Blechnum tomentosum M.Kessler & A.R.Sm., 2018

Smith, Alan R. & Kessler, Michael, 2018, Prodromus of a fern flora for Bolivia. XXXIII. Blechnaceae, Phytotaxa 334 (2), pp. 99-117 : 105-106

Blechnum tomentosum M.Kessler & A.R.Sm. , sp. nov. ( Fig. 1 A–D ).

Type.— BOLIVIA. La Paz: Prov. Franz Tamayo, senda Keara-Mojos, entre Tokuaqe y Karjata, pasando Fuertecillos, antes de cruzar el Río Tawakuni, 14°35’S, 68°57’W, 1600 m, 26 June 2005, I. Jimenez 3028 (holotype UC!, isotype LPB).

Differs from Blechnum polypodioides Raddi by being densely hairy on both laminar surfaces (versus laminae glabrous to hairy abaxially), lacking rachis scales (versus bearing scattered scales), having uniformly dark brown rhizome scales (versus scales bicolorous) and bicolorous petiole scales (versus scales uniformly pale brown), and relatively longer petioles (ca. 1/2 of the leaf length versus 1/3–1/10).

Plants terrestrial. Rhizomes ascending, stoloniferous. Rhizome scales lustrous red-brown, 2–3.5 × 0.5–1 mm, lanceolate, margins entire. Leaves 32–40 cm long, erect, clumped, monomorphic. Petioles 14–18 cm × 1–1.5 mm, ca. 1/2 of the leaf length, stramineous, sparsely scaly, the scales 1–3 × 0.5–1 mm, broadly lanceolate, spreading to appressed, pale brown with dark bases and/or dark apical spots. Laminae thin-chartaceaous, 16–20 × 3.5–4.5 cm, narrowly elliptic, pinnatisect, proximal pinnae partly or completely adnate, deflexed, distant, irregularly deltate, blade apices pinnatifid. Rachises stramineous, densely hairy, the hairs 0.2–0.8 mm long, sticky, catenate, uniseriate, with 2–8 cells, translucent, pale brown. Aerophores lacking. Pinnae ca. 28 pairs, to 22 × 4 mm, linear oblong, straight to slightly falcate, adnate, apices acute, margins entire, densely hairy on both sides, the hairs similar to those on the rachises but 0.1–0.6 mm, and especially adaxially darker. Costae stramineous, not grooved adaxially, densely hairy with hairs as those on the laminar tissue. Veins 1- to 4-forked, ending in small hydathodes adaxially. Indusia red-brown, to 0.5 mm wide, entire.

Distribution and habitat:— The sole collection was made along the side of a track through open secondary forest in a region of humid montane forest.

Notes:— Blechnum tomentosum resembles Blechnum polypodioides in the narrowly elliptic blades that gradually taper at both ends, pinnatifid blade apices, and greatly reduced, adnate proximal pinnae. It differs, however, in being densely hairy on both lamina surfaces (vs. laminae glabrous to hairy abaxially), lacking rachis scales (vs. bearing scattered scales), having uniformly dark brown rhizome scales (vs. scales bicolorous) and bicolorous petiole scales (vs. scales uniformly pale brown), and relatively longer petioles (ca. 1/2 of the leaf length vs. 1/3–1/10).

Etymology:— The name refers to the hairy leaves, distinctive in this species.

Figures

FIGURE 1. Blechnum tomentosum (from the holotype). A. Habit. B. Pinna, abaxial view. C. Petiole scale. D. Rhizome scale.