Amauropelta lanceolata A.R.Sm., 2017

Smith, Alan R. & Kessler, Michael, 2017, Prodromus of a fern flora for Bolivia. XXX. Thelypteridaceae, Phytotaxa 331 (1), pp. 1-34 : 12-13

Amauropelta lanceolata A.R.Sm. , sp. nov. ( Fig. 3 )

Notable for the relatively small, lanceolate fronds; gradually reduced proximal pinnae (the lowest ca. 1 mm long); small but persistent indusia; rachis, costae, veins, and laminar tissue abaxially lacking hairs; and glabrous costae, veins, and laminar tissue between veins adaxially.

Type:— BOLIVIA. Tarija: Prov. Eustaquio Méndez, ciudad de Tarija, posas de Coimata, subiendo a lo largo del Río Coimata , 21º29’S, 64º18’W, 2140 m, I. Jimenez 2481 (holotype UC!; isotype LPB) .

Plants terrestrial; stems short-creeping to ascending, caudices ca. 1.5–2.0 cm diam.; rhizome scales 4–5 × 0.3–0.5 mm, ascending, shiny brown, bearing hairs to 0.2 mm long on surfaces and margins; petioles dark brown at bases, stramineous distally, to ca. 2–4 cm long, 1–1.5 mm diam., proximally glabrescent or bearing acicular hairs ca. 0.2– 0.3 mm long; leaves to ca. 30 cm long; blades chartaceous, pinnate-pinnatifid, proximal ca. 7 pinna pairs gradually reduced, the shortest ca. 1 mm long, blade apex confluent, pinnatifid, gradually tapering; rachises stramineous to tan, glabrous or glabrescent abaxially; pinnae sessile, subopposite or opposite proximally, alternate distally, widest at the base, to ca. 4 × 1 cm, deeply pinnatifid to ca. 1 mm from costae, segments to 2 mm wide; aerophores lacking or obscure at pinna bases, reduced to small, lunate swellings; laminar buds lacking; veins to 7 pairs per segment, lowermost pair from adjacent segments meeting margins at or just above sinuses; costal scales lacking; costae, veins, and margins glabrous abaxially, but with tiny stipitate glands 0.05 mm long on costae, costules, veins, and laminar surfaces between veins, sessile resinous glands lacking; indument adaxially restricted to costal and rachial grooves, hairs sparse, ca. 0.2 mm long, costules, veins, and laminar tissue between veins lacking hairs; sori medial, round, discrete; indusia present, tan, round-reniform, to ca. 0.5 mm diam., lacking hairs or occasionally with a single marginal hairs ca. 0.2 mm long, stipitate-glandular on margins.

Range:— Endemic to Bolivia ( TA).

Ecology: —Rare (known only from the type); terrestrial in dry forests; 2140 m.

Notes: —Nearest affinities are uncertain, but possibly with A. exuta , known from Bolivia to Ecuador but represented by relatively few collections. That species has only 1 or 2 reduced pinna pairs and strictly opposite pinnate, but is similarly glabrous or glabrescent. Another relative may be A. jujuyensis (de la Sota) Salino & T.E.Almeida , from northwestern Argentina (Jujuy, Salta), also rather poorly known. Collectors often overlook small species of Amauropelta .

Figures

FIGURE 3. Amauropelta lanceolata. A. Habit. B. Medial pinna. C. Pinna segments, adaxial surface detail. D. Pinna segments, abaxial surface detail. E. Sorus. (All from the holotype: I. Jimenez 2481)