Sticherus jacha 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 : 29-30

Sticherus jacha J.Gonzales , sp. nov. ( Fig. 11 )

Affinis Sticherus blepharolepidi , sed differt segmentis bladeum angustioribus, linearibus, margine leviter revolutis in paginis abaxiali sparse squamatis. Rhachis primaria usque ad duplus longitudinis rachidis secondariae, remote pectinatis, in paginis abaxiali dense squamatis et squamis bicoloribus (non albidis).

Type: — BOLIVIA. La Paz: Nor Yungas, 5 km Chuspipata hacia Coroico, 16°23’S, 67°48’W, 2750 m, 18 September 1997, Kessler 11971 (holotype UC!, isotypes GOET!, LPB!) .

Rhizomes unknown. Petioles 3–5 mm thick, over 30 cm long, castaneous, weakly scaly. Rachises ca. 20– 40 cm long between pinnae, densely scaly, the scales usually bicolorous, brown with whitish margins; aphlebiae trifoliate with narrow, long segments. Fiddleheads 1.0– 1.5 cm in diameter, densely scaly, bicolorous whitish to pale orange with dark brown cell rows. Buds large, ascending, closed, the scales lanceolate with rounded bases, 1.4–3.2 × 0.5–1.2 mm, the margins with numerous thin, straight to slightly curled cilia 1/4–1/8 times the scale length, cell texture mixed, basally rigid and sometimes with scattered darkened apical cells to matte with translucent margins, cells rectangular, bicolorous with whitish margins and dark centers of varying extent; the youngest bud scales are usually more translucent. Pinnae 35–60 cm long, 3–4-forked, 1 st branch longer than the 2 nd, 10–25 cm long and 2–3 mm thick, when pectinate with only internal, long, remotely pinnatisect segments, 2 nd branch 8–12 cm long and 1.5–3.0 mm thick, usually fully pectinate with remote segments, 3 rd or distal branch 10–30 cm long and 1 mm thick, pinnatisect, both branches 5–6 cm wide with segments, 4 th and last branch lanceolate, apically gradually decreasing to a conform apex, 15–25 cm long, deeply pinnatifid, with 1.5–2.5 segments per cm, proximal segments gradually reduced and overlapping internally; adaxially with mixed scales, one type linear, 1.0–2.5 × 0.05–0.10 mm, the margins with short cilia, the second type rectangular, 0.2–0.6 × 0.1–0.2 mm, the margins with cilia 1/2–1 times the scale length, both scale types pale orange to whitish, cell texture translucent with rigid parts formed by some darkened cell walls, the cells rectangular to irregular; abaxially and laterally densely scaly, the scales lanceolate, (1–)2–4 × (0.2–)0.6–1.0 mm, usually pale orange on last and bicolorous on 1 st branches, the margins with delicate cilia, cell texture translucent with rectangular cells, sometimes with darkened cells at the bases and/or the apices. Segments linear, 1.8–3.2 cm × 0.4– 0.2 mm, the margins chartaceous, revolute; adaxially glabrous; abaxially densely scaly on midveins and veinlets; midvein scales mixed, one type linear to hair-like, 1.0–3.2 × ca. 0.5 mm, the second type rectangular, 0.2–0.6 × 0.1–0.2 mm, both scale types whitish to orange or speckled, the margins with usually curled cilia 1/2–1 times the scale length, cell texture translucent with linear to irregular cells; veinlets angular, raised, scatteredly scaly, the scales coarsely stellate, ca. 0.2–0.3 mm in diameter, marginally ciliate. Sori medial, not reaching segment apex, nested within arachnoid scales, 13–24 pairs per segment, 4–5 sporangia per sorus.

Distribution and ecology: —Endemic to humid montane forests at 1900–2750 m elevation in Bolivia (La Paz, Cochabamba). It is locally common along roadsides and on landslides.

Specimens examined (paratypes): — BOLIVIA. Cochabamba: Carrasco, km 117 old road Cochabamba- Villa Tunari, 17°08’S 65°38’W, 2350 m, 7 July 1996, Kessler 7073 (GOET, LPB, UC); Chapare, Incachaca, 2300 m, 24 January 1929, Steinbach 8928 (BM, GH, MO, NY, UC, US). La Paz: Nor Yungas, Estacion Biológica de Tunquini, Bajo Hornuni, 16°12’S 67°52’W, 2150 m, 18 August 2000, Bach 1200 (GOET, LPB, UC); Murillo, Zongo Valley, 16°07’S 68°05’W, 2100 m, 5–6 August 1990, Fay & Fay 2875 (AAU, LPB, MO, NY, UC, US).

Notes: — Sticherus jacha is characterized by having densely scaly rachises and branches with bicolorous scales, long 1 st branches that may be up to twice of the same length as the 2 nd branches, and ultimate pectinate branches narrower than the penultimate branches. The proximal bud scales are bicolorous with dark, rigid bases and whitish, translucent margins and apices. Sticherus jacha is most similar to S. blepharolepis but differs in having segmenta that are narrower, more linear, marginally slightly revolute, and abaxially sparsely scaly, proximal branches that are remote to pectinate (vs. deeply pinnatifid), and denser, bicolorous (vs. whitish) scales on the abaxial branches. Both species have narrow, raised veinlets, but in S. jacha these are placed at a narrower angle to the midveins. The scales on the midveins and veinlets in S. jacha are wavy and reminiscent of the scales of S. peruvianus .

Superficially, S. jacha also resembles S. melanoblastus , but S. jacha is more robust, and has conspicuous aphlebiae and larger scales. The scale darkening in S. jacha proceeds from the base, as in S. tomentosus , whereas in S. melanoblastus it starts at the scale center and proceeds towards the apex and margin, usually leaving the base translucent. Sticherus jacha and S. blepharolepis always have translucent scale margins with delicate cilia, whereas in S. melanoblastus the scale margins have thick, short setulae.

The name “jacha” is the word for “large” in the high-Andean Aymara language that is spoken in the range of this species.

Figures

FIGURE 11. Sticherus jacha A. bud scales; B. midvein scales; C. abaxial segment surface scales; D. adaxial segment surface scales. Kessler 11971. Scale bars in A–D are all 0.25 mm long.