Polystichum lionelii O.G.Martínez & M.A.Hern., 2023

Martínez, Olga G., Hernández, Marcela A. & Serapio, Fabiola, 2023, Polystichum lionelii (Dryopteridaceae), a new Andean species from northwestern Argentina, Phytotaxa 619 (2), pp. 189-196 : 190-195

Polystichum lionelii O.G.Martínez & M.A.Hern. , sp. nov. ( Figs. 1–3 , 4 A–J )

Diagnosis: Polystichum lionelii sp. nov. is closely related to P. pycnolepis , sharing pinnules with distinct spinules and weakly to strongly revolute margins, but it is distinguished by its rhizome scales ovate to ovate-lanceolate, basal petiolar scales, concolorous, orange-castaneous, and lamina with filiform scales and multicellular hairs on the abaxial side.

Type:— ARGENTINA. Salta: Dpto. Santa Victoria, Nazareno, Paraje Mono Abra 3700 m, 28 Mar 2020, F . Serapio 120 (holotype MCNS 13664 !, isotype LIL!) .

Rhizomes erect, ca. 3–5 cm diam. with petiole bases; rhizome scales 5–15 × 3–5 mm, concolorous, orange-brown, flat to slightly concave, ovate to ovate-lanceolate, the apex abruptly reduced to a twisted linear tip, the margins denticulate with two different hairs (2-cellular glandular and simple multicellular hairs to 1–2 mm with an apical gland at the apex), the scale surface with 1–2-celled glandular hairs. Leaves fastigiate, ascending, 15–20(–30) × 8–14 cm; petioles 3–6 cm long, 1/4 to 1/5 the leaf length, grooved adaxially, stramineous, weakly to moderately scaly; basal petiolar scales 8–15(25) × 1–3(4) mm, concolorous, ovate to lanceolate with twisted apex, often slightly concave, medial petiolar scales, 2–6 × 1–3 mm translucent, orange-castaneous, ovate-lanceolate to lanceolate, the long and twisted apex with a simple glandular cell at the end, the margin and surface scale, small petiolar scales between the large scale bases, 0.5-1 × 0.5 mm, orange-brown, finely denticulate; the scale size decreasing from petiolar bases towards rachises; laminae bipinnate-pinnatifid with gradually reduced apex, lanceolate, 20–30 × 5–9 cm, chartaceous to coriaceous, without a bulbil; free pinnae lanceolate, attenuate, 17–22 pairs, pinnate-pinnatifid, ascending, longest pinnae the 3rd to 11th pair, proximal pinnae to 2–3 × 0.8–1 cm, longest pinnae to 4–7 × 1–2 cm; pinnules 3–10 pairs per pinna, reduced to a pinnatifid apex, flat with slightly recurved margins, attached at slightly oblique angles, 4–8 × 3–6 mm, bases cuneate, with a weak acroscopic lobe, apex acuminate, margins strongly denticulate-spinulose, spinules predominantly on acroscopic side and apex; laminar tissue with scattered, filiform scales and pluricelular hairs, 0.2–1 mm, these denser abaxially than adaxially; rachises and costae grooved adaxially, moderately scaly with three scale types: the first type spreading, 2–5 × 1–2(3) mm, translucent, orange-brown, ovate-lanceolate with elongate apices, margins denticulate, the second type extending onto rachises and costae, 0.2–5 × 0.05–0.2 mm, filiform to long-lanceolate, twisted, the third type smaller, 0.2–0.5(–1) mm, translucent, shiny, orange-brown, circular to ovate with margins denticulate, extending along the rachises and costa bases between the other scales; veins free; sori 1–6 per pinnule; indusia lacking; 64 spores per sporangium, spores 33–40 × 20–28 µm, perispore plegate.

Observations: —The scales of P. lionelii are very variable in shape and size from rhizome to rachis, ranging from ovate, lanceolate, linear-lanceolate, filiform to circular-ovate microscales between the larger scales. Glandular hairs on the margins and on the surface of rhizome and petiole scales are also common in P. montevidensis ; in other species glands are found only either on the margin ( P. andinum and P. pycnolepis ) or on the surface ( P. chilense , P. mohrioides and P. tetragonum ) of the scale ( Morero et al. 2022). This new species is characterized by filiform scales and pluricellular hairs on the lamina versus glandular hairs in P. pycnolepis ( Fig. 4K–L ). The spore size does not exceed 40 µm, and the number of spores per sporangium is 64, so this is probably a sexual diploid species; Barrington et al. (2020) noted that diploid Polystichum species from western North America do not exceed 40 µm in spore diam., while tetraploid species measure about 50 µm.

Etymology: —The specific epithet honors Lionel Andrés Messi, the captain of Argentina’s national soccer team, not just because of his extraordinary professional performance but also because of his significant contributions to society, particularly in promoting equal opportunities for children and adolescents in areas such as health, education, and sports as a tool for social inclusion.

Specimens Examined (paratypes): — ARGENTINA. Salta: Dpto. Santa Victoria, Nazareno , 3200 m, 06 April 2019, Serapio s.n. ( MCNS 13610 ) ; 3300 m, Luna s.n. ( MCNS 13618 ) ; Arroyo Peña negra, RP 7, 15 km al W de Santa Victoria , 3100 m, 14 April 1987, Novara 6713 ( MCNS) .

Additional Specimens Examined: — Polystichum pycnolepis (Kunze ex Klotzsch) T. Moore. ARGENTINA.

Catamarca: Dpto. Capayán, El Crestón, 3000 m, 25 March 1909, Castillón 706 ( LIL 41251 ) ; Dpto. Belén, Los Nacimientos , May 1910, Castillón 1496 ( LIL 41248 ) . Jujuy: Dpto. Valle Grande, Santa Ana , 3400 m, 29 November 2008, Hernández & Mata 829 ( LIL 610073 , 610100 ) .

Distribution & Habitat: —This species grows in the highland grasslands of northwestern Argentina ( Fig. 3 ), above 3000 m. Polystichum lionelii is found among the rocks, on dry rock ledges, and in crevices in mountains; the populations are small, comprising only few individuals. Most of them are under pressure from grazing.

Conservation status: —We regard the conservation status of this species as Data Deficient (DD) following IUCN guidelines and criteria ( IUCN 2022), until additional collections are made. This species is found only outside protected areas in Argentina.

Key to Polystichum species from northwestern Argentina

1. One to two buds in axil(s) of distal pinnae................................................................................................................. P. platyphyllum

1’. Buds lacking ......................................................................................................................................................................................2.

2. Pinnule with a marked acroscopic lobe, thin-textured, without reflexed margins .................................................... P. montevidense

2’. Pinnule with a weak acroscopic lobe, thin-textured to coriaceous, weakly to strongly revolute margins........................................3.

3. Leaves to 80 cm long; rhizome scales lanceolate to narrowly lanceolate; basal petiolar scales bicolorous with the center atropurpureous; pinnules 5–7 × 2-4 mm, coriaceous, with spiny margins; laminar tissue with glandular hairs without filiform scales............................................................................................................................................................................... P. pycnolepis

3’. Leaves to 30 cm long; rhizome scales ovate to ovate-lanceolate; basal petiolar scales concolorous, orange-castaneous; pinnules 4–10 x 3–6 mm, thin-textured to coriaceous with strongly spinulose margins; laminar tissue with filiform scales and pericellular hairs ...................................................................................................................................................................................... P. lionelii

Figures

FIGURE 1. Polystichum lionelii. A. Habit. B. Petiole. C. Rachis. D. Pinnule (adaxial side). E. Pinnule (abaxial side). Drawn from F. Serapio 120 (holotype MCNS) by Lelia Bordón.

FIGURE 2. Polystichum lionelii. A. Section of lamina with pinnae. B. Scales on raquis.C. Microscales (arrowhead) on rachis. D. Filiform scales on rachis (arrowhead). Serapio 120 (holotype MCNS)

FIGURE 3. Polystichum lionelii. A. Distribution in Argentina. B. Plants and their habitat. Photo: Fabiola Serapio.

FIGURE 4. Polystichum lionelii. A. Rhizome scale. B. Petiole scale with denticulate margins. C. Linear-lanceolate scale of raquis with glandular-cell at the apex (detail). D. Filiform scales, twisted. E. Scale margin with 1–2-cellular glandular (arrowhead) and pluricellular hair. F. Detail of glandular hair on scale margin. G. Detail of surface scale with glandular hairs (arrowhead). H. Laminar tissue with filiform scales. I. Filiform scales. J. Spores. Polystichum pycnolepis. K. Laminar tissue with glandular hairs (adaxial side). L. laminar tissue with glandular hairs (abaxial side). A–J: Serapio 120 (holotype MCNS), K-L: Castillón 1496 (LIL 41248)