Terpsichore monosora 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 : 40-42

Terpsichore monosora Moguel & M. Kessler , sp. nov. ( Fig. 3 )

Terpsichore variabilis affinis sed in squamis rhizomatibus castaneis (vs. nigrescentibus) et rhachidibus abaxialiter cum setis pallidis, simplicibus et bifurcatis (vs. setis atropurpureis, stellatis) praestans.

Type:— ECUADOR: Pichincha: Andes of Quito , 1200 ft, Jun 1877, Jameson s. n., Herbarium Hookerianum 1867 (holotype, K!) .

Plants epiphytic or epipetric; rhizomes 0.5–2.0 cm long, short-creeping to suberect, radially symmetric, scaly, the scales lanceolate, castaneous, concolorous, dull, 0.5–1.5 × 0.3–0.6 mm, setulate and sometimes also puberulent, the setae present on the margins and sometimes on the surfaces of the scales, moderate, hyaline to yellowish, mostly shorter than the scale breadth, 0.1–0.4 mm long, the hairs 0.05–0.10 mm, simple, and globose to capitate on the margins and 0.10–0.15 mm, branched, and tubular to globose on the apices of the scales; fronds 10–35 × 2–10 cm, caespitose, pendulous, not forked, with indeterminate growth; stipes 1–5 cm long (often appearing longer because of deciduous proximal pinnae), 0.3–0.4 mm thick, castaneous to dark brown, with simple, hyaline to yellowish, 0.5–2.0 mm long setae, and with simple or branched, hyaline to yellowish, 0.1–0.4 mm long hairs; blades lanceolate, frequently irregularly formed, 1-pinnate-pinnatisect, thin-chartaceous, gradually tapering at both ends; rachises and costae sclerenchymatous, castaneous to dark brown, moderately covered with simple, abaxially rarely also bifurcate, hyaline to yellowish, 0.5–2.0 mm long setae, and also puberulent like the stipes; pinnae 1–5 × 0.3–1.0 cm, linear, perpendicular to the rachises or ascending at an angle up to 50°, bearing several to many 0.2–0.5 × 0.2–0.5 mm, circular to oblong, contiguous to moderately separated ultimate segments, the margins of the segments setose, the setae simple, bifurcate and basally stellate, 3-branched, hyaline to yellowish, 0.5–2.0 mm long; veins free, simple in each ultimate segment, inconspicuous; blade surface adaxially and abaxially moderately covered with simple, hyaline to yellowish, 0.5–2.0 mm long setae, and also puberulent like the rachises; hydathodes inconspicuous, lime dots lacking; sori round, arising at the vein apices, usually one, rarely two per ultimate segment; receptacles not or sparely setose; sporangia only sparsely ciliate, cilia up to 0.5 mm long. Spores globose, ca. 26 µm in diameter, trilete.

Distribution and Ecology:—Endemic to Ecuador (Carchi, Imbabura, Napo, Tungurahua). Epiphytic or saxicolous on trees, shrubs and rocks in shady places in humid montane forests, Polylepis forests and paramo vegetation from 3600 m to 3800 m.

Etymology:—The name of this fern species refers to the fact that almost all fertile terminal segments of these plants each only bear a single sorus.

Species examined (paratypes):— ECUADOR. Carchi: Páramo del Angel, Barclay & Juaijibioy 9407 ( MO) . Imbabura: Hacienda Yura Cruz, 10 km N of Ibarra, Holm-Nielsen et al. 6495 ( AAU, UC) . Napo: Oyacachi, Yarupaccha , Navarrete 1432 ( AAU) ; Road Quito-Baeza , 7-8 km NW of Laguna de Papallacta B. Øllgaard & Balslev 8152 ( AAU) . Tungurahua: Mount Atacazo Mille s.n. ( US). Locality unknown, Jameson s.n. (B) .

The syntypes of Polypodium variabile Mett. ex Kuhn are recognised by us as including two closely related, but distinct species. The specimens more closely corresponding to the type description of Terpsichore variabilis (Mett. ex Kuhn) C.V. Morton are here designated as lectotypes: Purdie s. n. (lectotype, K!, here designated; isolectotype, B!). The other specimens are here described as Terpsichore monosora . This new species differs from T. variabilis , which is more widespread, ranging from Colombia to Peru in similar habitats as T. monosora , by the following characters: pale, simple, and bifurcate setae on the rachises (vs. atropurpureous, stellate setae) and castaneous (vs. blackish) rhizome scales. The only other species of Terpsichore with one-pinnate-pinnatisect blades, T. immixta (Stolze in Tryon & Stolze, 1993: 115) Smith (1993: 487), differs from both of the above species by having the blade surfaces and costae abaxially obscured by yellowish to orangish, simple, bifurcate, and basally stellate, 3–5-branched setae, by bearing conspicuous lime dots, and by its pale orangish to castaneous rhizome scales.

Figures

FIGURE 3. Terpsichore monosora (Holm-Nielsen 6495); A, habit; B, abaxial and adaxial surfaces of pinna; C, rachis hairs; D, rhizome scale.