Sticherus chocoensis J.Gonzales, 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 : 20-21

Sticherus chocoensis J.Gonzales , sp. nov. ( Fig. 9 )

Sticherus statura delicata , pinnibus longe-lanceolatis, indumento paginae abaxialis segmentorum ferrugineo. Aphlebiae subtiles, tripartitae, squamae gemmarum basi induratae cellulis rotundatis, squamae costae stellatae margine ciliis induratis provisae.

Type: — COLOMBIA. Chocó : Istmia , Pepé, Río Peradó, 1500 m, 5 May 1990, Fernández, García & Velayos 8515 (holotype BM!) .

Rhizomes 2.5–3.0 mm thick, dark brown, deciduously scaly, the scales appressed, lanceolate, 3.0–4.5 × 1.5–2.0 mm, bicolorous, brown in the center with clear margins, the margins weak to markedly ciliate, translucent, with lattice-like cell texture, more rigid in the scale center, basally with rounded cells. Petioles ca. 70 cm long and 3 mm thick, dark brown, brittle. Rachises ca. 30 cm long between pinnae, weakly scaly, aphlebiae long and narrowly trifid. Fiddleheads ca. 6 mm in diameter, densely scaly, the scales appressed, dull orange to brown, matted. Buds small, ascending, the scales narrowly lanceolate to linear, 1.4–3.2 × 0.4–0.7 mm, ca. 12 cells wide at the base, bicolorous dull orange with darker bases, the margins with slightly curled cilia 1/8–1/3 times the scale length, translucent, with lattice-like cell texture, often rigid and dark at the bases, the cells rectangular to irregular with dark and thicker cells walls, lattice-like. Pinnae ca. 50–70 cm long, 2–3- forked, 1 st branch shorter than the 2 nd, 3–5 cm long and 2.0– 2.5 mm thick, with only proximal internal, overlapping segments adjacent to the aphlebiae, 2 nd branch ca. 8 cm long and 2 mm thick, when distal ca. 60 cm long, opposite branches of unequal length, partly or fully pectinate, 3 rd branch ca. 50 cm long and 1.5 mm thick, pectinate–pinnatisect, 5–10 cm wide with segments, long lanceolate with overlapping proximal and internal segments, with 3 segments per cm; adaxially scaly, the scales mixed, one type linear, basally hairlike, apically fringed, 0.8–1.8 × 0.05–0.1 mm, the second type square, 0.1–0.2 × 0.05–0.1 mm, the margins with numerous and straight with cilia 1–2 times the scale length, both scale types dark orange, with lattice-like cell texture and linear to irregular cells; abaxially densely scaly, matted, the scales mixed, one type deciduous, arachnoid, appressed, the second type patent, spreading, linear lanceolate, apically fringed and/or glandular or extended to a long hair, 0.8–1.6 × 0.2–0.5 mm, the margins with cilia 1/4–1/2 times the scale length, both scale types dark orange to cinnamon, translucent, with lattice-like cell texture and square to irregular cells. Segments 3–5 cm × 2 mm, linear, apically pointed, the margins narrowly revolute and ciliate with arachnoid scales; adaxially glabrous; abaxially sparsely scaly, the scales covering 20–35% of the leaf surfaces, arachnoid, 0.05–0.3 mm in diameter; veinlets thin, parallel, raised; midvein scales triangular to rhomboid, 0.2–0.4 × 0.1–0.2 mm, dark orange to cinnamon, the margins with thick and straight cilia 1/2–1 times the scale length (thus appearing stellate when seen directly above the veins), translucent, with lattice-like cell texture and well-defined irregular cells. Sori inframedial, restricted to the center of the segments, nested within arachnoid scales, 15–21 pairs per segment, 3–4 sporangia per sorus.

Distribution and ecology: —In wet forests from sea level to 1500 m in western Colombia and adjacent Panama (Darién) and Ecuador (Esmeraldas). Mostly growing in open habitats, e.g., along roads, often on nutrient-deficient soils.

Specimens examined (paratypes): — PANAMA. Darién: Cana, 530 m, 23 June 1959, Stern 495 pro parte ( US); Río Cocalito , 100 m, 21 February 1982, Whitefoord 275 ( BM) . COLOMBIA. Antioquia: Guatapé, Santa Rita, Finca Montepinar, 6°15’N 75°10’W, 1850 m, 22 May 1990, Contreras 342 ( NY) ; San Luis, Autopista Medellín – Bogotá, La Josefina, Quebrada La Salada , 800 m, 28 November 1983, Hoyos 485 ( MO) . Chocó: Río Atrato , Quibdó, 400 m, 23 January 1949, Araque Molina 19Ch154 ( US) ; Parque Nacional Natural Ensenada de Utría , Entrada Boroboro, 06°05’N 77°10’W, 0–100 m, 30 April 1990, Barbosa 6292 ( MO) ; NW side of Alto Buey, 1450–1750, 9 February 1971, Lellinger 273 ( US) . Nariño: Between Páramo and Barbacoas, 500 m, 7 May 1939, Alston 8463 ( BM, MO) . Norte de Santander : Ocaña, Teorama, 1220 m, 1846–1850, Schlim 224 ( BM, G, W) . Santander: Between Girón and Lebrija, 1300 m, 28 February 1939, Alston 7349 b ( MO) . Valle del Cauca: Río Blanco, Digua Valley , 900 m, 3 April 1939, Alsto 7853 ( BM, MO) ; Bajo Calima, Carretera Canalete, 100 m, 29 September 1987, Monsalve 1859 ( MO) . ECUADOR. Esmeraldas: Bilsa Biological Station, Mache Mts. , 35 km W. of Quinindé, 0°21’N 79°44’W, 400–600 m, 3 April 1995, Clark 592 ( MO) ; Lita, 9–10 miles above turnoff to Escopeta, 600–650 m, 8 September 1976, Croat 38941 ( MO) .

Notes: — Sticherus chocoensis is a relatively delicate species with long-lanceolate and slender ultimate branches bearing an orange-rusty indument and stellate, marginally ciliate midvein scales. Specimens of S. chocoensis were previously identified as S. bifidus in herbaria, but S. chocoensis is characterized by having aphlebiae, bearing proximal internal segments on the 1 st branches, by having overlapping segments on the distal branches, and by often having basally rigid, dull brown to bicolorous bud scales with lattice-like cell structure. In contrast, S. bifidus lacks aphlebiae and internal proximal segments, has non-overlapping segments, and has whitish, lax bud scales. In accordance with the harder scale texture, the marginal cilia in S. chocoensis are stouter and more widely spaced than those of S. bifidus , which are much more delicate. This is perhaps most readily visible on the midvein scales, which in S. chocoensis appear distinctly stellate whereas those of S. bifidus are diffuse and appear lanose. Accordingly, both species can most easily be distinguished by studying the abaxial midveins.

Sticherus chocoensis may also be confused with some specimens of S. ferrugineus , especially those from Mexico, by the similar dull orange indument. However, S. ferrugineus has generally more robust branches, longer, laxer scales with rectangular cells, and pinnatifid aphlebiae, whereas S. chocoensis has shorter scales with rounded cells and trifid aphlebiae.

Other similar species are S. maritimus and S. tepuiensis . The scales of S. chocoensis resemble those of S. maritimus in size and shape, but they lack the darkened cells that typically occur at the scale base in S. chocoensis . Sticherus tepuiensis is much smaller, with shorter and usually rigid scales.

The only specimen of S. chocoensis with rhizomes shows scales that are unique in the genus. They are rigid with dull centers and whitish, translucent margins that are highly abraded. All other species of Sticherus have concolorous or basally translucent rhizome scales with usually well-preserved margins.

Figures

FIGURE 9. Sticherus chocoensis. A. abaxial branch scales; B. bud scales; C1. midvein scales; C2. adaxial branch scales; D. arachnoid scales. Fernández 8515. Scale bars in A–C2 are all 0.5 mm long.