Dicksonia sellowiana, Hook., Sp. Fil.

Noben, Sarah, Kessler, Michael, Weigand, Anna, Tejedor, Adrian, Rodr´, Wilson D., Gallego, Luis Fernando Giraldo & Lehnert, Marcus, 2018, A Taxonomic and Biogeographic Reappraisal of the Genus Dicksonia (Dicksoniaceae) in the Neotropics, Systematic Botany (Basel, Switzerland) 43 (4), pp. 839-857 : 854

4. DICKSONIA SELLOWIANA Hook. ,

Sp. Fil. 1: 67. 1844. Balantium sellowianum (Hook.) C. Presl , Tent. Pterid. 134. 1836.

TYPE: BRAZIL. Without locality, without date, F. Sellow s.n. [no. 9] (lectotype K-000589710 !, designated by Tryon and Stolze, Fieldiana, Bot., n.s., 20: 105 (1989); isolectotype HBG [photo GH, US, fragment NY]).

Trunks mostly to 3 m, exceptionally to 10 m tall, 15–20 cm in diam including persistent petiole bases, with additional cover of adventitious roots of varying extent, with skirt of old fronds; no adventitious buds but lateral sprouting after injury or decapitation possible. Fronds to 200 cm long, monomorphic, erect to patent, larger ones arching. Petioles short, less than 20 cm, appressed to the trunk for most of the length, basally covered with long hairs to 2.5 cm long, turgid, ciliform, dark reddish brown, basally mixed with yellowish to orange catenate hairs, these forming an ephemeral undercoat covering the crozier but absent in mature fronds, leaving the epidermis smooth (or slightly rough near the very petiole base) if abraded. Laminae to 180 X 60 cm, bipinnate-pinnatifid to almost tripinnate, coriaceous, oblanceolate. Frond axes (rachises, costae, and costules) mostly green to yellowish with age, rarely rachis brown to blackish, smooth, few hairs on upper part of rachis, costae adaxially with reddish ciliform hairs, tortuous to atrorsely curved to 1.5 mm long, costule with similar hairs but fewer and becoming gradually paler, all axes abaxially glabrescent with appressed pale tortuous hairs from crozier indument, ususally absent in mature fronds, rarely with spreading hairs persisting ( Argentina), scattered red hairs or dense white ones ( Uruguay). Pinnae 35 X 11 cm, sessile, oblong-lanceolate with attenuate tips, 24–28 pairs per frond, basal ones strongly tapering. Pinnules to 6 X 1 cm, sessile, basally auriculate, oblong-triangular to triangular-lanceolate. Segments to 7.0 X 3.3 mm, sessile, weakly falcate, margins crenate to serrate, flat to weakly revolute; proximal segments not significantly smaller than medial ones. Veins glabrous. Sori 0.9–1.4 mm in diam, oblong when closed, circular when open, on the acroscopic and basiscopic side of the segment, one sorus per unbranched lateral vein, distance receptacle to the midvein 0.6–1.2 mm. Indusia bivalved, outer one brown with entire cartilaginous margin, inner one light brown with slightly subentire to slightly erose margins; paraphyses catenate. Spores tetrahedral-globose with prolonged, depressed lobes, spores not measured, exospore smooth, perispore bacillar-granular. Figure 7C .

Etymology —Named after Friedrich Sellow (also ‘Sello,’ 1789–1831), German gardener, botanist, and plant collector in South America, chiefly in Brazil; worked as assistant gardener under Carl L. Willdenow (1765–1812) at the Berlin Botanical Garden.

Vernacular Names —‘Xax´ım,’ or ‘xaxim bugio’ ( Brazil), ‘chanch´ıe manso’ ( Argentina).

Distribution and Habitat —Southeastern Brazil in the Mata Atlantica ˆ, and adjacent Paraguay, Argentina, and Uruguay at 100–1300 m ( Fig. 6 ). Found mainly in cloud forests and Araucaria forests as defined by Neves et al. (2017).

Selected Specimens Examined — Brazil.— ESPÍRITO SANTO: Castelo Trilha da Balança, Parque Estadual do Forno Grande , 20°31 ' 37"S, 41°06 ' 06"W, 1250–1600 m, 02 Jun 2008, P.H. Labiak 4832 ( RB-00532205 ) .— MINAS GERAIS: Catas Altas, cadeia do Espinhaço, RPPN Caraca , Bocaina , 20°07 ' 25"S, 43°27 ' 53"W, 1300 m, P. B. Schwartsburd 1779 (RB-00824355) .— PARANÁ: Iguassú, 1949, Rizzini 652 (RB-00656254); Guarapuava , 25°21 ' 50"S, 51°27 ' 41"W, 24 February 1971, G. Hatschbach 26489 ( MO) ; Palmas, rod. para Ponta Serrada, 12 Dec 1980, Hatschbach 43455 ( US) .— RIO DE JANEIRO: 22°47 ' 29"S, 43°27 ' 53"W, November 1879, A. Glaziou 11718 ( K, MO) ; Nova Friburgo, Distrito de Macaé de cima, próximo à cabeceira do rio das flores, 1350 m, 29 Apr 1990, S. C. Kurtz 89 (RB-00656264) .— RIO GRANDE DO SUL: Gramado , [ca. 09°23 ' 49"S, 50°53 ' 39"W] 18 Jan 1964, A. Burkart 25037 ( SI) ; Caxias do Sul , 10 Dec 1999, L. Scur 297 (RB-00702372) ; “von Alegrete über die Missiones durch den nördlichen Teil des Staates nach Porto Alegre , Mai–Nov 1826,” F. Sellow [#8] (paralectotypes B-20_0138600/-20_0138601/- 20_0138603/-20_0138604) ; Santa Cruz , 29°42 ' 13"S, 52°26 ' 01"W, 100 m, 1904, A. Stier s.n. ( STU) .— SANTA CATARINA: 26°57 ' 40"S, 50°12 ' 27"W, 1905, S. Bento and Noetsch 24 ( UC) ; 1300 m, 10 September 1969, U. Eskuche 1642–10 ( UC) ; Mun. Itaiópolis, roadside between Dr. Pedrinho and Itaió, near Indian village , 26°44’S, 49°40’W, 800 m, 20 March 2008, M. J. M. Christenhusz, S. Lehtonen, and P. B. Swartsburd 5015 ( MO) . Paraguay. — ALTO PARANÁ: [ca. 25°39’S, 54°37’W?] 1909/1910, K. A. G. Fiebrig 5796 ( SI) . Argentina. — MISIONES: San Pedro , [ca. 26°33’S, 54°04’W,] 550 m, M. J. Belgrano 592 ( SI) ; Gral. M. Belgrano, Dos Hermanas , 26°16 ' 56.6"S, 53°42 ' 56.3"W, 766 m, L.M. Miguel et al. 72 ( CTES, K) ; Guaran´ ı, 23 Nov 1993, S. G. Tressens 4631 ( SI) .— ENTRE RÍOS: Paraná , 830 m, 16 Jan 1914, P. K. H. Dusén 14425 (SI-169105) . Uruguay. — MONTEVIDEO: Montevideo , 07 Apr 1912, C. Osten 6132 ( SI) ; Jul 1841 Fruchart s.n. ( K) .— TACUAREMBO: Tacuarembo , [ca 31.68°S, 55.95°W, 100–250 m] January 1876, J. Arechavaleta 430 ( P) .

Notes — Dicksonia sellowiana is here defined as a species confined to the Mata Atlantica ˆ(southeastern Brazil and adjacent Paraguay, Argentina, Uruguay) and is generally smaller in size of the whole plant, segments, and sori than the previously included Andean species, D. karsteniana and D. navarrensis . For further discussion, see D. navarrensis . Lellinger (1989) reported soral paraphyses that are shorter than the sporangia as further distinguishing characters of D. sellowiana from the Andean D. navarrensis (as D. gigantea ) and D. karsteniana . We were unable to verify this because the shorter paraphyses may just be the result of fragmentation in the consulted specimens. Field studies may shed more light on this issue.

Dicksonia sellowiana is listed in Brazil as endangered ( IBAMA 1992; CNCFlora 2012) because of strong decline in many regions due to extraction for horticultural purposes. However, the species is locally still mono-dominant in the forest understory, e.g. in Santa Catarina state, near the town of Urubici (www.fernsoftheworld.com) and in the S~ ao Joaquim National Park (AT pers. obs.). The Uruguayan records are the southernmost of the genus in continental South America. The population in Tacuarembo (J. Arechavaleta 430) is still extant at a location regionally known as “La gruta de los helechos” and relatively near to the Brazilian population. A natural occurrence in Montevideo, which is the reported locality of some older specimens (C. Osten 6132; Fruchart s.n.), is dubious because neither has the species been recollected there recently nor do the local climate and vegetation appear suitable for Dicksonia ( Tejera and Beri 2005) .

Figures

FIG. 7. Important characters of Neotropical Dicksonia. A. Dicksonia lehnertiana. A1. Petiole. A2. Fertile pinnule, abaxially. (Lehnert 3019, BONN). B. Dicksonia stuebelii. B1. Petiole.B2. Fertile pinnule, abaxially (Sanchez 11111, UC). C.Dicksonia sellowiana. C1. Petiole, hairs only persisting near base (Hatschbach 43455, US). C2. Sterile pinnule, adaxially. C3. Immature fertile segments abaxially, with costae still covered in woolly undercoat. C4. Fertile segments abaxially, sori fully developed. D. Dicksonia antarctica. D1. Crozier, showing easily abraded woolly undercoat. D2. Fertile segments abaxially, with glabrescent costae and costules. (C2–C4, D: from living plant at Botanic Garden Bonn).

FIG.6. Distribution of Dicksonia in South America. A. Dicksonia karsteniana (squares), D.sellowiana (dots). Inset: varieties of D. karsteniana, var. arachenosa (triangles), var. spruceana (asterisks). B. Dicksonia lehnertiana (crossed circle), D. navarrensis (triangles), D. stuebelii (stars; occurrence in northern Colombia).