Sticherus nervatus 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 : 36-38

Sticherus nervatus J.Gonzales , sp. nov. ( Fig. 13 )

Affinis Sticherus revoluto , differt venulis in paginis abaxialibus evidenter prominentibus, fere parallelis, squamis reductis, frondibus 4– ad 6–furcatis, rhachidibus fere perfecte pectinatis, rhachide primaria longa, rhachides sequentes valde excedente. Aphlebiae et squamophori deficientes. Pagina abaxialis rhachidorum dense squamata, squamis obtegentibus minimum dimidium segmentis vicinis.

Type: — BOLIVIA. La Paz: Nor Yungas, 8 km from Chuspipata to Coroico, Kessler 12113 (holotype UC!, isotypes GOET!, LPB!) .

Rhizomes 1.5–2 mm thick, dark brown, lustruous, deciduously scaly, the scales lanceolate, 1.5–2 × 0.2– 0.4 mm, dark brown, the margins with slender setulae, cell texture rigid with hexagonal to linear cells. Petioles ca. 25 cm long and 1–3 mm thick, dark brown to reddish, brittle. Rachises ca. 20–35 cm long between pinnae, weakly scaly, the scales orange; aphlebiae absent. Fiddleheads ca. 2–5 mm in diameter, densely scaly, the scales matte brown. Buds small, appressed, the scales lanceolate, basally rounded, apically glandular or with a short hair, 1–3.2 × 0.2–0.6(–1.0) mm, matte, orange, the margins with short, often abraded cilia, translucent, with rectangular cells. Pinnae 15–35 cm long, branches (2–)4–6– forked, pectinate from the 2 nd branch onwards, 1 st branch longer than the following, 5–15 cm long and 1–3 mm thick, usually with only proximal internal segments, 2 nd and 3 rd branches (2–) 6–10 cm long and 1.0– 2.5 mm thick, 4 th branch the longest, 4–15(–20) cm long and 0.8–1 mm thick, 5 th and 6 th branches narrowly linear and uniform, ca. 5–10 cm long and (5–) 9–13 mm wide with segments, the last two branches usually of similar length; scales adaxially usually deciduous, proximally rectangular, ca. 0.4 × 0.2 mm, the margins with very few cilia of the same length as the scales, distally long-linear, sometimes apically long-ciliate, (1.2–)2.5–4.0 × (0.05–) 0.10– 0.50 mm, ca. 2–3 cells row wide, the margins with few cilia ca. 1/12 times the scale length, all scales whitish to orange, cell texture translucent with rectangular cells; scales abaxially and laterally dense, ovate-lanceolate to narrowly lanceolate, apically usually glandular or bearing a short, pectinate hair, (0.8–)1.4–3.0(–4.0) × (0.2–)0.4–0.8(–1.0) mm, concolorous, beige-brown, the margins with cilia 1/15 times the scale length, translucent, with lattice-like cell texture. Segments (2–) 5–7 cm × (1.0–) 1.5–2.5 mm, oval, the margins strongly revolute, coriaceous; adaxially glabrous; veinlets nearly parallel, abaxially strongly raised; abaxially densely scaly on the midveins and with scattered scales on the veinlets; midvein scales narrowly lanceolate, apically usually glandular, (0.8–)1.0–2.0 × (0.1–) 0.2–0.4 mm, the margins with scattered cilia 1/5–1/3 times the scale length; veinlet scales mixed, one type simple to pectinate, hairlike, the second type (0.4–)0.6–1.0 × 0.05–0.10 mm, the margins with scattered cilia of the same length as the scales, translucent. Sori medial, usually placed distally on the segment, 4–6 pairs per segment, 3–4 sporangia per sorus.

Distribution and ecology:— Guayana Shield and southeastern Venezuela, and Andes in northwestern Venezuela, Colombia, Ecuador, Peru, and Bolivia. It grows in open habitats in humid montane forests at 1200–2800 m.

Specimens examined (paratypes):— COLOMBIA. Caquetá: Río Hacha, Gabinete, 2100–2250 m, 23 March 1940, Cuatrecasas 8530 a ( US). Cauca: Road Totoro–Inza , 2745 m, 13 August 1974, Plowman 4135 ( GH, U) . Cundinamarca: Cordillera de Heliconia , 12 km SE of Gachalá, 2375 m, 21 September 1944, Grant 10200 ( US) . VENEZUELA. Amazonas: Cerro de la Neblina , 00°51’N 65°58’W, 1735 m, 2 February 1985, Beitel 85126 ( NY) ; Atures, Sierra Maigualida , 5°30’N 65°15’W, 2000 m, 28 Feb–3 March 1991, Berry 4901 ( MO) ; Atabapo, Cerro Marahuaca , 03°37’N 65°21’W, 2700 m, 12 October 1988, Liesner 24712 ( MO, UC) . Bolívar: Chimantá , 5°19’N 62°07’W, 2150 m, 6–9 February 1984, Huber 8910 ( NY) ; Mt. Roraima , 2040– 2255 m, 30 September 1944, Steyermark 58984 ( NY) . Mérida: 19–21 km S of Tovar on road to Canaguá , 8°15’N 71°44’W, 2150 m, 16 April 1984, Luteyn 10008 ( NY) . GUYANA. Cuyuni-Mazaruni: Pakaraima Mts., Mt. Ayanganna , 5°23’N 59°59’W, 1800–2000 m, 3 November 1992, Henkel 106 (US) . Mazaruni- Potaro: Mt. Roraima , 5°16’N 60°13’W, 2800 m, 13 April 1988, Liesner 23234 ( MO) . ECUADOR. Morona- Santiago: Cordillera del Cóndor , 15 km E of Gualaquiza, 3°27’S 78°22’W, 2090 m, 25 July 1993, Gentry 80445 ( MO) ; Cordillera de Cutucú, Logroño to Yaupi , 2°46’S 78°06’W, 2000 m, November 1976, Madison 3536 ( GH) . Zamora-Chinchipe: Road Loja – Zamora , 3°58’S 79°07’W, 2500 m, 25 April 1987, van der Werff 8961 ( MO, NY) . PERU. Cuzco: La Convención, Palmayo , 3050 m, May 1938, Bües 2032 (US) . Huánuco: Cerros del Sira , 9°25’S 74°43’W, 2000 m, 30 July 1969, Dudley 13472 ( GH) . Pasco : 20 km W of Oxapampa, 10°35’S 75°33’W, 2100–2150 m, 27 December 1983, Smith 5400 ( MO, NY) ; Oxapampa, Río El Tunqui , 10°15’S 75°31’W, 1720 m, 2 January 1984, Smith 5546 ( MO) . San Martín: Road Ríoja–Pedro Ruiz , 05°40’S 77°46’W, 1850 m, 25 March 1998, van der Werff 15679 ( MO, NY) . BOLIVIA. Cochabamba: Carrasco, Km 133, old road Cochabamba – Villa Tunari , 17°07’S 65°36’W, 2000 m, 14 July 1996, Kessler 7277 ( LPB, UC) ; Chapare, Cordillera de Mosetenes , 16°14’S 66°25’W, 1550 m, 9 September 2003, Kessler 13164 ( GOET, LPB) . La Paz: Sud Yungas, La Paz–Chulumani road, 15.1 km W of Chulumani, 16°15’S 67°30’W, 2450 m, 2 August 1989, Fay & Fay 2572 ( LPB, MO, UC) ; Bautista Saavedra, Pauji-Yuyo , 15°02’S 68°29’W, 1200 m, 12 June 1997, Kessler 10073 ( GOET, LPB, UC) . Santa Cruz: Ichilo, Amboró National Park, Cerro Bravo , 17°49’S 64°32’W, 2300–3000 m, 23 June 1995, Abbott 17212 ( USZ) .

Notes: — Sticherus nervatus differs from the very similar S. revolutus by the abaxially strongly raised, nearly parallel veinlets with reduced scales, the usually 4–6-forked blades, the almost fully pectinate branches lacking aphlebiae, the lack of squamophores, and by the densely scaly abaxial branches, with scales covering at least 50% of the ultimate segments. In contrast to S. nervatus , S. revolutus has weakly marked, divergent, glabrous veinlets, usually 2–4-forked blades, aphlebiate branches bearing segments only on the last two branches, conspicuous squamophores, and less densely scaly abaxial branches, with the scales covering less than 50% of the adjacent segments. Sticherus nervatus is further recognized by long 1 st branches, which generally greatly exceed more distal branches in length, and by the uniform length of all branches from the 2 nd onwards. Specimens from Colombia and Venezuela have relatively short abaxial branch scales that do not cover the entire segments, whereas in Peru and Bolivia the scales are much longer and usually cover the segments entirely. The name of the species refers to the conspicuously raised veinlets.

Figures

FIGURE 13. Sticherus nervatus A. abaxial branch scales; B. bud scales; C. adaxial branch scales. Kessler 12113. Scale bars in A–C are all 0.5 mm long.