Blechnum auriculatum Cavanilles (1802: 262)

Dittrich, Vinícius Antonio De Oliveira, Salino, Alexandre & Monteiro, Reinaldo, 2015, The Blechnum occidentale (Blechnaceae, Polypodiopsida) species group in southern and southeastern Brazil, Phytotaxa 231 (3), pp. 201-229 : 205-207

2. Blechnum auriculatum Cavanilles (1802: 262) . Fig. 1D–F

Blechnum australe Linnaeus (1767: 130) subsp. auriculatum (Cav.) Sota (1972a: 178) . Mesothema auriculatum (Cav.) Presl (1849: 112) . Type:— ARGENTINA. Buenos Aires: Peña Blanca, without date, L. Née s.n. (holotype MA 475444).

Blechnum australe Linnaeus (1767: 130) f. mucronato-dentata Rosenstock (1907: 97). Type:— BRAZIL. Rio Grande do Sul: Rio Pardo, Santa Cruz, Boa Vista, C. Jürgens & A. Stier 292 [Rosenst. fil. austrobras. no. 368] (holotype B200030373, isotypes HB, S05-10131, US 00067409).

Plants terrestrial; rhizomes erect or ascending, stoloniferous, the scales narrowly triangular, tan or brown, concolorous or with a dark central stripe, 1.8–2.3 × 0.6 mm at the base, margins entire; fronds subdimorphic, the fertile ones with green tissue, the pinnae somewhat narrower or much narrower than the sterile ones, 22.5–70.7 cm long, the sterile fronds shorter, 18.6–45.4 cm long; stipes of sterile fronds 2.5–9.1 cm long, 0.9–1.4 mm diam., stramineous or atropurpureous, with linear-lanceolate, enlarged at the base, tan, concolorous, light tan toward the stipe apex, long ciliate scales; stipes of fertile fronds 9.5–14.5 cm long; sterile blades 15.0–33.5 × 2.9–6.1 cm, papyraceous, on the abaxial side with whitish, appressed, unicellular hairs on and between the veins, narrowly elliptic to narrowly oblanceolate, mostly pinnate, pinnatisect near apex, gradually reduced to apex and base, at the base to pinnae 2.5–4 times shorter than the median ones, fertile blades 20.1–63.2 × 4.5–8.7 cm, narrowly obtrulate, mostly pinnate, pinnatisect near apex, gradually reduced to apex and base; rachis with short, unicellular, rigid hairs and scaly on both sides, the scales filiform or narrowly triangular, sometimes enlarged at the base, tan, margins entire, or scales with very expanded bases, concave-convex, filiform at the apex, margins entire, very sparsely denticulate; sterile pinnae 28–48 pairs, 1.2–3.0 × 0.4–0.7 cm, on both sides with basal auricle with mucronate or acute apex, mostly on basal pinnae, the median ones ensiform, the basal ones triangular to deltoid, the basal ones reflexed, the median ones patent and the apical ones ascending, margin entire to crenate, finely denticulate, plane to commonly revolute, the apex mucronate or apiculate; fertile pinnae 32–47 pairs, 15–50 × 1.8–5.6 mm, veins free, once bifurcate (rarely twice bifurcate at pinna bases and simple at the apices), with clavate ends on the margin.

Distribution and habitat: — Brazil (Paraná, Santa Catarina, and Rio Grande do Sul), Uruguay, and Argentina. A very common species in Rio Grande do Sul, less common in Santa Catarina, rare in Paraná and completely absent northwards. It grows in coastal lowland forests and Araucaria forests, at the edge of forests, in roadsides, in younggrowth secondary forests and in grasslands, between 50 and 1000 m.

Comments: — Blechnum auriculatum can be separated from all other monomorphic species from southern and southeastern Brazil by its typical subdimorphic fronds associated with its free venation ( Fig. 1 ). In the study area, the closest taxon is Blechnum × leopoldense . It differs from this last taxon mainly by the much reduced basal pinnae (2.5–5.0 times shorter than the longest pinnae in B. auriculatum vs. at most 2(–3) times shorter in the hybrid) and by the narrower sterile blade (up to 6.1 cm wide in B. auriculatum vs. at least 8 cm wide in the hybrid). The sori can be partially interrupted, but in general they are uninterrupted. Very close to this species is Blechnum hastatum Kaulfuss (1824: 161) ( Peru, Chile, Argentina). According to Sota (1972b), B. hastatum can be distinguished from B. auriculatum by its concolorous, flaccid, linear, tan rhizome scales; axes and blades generally hairy, rarely glabrous; sori tending to a submarginal position, frequently interrupted; and, ultimately, the species have different geographic areas of occurrence. Sota annotated the specimen Jürgens & Stier 292 at S as the holotype of Blechnum australe f. mucronato-dentata, but according to Jens Klackenberg (personal communication) from S herbarium, there are no holotypes of Rosenstock at S, only duplicates of them.

Selected specimens examined: — BRAZIL. Paraná: Campo Largo, Serra de São Luiz do Purunã , 1200 m, 23 February 1960, E. Pereira 5402 ( HB) ; Candói , 18 June 2004, P.B. Schwartsburd s.n. ( UPCB 54422 ) ; Guarapuava, Rodovia BR-277, Rio das Mortes , 05 December 1968, G.G. Hatschbach & O. Guimarães 20495 ( MBM, PACA) ; Ponta Grossa, Parque Estadual de Vila Velha, 15 December 2003, P.B. Schwartsburd & A.C. Hatschbach 52 ( HRCB, UPCB). Santa Catarina: Bom Retiro , Figueiredo , 1000 m, R. Reitz 3468 ( PACA) ; Campos Novos, 32 km south of Campos Novos on the road to Anita Garibaldi , 01 March 1957, L.B. Smith & R.M. Klein 11994 ( HBR, R) ; Capinzal, 500 m, R. Reitz & R.M. Klein 14354 ( PACA) ; Lages, 1921, C. Spannagel 23 ( SP, SPF) ; São Joaquim, Altos , 02 February 1958, J. Mattos 5452 ( PACA) ; Urubici, margem do Rio Canoas, 18 February 1960, J. Mattos 7542 ( PACA). Rio Grande do Sul: Bagé , Casa de Pedra , ca. 260 m, 15 December 1989, I. Fernandes 753 ( ICN, PACA) ; Bento Gonçalves, Monte Belo , 28 July 1962, O.R. Camargo 3689 ( PACA) ; Bom Jesus, Fazenda Caraúna, without date, J. Dutra 279 ( ICN) ; Bossoroca, São Luiz das Missões , 300 m, 13 January 1953, A. Sehnem 6199 ( PACA) ; Caçapava do Sul, near Caçapava do Sul , 09 November 1977, T.M. Pedersen 11964 ( MBM) ; Cambará do Sul, Itaimbezinho , 10 January 1964, O.R. Camargo 3947 ( PACA) ; Canela , arredores da Cascata do Caracol, 21 April 1959, A. Backes 245 ( ICN) ; Caxias do Sul, Vila Oliva , 780 m, 07 January 2000, A. Kegler 509 ( MBM) ; Esmeralda , 31 July 1982, R.M. Bueno 20 ( ICN) ; Gramado , 800 m, 28 December 1949, A. Sehnem 4167, 4182 (B, PACA) ; Gravataí, Morro Itacolomi , 11 July 1958, A. Backes 88 ( ICN) ; Herval , 09 January 1980, A. Sehnem 16750 ( PACA) ; Lajeado , February 1989, R.M. Senna s.n. ( ICN 83983 ) ; Lavras do Sul, Fazenda do Posto , 12 km a leste da cidade, 17 October 1971, J.C. Lindeman s.n. & B.E. Irgang ( ICN 8670 ) ; Nova Petrópolis , 08 July 1949, T. Luis s.n. ( ICN 17603 ) ; Pelotas, Encruzilhada , 22 May 1959, G.L. Brauner 90 ( PACA) ; Pinheiro Machado, Rod. BR-293, ca. 5 km da cidade em direção a Bagé , 10 December 1989, J.A. Jarenkow 1548 ( MBM, PACA) ; Porto Alegre, Morro Santana , 30°05’S, 51°08’W, 24 January 1991, R.A. Záchia et al. 305 ( ICN) ; Salvador do Sul, 450 m, 15 November 1948, A. Sehnem 3510 ( MBM, PACA) ; Santa Cruz do Sul, December 1897, J. Dutra 230 ( ICN) ; Santa Maria do Herval, Cascata de Santa Maria do Herval , 13 December 1958, A. Backes 112 ( ICN) ; Santana da Boa Vista, Fazenda do Papagaio , 02 December 1978, A. Sehnem 16346 ( PACA) ; São Francisco de Paula, Floresta Nacional de São Francisco de Paula , 800 m, 10 June 1994, C. Dalla Rosa et al. s.n. ( MBM 173291 ) ; São Leopoldo, Morro das Pedras , 200 m, 09 July 1935, A. Sehnem 612 ( PACA) ; Taquara, Rodovia RS-020, ca. 8 km da cidade em direção a São Francisco de Paula , 27 November 1988, J.A. Jarenkow & R.M. Bueno 1197 ( MBM) ; Vacaria, Passo do Socorro , 800 m, 28 January 1951, A. Sehnem 5736 ( PACA) .

Figures

FIGURE 1. A–C. Blechnum asplenioides. A. Habit. B. Basal pinnae. C. Rhizome scale. D–F. Blechnum auriculatum. D. Habit. E. Part of a pinna showing venation. F. Rhizome scale. (A–C from A.C. Brade s.n., CESJ3366; D–F from A. Salino et al. 14733, CESJ).