Janssen, Janssen & Rakotondrainibe, 2008

Janssen, Thomas & Rakotondrainibe, France, 2008, A revision of the indusiate scaly tree ferns (Cyatheaceae, Cyathea subgen. Alsophila sect. Alsophila) in Madagascar, the Comoros and the Seychelles, Adansonia (3) 30 (2), pp. 221-376 : 243-244

4. Cyathea auriculata Tardieu ( Figs 44D; 47C )

Naturaliste malgache 3: 75, pl. 1 fig. 1 (1951); Tardieu in Humbert, Flore de Madagascar et des Comores, IVe famille, Cyathéacées : 25, fig. 3 (1-5) (1951). — Alsophila auriculata (Tardieu) R.M.Tryon, Contributions from the Gray Herbarium 200: 29 (1970). — Type: Madagascar, contreforts occidentaux du massif de Marojejy (nord-est), près du col de Doanyanala (limite des bassins de la Lokoho et de l’Andraronga), 14°28’S, 49°32’E, 900-1000 m, II.1949, Humbert 23163 (holo-, P! [P00404420]; iso-, MO!, P! [3 sheets and 1 trunk fragment (P00404421)], TAN!).

ADDITIONAL MATERIAL EXAMINED. — Madagascar. Prov. deToamasina, Maroantsetra, Ambanizana, piste menant au sommet d’Ambohitsitondroinan’Ambanizana, 15°34’31”S, 50°00’37”E, 620-1109 m, 23.X.2004, Janssen et al. 2506 (P, TAN) , 2508 (P, TAN).— Prov. de Fianarantsoa, RS Pic d’Ivohibe, haute vallée de l’Andranomainty, 22°29’49’’S, 46°57’22’’E, 1450-1520 m, 23.IV.2005, Janssen et al. 2804 ( MO, P, TAN), 2805 ( MO, P, TAN). — Prov. de Toamasina, Maroantsetra, Ambanizana, piste menant au sommet d’Ambohitsitondroinan’Ambanizana, sur le versant ouest, 15°34’S, 50°00’E, 820 m, 6.XII.1993, Rakotondrainibe et al. 2048 ( MO, P), 2055 ( MO, P, TAN). — Mananara-Avaratra, Sandrakatzy, forêt de Verezanantsoro, 16°26’S, 49°38’E, 460 m, 6.I.1994, Rakotondrainibe et al. 2056 (P). — Prov. de Fianarantsoa, RS Pic d’Ivohibe, près de la source de la rivière Andranomainty, 22°29’48’’S, 46°57’18’’E, 1500-1650 m, 24.X.1997, Rakotondrainibe et al. 4187 (P, TAN) .

FIELD OBSERVATIONS. — Trunk: HT up to 4 m, DT 5-8 cm, dead petioles caducous and leaf scars exposed; trunk surface blackish brown, tuberculate with distant, conical squaminate spines up to 0.5 cm long; more or less annulated between the pseudo-whorls.

Petiole: with 1 row of very distant, small, brown aerophores on either side; petiole base straight or arched, but not sigmoid.

Leaf scars: 1.3-2 × 1.3-3.5 cm, rounded to ovate, slightly concave, 1-5 conspicuous orifices on or below their lower rim, arranged in distinct pseudo-whorls that are 3-5 cm distant.

Crown: more or less umbrella-shaped, 6-8 leaves per pseudo-whorl.

Trunk apex: densely covered with small conical brown scales, elevated beyond the last whorl of developed leaves and visible through the distant petiole bases.

Lamina: (narrowly) elliptic; LL 115-160 cm, WL 40- 70 cm, FW 50-55 cm, NP 42-48.

DESCRIPTION

Petiole: 10-22 cm long, 1-2 cm in diameter; green to stramineous or light brown, abaxial face reddish brown; aphlebia absent.

Lamina: bipinnate, subcoriaceous, light green below, dark green above, lamina base attenuate, but basalmost pinna pair usually more than 5 cm long, basal pinnae conduplicate and reflexed; rachis of the same colour as the petiole.

Largest pinnae: 21-33 cm long, distant by 2.5-3 cm, adjacent pinnae contiguous to overlapping, their apex acute, pinnatifid, pinnae twisted to about 45° with respect to the leaf surface; costae and costulae of the same colour as the petiole.

Largest pinnules: 1.1-2.2 × 0.3-0.5 cm, spaced by less than their width to slightly overlapping, distinctly petiolulate (c. 0.1 cm), ovate-oblong, margin distantly and shallowly crenate to entire; apex rounded, base truncate-cordate and conspicuously biauriculate, rarely only the distal auricle developed, adjacent auricles overlapping; pinnule surface twisted to about 45° with respect to the pinna surface; veins once to twice furcate, pinnate in the auricles.

Scales and hairs: scales present from the petiole base upwards to 20 cm on the petiole and rachis, spaced from each other, persistent, 0.2-0.4 × 0.1- 0.2 cm, indurated and transformed into slender, patent, black conical spines, sometimes with an antrorse apex, distally transforming into shiny brown to black appressed scales with a light brown margin, up to 0.4 cm long, spaced and persistent on the rachis; abaxial face of the costae with a dense indument consisting mostly of appressed, filiform, shiny dark brown scales, up to 0.3 cm long, in the lower third of the costae and consisting mostly of multicellular, patent, hyaline hairs and scale-topped hairs further up on the costae; adaxial face of petiole and rachis with filiform, patent, dark shiny brown scales with narrow, light brown margins, 0.7-1 cm long; adaxial face of rachis and costae with dense crispate, soft, multicellular, light brown, more or less appressed hairs.

Sori: subcostular, spaced to contiguous, covering the lower half of the pinnules; mature indusia a shallow cup or collar with a lacerate rim or irregularly lobed, membranous, stramineous to light brown; receptacle capitate, usually longer than the mature indusium, paraphyses inconspicuous.

DISTRIBUTION

Disjunct in Northern Madagascar (Masoala peninsula) and southern Central Madagascar (Ivohibe and Mananara region); endemic.

ECOLOGY

(500-) 600-1500 m. Dense evergreen rainforests of higher altitudes, usually in wet valleys and gorges.

REMARKS

A complete illustration of this species can be found in Tardieu-Blot (1951: 27).

Figures

FIG. 47. — Photographic documentation of field characters in Cyathea: A-E, habit; A’-E’, trunk apex; A”-E”, trunk surface at breast height. A-A”, Cyathea marattioides Willd. ex Kaulf.; B-B”, C. perrieriana C.Chr.; C-C”, C. auriculata Tardieu; D-D”, C. decrescens Mett. ex Kuhn; E-E”, C. ivohibensis (C.Chr.) Janssen & Rakotondr. A, Janssen et al. 2488; A’, B’, uncollected; A”, Janssen et al. 2484; B, Janssen et al. 2504; B”, Janssen et al. 2505; C-C”, Janssen et al. 2508; D, Janssen et al. 2521; D’, Janssen et al. 2562; D”, Janssen et al. 2406; E, E’, Janssen et al. 2790; E”, Janssen et al. 2794. Vouchers at P. Photos B-D, A’-D’, A”-D” by G. Rouhan (MNHN); all other photos by T.Janssen. Scale bars: A-E, 1 m; A’-E’, A”, B”, D”, E”, 10 cm; C”, 5 cm.