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 : 268-270

13. Cyathea appendiculata Baker , mut. char. (emend. Janssen & Rakotondr.)

( Figs 13 ; 44B; 48E )

Journal of the Linnean Society 15: 411 (1876); Christensen, Dansk Botanisk Arkiv 7: 26, pl. 5 figs 14-16 (1932); Tardieu in Humbert, Flore de Madagascar et des Comores, IVe famille, Cyathéacées : 18 (1951). — Alsophila appendiculata (Baker) R.M.Tryon, Contributions from the Gray Herbarium 200: 29 (1970). — Type: Madagascar, Antananarivo, VI.1876, Pool s.n. (lecto-, K! [K000009957], here designated; isolecto-, B!). — Madagascar, Fianarantsoa, 35 km S Ambositra, Ambatofitorahana, forêt d’Ankazomivady, 20°49’07’’S, 47°11’54’’E, 1719 m, 15.IV.2005, Janssen et al. 2766 (epi-, P! [3 sheets: P00589535-37], here designated; isoepi- P! [3 sheets], TAN!).

ADDITIONAL MATERIAL EXAMINED. — Madagascar. Antananarivo, Ost-Imerina, Andrangoloaka, 19°02’S, 47°55’E, XI.1880, Hildebrandt 3763 (B, BM, G, K, P, W). — Environs d’Ambositra, forêt d’Ambatofitorahana, 20°49’S, 47°11’E, 1600-1700 m, 26.VII.1928, Humbert & Swingle 4881 (BM, K, P). — Fianarantsoa, Ambositra, Ambatofitorahana, forêt d’Ankazomivady, 20°46’19’’S, 47°10’57’’E, 1708 m, 14.IV.2005, Janssen et al. 2755 (MO, P, TAN). — Idem, 20°49’07’’S, 47°11’54’’E, 1719 m, 15.IV.2005, Janssen et al. 2763 (MO, P, TAN), 2764 (MO, P, TAN), 2765 (MO, P, TAN).— Ambatofitorahana, à 35 km au sud d’Ambositra, 20°49’S, 47°11’E, 1700 m, 21.I.1970, Onraedt 70M59 (BR). — Antananarivo, 18°55’S, 47°31’E, IV.1876, Pool s.n. (B, K). — Région de Tsinjoarivo, forêt de Mahatsinjo, 19°40’51’’S, 47°46’12’’E, 1450-1500 m, 7.I.1999, Rakotondrainibe 4544 bis (P). — Idem, 1550 m, 7.I.1999, Rakotondrainibe 4577 (P). — Idem, 8.I.1999, Rakotondrainibe 4578 bis (P).

FIELD OBSERVATIONS. — Trunk: HT up to 3.5 m, DT 12-14 cm including a sheath of persistent dead petiole bases, each 15-20 cm long and appressed, forming distinct vertical rows, rarely only a petiole rudiment present on the scar rim; some dead rachises persistent and hanging from the apex.

Petiole: with 1 or 2 rows of small, light brown, slightly raised, very distant aerophores on either side; petiole bases arched to sigmoid.

Leaf scars: about 2 × 2 cm, rounded, contiguous, somewhat raised, with a rudiment of the petiole on their rim, spirally arranged.

Crown: funnel-shaped to horizontal, several whorls of green leaves present.

Trunk apex: truncate appearance, densely scaly, visible through the spaced petioles.

Lamina: elliptic to ovate; LL (70-) 140-160 cm, WL (35-) 60-70 cm, FW (30-) 65-70 cm, NP 16-25.

DESCRIPTION

Petiole: 25-45 cm long, 1.7-2 cm in diameter, green to stramineous, abaxial face dark reddish brown, black at its base, with a dense, but very caducous indument of light brown squamules; aphlebia and aphlebioid pinnae absent.

Lamina: bipinnate, subcoriaceous, dull light green below, shiny dark green above, lamina base abruptly attenuate to truncate, basal pinnae patent or reflexed, slightly conduplicate; rachis brown below, green above.

Largest pinnae: up to 35 cm long, distant by 4-6 cm, adjacent pinnae overlapping or spaced, their apex acute or shortly caudate, pinnatifid; costae and costulae stramineous to green (sometimes reddish?).

Largest pinnules:(2.5-)3.5-4(-5)×0.5-0.6(-0.8) cm, spaced by about their width, shortly petiolulate with the petiolule up to 0.1 cm, oblong to lanceolate, margin deeply crenate to subentire, apex acute to obtuse and crenulate or serrulate, pinnule base mono- or biauriculate, the acroscopic auricle usually much more prominent; basalmost pinnule pair deeply lobed and overlapping the rachis; veins once to three times furcate, pinnate in deeply crenate forms.

Scales and hairs: scales present from the petiole base upwards to about 10 cm on the petiole, dense, very caducous, narrowly triangular, 3-4 × 0.2-0.3 cm, straight, their apex crispate, but rarely preserved, dull to shiny brown, scarious, margin erose; abundant appressed trichomidia and scattered, stramineous to hyaline, soft, contorted hairs and acaroid squamules on the abaxial face of the costae and costulae in young leaves; more or less dense, brown, crispate, patent to antrorse, multicellular hairs on the adaxial face of the rachis and costa; leaf otherwise glabrous.

Sori: subcostular, contiguous to distant by about their width, about 0.1 cm in diameter, covering entire pinnules or restricted to their lower half; indusia globular, brown, subcoriaceous, at maturity dehiscing in 2-4 lobes; receptacle capitate, shorter than the rim of mature indusia; filiform paraphyses short and inconspicuous.

DISTRIBUTION

Central Madagascar: Ambositra region; endemic.

ECOLOGY

About 1700 m. Dense evergreen rainforests and on forest margins, many specimens collected next to small streams or on marshy ground.

REMARKS

This taxon has been described from heterogeneous original material. We here lectotypify on the specimen corresponding best with the protolog and amend the original description. Cyathea appendiculata has never been observed with aphlebia or aphlebioid pinnae near the base of the petiole; neither on specimens, nor in the field. We cannot confirm Christensen’s (1932: 26) observation of such structures in Hildebrandt 3763.

Hildebrandt 3763 is a widely distributed collection with narrow pinnules up to 2.5 × 0.4 cm with a revolute margin. Considering variation in pinnule size in the available material it is not recognized here as a distinct taxon. Humbert & Swingle 4881 and Janssen et al. 2765 with distinctly spaced pinnae up to 13-17 cm long and the largest pinnules 1.4-2 × 0.3-0.5 cm are from young, fertile plants, but otherwise agree with all characters described above.

All known collections stem from Central Madagascar and most are from the same relictual forest region near Ambositra. Only a few specimens come from the Mahatsinjo forest near Tsinjoarivo. Its very restricted habitat being under anthropogenic pressure, the species is likely to be highly threatened.

TYPIFICATION AND SYNONYMY

The type material at K comprises four sheets all carrying identical labels in Baker’s hand. K000009960 comprises two detached aphlebia, most likely of Cyathea boiviniiformis Rakotondr. & Janssen , and two detached aphlebioid pinnae, most likely of C. melleri (Baker) Domin. K 000009958 carries a juvenile leaf, which cannot be unambiguously determined. K000009959 carries a stramineous rachis fragment with seven sterile and glabrous pinnae with reddish costae and is most likely conspecific with K000009957, although not from the same plant. K000009957 comprises a stramineous rachis fragment with six fertile pinna pairs with stramineous costae and is chosen here as the lectotype of the species. In the light of our observations, it is best to treat the original material as a mixture of different gatherings and the four sheets as being unrelated, unnumbered collections. Hence, no isolectotype specimens exist at K. An analogous set of specimens – three aphlebia, a juvenile fragment with a red rachis and a fertile fragment with a stramineous rachis – is glued on a single sheet at B. The fragment in the lower left corner of that sheet, morphologically perfectly corresponding with K000009957, should be considered an isolectotype.

Although the species can be characterized by its auriculate glabrous pinnules, petiole scales are necessary for an unambiguous differentiation from certain forms of C. decrescens and we here designate a complete specimen as epitype.

Figures

FIG. 13. — Cyathea appendiculata Baker: A, pinnules abaxially with a fragment of the costa; B, pinnules abaxially with a fragment of the costa, small and weakly auriculate form, veins not indicated, sori only partly indicated; C, pinnules abaxially with a fragment of the costa, crenate form, veins not indicated, sori only partly indicated; D, trunk surface with close standing leaf scars and rudiments of dead petioles; E, habit; F, trunk surface, common aspect with close standing appressed petiole bases in pseudo-whorls; G, pinnae abaxially with a fragment of the rachis, sori only partly indicated; H, basal part of the leaf (from the petiole base up to the second pinna pair), lateral view, scales caducous; I, scale from the base of the petiole. A, G-I, Janssen et al. 2766 (P); B, Janssen et al. 2765 (P); C, F, Janssen et al. 2764 (P); D, Janssen et al. 2755 (P); E, uncollected, photograph at P. Scale bars: A-D, F, H, 1 cm; E, 1 m; G, 5 cm; I, 0.5 cm.

FIG. 48.— Photographic documentation of field characters in Cyathea: A, B, D-F, habit;A’, B’, D’-F’, trunk apex;A”, B”, D”-F”, trunk surface at breast height.A-A”, Cyathea meridionalis Janssen & Rakotondr.; B, B’, C. ligulata Baker; C, trunk apex of C. acutula Tardieu var.acutula; D-D”, C. acutula Tardieu var.deltoidea Janssen & Rakotondr.; E-E”, C. appendiculata Baker; F-F”, C. costularis Bonap. A, A”, E, F, uncollected; A’, Janssen et al. 2599; B, B’, Janssen et al. 2494; C, Janssen et al. 2401; D-D”, Janssen et al. 2788; E’, E”, Janssen et al. 2764; F’, Janssen et al. 2489; F”, Janssen et al. 2518. Vouchers at P. Photos B, C, F, A’, B’, F’, F” by G. Rouhan (MNHN); all other photos by T. Janssen. Scale bars: A, B, D-F, 1 m; C, A’, B’, D’-F’, A”, D”-F”, 10 cm.