Parablechnum wohlgemuthii 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 : 113-114

Parablechnum wohlgemuthii M.Kessler & A.R.Sm. , sp. nov. ( Fig. 3 A–G )

Type:— BOLIVIA. La Paz: Prov. Franz Tamayo, Parque Nacional Madidi, entre Chuncani e Ichocarpa, por el camino Mojos-Queara, 3200 m, 13 May 2007, A. Fuentes 11864 (holotype UC!, isotypes LPB, MO).

Differs from Parablechnum bicolor and related species by having gland-tipped hairs on the laminar surfaces and more strongly dentate rachis and costal scales.

Plants terrestrial. Rhizomes stout, erect, ca. 1.5 cm in diameter including petiole bases. Rhizome scales 6–10 × 1–2.2 mm, lanceolate, dark red-brown with narrow, sharply defined pale margins, cells elongate, margins entire. Sterile leaves to 32 × 6.5 cm, erect. Petioles to 15 cm long and 1.5 mm thick, proximally dark reddish brown, distally stramineous, glabrous except for 1–2 basal cm that bear a few reduced scales similar to those of the rhizomes. Sterile laminae broadly lanceolate, 1-pinnate with an abruptly reduced base and gradually reduced apex with a conform apical pinna. Pinnae ca. 12–15 pairs, to 37 × 8 mm, oriented at roughly 90° to the rachises (proximally) or slightly ascending (distally), the longest pinnae located in the middle of the blades, the lowermost pinnae ca. 90% as long as the longest ones. Pinnae petiolulate (0.5–2 mm), slightly falcate, apices acuminate, margins narrowly hyaline, finely serrulate. Aerophores at pinna bases small, tuberculate. Rachises stramineous, with scattered scales, the scales 0.5–1.5 × 0.2–0.8 mm, broadly lanceolate, the margins strongly dentate, pale to medium brown, the larger scales with darker bases. Laminar tissue chartaceous, drying to a similar pale olive-green on both sides, adaxially glabrous, abaxially with scattered scales on the costae and veins, and scattered hairs on the laminar surfaces, the scales 0.2–1.5 × 0.1–0.8 mm, broadly lanceolate, the margins strongly dentate, pale brown, the larger scales with darker bases, the hairs 0.05–0.15 mm long, mostly 2- or 3-celled, with whitish glandular apical cells. Veins simple or 1-forked, not immersed, ending in small hydathodes adaxially. Fertile fronds similar to the sterile ones, but longer, to 38 cm long, the pinnae narrower and longer, to 50 × 5 mm, the scales on rachises and pinnae larger, darker and more dense than on the sterile pinnae, extending more onto the laminar surfaces, hairs fewer and darker. Sori lacking in the proximal 1–4 mm and the distal 12–20 mm of pinnae, with green laminar tissue extending beyond the indusia. Indusia brown, entire to erose at maturity.

Distribution and habitat:— This species is known only from the type collection made at 3200 m in humid montane forest.

Notes:— Parablechnum wohlgemuthii belongs to a group of species including P. bicolor , P. bolivianum , P. cochabambense , and P. pazense , four species recently described from the Bolivian Andes ( Kessler et al. 2007). From these, P. wohlgemuthii differs primarily by the gland-tipped hairs on the laminar surfaces. No such hairs have been found on the aforementioned similar species of Parablechnum nor on any other closely related species examined by us. In addition, the rachis and costal scales are more strongly dentate than on relatives.

Etymology:— We name this species after Dr. Thomas Wohlgemuth, in recognition of his outstanding ecological and floristic research on plants.

Figures

FIGURE 3. Parablechnum wohlgemuthii (from the holotype). A. Habit. B. Detail of sterile pinna, abaxial view. C. Fertile pinna, abaxial view. D. Detail of fertile pinna, abaxial view. E. Rhizome scale. F. Costal scale. G. Glandular hair from abaxial lamina surface.