Sticherus holttumii

Lima, Lucas Vieira & Salino, Alexandre, 2018, The fern family Gleicheniaceae (Polypodiopsida) in Brazil, Phytotaxa 358 (3), pp. 199-234 : 218

3.4. Sticherus holttumii Lima & Salino (2018: 182). Figs. 4M–R , 5D , 6B .

Type:— BRAZIL. Pará: Monte Alegre, trilha para cachoeira de prata no Iguarapé do Ambrósio, Mata da Alegria, 01º26’11.5”S, 54º32’40”W, 302 m, 09 December 2015, Almeida , T.E. et al. 4174 (holotype BHCB!, isotypes CESJ!, HSTM!).

Plants terrestrial. Rhizomes 2.15–3 mm thick, with scales brown, rigid, linar-lanceolate, with apex attenuate to filiform, base truncate, margins dentate. Fronds scrambling, 2–3-forked, petiole 1.98–2.04 mm thick, ultimate branches 20–22.5 × 2.5–4.5 cm, eliptic, apex caudate, base slightly reduced, abaxial surface moderately scaly on the rachis, with light-brown, triangular, scales, with occasional apical darkening, apex attenuate, base truncate, margins setose, adaxial surface sparsely covered by hyaline filiform scales, segments linear 1.35–2.6 × 0.15–0.25 cm, margins slightly revolute, abaxial surface pubescent, with hyaline, linear scales, margins setose on the segments midrib and hyaline filiform scales on secondary veins, laminar tissue glabrous. Buds with brown, narrow-triangular scales, apex acuminate, base truncate, margins setose, pseudoestipule present only at the first branch. Veins 1-forked. Sori medial, with hyaline paraphyses.

Distribution: —Endemic of Brazil (Minas Gerais, Mato Grosso and Pará). This species occurs in gallery forest, between 300 m and 500 m.

Notes: — Sticherus holttumii is morphologically related to Sticherus gracilis and differs from it by having sparse scales distributed on the abaxial segment surfaces, scales of the buds and rachises with setose margins and occasional apical darkening. Sticherus holttumii has a disjunct distribution, with populations in Minas Gerais, Mato Grosso, and Pará state. This distribution pattern is also known for others species of leptosporangiate ferns, like Blechnum heringeri Brade (1966: 87) . The type of that species is from Paracatu, Minas Gerais state, as is the paratype of S. holttumii . Dittrich et al. (2015) pointed out the record of Blechnum heringeri from Pará state, as a disjunct population.

Selected specimens examined: — BRAZIL. Mato Grosso: Campos Novos do Pareci , 13º34’S 57º21’W, 06 October 1996, Windisch 8421 (ICN) ; Chapada dos Guimarães, Parque nacional da Chapada dos Guimarães, cachoeira do Pulo 15º24’59”S 55º50’31W, 591 m, 2 March 2011, Almeida et al. 2674 (BHCB). Minas Gerais: Grão Mogol, entre a BR251 e a cidade de Grão Mogol, Cachoeira Véus das Noivas, Serra de Grão Mogol , 16º35’43.6”S 42º57’17.3W, 875 m 15 March 2007, Salino et al. 11798 (BHCB) ; Paracatu, Reserva do Acangaú , 17º08’59”S 47º04’43.3W, 665 m, 03 March 2006, Salino et al. 10716 (BHCB) .

Figures

FIGURE 4. A–E. Sticherus bifidus (Krieger s.n., CESJ 10201). A. Detail of the abaxial segment surface. B. Rhizome scale. C. Bud scale. D. Rachis scale. E.Arachnoid scale of the abaxial side of the laminae. F–I. S. brevitomentosus (Forzza et al. 7225, BHCB). F. Detail of the abaxial segment surface. G. Rhizome scale. H. Bud scale. I. Rachis scale. J–L. S. gracilis (Salino 3611, BHCB). J. Detail of the abaxial segment surface. K. Rhizome scale. L. Bud scale. M–R. S. holttumii (Almeida et al. 4174, BHCB). M. Detail of the abaxial segment surface. N. Detail of the abaxial segment surface. O. Bud scale. P–Q. Rhizome scales. R. Rachis scale.

FIGURE 5. Habit. A. Sticherus bifidus. B. S. brevitomentosus. C. S. gracilis. D. S. holttumii.

FIGURE 6. Distribution of five taxa of Sticherus in Brazil. A. Sticherus bifidus. B. S. brevitomentosus and S. holttumii. C. S. gracilis. D. S. lanuginosus.