Sticherus ovatus 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 : 39-41

Sticherus ovatus J.Gonzales , sp. nov. ( Fig. 14 )

Affinis Stichero bifido, differt statura minori, pinnis brevioribus latioribusque, squamis brevioribus, distincte rotundatis, ciliis brevioribus vel fere nullis (praecipue in squamis costarum).

Type:— COLOMBIA. Santander: Páramo de Fontibon, Pamplona , 2400 m, 25 February 1939, Alston 7279 (holotype BM!, isotypes COL, MO!) .

Rhizomes 2.5–3.5 mm in diameter, brittle, the scales somewhat deciduous, ovate, ca. 2 × 1 mm, orange, the margins entire, cell texture translucent with rounded cells. Petioles 2.5–3.5 mm thick and ca. 30 cm long, dark brown, brittle. Rachises ca. 10–20 cm long between pinnae, weakly scaly, the scales ovate, bicolorous whitish to orange; aphlebiae absent. Fiddleheads 2–3 mm in diameter, sparsely scaly, the scales matte brown. Buds small, rounded and closed, the scales ovate to rounded, apically erose or glandular, 1.5–3.2 × 0.8–1.5 mm, orange to slightly bicolorous with dark orange bases, the margins with delicate, straight to contorted cilia 1/5–1/4 times the scale length, translucent, with lattice-like cell texture and usually rigid, translucent bases, the cells rounded with thickened cell walls at the scale bases. Pinnae ca. 15–30 cm long, 2–3-forked, when 3- forked the 1 st branch usually longer than the second, 1 st branch 3–6 cm long and 1.5–2 mm thick, not pectinate, opposite 2 nd branches usually of unequal length, the shorter one 2.5–5.0 cm long and 1–2 mm thick, scatteredly pectinate, the longer 2 nd and the 3 rd branches lanceolate to long-triangular, 20–30(–40)cm long and 1.0– 1.5 mm thick, pectinate but lacking proximal internal segments on the first 0.5–2.5 cm, 2.5–4.0 cm wide with segments, with 2–3 segments per cm; scales adaxially mixed, one type rectangular, ca. 0.5 × 0.2 mm, the margins with cilia 1/2–1 times the scale length, the second type filamentous, both scale types translucent, whitish; abaxially and laterally moderately scaly, the scales ovate to rounded, 0.6–2.0 × (0.2–) 0.4–0.8 mm, orange, the margins translucent with delicate cilia, cell texture translucent with rounded to irregular cells. Segments 1.5–3.0 cm × 2.0– 3.5 mm, long-ovate, subchartaceous, the margins slightly revolute, proximal internal segments usually not overlapping; veinlets parallel, dark, abaxially raised; adaxially glabrous; abaxial midvein scales ovate to rounded, apically usually glandular, 0.3–1.5 × 0.3–0.6 mm, orange to whitish, the margins with few, delicate cilia 1/2–1 times the scale length, translucent, with lattice-like cell texture and rounded to irregular cells; abaxial scales on the surfaces between the veinlets arachnoid. Sori inframedial, restricted to the segment centers, nested within arachnoid scales, 9–15 pairs per segment, 3–4 sporangia per sorus.

Distribution and ecology:— Mountains of Colombia and Venezuela. It is locally common in open habitats in humid montane forests at ca. 1500–2700 m.

Specimens examined (paratypes):— COLOMBIA. Cundinamarca: Usme , 2800 m, 8 March 1959, Bischler 1922 ( G) ; Bogotá, Río Arzobispo , 23 October 1852, Holton 23 ( GH) . Santander: Borcova , 2500 m, 5 November 1969, Murillo 1150 ( NY) . VENEZUELA. Amazonas: Cerro Marahuaca , 3°30’N 65°26’W, 2500 m, 16 February 1981, Steyermark 124397 ( MO) . Aragua: Tovar , 20 October 1959, Moritz 92 pp ( GH) . Miranda: Between Antímano and Aguas Negras , 900–1500 m, 6–7 May 1913, Pittier 6015 pp ( US).

Notes: — Sticherus ovatus is characterized by lacking aphlebiae and internal proximal segments, by having lanceolate ultimate branches with shortened bases and (often) almost conform apices, and by bearing ovate, lax, translucent scales (hence the species name) with rounded cells. The midvein scales are especially translucent, which gives a papyraceous appearance to the indument when observed with an unaided eye. The buds and midvein scales bear glandular apices. Sometimes the bud scales are bicolorous with dark bases, but this is only based on the darker color of the cell walls and not (as is usually the case in Sticherus ) on a thickening of the walls.

Because of its dense abaxial segment indument and lack of proximal internal segments, Sticherus ovatus is most similar to S. bifidus , and collections have usually been identified as that species. However, there are some clear, consistent differences between these taxa. Sticherus ovatus is smaller, has shorter, more rounded scales with shorter cilia (especially on the midvein scales), and has shorter, relatively broader pinnae. Sticherus ovatus is probably most closely related to S. nudus , but that species lacks scales abaxially on the segments, has lanceolate, rigid to subclathrate rhizome scales, and has sori restricted to the central part of segments.

Figures

FIGURE 14. Sticherus ovatus A. abaxial branch scales; B. midvein scales; C. adaxial branch scales; D. arachnoid scales. Alston 7279. Scale bars in A–D are all 0.5 mm long.