Austroblechnum andinum (Baker) Gasper & V.A.O.Dittrich

Dittrich, Vinícius Antonio De Oliveira, Salino, Alexandre, Monteiro, Reinaldo & Gasper, André Luís De, 2017, The family Blechnaceae (Polypodiopsida) in Brazil: key to the genera and taxonomic treatment of Austroblechnum, Cranfillia, Lomaridium, Neoblechnum and Telmatoblechnum for southern and southeastern Brazil, Phytotaxa 303 (1), pp. 1-33 : 4

1. Austroblechnum andinum (Baker) Gasper & V.A.O.Dittrich in Gasper et al. (2016a: 202).

Lomaria andina Baker (1874: 482) . Blechnum andinum (Baker) Christensen (1905: 150) . Type:— BOLIVIA. La Paz, Unduavi, without date, R.W. Pearce s.n. (holotype K). Fig. 1A–C .

Plants epipetric; rhizomes erect, short, stoloniferous, the scales tan, concolorous, narrowly triangular, ca. 1–3 × 0.3 mm, margins entire; fronds dimorphic, the fertile ones as long as the sterile or longer, 9–11.8 cm long, the sterile 8–12 cm long; stipes filiform, dark tan to rarely stramineous, lustrous, longer on fertile fronds, of sterile fronds 1.1–3.2 cm long, 0.2–0.5 mm diam., proximally with few scales, these similar to those on rhizomes, of fertile fronds 4.5–5.2 cm long; sterile blades 3.2–9.2 × 1–2.6 cm, membranaceous, pinnate proximally, pinnatisect toward apices, glabrous, generally oblanceolate, rarely linear-oblanceolate or lanceolate, more or less abruptly reduced or truncate at bases, without vestigial pinnae, apices gradually reduced; fertile blades 4.5–7 × 0.6–0.8 cm, pinnate, linear to narrowly oblanceolate, gradually or abruptly reduced proximally, without vestigial pinnae; rachises glabrous on both sides or sparsely covered with short, pluricellular hairs abaxially; sterile pinnae 10–21 pairs, 0.4–1.2 × 0.2–0.4 cm, slightly to strongly ascending, partially to completely adnate, narrowly oblong to narrowly triangular, margins entire, plane, apices obtuse or rounded, fertile pinnae ca. 15 pairs, 2.3–5.4 mm × 1.3–1.5 mm, linear to more or less rounded (short and with spreading sporangia), strongly contracted; veins free, simple or rarely 1(–2) proximal pairs once forked, 2–5 secondary veins per pinna, with slightly clavate ends before margins.

Distribution and habitat:— Brazil (Minas Gerais, Rio de Janeiro and Espírito Santo [first record]), furthermore Peru and Bolivia. In the study area, the species is known from only two distant areas, both in southeastern Brazil: Serra do Itatiaia and Serra do Caparaó, in two National Parks, always above 2700 m. In Brazil, the species is considered as critically endangered ( Dittrich et al. 2013). According to herbarium labels, plants of this species grow on, between, or even under rocks, in open as well as shaded areas. The vegetation type where the plants grow is the campo de altitude, a grassland of the Brazilian highlands restricted to southern and southeastern Brazil inside the Atlantic Forest domain, above the tree line.

Comments:— the closest species in the study area are Austroblechnum squamipes (Hieronymus) Gasper & V.A.O.Dittrich and A. penna-marina (Poiret) Gasper & V.A.O.Dittrich. It can be distinguished from A. squamipes by leaf blade base: truncate or not, but not reduced to semicircular lobes as in A. squamipes . Furthermore, A. squamipes is a more robust species, with thicker stipes (0.5–1 mm) and wider pinnae (0.5–0.7 cm) in the sterile fronds - vs. 0.2–0.5 mm and 0.2–0.4 cm respectively. From A. penna-marina , it is distinguished by the rhizomes (erect in A. andinum , long-creeping in A. penna-marina ) and the blade division and texture (pectinate and subcoriaceous in A. penna-marina , not pectinate and membranaceous in A. andinum ). From both species, A. andinum differs in having simple vs. regularly forked veins (in A. andinum just one or two proximal pairs of veins can be once forked).

Additional specimens examined:— BRAZIL. Minas Gerais: Itatiaia, without date, A.C. Brade s.n. ( MBM 4715 ). Espírito Santo: Ibitirama, Parque Nacional do Caparaó , 20°26’25”S, 41°47’59”W, 2,800 m, 15 October 2011, J.P.S. Condack et al. 706 ( RB —photo) ; ibidem, 10 May 2014, A. Salino et al. s.n. ( BHCB 169849 ). Rio de Janeiro: Itatiaia, 2,800 m, 4–10 June 1913, A.C. Brade & F. Tamandaré de Toledo Jr. 6484 (B, HB, K, SP, SPF) ; idem, Agulhas Negras , 2,787 m, 27 May 1935, A.C. Brade 14540 ( CESJ, K, RB) ; Resende: Parque Nacional do Itatiaia, Agulhas Negras , 2,700 m, 08 August 2006, J.P.S. Condack & C.G.V. Ramos 517 ( RB —photo) .

Figures

FIGURE 1. A–C.Austroblechnum andinum.A.Habit.B. Pinna pair showing venation.C. Rhizomescale. D–G.Austroblechnum divergens. D. Habit. E. Base of sterile blade showing vestigial pinnae. F. Pinna pair showing venation. G. Rhizome scale. (A–C from A.C. Brade s.n., CESJ0003368; D–G from V.A.O. Dittrich et al. 1807, CESJ).