Trichocline cisplatina E. Pasini & M.R.Ritter, 2012

Pasini, Eduardo & Ritter, Mara Rejane, 2012, Trichocline cisplatina (Asteraceae, Mutisieae), a new species from southern Brazil and Uruguay, Phytotaxa 42, pp. 19-25 : 20-24

Trichocline cisplatina E. Pasini & M.R.Ritter , sp. nov. ( Figs. 1 and 2 )

Trichoclini catharinense affinis sed ab ea habitu prostrato, scapo procumbente, foliis adpressis ad solo, fortiter pinatifida, usque ad decem paribus lobis rotundatis in marginibus, denique lobis secundariis formanti; involucris longioribus; floribus marginibus aureis cum corolla bilabiato-ligulata; ovario papillis claviformibus elongatis et albis differt.

Type: — BRAZIL. Rio Grande do Sul: Arroio Grande, próximo à ponte do Passo do Ricardo, em campo limpo, úmido e arenoso, às margens do Rio Piratini , associado à Eryngium horridum Malme , hábito prostrado, escapo procumbente, 31º54’48.9’’S, 52º39’542. 21’’W, 60 m, September 2011, fl., E. Pasini , A. A. Schneider e F. Torchelsen 898 (holotype: ICN!; isotype: ICN!; LP!; MO!; RB!) .

Herbs perennial, acaulescent, with scape reaching up to 23 cm when flowering, glabrous to tomentose. Xylopodium 2–5 × 2 cm. Leaves rosulate, sessile; blade discolorous, glabrous to pubescent above and glabrescent to tomentose below, flexuose, oblanceolate or spatulate, 4.5–24 × 0.5–5.5 cm, base sessile, attenuate, margin pinatisect, 4–10 pairs of rounded and flexuose lobes, 0.5–2.5 × 0.5–2.0 cm, eventually forming secondary lobes, apex obtuse to subacute. Inflorescence monocephalic, scapigerous, scape glabrescent to tomentose, procumbent, 6–20 × 0.2–0.4 cm, with leafy bracts; bracts 1-6, linear, glabrescent to tomentose, 1.0– 6.5 cm long, eventually coming from the base of the rosette. Capitula radiate, heterogamous; involucre hemispheric to campanulate, 1.8–3.0 × 1.8–5.0 cm; phyllaries 3-4-seriate, imbricate, green, the outermost phyllaries spreading, lanceolate to spatulate, 10–20 × 1.7–5.0 mm, adaxial surface glabrescent to tomentose, apex acute, eventually mucronate, the median phyllaries spatulate, 12–22 × 1.7–2.7 mm, adaxial surface tomentose, apex acute, the inner most phyllaries lanceolate, membranaceous, 14–24 × 1.7–2.7 mm, glabrous to glabrescent on both surfaces, apex acuminate, brownish red at apex and margins; receptacle concave, epaleaceous, alveolate, glabrous. Florets dimorphic, ray florets pistillate, uniseriate, 15–25, corollas ligulate-bilabiate, abaxial lip liguliform, lanceolate, 14–22.3 × 2.3–4.2 mm, 3-lobed in the apex, adaxial surface tomentose, with 4-celled trichomes, sparsely distributed, adaxial lip bisect, lobes filiform and spiral, 7.5–13.6 mm long; corolla yellow-orange, tube 5.5–9.8 mm long, with 4-celled trichomes sparsely distributed; staminodes 1.7–3.4 mm long, apex acute to acuminate, base caudate, papillose, margin reflex near the apex when acuminate; style 11–19 mm long, bifid, exserted, style lobes dorsally papillose, 0.7–1.2 mm long; disc florets bisexual, 50-80, corollas bilabiate, abaxial lip 3-lobed, reflex to revolute, 2.6-5 × ca. 1 mm, with 4-celled trichomes sparsely distributed, adaxial lip bifid, lobes lanceolate, reflex to revolute, 1.2-4.5 mm long, corolla tube 10–18 mm long; stamens 7.6–9.3 mm long, apical appendages lanceolate, apex acute, base slightly constricted, basal appendages caudate, papillose, 2–3.2 mm long, filaments papillose at the base, style 10.8–19.7 mm long, bifid, exserted, style lobes dorsally papillose, 0.7–1.2 mm long. Ovary cylindrical, obovate or obconical, truncate at the apex, 2.3–5 × 2–3.2 mm, with whitish 2-seriate trichomes, inflated at the apex, densely distributed, 170–230 µm long; pappus uniseriate, 12–18.3 mm long, whitish, with barbellate bristles.

Distribution and habitat: — Trichocline cisplatina was collected in southern Brazil, in the State of Rio Grande do Sul ( Fig. 3 ) in the physiographic regions locally known as Encosta do Sudeste, Litoral and Serra do Sudeste. It is also known from southeastern Uruguay, municipality of La Pedrera, Rocha Province. The region where the species occurs belongs to the Pampean Biogeographical Province, which is restricted to Rio Grande do Sul State in Brazil ( Cabrera & Willink 1973). The floristic physiognomies in which this species in found vary from grasslands and shrublands to pioneer vegetation along coastal plains in the southeastern part of the State, at an elevation range between 0 to 400 m a.s.l. According to field observations and notes associated with herbarium specimens, T. cisplatina grows on grasslands and shrublands with rocky or sandy soils and dunes.

Phenology: —Flowering and fruiting specimens have been collected from September to May.

Conservation Status: —According to the IUCN Red list ( IUCN 2001) the species is considered to be vulnerable (VU, subcriteria A3, A1’s (c) and (e)–a decline of quality of habitat and the effect of introduced taxa), due to the introduction of Pinus spp. and the presence of Ulex europaeus L. (1753: 741) in the area of occurrence of the species.

Etymology: —The specific epithet refers to the species occurrence in the former Cisplatina Province, which once belonged to Brazil and today is within Uruguayan territory. In Latin, “cis” means on this side, and “Platina” refers to Río de la Plata or Riverplate.

Additional specimens examined (paratypes): — BRAZIL. Rio Grande do Sul: Arroio Grande, Passo do Ricardo, rio Piratini , campo arenoso, 4 November 1961, G . Pabst & E . Pereira 6782 ( HB) ; Capão do Leão, Cerro das Almas, 21 September 2011, fl., E . Pasini, A. A . Schneider & F . Torchelsen 987 ( ICN) ; Herval, em campo arenoso, 21 September 2011, fl., E . Pasini, A. A . Schneider & F . Torchelsen 899 ( ICN) ; Pedro Osório, 8 November 1973, fl., J. C . Sacco, E. C . dos Santos & E. dos Santos s.n. ( CTES 121249 , FLOR 18222 , PACA 68784 , PEL 8759 ) ; Pelotas, Fazenda Capão Redondo, a 23 km do IBDF , na rodovia para Jaguarão, no campo limpo, 16 January 1981, J . Mattos, N . Silveira & N . Mattos 22263 ( HAS); Rincão do Meio , 19 May 1959, J. C . Sacco 1199 ( HBR) ; Rio Grande, Domingos Petroline , 5 October 1982, I. V . Gonçalves 135 ( HURG) .

URUGUAY. Rocha: La Pedrera, dunas, Jan 1981, A. L . Cabrera 32311 ( SI, LP); Punta de las Rocas , 9 December 2001, E . Figueredo s.n. ( MVJB 21080 ) .

This new species was first collected by Sacco (Sacco 1199) in 1959 and identified by B. Rambo in the same year as T. incana Cass. (1826: 216) . In the last fifty years the species has been identified by taxonomists as T. catharinensis , T. incana , T. macrocephala Less. (1830: 288) , T. sinuata (Don) Cabrera (1953: 531) or as Trichocline sp. In fact, the renowned botanist A.L. Cabrera, who described the most morphologically similar species, T. catharinensis , in 1973, collected this new species, and identified it as Trichocline sp.

According to Zardini (1975) T. catharinensis is restricted to southern Brazil, endemic to high elevation areas between 750 and 1500 m (Santa Catarina and Rio Grande do Sul States). However in the examined material of T. catharinensis, Zardini cites some herbarium specimens (E. Pereira 8445, Pereira & Pabst 7720, Pereira 6782 & Pabst 6608, Burkart 25200) that occur in the southern region of Rio Grande do Sul state, in lower elevations areas between 0 to 400 m. In the present work these materials indicated by Zardini were analyzed and identified as T. cisplatina .

Trichocline cisplatina is similar to T. catharinensis in the morphology of the innermost phyllaries. These are lanceolate, brownish red and 1-2-seriate in both species. According to Cabrera & Klein (1973), there are two varieties of T. catharinensis : T. catharinensis var. catharinensis and T. catharinensis var. discolor Cabrera (1973: 48) . The new species is most similar to T. catharinenses var. discolor , with which it shares pinatifid leaves and whitish ovary trichomes. Trichocline cisplatina can be distinguished from both varieties of T. catharinensis by its procumbent scape, deeply pinatifid leaves with 4-10 pairs of rounded lobes, yelloworange ray floret corollas, broader capitula and phyllaries and ovaries with 2-seriate trichomes that are inflated at the apex and densely distributed. Furthermore, these two species have a disjunct distribution in southern Brazil. Trichocline catharinensis occurs in grasslands and shrublands of high elevation areas between 750 to 1500 m and T. cisplatina is endemic to low elevation areas in the coastal region of southern Rio Grande do Sul State and southeastern Uruguay, occurring on grasslands and shrublands with rocky or sandy soils and dunes.

Figures

FIGURE 1. Trichocline cisplatina. A. Habit (E. Pasini et al. 897, ICN). Black arrows indicates the position of the secundary lobes of the leaves. B. Representative capitulum (E. Pasini et al. 898, ICN). C. Outermost to innermost phyllaries (E. Pasini et al. 898, ICN). D. Pistillate ray floret (Cabrera 32122, SI). E. Bisexual disc floret (Cabrera 32122, SI). F. Stamen of bisexual disc floret (Cabrera 32122, SI). G. Staminode of pistillate ray florets (Cabrera 32122, SI). H. Ovary (Cabrera 32122, SI). I. Trichome of the ovary (E. Pasini et al. 897, ICN). Illustration by João Vieira Iganci.

FIGURE 2. Trichocline cisplatina. A. Habit. B. Habitat. C. Population along River Piratini, Arroio Grande, Rio Grande do Sul State, Brazil. D. Detail of the species showing the procumbent scape. E. Capitulum showing the phyllaries. F. Ocurrence site on sandy grasslands. G. Ocurrence site on hill with shrubland vegetation. Photo credits: A, B, C, D, F, G, H by E. Pasini and E by F. Torchelsen.

FIGURE 3. Distribution map of Trichocline cisplatina (circles) and Trichocline catharinensis (squares).