Terpsichore semilunaris Moguel & M. Kessler, 2009

Velázquez, Ana Laura Moguel & Kessler, Michael, 2009, Taxonomic notes on the fern species group around Terpsichore lanigera (Polypodiaceae), including the descriptions of three new species and one new variety, Phytotaxa 2, pp. 35-45 : 42-44

Terpsichore semilunaris Moguel & M. Kessler , sp. nov. ( Fig. 4 ).

Terpsichore longa affinis sed pinnae angustiores (0.5–0.9 cm vs. 0.8–1.2 cm), laeve falcatae, ascendentes; squamae rhizomatis 0.5–3.0 mm longae, aurantiacae pallidae vel dilute brunneus, opacae (vs. squamae 0.5–1.5 mm longae, castaneae, nitentes).

Type:— ECUADOR: Napo: About 3 km W of Oyacachi, 00°12’S, 78°06’W, 3550 m, 27 Mar 1996, Ståhl & Navarrete 2295 (holotype, AAU!; isotype, QCA) .

Plants epiphytic; rhizomes 1–4 cm long, short-creeping to suberect, radially symmetric, scaly, the scales linear-lanceolate, pale orangish, concolorous, dull, 0.5–3.0 × 0.3–0.5 mm, setulate and sometimes also puberulent, the setae moderate, hyaline to yellowish, mostly shorter than the width of the scale, on margins and sometimes surfaces of the scales, the hairs simple, tubular, 0.05–0.10 mm on the margins and branched, tubular, 0.1–0.2 mm on the apices of the scales; fronds 30–70 × 2.5–8 cm, caespitose, pendulous with indeterminate growth; stipes 0.4–0.6 mm × 0.5–2.0 cm, castaneous to dark brown, with simple, yellowish, 0.5–3.5 mm long setae, and with simple or branched, hyaline to yellowish, 0.1–0.3 mm long hairs; blades linear-lanceolate to lanceolate, pinnatisect, thin-chartaceous, gradually tapering at both ends, sometimes with 2–3 reduced segment pairs at the bases; rachises sclerenchymatous, dark brown, moderately covered with simple, yellowish, abaxially also branched and stellate, 3–5-branched, yellowish to golden-orangish (sometimes basally reddish), 0.5–4.0 mm long setae, and puberulent like the stipes; pinnae perpendicular to up to a 50º angle oblique to the rachises, alternate to moderately separated, 1.3–4.5 × 0.5–0.9 cm, linear-deltate, frequently slightly falcate, slightly asymmetric at the bases, ca. 2/3 of their width adnate to the rachises, slightly to strongly curved acroscopically and slightly curved to slightly decurrent basiscopically, apices conspicuously acute, margins setose, the setae yellowish to golden-orangish, simple, bifurcate and basally stellate, 3–5-branched, 0.5–4.0 mm long; sinuses 2–10 mm wide; veins free, 1-furcate, ending medially to inframedially, conspicuous, black; blade surfaces adaxially and abaxially moderately covered with simple, yellowish to golden, 0.5–2.0 mm long setae; hydathodes inconspicuous, lime dots lacking; sori round, arising at the vein apices, to 24 per pinna, regularly distributed along almost the entire pinnae; receptacles not or sparingly setose; sporangia sparely ciliate, cilia up to 0.6 mm long. Spores tertrahedral, ca. 26 µm in diameter, trilete.

Distribution and ecology:—Endemic to Ecuador (Chimborazo, Napo). Epiphytic in moist montane, elfin forests and paramo vegetation at 3500–3600 m.

Etymology:—The Latin name of this fern species means “half-moon-shaped” and refers to the falcate, narrow pinnae of these plants.

Specimens examined (paratypes):— ECUADOR: Chimborazo: Alao Valley, 40 km SE of Riobamba, Ramsay et al. 57 (K); road ca. 10 km NE of Alao, at Cuspipaccha, B. Øllgaard et al. 38162 ( AAU) , B. Øllgaard et al. 38194 ( AAU, UC) . Napo: Páramo, km 45 on road Salcedo-Napo, Laegaard 53347 ( AAU) .

Terpsichore semilunaris can be recognised by the following combination of characters: pinnae lineardeltate, slightly falcate, 1.3–4.5 × 0.5–0.9 cm, slightly to strongly curved (sometimes even auriculate) acroscopically, adnate to slightly curved basiscopically and with conspicuously acute apices, lack of lime dots on the hydathodes, stipes, blade surfaces, and rachises with simple, yellowish to golden, up to 4 mm long setae, abaxially on the rachis also stellate setae, and pinna margins with basally stellate setae, these setae conspicuously long (easy to observe on the fiddleheads). It is most similar to T. smithii Rojas (2008: 15) and T. longa ( Christensen, 1906: 541) Smith (1993: 487) with which it shares 20–110 cm long fronds with 1.0– 4.5 cm long, oblong-deltate or deltate to linear-deltate pinnae that are 3–5 times as long as wide, and have acute or obtuse apices and entire margins entire. Among these, T. smithii has contiguous to moderately separated (maximally 0–2 mm spaced) pinnae with basiscopically decurrent margins, while in the other two species the pinnae are spaced 2–10 mm with curved to entirely adnate basiscopical margins. Compared to T. semilunaris , T. longa has broader (0.8–1.2 cm), patent pinnae that are only up to 4 times as long as wide and are not falcate, as well as shorter (0.5–1.5 mm), castaneous, shiny rhizome scales

Figures

FIGURE. 4. Terpsichore semilunaris (Ståhl 2295); A, habit; B, rhizome scale; C, rachis seta; D, detail of pinna.