Cyathea tsilotsilensis Tardieu

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 : 242-243

3. Cyathea tsilotsilensis Tardieu ( Figs 4F, G ; 46J )

Bulletin de la Société botanique de France 88: 682 (1941); Tardieu in Humbert, Flore de Madagascar et des Comores, IVe famille, Cyathéacées : 6, fig. 2 (1-3) (1951). — Alsophila tsilotsilensis (Tardieu) R.M.Tryon, Contributions from the Gray Herbarium 200: 31 (1970). — Type: montagnes entre l’Andohahela et l’Elakelaka: col de Tsilotsilo (à 6 km NE de l’Elakelaka), 24°50’S, 46°45’30’’E, 1300 m, II.1934, Humbert 14115 (holo-, P! [P00389552]; iso-, P! [2 sheets]).

ADDITIONAL MATERIAL EXAMINED. — Madagascar. Toliara, Tolanaro, RNI d’Andohahela , NW d’Eminiminy, 24°37’55’’S, 46°45’29’’E, 520 m, 22.X.1995, Rakotondrainibe 2890 (P). — Idem, 24°38’S, 46°40’E, 500- 1000 m, II.1993, van der Werff et al. 12902 (BR, G, MO, P), 12905 (G, MO, P) .

FIELD OBSERVATIONS. — Trunk: HT up to 6 m. Lamina: LL 200 cm.

DESCRIPTION

Petiole: about 30-83 cm long, 1-1.8 cm in diameter when dry; completely stramineous to light brown when dry, sometimes tinged with red, with a thin and caducous tomentum of light brown squamules.

Lamina: bipinnate, subcoriaceous, light green below, shiny green to dark green above when dry; rachis of the same colour as the petiole.

Largest pinnae: 40-63 cm long, distant by 9-11 cm, adjacent pinnae contiguous to overlapping, their apex more or less truncate and the apical pinnule conform, i.e. resembling the lateral pinnules; costae and costulae of the same colour as the petiole.

Largest pinnules: 4-6(-8) × 1-1.5 cm, spaced by less than their width, petiolulate, the petiolule 0.1-0.2 cm long, articulated and the pinnules easily shed upon drying, pinnules lanceolate-oblong, straight, their margin subentire, serrate in the acute to caudate apex, their base truncate, rounded or cordate; veins once, rarely twice furcate.

Scales and hairs: scales present from the petiole base upwards to 15-50 cm on the petiole, usually not reaching the first pinna pair, dense and overlapping, persistent, narrowly triangular, (1.5-)2-2.5 × 0.1(-0.2) cm, straight to slightly falciform, with a shiny light to dark brown centre and a distinct stramineous border of elongate cells, with a light brown erose margin of irregularly shaped cells, appressed, adaxial scales not appressed, antrorse, not indurated; scattered dark brown acaroid squamules on the abaxial face of the costulae and veins; adaxial face of the costae moderately densely tomentose with more or less contorted and antrorse, dark brown multicellular hairs; leaf otherwise glabrous.

Sori: contiguous to spaced by about their width, spaced from the costula by at least their width, about 0.1 cm in diameter, covering the entire pinnule or its lower half, but usually not the apex and the base; indusia most likely globular, light brown, very thin and membranous, at maturity dehiscing irregularly, only a rudiment persistent as a collar around the base of the receptacle; receptacle capitate to disciform, usually longer than the rim of mature indusia, with inconspicuous filiform paraphyses much shorter than the sporangia.

DISTRIBUTION

Southern Madagascar: Andohahela massif; endemic.

ECOLOGY

500-1300 m. Dense evergreen rainforests.

REMARKS

Cyathea tsilotsilensis has more delicate leaves than its close relatives of group IIa, with smaller pinnules that have a truncate to rounded, rarely cordate base. The petiole scales are much denser than in C. perrieriana and differ from those of C. marattioides in having a distinct brown centre and stramineous border even in old leaves. Cyathaea tsilotsilensis furthermore distinct by its petiole and leaf axes being of much lighter colour in the dry and consequently most likely also in the fresh state.

Figures

FIG. 4. — A-E, Cyathea marattioides Willd.ex Kaulf.; A, pinna abaxially with a fragment of the rachis, sori only partly indicated;B, habit; C, pinnules abaxially with a fragment of the costa;D, scale from the base of the petiole; E, trunk segment with leaf scars;F, G, C. tsilotsilensis Tardieu; F, pinnules abaxially with a fragment of the costa; G, scale from the base of the petiole; H-K, C. perrieriana C.Chr.; H, pinnules abaxially with a fragment of the costa; I, trunk segment with leaf scars; J, scale from the base of the petiole; K, habit. A-E, Janssen et al. 2488 (P); F, G, van der Werff 12905 (P); H-J, Janssen et al. 2503 (P); K, uncollected, photograph at P. Scale bars: A, 5 cm; B, K, 1 m; C, E, F, H, I, 1 cm; D, G, J, 0.5 cm.

FIG. 46. — Distribution maps for Cyatheaceae (genus Cyathea) of Madagascar and the Comoros. Species are arranged in alphabetical order.