Polystichum wilsonii Christ

Roux, Jacobus P., 2001, A review of the fern genus Polystichum (Pteropsida: Dryopteridaceae) in Madagascar and the Mascarene region, Adansonia (3) 23 (2), pp. 265-287 : 285-286

8. Polystichum wilsonii Christ

Bot. Gaz. 51: 353 (1911); Roux, Bull. Nat. Hist.

Mus. Lond. (Bot.) 30: 53 (2000). — Type: Wilson

2614, China, Szechuan Province, Mupin, woodlands,

4000-6000 ft. (holo-, BM!).

Polystichum lobatum var. ruwenzoriense Pirotta in di Savoia, Il Ruwensori I: 478 (1909) . — Polystichum fuscopaleaceum var. ruwenzoriense (Pirotta) Pic. Serm., Webbia 32: 90 (1977). — Type: Roccati & Cavalli-Molinelli s.n., Ruwensori: Nella foresta scendendo da Kichuchu a Nakitava, (holo-, TO).

Polystichum aculeatum var. mildbraedii Brause, Bot. Jahrb. Syst. 53: 379 (1915). — Type: Mildbraed 7180, Fernando Poo (Bioko), Nordseite des Pics Sta. Isabel oberhalb Basilé , Grasflur-Region des Gipfels mit viel Ericinella , zwischen Gras, c. 2700 m ü. M. (holo-, B!) .

Polystichum aculeatum var. rubescens Bonap. , Notes Ptérid. 14: 214 (1923). — Type: Alluaud 48, Tanzania, Kilimanjaro. Zone supér. des forêts, 2760 m (holo-, P!).

Polystichum aculeatum var. stenophyllon Bonap. , Notes Ptérid. 14: 215 (1923). — Type: Alluaud 241, Kenya, Mt. Kenya, versant ouest, forêt inféreure, 2400 m (holo-, P!).

Polystichum fuscopaleaceum Alston, Bol. Soc. Brot. , sér. 2, 30: 22 (1956). — Polystichum setiferum var. fuscopaleaceum (Alston) Schelpe, Bol. Soc. Brot. , sér. 2, 41: 216 (1967). — Type: Keay FHI 28602, Cameroon, Victoria District , Cameroon Mountain, SW of hut 2, in gully woodland, 9100 ft. (holo-, BM!) .

Polystichum alticola Schelpe & N.C. Anthony, Contr. Bolus Herb. 10: 144 (1982). — Type: E. Esterhuysen 26699, South Africa, Ladismith , Swartberg, Toverkop, 2160 m (holo-, BOL!; iso-, NBG!, PRE!) .

Plants terrestrial or epilithic. Rhizome short, erect to suberect, to 130 mm long, to 10 mm in diameter, rarely branched, beset with roots, crowded, persistent stipe bases and paleae, the paleae castaneous, chartaceous, broadly attached, narrowly linear, the margins with small, widely spaced cellular outgrowths, the apex mostly terminating in an acicular cell, rarely terminating in a small thin-walled cell, to 12 × 1 mm. Fronds caespitose, 8-12 per plant, suberect to arching, to 1.05 m long; stipe proximally castaneous, stramineous higher up, adaxially sulcate, to 450 mm long, to 5 mm in diameter, sparsely to densely paleated, the larger paleae concolorous or bicolorous, chartaceous to crustaceous, broadly attached, often slightly bullate, spreading, extending to the rachis, broadly ovate-acuminate to ovate-acuminate, cordate to cordate-imbricate, the margins widely to closely fimbriate, the fimbriae generally straight, the apex entire, terminating in an acicular cell, to 23 × 9 mm, the smaller paleae apically or basally directed, stramineous, chartaceous, short-stalked, narrowly triangular to subulate, often somewhat auricled, the margins proximally with long straight, angular or curved outgrowths, distally with few widely spaced, short or long marginal outgrowths, the apex entire, terminating in an acicular cell, to 13 × 7 mm; lamina 2-pinnate, with up to 29-stalked pinna pairs, herbaceous to firmly herbaceous, pale to dark green adaxially, paler abaxially, narrowly elliptic, to 625 mm long, the proximal pinnae reduced, deflexed; rachis stramineous, adaxially sulcate, densely beset with paleae similar to, but smaller than those on the stipe, the paleae restricted to the abaxial surface, to 9 × 3 mm; pinnae 1-pinnate, with up to 12-stalked pinnule pairs, opposite to alternate, proximally widely spaced, distally closely spaced and somewhat overlapping, folded ventrally along the rachis (conduplicate) narrowly triangular to oblong-attenuate, the proximal pinnae to 88 mm long, to 20 mm wide; pinna-rachis stramineous, adaxially sulcate, densely paleated, the paleae short-stalked, narrowly ovate to narrowly triangular, the margins proximally with long straight or angular outgrowths, apically with few widely spaced short or long outgrowths, the apex entire, terminating in an acicular cell; pinnules asymmetric, acroscopically auriculate, narrowly trullate to trullate, to 12 mm long, serrate, long-aristate, adaxially with straight or slightly twisted filiform paleae, simple or proximally with short straight or curved marginal outgrowths, the apex terminating in an acicular cell, abaxially with straight or proximally somewhat twisted, subulate-hastate paleae, the margins with short straight or angular outgrowths at the base, the apex entire, terminating in an acicular cell. Venation evident. Sori circular, c. 1 mm in diameter, terminal or near terminal on abbreviated vein branches; sporangium stalk eglandular, with 11(-15-)24-indurated annulus cells; indusium stramineous, peltate, circular or reniform, repand to erose, often with small central processes, persistent, maximum radius 0.51(-0.75-) 1.09 mm. Spores 64 per sporangium, brown, the perispore smooth or tuberculate, spiculate, closely perforated, exospore 32(-41.74-)52 × 24(-30.16-)40 µm. Chromosome number 2n = 164. — Fig. 6 K-M.

MATERIAL EXAMINED. — GRANDE COMORE: Humblot 265 ( B, P); Boivin s.n., près du grand cratère ( P); Humblot s.n., ole, 1000-1400 m ( P); Van Denken 22, 43, Insula Angantiae monte ignivoms, 6000-9000 ft. ( B); Kersten 43, Angasilia, vulkan, 6000-9000 ft. ( B). — LA RÉUNION: Cadet 1975, Piton des Neiges, 3000 m ( P).

VARIATION. — Morphological variation in Polystichum wilsonii is mostly restricted to the larg- er paleae present on the stipe and abaxially on the rachis. Variation is most apparent in the size, density, and colour of the paleae. The larger paleae are broad in plants growing in more exposed habitats and are also more closely spaced. No correlation could be drawn between habitat and paleae colour. The large paleae are generally stramineous and concolorous, but in some plants the larger stipe paleae are bicolorous with the proximal central part being densely impregnated and castaneous. In some plants these bicolorous paleae are restrict- ed to the proximal part of the stipe whereas in others they may extend to the basal pinnae.

DISTRIBUTION AND ECOLOGY. — Polystichum wilsonii has a wide distribution ranging from Africa to the Uttar Pradesh Mountains in northern India to Bhutan, China (Szechuan) and Taiwan (Ilan, Taichung, Hsinchu). In the study area, P. wilsonii is known only from Grande Comore and La Réunion.

Figures

Fig. 6. — Stipe and lamina paleae in Polystichum species.— Polystichum maevaranense: A, rachis palea; B, proliferous bud palea; C, apex of B showing the cellular structure. Humbert 15019 (P). — Polystichum pauciaculeatum: D, stipe palea. Leandri et al. s.n. (P); E, margin of D showing the cellular structure; F, lamina palea, abaxial surface. Humbert 11121 (P). — Polystichum tsaratananense: G, stipe palea; H, apex of G showing the cellular structure. Humbert & Capuron 25035 (P); I, lamina palea (abaxial surface); J, apex of I showing the cellular structure. Humbert 18144 (P). — Polystichum wilsonii: K, stipe palea; L-M, lamina palea, abaxial surface. K-L, Alluaud 241 (P); M, Esterhuysen 26699 (BOL).