Sticherus rufus J.Gonzales & A.R.Sm., 2011

Gonzales, Jasivia & Kessler, Michael, 2011, A synopsis of the Neotropical species of Sticherus (Gleicheniaceae), with descriptions of nine new species, Phytotaxa 31, pp. 1-54 : 44-45

Sticherus rufus J.Gonzales & A.R.Sm. , sp. nov. ( Fig. 15 )

Folia tripartita ad sexies partita, rachidibus circiter aequilongis, perfecte pectinatis, laminis (pinnis) linearibus, segmentis oblongis, parvis, aphlebiis simplicibus. Indumentum densum e squamis apice fimbriatis margine longe ciliatis, cellulis elongatis indistinctis; squamae rhizomatis splendide aureo-brunneae, lineari-lanceolatae, cellulis valde indistinctis.

Type:— VENEZUELA. Portuguesa: Ospino, 11–12 km WNW of La Estación, road to Palma Sola , ca. 9°27’N, 69°35’W, ca. 1300 m, 10 November 1982, Smith 1139 (holotype UC, isotypes MO, PORT, UNELLEZ, Z) .

Rhizomes 3.0– 3.5 mm thick, dark brown, the scales persistent, spreading, linear-lanceolate, basally slightly auriculate, apically long-acuminate with 2 setulae, 1.2–2.8 × 0.3–0.5 mm, golden-orange to bicolorous with dark brown scale centers, the margins with irregularly arranged setulae, cell texture rigid with linear cells. Petioles ca. 20–40 cm long and (1.5–)2.5–3.5(–4.5) mm thick, light-castaneous. Rachises (7.5–)12.0–35.0 cm between pinnae, weakly scaly, aphlebiae simple, longer than the adjacent internal segments, usually overlapping. Fiddleheads 4–9 mm in diameter, densely scaly, the scales brilliant orange. Buds small to medium-sized, ascending, opening rapidly, the scales lanceolate, basally rounded, apically acuminate, fringed, (0.6–)1.5–2.0(–3.0) × 0.2–0.6 mm, basally approximately 18 cells wide, golden and brilliant orange, the margins with irregularly arranged, slightly curled cilia (1/7–)1/4–1/2 times the scale length, translucent, with lattice-like cell texture and rectangular to narrowly elongate cells. Pinnae 25–40(–60) cm long, 3–5-forked, 1 st branch shorter than the 2 nd, 3–11 cm long, opposite pairs of equal length, with only internal segments, 2 nd and 3 rd branches equal in size, (4–)10–20(–35) cm long and 0.6–1.5 mm wide, pectinate-pinnatisect, (1.5–)2.0– 3.0(–4.0) cm wide with segments, with ca. 3 segments per cm when 4–5-forked, 4 th and 5 th branches linear, shorter than the previous, fully pectinate, proximal internal segments gradually reduced; adaxially with scattered, mixed scales, one type linear, 0.8–1.5(–2.7) × 0.05–0.10 mm, the margins apically with cilia 1/4 times the scale length, the second type reduced, 0.06–0.20 × 0.03–0.10 mm, the margins with cilia 1–2 times the scale length, both scale types brilliant orange, translucent, with lattice-like cell texture and long rectangular cells; abaxially with mixed scales, one type on the branch surfaces, deciduous, narrowly triangular to linear, 0.4–0.6 × 0.06–0.20 mm, the second type lateral, basally shortened, apically usually long-fringed to 0.1 mm, 1.5–2.0 mm × 0.1–0.3 mm, both scale types brilliant orange, sometimes darker at the apices, the margins with irregularly arranged, spreading cilia 1/5–1/2 times the scale length, translucent, with lattice-like cell texture and rectangular or linear cells. Segments oblong, (1.5–)3.0–10.0(–19.0) × 1.5–2.5 mm, the margins slightly revolute, chartaceous, the margins abaxially ciliate; veinlets parallel, slightly raised; adaxially glabrous; abaxially densely scaly on midveins and veinlets; midvein scales linear to narrowly triangular, apically usually glandular, (0.1–)0.3–0.6(–1.3) × (0.03–) 0.06–0.10 mm, brilliant orange, the margins with spreading cilia (1/2–)1–2 times the scale length, lax, translucent, with lattice-like cell texture and rectangular to irregular cells; abaxial surfaces densely scaly, the scales mixed, one type arachnoid, the second type linear, 0.2–0.4 × 0.05–0.10 mm, pale orange, translucent, with lattice-like cell texture, the margins with cilia 1/2–2 times the scale length. Sori medial, superficially nested within a few arachnoid scales, 8–10(–15) pairs per segment, 3–4 sporangia per sorus.

Distribution and ecology:— Northwestern Venezuela and adjacent Colombia, in wet montane forests, often forming colonies at forest borders and on steep, sunny slopes, 500–2700 m.

Notes:— Sticherus rufus is a distinctive species with highly divided pinnae (3–6-forked), linear, fully pectinate branches of roughly similar length, oblong segments, and short, simple aphlebiae. The indument consists of linear-lanceolate, translucent, brilliant orange, apically fringed scales with long marginal cilia and ill-defined, elongate cells. The rhizome scales are linear-lanceolate, brilliantly golden-brown, and with barely discerneable cells.

The scale color is reminiscent of S. chocoensis , S. tepuiensis , and S. maritimus , but they all differ in numerous details from S.rufus . Sticherus chocoensis usually has basally rigid scales with a lattice-like cell structure, much longer segments, and trifid aphlebiae. Sticherus tepuiensis is shorter, lacks aphlebiae, and has rigid, dark scales. The dark scales are especially conspicuous on the buds, which can look almost black. Sticherus maritimus is much shorter with the branches only 1- or 2-forked; furthermore, it has oblong segments and lacks aphlebiae.

Figures

FIGURE 15. Sticherus rufus A. abaxial branch scales; B. bud scales; C. midvein scales; D. scales of adaxial segment surface. Smith 1139. Scale bars in A–D are all 0.25 mm long.