Blechnum × caudatum 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 : 210-211

4. Blechnum × caudatum Cavanilles (1802: 262) . Fig. 2E–G

Blechnum occidentale var. caudata (Cav.) Rosenstock (1907: 94) . Lectotype (designated by Christensen 1937: 20):— ECUADOR. without date, Née s.n. (MA).

Plants terrestrial or epipetric; rhizomes erect to ascending, stoloniferous, the scales narrowly triangular, tan, concolorous or with a dark central stripe, 5–8 × 1–1.7 mm, margin entire; fronds monomorphic, 9.0– 61.8 cm long; stipes 2.8–23.3 cm long, 1.1–2.2 mm diam., paleaceous, at least lower scales similar to those of the stem; blades 6.5–38.5 × 3.1– 16.6 cm, deltoid or ovate, base truncate, without vestigial pinnae, pinnate at base, pinatissect toward the apex, more or less abruptly reduced to a conform or subconform apical section, 1.1–2.0 times the length of the longest lateral pinnae, chartaceous to subcoriaceous, glabrous on abaxial surface, glabrous on adaxial surface or with rare glandular trichomes near margin, between veins; rachis glabrous on both surfaces or hairy, with hyaline glandular trichomes; pinnae 7–17 pairs, 1.7–9.9 × 0.5–0.9 cm, usually ascending, sometimes patent, especially the basal ones, petiolulate, with basiscopic cuneate base (proximal ones) to gradually adnate, ensiform or linear, slightly falcate or falcate, apex acute, obtuse-acuminate or acuminate, margin apparently entire (finely denticulate), plane or slightly revolute, veins free, simple to 1-bifurcate, with clavate ends just before the margin.

Distribution and habitat: — Mexico, Belize, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica, Panama, Colombia, Venezuela, Suriname, Ecuador, Peru, Bolivia, and Brazil (Minas Gerais, Espírito Santo, Rio de Janeiro, São Paulo, Paraná, Santa Catarina, and Rio Grande do Sul). A relatively common taxon in the study area, it is not locally endangered. Specimens of this hybrid grow in the same areas as those of Blechnum gracile Kaulfuss (1824: 158) , namely, preferably on riverbanks, usually on ravines in relatively well illuminated areas and also in degraded places such as roadsides. In the study area, it occurs between 50 and 1200 m.

Comments: —According to morphological (pers. obs.; Kazmirczak, 1999) and chromosomal ( Walker 1966, 1973, 1985) evidence, this taxon is a hybrid between Blechnum occidentale and B. gracile . It can be differentiated from B. gracile by the more numerous pinnae (at least seven pairs in B. × caudatum ; 3–5(–8) pairs in B. gracile ), but especially by the shape of the blade (pinnatisect, at least near the apex, in B. × caudatum , pinnate in B. gracile ) and by the apical pinnae, surcurrent in B. × caudatum , not surcurrent in B. gracile . It can be differentiated from B. occidentale by the subconform apex of the blade and by the proximal pinnae with basiscopic cuneate base, not cordate. As there are no chromosome counts of the material from the study area, it is difficult to know whether this taxon is triploid or tetraploid, despite parental taxa being tetraploid ( B. occidentale ) and probably tetraploid (see discussion about B. gracile ). If B. × caudatum is tetraploid, this will add more evidence that the Brazilian material corresponds to the hybrid between B. occidentale and B. gracile and that this is in fact the correct name for these plants. If B. × caudatum is triploid, then one of the parents is diploid and the name adopted here is incorrect. Although monomorphic in the usual sense (that there is no clear distinction between fertile and sterile fronds regarding the width of the pinnae), the fronds of B. × caudatum are different in that there are different sizes (the fertile ones are larger, with longer stipes), the pinnae of the fertile fronds are proportionally narrower, the apex of the pinnae may also be different (e.g. obtuse-acuminate apices were only seen in pinnae of sterile fronds and the pinnae of sterile fronds are more approximated than those of fertile fronds) and the sterile fronds are almost completely pinatissect, while the fertile ones are pinatissect only close to the apex.

Selected specimens examined: — BRAZIL. Minas Gerais: Alto Caparaó, Parque Nacional do Caparaó, trilha para Macieira , 16 May 1990, L. Krieger et al. s.n. ( CESJ 24185 ) ; Caldas, Serra dos Poços, Pocinhos do Rio Verde , ca. 21°56’S, 46°23’W, ca. 1150–1200 m, 16 June 1995, M.R. Pietrobom-Silva 1920 ( MBM, SJRP) ; Lima Duarte , 26 August 1978, L. Krieger & M.C. Brügger s.n. ( CESJ 15908 ) ; Nova Lima, Estação Ecológica de Fechos , 20°03’58”W, 43°57’33”W, 11 July 2001, A. Salino et al. 7157 ( BHCB, HRCB) ; Poços de Caldas, Serra dos Poços, Cachoeira das Antas , ca. 21°47’S, 46°34’W, ca. 1200–1250 m, 15 June 1995, M.R. Pietrobom-Silva 1823 ( MBM) ; Santa Rita de Jacutinga, Cachoeira da Vargem do Sobrado , 19 April 1992, L. Krieger s.n. ( CESJ 29463 ) ; Santana do Garambéu, trecho do alto Rio Grande adjacente a zona urbana de Santana do Garambéu , 21°36’05”S, 44°06’16”W, 1100–1150 m, 11 May 2001, A. Salino & P.O. Morais 6795 ( BHCB) ; São Roque de Minas, Parque Nacional da Serra da Canastra, Casca D’Anta , 20°18’20”S, 46°31’13”W, 14 July 1997, A. Salino 3197 ( BHCB) ; Serro, Milho Verde, Lago Azul , 26 February 2000, A. Salino & P.O. Morais 5108 ( BHCB, HRCB — collection mixed with B. occidentale ) ; Jequeri / Canaã, área da Usina Hidrelétrica de Cachoeira Grande , às margens do Rio Casca , 02 May 1998, A. Salino & P.O. Morais 4206 ( BHCB) ; Parque Nacional do Caparaó, 15 June 1988, L. Krieger et al. s.n. ( CESJ 22232 ). Espírito Santo: Alegre, Parque Nacional do Caparaó , 22 February 2000, V.C. Souza et al. 23764 ( ESA). Rio de Janeiro: Nova Friburgo, 1957, Vale s.n. ( BHCB 1396 ). Unknown municipality: Serra dos Órgãos, 21 April 1941, A.C. Brade 16802 ( RB). São Paulo: Analândia, Serra do Cuscuzeiro , 15 January 1993, A. Salino 1669 ( BHCB) ; Caraguatatuba , proximidades de Caraguatatuba, 15 July 1953, W. Hoehne 4105 (K, MBM, SJRP, SPF) ; Natividade da Serra, Parque Estadual da Serra do Mar, Núcleo Santa Virgínia , Base de Vargem Grande , trilha para a Cachoeira da Boneca , 23°25’57”S, 45°12’36”W, ca. 800 m, 10 August 2001, V.A.O. Dittrich et al. 912 ( HRCB) ; Ribeirão Preto , ca. 21°30’S, 48°12’W, 02 November 1999, C.B. Novaes et al. 8 ( SJRP) ; São Luís do Paraitinga, Parque Estadual da Serra do Mar, Núcleo Santa Virgínia , 800 m, 29 October 2001, V.A.O. Dittrich et al. 971 ( HRCB) ; Silveiras , cascata a 1.5 km da SP-66, km 221, 25 September 1978, A. Tosta-Silva 128 ( SP) ; Ubatuba, Parque Estadual da Serra do Mar, Núcleo Picinguaba , ca. 50 m, 02 May 2001, V.A.O. Dittrich et al. 874 ( HRCB) ; Freguesia da Ribeira, Distrito de Apiaí, Sítio de Thomé Diar , March 1881, Rocha 258 ( FI). Paraná: Antonina, Bairro Alto , Rio Cachoeira (usina velha), 21 March 1974, L.T.D. Dombrowski & Y.S. Kuniyoshi 5228 ( PACA) ; Campina Grande do Sul, estrada para o Parque das Lauráceas, Rio Capivari , 15 October 1996, J. Cordeiro & E. Barbosa 1325 ( BHCB, MBM) ; Cerro Azul, Rio Turvo, Salto Grande , 23 June 1992, G.G. Hatschbach & R. Kummrow 57103 ( MBM, UPCB) ; Foz do Iguaçu, Rio Ocuí , 150 m, 07 December 1969, G.G. Hatschbach 23151 ( MBM, PACA) ; Guaraqueçaba, Reserva Natural Salto Morato , 11 September 1999, G. Gatti 492 ( UPCB) ; Guaratuba, Pedra Branca de Araraquara , 15 July 1961, G.G. Hatschbach 8155 ( MBM, UPCB) ; Morretes, estrada para Colônia Limeira, Fazenda Morro Azul , 150 m, 30 March 1990, G.G. Hatschbach & V. Nicolack 54100 ( MBM). Santa Catarina: Ibirama , Nova Bremen , 150 m, 20 September 1956, R. Reitz & R.M. Klein 3730 ( HBR, PACA) ; Itajaí, Luiz Alves , 13 January 1941, R. Reitz s.n. ( PACA 84898 ) ; Peritiba, Estreito do Rio Uruguai, 06 June 1997, R.A. Wasum s.n. ( MBM 220249 ). Rio Grande do Sul: Derrubadas , Parque Estadual do Turvo , 10 January 1982, R.M. Bueno 48 ( ICN) ; Marcelino Ramos, Estreito, without date, J. Dutra 102b ( ICN). Unknown state [Minas Gerais / Rio de Janeiro]: Parque Serra do Itatiaia (sic), 04 February 1967, A. Sehnem 9029 ( PACA) .

Figures

FIGURE 2. A–D. Blechnum austrobrasilianum: A. Habit. B. Part of a pinna showing venation. C. Basal pinnae. D. Rhizome scale. E–G. Blechnum × caudatum: E. Habit. F. Basal pinnae. G. Rhizome scale. (A–D from L. Krieger s.n., CESJ8355; E–G from L. Krieger & M.C. Brügger s.n., CESJ15908).