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 : 282-283

20. Cyathea viguieri Tardieu

( Figs 19 ; 46L ; 49D )

Bulletin de la Société botanique de France 88: 682 (1941); Tardieu in Humbert, Flore de Madagascar et des Comores, IVe famille, Cyathéacées : 15, fig. 1 (12-15) (1951). — Alsophila viguieri (Tardieu) R.M.Tryon, Contributions from the Gray Herbarium 200: 31 (1970). — Type: Madagascar, district de Moramanga, forêt d’Analamazaotra, vers 950 m, 21.X.1912, Viguier & Humbert 825 (holo-, P! [P00404447]; iso-, B!, P! [3 sheets]). — Madagascar, Fianarantsoa, Ambalavao, RS d’Ivohibe, 22°28’12’’S, 46°57’36’’E, 850-950 m, 7.X.1997, Rakotondrainibe et al. 4020 (epi-, P! [2 sheets: P00134023, -24], here designated; isoepi-, TAN!).

ADDITIONAL MATERIAL EXAMINED. — Madagascar. Toamasina, Sahalampy à Ampitanonoka, 17°46’S, 48°54’E, 1200 m, 18.I.1945, Cours 2413 (P). — Brickaville, Ambalarondra, 18°50’S, 49°04’E, 300 m, 21.IV.1951, Cours 4498 (P). — Farafangana, Vondrozo, 22°49’S, 47°19’30’’E, 26.VIII.1926, Decary 5077 (P). — Antsiranana, massif du Manongarivo, Bekolosy, Gautier 2926 (G). — Idem, Haute Ambahatra, 13°59’51’’S, 48°25’43’’E, 1150 m, 24.IX.2004, Janssen et al. 2380 (P, TAN). — Idem, 14°01’33’’S, 48°24’47’’E, 1566 m, 27.IX.2004, Janssen et al. 2403 (MO, P, TAN). — Toamasina, Maroantsetra, Ambanizana, 15°32’S, 50°00’30’’E, 620-1109 m, 23.X.2004, Janssen et al. 2510 (P, TAN). — Andasibe, Station forestière Mitsinjo, 18°56’S, 48°26’E, 930-950 m, 11.XI.2004, Janssen et al. 2563 (P, TAN). — Idem, PN de Mantadia, 18°49’30’’S, 48°28’E, 930-1000 m, 12.XI.2004, Janssen et al. 2575 (MO, P, TAN). — Antsiranana, R.N. Marojejy, trail to summit of Marojejy Est, north of Mandena, 14°26’S, 49°46’E, 700-1150 m, X.1988, Miller et al.3455 (P). — Idem, 700-900 m, 24.XI.1989, Miller et al. 4560 (MO, P). — Fianarantsoa, Maroangira, 21°44’S, 47°24’E, 720 m, 4.XI.2000, Rabarimanarivo et al. 118 (P). — Antsiranana, Manongarivo, Bekolosy, 14°02’S, 48°19’E, 1000 m, 5.II.1992, Rakotondrainibe 1412 (P). — Idem, Mt. d’Antsatrotro, 14°05’S, 48°23’E, 1540 m, 18.V.1992, Rakotondrainibe 1710 (K, MO, P). — Toamasina, Maroantsetra, Ambanizana, 15°34’S, 50°00’E, 670 m, 5.XII,1993, Rakotondrainibe 2069 (P). — Fianarantsoa, Ambalavao, RS d’Ivohibe, 22°28’12’’S, 46°57’36’’E, 850-950 m, 7.X.1997, Rakotondrainibe et al. 4020 bis (P). — Toamasina, Ambatondrazaka, PN de Zahamena, 17°41’08’’S, 48°59’43’’E, 650 m, 12.VI.2001, Rasolohery 498 (MO, P, TAN). — RNI Zahamena, Androrangabe,

vers le sommet Andrangovalo, 17°40’34’’S, 48°45’32’’E, 1100-1351 m, 14.IX.2002, Rasolohery et al. 662 ( MO, P, TAN). — Andasibe, forest of Mantadia, 18°55’S, 48°25’E, 900 m, 3.XI.1994, van der Werff et al. 13616 ( MO, P). — Idem, 1000-1200 m, 7.XI.1994, van der Werff et al. 13726 ( MO, P) .

FIELD OBSERVATIONS. — Trunk: HT up to 6 m, DT (5-)7-9(-12) cm, dead petioles caducous and the leaf scars exposed, rudiments persistent only in the upper quarter of the trunk or on scar rims; trunk surface brown to black, muricate to rather smooth.

Petiole: with 1 or 2, rarely more, irregular rows of light brown aerophores on either side; petiole bases short to long sigmoid.

Leaf scars: 2.5 × 4.5-5 cm, ovate, not or only slightly raised, 3-6 orifices near and below their lower rim, no pronounced spines on the scar rim; spirally arranged.

Crown: umbrella-shaped, juvenile plants with more or less erect rachises and a funnel-shaped crown.

Trunk apex: densely scaly, light brown to ferruginous; petioles distant or forming a short fascicle hiding the apex.

Lamina: elliptic to obovate; LL (100-) 150-250 cm, WL (50-) 80-110 cm, FW (30-) 50-80 cm, NP (10-)17-26.

DESCRIPTION

Petiole: 30-60(-100) cm long, 1.5-2.5 cm in diameter; usually dark reddish or violaceous to blackish brown on both faces, rarely light brown.

Lamina: bipinnate, coriaceous, light green below, shiny green to dark green above; lamina base shortly attenuate to truncate, basal pinnae more or less reflexed and conduplicate; rachis of the same colour as the petiole.

Largest pinnae: 40-50 cm long, distant by 7-9 cm, adjacent pinnae contiguous to overlapping, their apex acute, pinnatifid; costae and costulae light brown when dry.

Largest pinnules: 4-5.5(-7.5) × 0.7-1 cm, spaced by less than their width to contiguous, petiolulate, triangular-oblong, apex acute to obtuse, base truncate to cordate, more or less biauriculate, the acroscopic auricle more strongly developed, margin subentire to deeply crenate, in the first 2 proximal pinnule pairs often deeply crenate-lobate; veins twice furcate, more often divided in sterile pinnules, 15-17(-20) veins per cm.

Scales and hairs: scales ascending on the petiole and reaching the first pinna pair, dense and overlapping, persistent, narrowly triangular, 2.5-5 × 0.1-0.3 cm, straight, twisted, not appressed to the petiole, further up more or less sinusoid and appressed, shiny copper to dark brown, not indurated; dense multicellular, brown, antrorse hairs mixed with light brown, filiform scales on the adaxial face of the costae; sparse hairs and more abundant filiform scales on the adaxial face of the rachis; leaf otherwise glabrous.

Sori: subcostular, contiguous to spaced by less than their width, 0.15-0.2 cm in diameter, covering the entire pinnule; indusia globular, brown to blackish brown, coriaceous, at maturity dehiscing in 2-4 stiff and persistent lobes; receptacle capitate, shorter than the rim of mature indusia, paraphyses inconspicuous.

DISTRIBUTION

Northern Madagascar to southern Central Madagascar: Manongarivo to Ivohibe massifs; endemic.

ECOLOGY

(300-) 700-1600 m. Dense evergreen rainforests.

REMARKS

Forms of C. viguieri with small pinnules are close to rare forms of C. appendiculata with large pinnules, but can be differentiated by their dark coriaceous indusia and persistent, ascending petiole scales. Judging from its petiole scales and the colour range observed in petioles and rachises, C. bellisquamata may be considered near C. viguieri but it is easily distinguished by its pinnules being broadly adnate to the costa. Note, that juvenile plants of C. viguieri may have reduced pinnae near the petiole base, but then normally lack a gradual transition to the fully developed pinnae of the lamina.

Gautier 2926 (G) is placed here with hesitation, but its long, shiny dark brown, ascending petiole scales in combination with large, sessile coriaceous pinnules currently do not justify another determination. In Janssen et al. 2380, Rakotondrainibe et al. 1412 and 1710 the petiole scales are restricted to the lower 15 cm of the reddish to light brown petiole. Janssen et al. 2403 has light brown indusia and scales ascending only halfway on the petiole. Cours 4498 exhibits a slight fertile-sterile dimorphism. With respect to their other characters and considering the closely related taxa, these specimens are currently best assigned to C. viguieri although recognition of further taxa might prove necessary with more material at hand.

TYPIFICATION AND SYNONYMY

The original material lacks the petiole base and scales are only available on a rachis fragment. We hence consider it useful to designate an epitype more precisely establishing the identity of this taxon with respect to arrangement and morphology of the petiole scales.

Figures

FIG. 19. — Cyathea viguieri Tardieu: A, basal part of the leaf (from the petiole base up to the first pinna pair), lateral view; B, scale from the abaxial face of the base of the petiole; C, habit; D, pinnae abaxially with a fragment of the rachis, sori only partly indicated; E, scale from the lateral face of the middle part of the petiole; F, pinnules abaxially with a fragment of the costa; G, sori with dark brown, coriaceous indusia; H, leaf scars and trunk surface. A, B, D-G, Janssen et al. 2575 (P); C, H, Janssen et al. 2380 (P). Scale bars: A, D, 5 cm; B, E, 0.5 cm; C, 1 m; F, H, 1 cm; G, 0.1 cm.

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

FIG. 49.— Photographic documentation of field characters in Cyathea: A-E, habit;A’-E’, trunk apex;A”-E”, trunk surface at breast height.A-A”, Cyathea hebes Janssen & Rakotondr.; B-B”, C. serratifolia Baker; C-C”, C. tsaratananensis C.Chr.; D-D”, C. viguieri Tardieu; E-E”, C. approximata Bonap.; E’, left: apex of a form with distant petioles (apical view), right: apex of a form with close standing petioles (lateral view).A-A”,Janssen et al. 2519; B, B”, C,C’,E-E”,uncollected;B’, Janssen et al.2538; C”, Janssen et al. 2446; D-D”, Janssen et al. 2575. Vouchers at P. Photos A-A”, B-B”, C-C”, E, E’ right, E” 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.