, never reaching the median third of the petals).

Perennial herbs, 40–120 cm high when flowering, pubescent, with trichomes hyaline up to 1.5 mm long on leaves and spathes (mostly capitate on the leaves), and 0.2–0.6 mm long on the scapes. Roots white, spongiose, articulated by transversal diaphragms in the aerenchyma. Leaves rosulate, distichous equitant in the vegetative phase, spirally in the flowering period, decaying leaves persisting at the base of the rosette, 32–78 × 2–5.5 cm, naviculate, linear-lanceolate, wider at the base, crassus, coriaceous, opaque-green to greyish, apex cucullate and pungent, flavescent. Spathes 24–45 cm long, apical opening very small, the growing capitula causing a lateral rupture where the capitula leaves the spathe, slit 40–180 mm long. Scapes 6–18 per rosette, in central (terminal) clusters, 50–110 cm long, 9–13-costate. Capitula solitary, hemispheric to globose, 10–15 mm diameter, white; receptacle 3.5–7 mm diameter, glabrous. Involucral bracts in 3–5 series, 4.5–5 (5.5) × 2.5–4 mm, patent, ovate to lanceolate, thinner at the margins, stramineous, apex attenuate, trichomes hyaline, sparse, up to 0.2 mm long on the margins and abaxial surface. Floral bracts 4.5–5 (6.2) × 1–1.5 (2) mm, naviculate, lanceolate, chartaceous, light black towards the margin at the median third, stramineous at base and apex, apex long-attenuate, trichomes white, 0.1–0.2 mm long, mainly appressed, on the margins and abaxial surface, forming a rhombic pilose area at the distal third. Flowers strictly unisexual, 3-merous, perianth similar in flowers of both sexes; sepals equal, free, slightly concave, spathulate to oblanceolate, light black to black (usually darker in the pistillate flowers), apex acuminate; lateral petals different in shape and size from the median petal, larger and wider, indument similar as presented by the floral bracts, trichomes on both surfaces and margins (the abaxial surface usually less pilose), plus trichomes hyaline, crispate, 2–3 mm long, mainly within the corolla of the pistillate flower and on the gynophore; epipetalous glands 0.2–0.5 × 0.1 mm, irregular surface, black, deltoid to ovoid, subapical, frequently reaching the median third of the petal. Staminate flowers 2.5–4.2 × 1–2.5 mm (including up to 1.5 mm long pedicel); antophore up to 1 mm long; sepals 2–2.8 × 0.8–1 mm; petals slightly fused at the base, median petal 2.5–3 × 1–1.2 mm, cream, spathulate to oblanceolate, apex attenuate, lateral petals reduced, 1.8–2 × 0.3–0.5 mm, spathulate to oblanceolate, apex attenuate; diplostemonous, stamens 6 (3 of them epipetals), up to 1.3 mm long, included, dorsifixed, irregular surface, filaments cream to stramineous, ca. 1.1 mm long, anthers black, ca. 0.2 mm long, bithecal, elliptical, pistillode black, up to 0.1 mm long. Pistillate flowers 3.8–4.3 (6) × 2.5–3 (4.5) mm (including the up to 0.5 mm long pedicel); antophore ca. 1.5 mm long; sepals 2–3 (5) × 1–1.3 (1.5) mm; petals free, median petal 2.5–3 (5) × 1.1–1.4 (2) mm, rhombic-spathulate, apex obtuse or acute to attenuate, cream, becoming blackish towards the base, sometimes forming a well-delimited rhombic cream spot from median to distal third, lateral petals 2.1–2.5 (4) × 0.8–1.2 mm, spathulate to oblanceolate, apex obtuse to acute, color pattern as presented by the dorsal petal; gynophore up to 1 mm long; gynoecium 2.5–3 long, irregular surface, ovary hypogynous, 3-carpellate, ca. 1 mm long, black, styles forming a column and 3 stramineous stigmatic branches, twice as long as the ovary. Fruit a loculicidal capsule. Seeds 0.8–1 × 0.5–0.6 mm, elliptical, dull to bright brown; seed coat with hexagonal cells, transversely elongated, ca. three times as long as wide, ca. 35 cells in longitudinal direction and 12 along the circumference; primary projections mostly absent, sometimes present, columnar appendages of the transversal walls (secondary projections) 3 or 4 on either side, sometimes flanked by unthickened remains of the anticlinal wall and topped by remains of the periclinal wall of outer layer of the outer integument.

Distribution and habitat: — Eriocaulon itapevense is recorded only in the municipalities of Torres, Passo de Torres, São João do Sul and Sombrio, and is thus restricted to the Coastal Plain grasslands of Rio Grande do Sul and Santa Catarina states, Southern Brazil. The species grows in wetlands, in marshy and organic soils near lagoons, up to 32 m elevation ( Fig. 4 ).

Etymology: —The specific epithet “ itapevense ” refers to the type-locality, Itapeva, in Torres municipality, Rio Grande do Sul, Brazil. From the tupi-guarani language meaning “flat stone” (ita = stone; peba = flat) ( Ruschel 1966).

Phenology: —Flowers were observed from June to October, less frequently from January to February.

Conservation: — Eriocaulon itapevense is Critically Endangered (CR) according to IUCN (2017) criteria B2a+bii,iii. Its extent of occurrence (EOO) is 120.352 km ² and its area of occupancy (AOO) is 0.050 km ². The species is currently included within two protected areas: Itapeva State Park and Lagoa Itapeva Environmental Protection Area. The most abundant subpopulation of the species is located in Itapeva, in the Itapeva State Park, near the Lagoa do Simão. The subpopulation located in Campo Bonito, in the Lagoa Itapeva Environmental Protection Area, as well as the subpopulations from Santa Catarina (municipalities of Passo de Torres, São João do Sul and Sombrio), consists of a few sparse individuals, threatened by overgrazing and growing habitat conversion due to the drainage of wetlands for agricultural use and human occupation.

Paratypes: — BRAZIL. Rio Grande do Sul: Torres, Parque de Torres , 11 July 1972, B.Irgang & A.M.Girardi s.n. (ICN 27895!) ; Torres, na entrada para Itapeva , 13 October 1984, N.Silveira 1796 (HAS!) ; Torres, próximo ao posto da Corlac , na BR-101, 27 September 1985, R.Frosi, N.Silveira & N. Model 411 (HAS!) ; Torres, em Itapeva próximo ao aeroporto, 19 January 1990, N.Silveira 9102 (HAS!) ; Torres, Itapeva , 6 September 1993, N.Silveira 11590 (HAS!) ; Torres, Itapeva, Parque Estadual de Itapeva , Lagoa do Simão , 29°22’38”S 49°46’21”W, 14 m elev., 28 August 2016, C.Rabuske, C.C.Alff & C.R.M.Reis 54 (ICN!) ; Torres, Itapeva, Parque Estadual de Itapeva , Lagoa do Simão , 29°22’37.8”S 49°46’22.1”W, 20 m elev., 3 February 2018 (remains of scapes and bracts), C.C.Alff, C.Rabuske, R.Frizzo & U. Brocca 100 (ICN!) ; Torres, Campo Bonito , 29°22’21”S 49°46’45”W, 12 m elev., 30 June 2018, C.C.Alff & C.Rabuske 133 (ICN!) ; Torres, Campo Bonito, Olhos d’Água , 29°20’39.95”S 49°46’28.19”W, 32 m elev., 21 September 2018, M.Grings 1925 (ICN!) ; Torres, Itapeva, Parque Estadual de Itapeva , Lagoa do Simão , 27 October 2018, 29°22’38”S 49°46’21”W, 14 m elev., C.C.Alff, T.Stützel & J.D.T.Carvalho (ICN!). Santa Catarina: Passo de Torres , 29°18’04.7”S 49°42’21.9”W, 8 m elev., 30 January 2019, C.C.Alff & C.Rabuske-Silva 176 (ICN!) ; São João do Sul, 6 September 1977, K.Hagelund 11423 (ICN!) ; Sombrio, Sombrio p. Araranguá , 3 February 1946, B.Rambo SJ 37322 (PACA!) .

Comments: —Specimens of Eriocaulon itapevense were first collected in the 1940s, and are only now being described as distinct species, well over half a century later. The new species is represented in regional herbaria by less than 15 specimens. In the field, the new species stands out at a distance by its robust size and opaque-green to greyish color, resulting from the plentiful presence of trichomes, while the typical green of E. magnificum is bright and clear. The leaves in E. itapevense are stiffer when compared to E. magnificum , the apex of the leaves of the new species being strongly cucullate and pungent to touch, characters that are distinctive even in dried material. The apical opening of the spathe is very small at first, but changes into a long lateral slit in E. itapevense by rupturing caused by the initial ascension of the growing capitulum ( Fig. 5 ). The pistillate flowers in E. itapevense are densely covered in trichomes, concealing the epipetalous glands and the gynoecium, unlike in E. magnificum , which has fewer trichomes. Comparative diagnostic characters between the two species are provided ( Table 1). Besides morphological characters, records in herbaria and fieldwork observations point to differences in their phenology, which might be better elucidated in further studies. While E. magnificum flowers all year, blooming during summer, the new species has a more restricted flowering period, from June to October, with sparse records from January and February.

Checklist:— Rambo (1954) cites seven species of Eriocaulaceae for the Coastal Plain of Rio Grande do Sul: Paepalanthus polyanthus ( Bongard 1831: 622) Kunth (1841: 516) (= Actinocephalus polyanthus (Bong.) Sano (2004: 103)) , Eriocaulon magnificum , E. megapotamicum , E. modestum , Leiothrix flavescens ( Bongard 1831: 628) Ruhland (1903: 231) , Syngonanthus caulescens ( Poiret 1813: 162) Ruhland (1903: 267) and S. chrysanthus ( Bongard 1831: 628) Ruhland (1903: 256) . Moldenke & Smith (1976) cite the same species for this formation in the southern portion of Santa Catarina, except for E. megapotamicum and S. caulescens , and with the addition of E. ulaei and P. catharinae Ruhland (1903: 147) , thus also resulting in seven species.

Here we present an updated checklist, which includes nine species of Eriocaulaceae from the Coastal Plain grasslands of Southern Brazil ( Table 2). Despite the current recognition of Eriocaulon megapotamicum , described for the southern part of the Patos Lagoon, in RS, the material we examined of this species actually corresponds to E. magnificum , in agreement with Rambo (1954). Thus, neither E. megapotamicum nor E. ulaei are included in our checklist, because no supporting voucher specimens were found. Further studies on the species of the E. magnificum complex are necessary before taxonomic changes can be made. The single specimen cited by Moldenke & Smith (1976) as Paepalanthus catharinae (Reitz & Klein 22, HBR!, US image!, S image!), corresponds to E. modestum . Paepalanthus catharinae is in fact a species endemic to the Subtropical Highland Grasslands ( Iganci et al. 2011). Our checklist differs from the previous surveys also by the inclusion of Eriocaulon arechavaletae Herter (1935: 125) , E. itapevense and Paepalanthus planifolius ( Bongard 1831: 629) Koernicke (1963: 413) , which are new records for the region.

Of the nine species recorded in our checklist, four are considered to be under threat in Rio Grande do Sul ( Rio Grande do Sul 2014). This is because the Coastal Plain grasslands are an extremely threatened vegetation type in RS, with one of the highest conversion rates among the grasslands ( Andrade et al. 2015, Bonilha et al. 2017). Frequent threats include invasion by exotic species, agricultural expansion (including silviculture), growing urban expansion and associated impacts ( Brack 2009). In Santa Catarina, none of the species cited in the checklist is included as threatened in the state list ( Santa Catarina 2014).

Figures

FIGURE 1. Eriocaulon itapevense. A) Habit. B) Spathe showing the lateral slit, after rupture by the growing capitulum. C) Capitulum. D) Receptacle surrounded by involucral bracts. E) Involucral bract. F) Floral bract. G) Sepal. H) Median petal of the pistillate flower. I) Lateral petal of the pistillate flower. J) Gynoecium. C.Rabuske, C.C.Alff & C.R.M.Reis 54 (ICN 195207). Drawings by Anelise Scherer.

FIGURE 2. Eriocaulon itapevense. A) Habit. B) Detail of the leaves. C–D) Capitulum. C) Top view of the capitulum. D) Lateral view of the capitulum. Images by Cassio Rabuske da Silva.

FIGURE 3. Seeds of Eriocaulon itapevense. A) Seed in light microscope. B–D) Seed in SEM microscope. B) Seed as released from the fruit. C–D) Seed after wetting and redrying. D) Detail of the seed surface, showing single cell delimitation (red). E) Single cell illustration, showing primary projections (a), secondary projections (b), remains of the unthickened anticlinal wall (c) and of the periclinal wall (d). Scale:A–C) 100 μm; D) 20 μm.

FIGURE 4. Distribution map of Eriocaulon itapevense, showing the known locations where the species occurs in Southern Brazil.

FIGURE 5. Development of the capitulum after the rupture of the spathe in Eriocaulon itapevense. A–B) Capitulum emerging from the spathe. C) Immature capitulum. D) Newly developed capitulum. Images by Cassio Rabuske da Silva.