Dryopteris Adans. sect. Marginatae Fraser-Jenk.

Roux, Jacobus P., 2011, The fern genera Dryopteris and Nothoperanema (Dryopteridaceae) in Madagascar and neighbouring Indian Ocean islands, including Saint Paul, Adansonia (3) 33 (1), pp. 7-67 : 25-28

Dryopteris Adans. sect. Marginatae Fraser-Jenk.

Bulletin of the British Museum (Natural History), Botany 14 (3): 194 (1986). — Type: Dryopteris marginata (Wall. ex C.B.Clarke) H.Christ ; Aspidium marginatum Wall. ex C.B.Clarke.

A group of about 26 species throughout southern and eastern Asia and Africa, with one species reaching Yemen (Fraser-Jenkins 1986: 194).

KEY TO THE DRYOPTERIS SPECIES IN SECTION MARGINATAE (EXCLUDING PUTATIVE HYBRID)

1. Lamina generally with one or more proliferous buds adaxially on the rachis near the lamina apex; sori exindusiate ........................................................................... 5. D. manniana

— Lamina never with proliferous buds along the lamina axes; sori indusiate ................... 2

2. Lamina axes with or without hairs and scales, generally with some glands .................. 3

— Lamina axes with hairs and scales, but never with glands ............................................ 4

3. Segments adaxially and abaxially closely set with capitate glands along and between the vein branches .......................................................................................... 2. D. bernieri

— Segments without conspicuous glands between the vein branches .............. 3. D. bojeri

4. Lamina with 2-celled hairs mostly along the axes and abaxially on the veins .................. ................................................................................................................ 6. D. pentheri

— Lamina without 2-celled hairs occurring along the lamina axes and veins ................... 5

5. Larger stipe base scales with oblong glands along the margins and on the scale laminae .......................................................................................................... 1. D. aquilinoides

— Larger stipe base scales occasionally with glands along the margins, but never on the scale laminae ...................................................................................................................... 6

6. Plants with fronds up to 1.9 m long; lamina to 3-pinnate ................... 4. D. comorensis

— Plants with fronds up to 1.2 m long; lamina to 2-pinnate-pinnatifid ..... 7. D. subcrenulata

1. Dryopteris aquilinoides (Desv.) C.Chr. ( Fig. 6 )

Index filicum : 252 (2 Oct. 1905). — Nephrodium aquilinoides Desv., Mémoires de la Société linnéenne de Paris 6 (2): 261, 262 (Jul. 1827). — Aspidium aquilinoides (Desv.) Mett. ex Kuhn, Filices africanae: 126 (Oct. 1868). — Type: feuilles de 3 à 4 pieds dans les forêts, Île Bourbon, J.M.C. Richard 363 (holo-, P00349567!).

Nephrodium aquilinoides Desv. var. angustatum Desv., Mémoires de la Société linnéenne de Paris 6 (2): 262 (Jul. 1827.). — Type: Habitat in insula Borboniae, sine coll. s.n. (holo-, P00349566!).

Aspidium grande Fée, Mémoires sur la famille des fougères 5: 292, 295 (1852). — Type: Habitat in insulâ Borboniâ, De Montbrison s.n. (?holo-, P00349529!).

OTHER MATERIAL EXAMINED. — Mauritius. Île Maurice, régions élévées, 1906, Bijoux, F. 20 (P00349531). — Île Maurice, 2.XII.1909, Royal Gardens Pamplemousses s.n. (P00349570).

Réunion. Brûlé de St Denis, route forestière de la Roche écrite, env. 4 km après le village Le Brûlé, 31.X.1973, Badré 738 (P00349538, P00349552). — Île de la Réunion, forêt hygrophile, Bonnet Carré, Cilaos, 1400 m, 15.XI.1973, Badré 913 (P00349550, P00349551). — Fourré à Philippia , sentier de la mare à Joseph au coteau Kerveguen, cirque de Cilaos, 16.XI.1973, Badré 938 (P00349555); Badré 946 (P00349553, P00349554); Badré 950 (P00349561, P00349562, P00349563); Badré 956 (P00349564, P00349565). — Sentier vers la Roche écrite, forêt avant La plaine des Chicots, 25.XI.1973, Badré 1019 (P00349539, P00349540, P00349541). — Plateau de Bébour, forêt d’altitude alt. 1300 m, 28.XI.1973, Badré 1038 (P00349560). — Forêt d’altitude alt. 1300 m, 28.XI.1973, Badré 1039 (P00349559). — Cirque de Salazie, sentier vers la Nouvelle, forêt hygrophile d’altitude, alt. 1300-1400 m, 29.XI.1973, Badré 1056 (P00349568, P00349569). — Bourbon, Barkly 23 (K, 2 sheets). — Réunion, Baudouin 903 (P00349583). — St Denis, Boivin 98 (P00349580). — Dans les bois élevés à Bourbon, Boivin 668 (P00349581). — Île Bourbon, Boivin 885 (B200052452, B200052454, B200052456, P00349530). — Sous-bois de formation arbustive-col de Bébour, 1400 m, 11.XI.1966, Cadet 540 (P00349548, P00349549). — Île de la Réunion, Cadet 638 (P0034954, P0034955, P0034956, P0034957). — Humicole-végetation éricoïde à Philippia Plateau de Bébour, 1300 m, 16.XII.1970, Cadet 2968 (P00349536, P00349537). — Sous-bois de la forêt à Nastus -plaine des Chicots, 1700 m, 13.III.1971, Cadet 3149 (P00349534). — Sous-bois forêt hygrophile-col de Bébour, 1400 m, 15.I.1973, Cadet 4026 (P00349535).— Petite plaine des Palmistes, Cadet 4346 (P00349533, P00349556, P00349557, P00349558). — Île Bourbon, De Montbrison s.n. (P00349529). — Bébour, 16.XII.1970, Friedmann 850 (P00349542, P00349543). — Île Bourbon, voyage de M. Gaudichaud sur La Bonite, 1836-37, Gaudichaud s.n. (P00349585). — Bourbon, Johnstone s.n. (BM000800980). — Bourbon, Salazie, Lépervanche- Mézière s.n. (P00349578). — Île Bourbon, Richard 318 (P00349582).— Bourbon, Richard s.n. (B200052453). — Île Bourbon, sine coll. s.n. (P00349573). — Île Bourbon, sine coll. s.n. (P00349574). — Salazie, Bourbon, sine coll. 40 (P00349572).

Sine Loco. 2.X.1882, Bellouve 145 (P00349579, P00349586); Desvaux s.n. (P00349576); Du Petit-Thouars s.n. (P00349532); Richard 307 & 308 (P00349584); Richard 307 (BM000800983); Richard 318 (P00349577).

DESCRIPTION

Plants terrestrial. Rhizome short-decumbent, up to 250 mm long and 25 mm in diameter, set with roots, closely spaced persistent stipe bases and scales, the scales ferrugineous, thinly chartaceous, broadly attached, lanceolate, up to 35 × 10 mm, with clavate to oblong glands along the margin and scale laminae, often also with pluricellular, uniseriate hairs along the margins and on scale laminae. Fronds up to 1.4 m long, arching, anadromous, catadromous towards apex; stipe up to 800 mm long and 10 mm in diameter, mostly nitid to atrocastaneous, glossy, sulcate adaxially, proximally densely scaled, sparsely scaled to glabrous higher up; lamina up to 3-pinnate, broadly ovate to deltoid, up to 780 × 420 mm, with up to 15 petiolated pinna pairs; rachis castaneous, or stramineous with castaneous markings, glossy, sulcate adaxially, initially sparsely scaled, glabrous later, the scales castaneous, chartaceous, sessile, lanceolatecaudate, up to 5 × 2 mm, broadly cuneate, often with pluricellular, uniseriate hairs along the margin, generally also with oblong glands along margin and scale laminae; pinnae near opposite to alternate, proximally widely spaced and slightly overlapping, more closely spaced distally, proximal 2 or 3 pinna pairs inaequilaterally ovate, up to 425 × 245 mm, pinnae higher up symmetric, narrowly ovate to oblong-acuminate, up to 2-pinnate, with up to 13 petiolated pinnule pairs, the petiole up to 20 mm long; pinna-rachis stramineous to ferrugineous, adaxially sulcate, matt or glossy, glabrous or sparsely scaled, the scales similar to, but slightly smaller than those on the rachis; pinnules near opposite to alternate, proximally widely spaced, acroscopic pinnae on basal pinnae oblong-acuminate, narrowly ovate, or narrowly triangular, up to 110 × 32 mm, basiscopic pinnae on basal pinnae oblong-acuminate, narrowly ovate, or narrowly triangular, up to 145 × 50 mm, 1-pinnate, petiolate, the petiole up to 5 mm long; pinnule-rachis adaxially sulcate, often flexuose and narrowly winged towards the apex, sparsely scaled, the scales ferrugineous, chartaceous, sessile, ovate-caudate to subulate, up to 4 × 1.5 mm, often somewhat bullate, often with pluricellular, uniseriate outgrowths along the margin, also with oblong glands along the margins and laminae, the apex terminates in a long uniseriate series of oblong cells; segments firmly herbaceous to subcoriaceous, near opposite to alternate, widely spaced, narrowly ovate, oblongacute, or oblong-obtuse, up to 30 × 13 mm, proximally petiolate, adnate and basiscopically decurrent towards the apex, petiole up to 1.5 mm long, lobed, the lobes oblong-obtuse, denticulate, glabrous adaxially, abaxially with rigid hairs and scales similar to, but smaller than those along the costules and veins. Stomata (34-)45(-58) µm long. Venation evident, forked twice in proximal lobes, vein branches end in teeth near the margin. Sori medial to inframedial on predominantly anadromous vein branches, essentially 2-seriate on segments, up to 1.4 mm in diameter, discrete when mature; indusium firmly herbaceous, castaneous, entire to repand, strongly recurved, eglandular or rarely with a few glands on the laminae. Sporangium stalk simple, capsule with (11-)14(-19) indurated annulus cells, epistomium (3-)4(-6)-celled, hypostomium (3-)4(-6)-celled. Spores 64 per sporangium, brown, with narrow reticulate ridges, (26-)36(-44) × (20-)23(-30) µm.

DIAGNOSTIC FEATURES AND RELATIONSHIPS Dryopteris aquilinoides is characterized by the large rhizome and stipe bases scales, the near glabrous dark brown stipe and glossy frond axes, and the small ovate-caudate scales occurring abaxially along the lamina axes and veins, which bear numerous oblong glands along the margins and laminae. The similar scale morphology of D. aquilinoides and D. bernieri may suggest an affinity.

DISTRIBUTION AND HABITAT

Dryopteris aquilinoides is restricted to Mauritius (20°17’S, 57°33’E) and Réunion island (21°18’S, 55°32’E) in the Indian Ocean ( Fig. 7 ). The species appears to be rare on Mauritius, having been recorded from cloud forests (600-700 m) on Mt Le Pouce by Lorence (1978: 227). The species is more common on Réunion island, chiefly occurring in moist forests and heath scrub at elevations ranging between 1300 and 1400 m, extending up to 1700 m at plaine des Chicots .

REMARKS

Dryopteris aquilinoides is based on material from J.M.C. Richard collected in the early 1800’s during his stay on Réunion island («Bourbon»). Attached to the sheet is a label in the hand of Richard, which reads: “363 Aspidium speciosum? Feuilles de 3 à 4 pieds dans les forêts, Île Bourb.” A sheet in the Berlin Herbarium (B200052453), collected by Richard on Réunion island is indicated as being an isotype of D. aquilinoides . The label, however, does not provide a collecting number, which places its authenticity as type in question. Although D. aquilinoides was recognised by Kuhn (1868: 126) as distinct, it was not mentioned by Baker (1877). Baker most likely incorporated material belonging to this species into Nephrodium filix-mas (L.) Rich. var. elongatum , as did Cordemoy (1891: 76). Tardieu-Blot (1956a: 163) recognised D. aquilinoides as a distinct species, but erroneously included D. bojeri (Baker) Kuntze in it.

A.De Montbrison collection(P00349529)from “Île Bourbon”, named Aspidium grande , is housed in the Paris Herbarium. The sheet contains two fragments, the larger bearing two pinnae and the smaller a pinna pair of D. aquilinoides . The label is in an unknown hand.There is no indication that the sheet forms part of the original De Montbrison collection.

Three sheets in the Berlin Herbarium(B200052452, B200052454 and B200052456), all of which are Boivin 885 collections from Réunion island, has a label attached to them, which reads: “ A. politum Kze Herb ”. All these sheets contain lamina portions of D. aquilinoides and have been indicated as types. Aspidium politum Kunze appears to be a manuscript name, as no reference could be located where the name was published. Desvaux (1827: 250), however, published the name A. politum , but it appears to represent a different species. The origin of Desvaux’s plant is from Mauritius and not Réunion and he also gave no collector. Christensen (1905: 88) considers Desvaux’s plant synonymous with Rumohra adiantiformis (G.Forst.) Ching.

Figures

FIG. 6. — Indumentum and indusium of Dryopteris aquilinoides (Desv.) C.Chr.: A, stipe scale; B, C, rachis scales; D, E, scales from abaxial lamina surface; F, indusium; G, hair from abaxial lamina surface. Badré 1039 (P00349559). Scale bars: 1 mm.

FIG. 7. — Distribution of Dryopteris aquilinoides (Desv.) C.Chr. in Mauritius and la Réunion.