Blechnum × leopoldense (Dutra) V.A.O. Dittrich & Salino, 2015

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 : 217-219

9. Blechnum × leopoldense (Dutra) V.A.O. Dittrich & Salino , comb. et stat. nov. (= B. auriculatum Cav. × B. occidentale L.) Fig. 5A–C

Blechnum occidentale var. leopoldensis Dutra (1938: 36) . Lectotype (designated here):— BRAZIL. Rio Grande do Sul: without date, J. Dutra 651 (ICN).

Plants terrestrial; rhizomes erect, stoloniferous, the scales tan with a dark central stripe, lanceolate, margins predominantly entire, with few teeth and long projections, 4.9–5.5 × 1.2 mm at base; fronds monomorphic or slightly dimorphic, the fertile pinnae slightly contracted, 56.0– 90.5 cm long; stipes 26.7–37.2 cm long, 1.1–3.2 mm diam., at the base with scales identical to rhizome scales, in upper part scales either linear or linear with broad base, concolorous tan or with darker apex, margins entire or with long projections; blade 18.4–53.7 × 8.0– 18.3 cm, lanceolate or narrowly elliptic, pinnate at the base and in the center, pinatissect at the apex, gradually reduced at the apex, slightly reduced at the base to pinnae with more than half the length of the largest pinnae, rarely smaller, chartaceous, glabrous or, on the abaxial side, particularly in the proximal portion of the pinnae, with unicellular, appressed, whitish hairs, between and on veins; rachis with sparse linear scales on both sides, loosely adhered; pinnae 36–43 pairs, 3.9–9.5 × 0.5–1.0 cm, patent to rarely ascending (median and apical) or reflexed (basal), the basal ones sessile, adnate toward the apex, the median ones linear or narrowly triangular with acroscopic and basiscopic expanded base (not surcurrent), the basal ones narrowly triangular or triangular, the basal ones and some median ones auriculate, the auricles with mucronate or obtuse apex on both surfaces, the pinnae apex acute to acuminate, the margin apparently entire (finely denticulate), the abaxial costa glabrescent with rare multicellular trichomes; veins free, 1– (most parts) to 4(6)-bifurcate (proximal veins), with clavate ends just before the margin.

Distribution and habitat: —Northwest Argentina and Rio Grande do Sul, Brazil. Sehnem (1968) cited two specimens for the state of Santa Catarina: one not seen (Bathke 42), the other is Blechnum auriculatum (C. Spannagel 23). This is an uncommon taxon in Brazil, with few collections, all in Rio Grande do Sul. It grows within and at the edge of forests, secondary forests and ravines off the road. In the study area, it occurs between 120 and 550 m, in areas dominated by Araucaria forest and seasonal deciduous forest as well as transitional areas.

Comments: —This hybrid presents intermediate features between the parental species ( B. occidentale L. and B. auriculatum Cav. ). Sota (1973) has mentioned all distinguishing characters between the hybrid and parental species in his synopsis of the ferns of northwestern Argentina. The sori are partial to completely interrupted or continuous, one of the most striking features of this notospecies. Dutra (1938), in his description of Blechnum occidentale var. leopoldense , called attention to the possibility of this variety to be, in fact, a hybrid. Furthermore, Sota (1973) and Morbelli (1974) demonstrated the presence of abortive spores in this taxon, reinforcing the possibility of it actually being a hybrid. Since there is no name for this hybrid, the combination is made and the status is changed here.

Selected specimens examined: — BRAZIL. Rio Grande do Sul: Esmeralda , 31 July 1982, R.M. Bueno 22, 23 ( ICN) ; Farroupilha, Rio das Antas, Linha Jacinto , 06 August 1962, O.R. Camargo 3683 ( PACA — on the same sheet with B. occidentale L.) ; Montenegro, L. Pinhal , 550 m, 30 April 1953, A. Sehnem 6456 ( PACA) ; São Leopoldo, Vila Gonzaga , 20 February 1936, A. Sehnem 3386 ( PACA) ; São Leopoldo, Quinta São Manoel , without date, J. Dutra 650 ( ICN, R) ; Santo Amaro, Serra da Cria , 180 m, 1906, C. Jürgens s.n. (Rosenst. filices austrobr. exsic. 274) (K) .

Figures

FIGURE 5.A–C. Blechnum × leopoldense:A. Habit. B. Part of a pinna showing venation. C. Rhizome scale. D–F. Blechnum occidentale: D. Habit. E. Sterile basal pinnae. F. Fertile basal pinnae. (A–C from J. Dutra 651, ICN; D–F from D.S. Pifano 34, CESJ).