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 : 352-358

41. Cyathea similis C.Chr.

REMARKS

Globular coriaceous indusia dehiscing in lobes (except in var. leptoderma ), an abaxially strongly glaucous lamina, absence of a conspicuous hairy and scaly lamina indument and scales usually persistent up to first pinna pair characterize this species.

KEY TO THE VARIETIES OF CYATHEA SIMILIS

1. Lamina very coriaceous; pinnule segments strongly concave with revolute margins; scales not reaching the first pinna pair, occasionally restricted to the petiole base; indusia very coriaceous, dark brown; (1100-) 1600-2100 m, Marojejy ................. 41c. var. montana

— Lamina subcoriaceous; pinnule segments flat to slightly concave; scales ascending on the petiole often to first pinna pair; indusia membranous to coriaceous, light to dark brown; up to 1600 m, North and Central Madagascar........................................................... 2

2. Indusia subcoriaceous to coriaceous, light to dark brown, dehiscing in 2-3 lobes that are persistent in mature sori ....................................................................... 41a. var. similis

— Indusia membranous, light brown to whitish, withering quickly and only degraded, lacerate lobes or a more or less collar-like rudiment persistent in mature sori ..................... ...................................................................................................... 41b. var. leptoderma

41a. Cyathea similis C.Chr. var. similis ( Figs 1F ; 41; 46G ; 53C )

Index Filicum : 195 (1905), nom. nov.; Christensen, Dansk Botanisk Arkiv 7: 32, pl. 6 figs 21-23 (1932); Tardieu in Humbert, Flore de Madagascar et des Comores, IVe famille, Cyathéacées : 30 (1951). — Cyathea discolor Baker , Journal of the Linnean Society 15: 412 (1876), nom. illeg. non Bory, Voyage autour du monde, Cryptogamie 1: 281 (1828), nec Fée, Mémoires sur les familles des fougères, Genera Filicum 5: 353 (1850-52). — Alsophila similis (C.Chr.) R.M.Tryon, Contributions from the Gray Herbarium 200: 31 (1970). — Type: Madagascar, Antananarivo, Pool s.n. (holo-, K! [2 sheets: K000009915, -16]). — Madagascar, Toamasina, Andasibe, PN de Mantadia, sur piste commençant au P.K. 14 et continuant sur la crête, 18°49’30’’S, 48°28’E, 930-1000 m, 12.XI.2004, Janssen et al. 2576 (epi-, P! [4 sheets: P00589653-56], here designated; isoepi-, P! [3 sheets], MO!, TAN!; one trunk surface mould at P!).

Cyathea albida Tardieu , Bulletin de la Société botanique de France 88: 680 (1941); Tardieu in Humbert, Flore de Madagascar et des Comores, IVe famille, Cyathéacées : 28 fig. 4(4-5) (1951). — Alsophila albida (Tardieu) R.M.Tryon, Contributions from the Gray Herbarium 200: 29 (1970). — Type: Madagascar, massif du Tsaratanana et haute vallée du Sambirano, 1800-2000 m, XI-XII.1937, Humbert 18241 (holo-, P! [3 sheets: P00422563-65]; iso-, P!).

ADDITIONAL MATERIAL EXAMINED. — Madagascar. Forêt d’Ankeramadinika, Colin s.n. (P). — Ambodiriana, 18°40’S, 44°44’E, 14.XII.1944, Cours 1920 (K, P, MO, TAN). — Mahajanga, massif de l’Andringitra, Antsoabe, forêt Ambodipaiso, 17°18’30’’S, 46°24’E, 12.I.1945, Cours 2280 (G, MO, P, TAN). — Toamasina, de Sahalampy à Ampitanonoka, 17°46’S, 48°54’E, 1200 m, 18.I.1945, Cours 2414 (K, P). — Antsiranana, Anjanaharibe-Sud, 14°42’30’’S, 49°27’30’’E, 1700 m, 24.XII.1950, Cours 3848 (P). — Androndramanitra Rahobevava, 18°00’S, 48°47’E, 830 m, 10.III.1951, Cours 4259 (P). — Antsiranana, Manongarivo, Andranomalaza, 14°00’S, 48°23’30’’E, 1590 m, 22.III.1999, Gautier et al. 3640 (G, P). — Massif de l’Ankaratra, Mt. Tsiafajavona, 1700-2000 m, X.1933, Humbert 11167 (P). — Antsiranana, massif du Manongarivo, 14°00’37’’S, 48°25’23’’E, 1150 m, 25.IX.2004, Janssen et al. 2389 (P). — Idem, 14°01’22’’S, 48°25’03’’E, 1614 m, 26.IX.2004, Janssen et al.2393 (MO, P,TAN). — Idem, 14°01’33’’S, 48°24’47’’E, 1566 m, 27.IX.2004, Janssen et al. 2402 (MO, P, TAN). — Fianarantsoa, PN Ranomafana, forêt de Vohiparara, 21°14’03’’S, 47°23’52’’E, 1100-1150 m, 27.IV.2005, Janssen et al. 2835 (MO, P, TAN). — Mampakatompo, 9.VII.1937, Jardin Botanique de Tananarive 2503 (P). — Périnet, forêt d’Analamazaotra, 18°56’S, 48°26’E, 5.XI.1970, Keraudren-Aymonin et al. 25393 (P). — Antsiranana, RN de Marojejy, along the trail to the Marojejy Est, 14°26’S, 49°46’E, 700-850 m, 10.II.1989, Miller et al. 3923 (P). — Antsiranana, Daraina, forêt d’Antsahabe, 20.I.2004, Nusbaumer et al. 1063 (P). — Mt. Tsaratanana, 14°02’30’’S, 48°57’30’’E, 2000 m, IV.1924, Perrier de la Bâthie 16450 (P). — Fianarantsoa, cor- ridor entre PN de Ranomafana et PN d’Andringitra, WNW d’Ikongo, 21°49’17’’S, 47°24’55’’E, 650 m, 19.XI.2000, Rabarimanarivo 156 (P). — Fianarantsoa, PN de Ranomafana, Ranomena, 21°12’S, 47°27’E, 990 m, 3.XII.2000, Rabarimanarivo et al. 186 (P). — Antsiranana, massif du Manongarivo, Mt. d’Antsatrotro, 14°05’S, 48°24’E, 1350 m, 15.V.1992, Rakotondrainibe 1713 (P). — Toamasina, Maroantsetra, Ambanizana, piste menant au sommet d’Ambohitsitondroinan’Ambanizana, 15°34’S, 50°00’E, 670 m, 5.XII.1993, Rakotondrainibe et al. 2043 (MO, P, TAN). — Antsiranana, RS d’Anjanaharibe-Sud, WSW de Befingotra, 14°44’42’’S, 49°27’42’’E, 1300 m, 4.XI.1994, Rakotondrainibe et al. 2339 (K, MO, P,TAN). — RNI 12 du Marojejy, NW de Manantenina, 14°26’S, 49°45’42’’E, 760 m, 15.X.1996, Rakotondrainibe 3376 (K, P, TAN). — Idem, 16.X.1996, Rakotondrainibe 3407 (P, TAN). — Idem, 14°26’12’’S, 49°44’30’’E, 1260 m, 26.X.1996, Rakotondrainibe 3563 (P, TAN). — Idem, 14°26’24’’S, 49°44’30’’E, 1520 m, 5.XI.1996, Rakotondrainibe 3609 (MO, P, TAN). — Forêt de Betaolana, NW d’Ambodiangezoka, 14°32’18’’S, 49°26’18’’E, 800-950 m, 8.X.1999, Rakotondrainibe et al. 4845 (P). — Idem, 14°32’36’’S, 49°25’30’’E, 1200 m, 16.X.1999, Rakotondrainibe et al. 4925 (MO, P,TAN). — Idem, 1160 m, 16.X.1999, Rakotondrainibe et al. 5007 (P, TAN). — Antsiranana, massif d’Anjanaharibe-Sud, forêt d’Analabe, SW de Befingotra, 14°46’S, 49°26’30’’E, 1120 m, 26.X.1999, Rakotondrainibe et al. 5018 (P, TAN). — Idem, 14°45’54’’S, 49°25’55’’E, 1650 m, 4.XI.1999, Rakotondrainibe et al. 5162 (K, MO, P). — Antsiranana, PN de Marojejy, SE de Doany, 14°26’12’’S, 49°37’12’’E, 1100 m, 28.X.2001, Rakotondrainibe et al. 6428ter (K, P, TAN). — Doany, Anjialavahely, forêt d’Ankarongameloka, 14°15’50’’S, 49°26’17’’E, 1170 m, III.2006, Rakotovao et al. 2877 (P, TAN). — RNI du Tsaratanana, Marotolana, E de Beangona, 14°14’40’’S, 48°39’50’’E, 1550 m, 29.XI.2000, Rasolohery 128 (MO, P, TAN). — Toamasina, PN de Zahamena, Ankosy, 17°30’14’’S, 48°43’52’’E, 1100-1330 m, 28.I.2001, Rasolohery 233 (MO, P, TAN). — Idem, 17°41’S, 48°59’43’’E, 650 m, 13.VI.2001, Rasolohery 528 (MO, P,TAN). — Ambatovy, Ambohibary, 18°51’05’’S, 48°19’21’’E, 1042 m, 15.I.2005, Razanatsoa et al. 53 (P). — Andranobe, d’Andranobe à Bedinta, 15°40’54’’S, 49°57’26’’E, 500- 700 m, XI.2001, Sauquet et al. 88 (P). — Moramanga et Anosibe, Chutes de la Mort, 18°56’S, 48°13’E, 1000 m, III.1968, Stone et al. 7898 (P). — Toamasina, Masaola peninsula, Ambizana, 15°38’S, 49°59’E, 300-700 m, 1.XI.1992, van der Werff et al. 12827 (MO, P). — Toamasina, Andasibe, forest of Mantadia, 18°55’S, 48°25’E, 1000-1200 m, 7.XI.1994, van der Werff et al. 13727 (MO, P).

FIELD OBSERVATIONS. — Trunk: HT up to 6(-8) m, DT 9-12 cm excluding, and up to 19 cm including the persistent petiole bases, which usually cover the trunk

at least in its upper part, more or less caducous below and the trunk then developing a mantle of adventitious roots gradually thickening towards its base; trunk surface blackish brown, densely and irregularly muricate, bearing caducous scales similar to those of the petiole.

Petiole: sometimes covered with a whitish waxy layer that can be wiped off easily; 1 or 2 more or less subcontinuous rows of light brown aerophores on either side; petiole base sigmoid, sometimes slightly inflated.

Leaf scars: usually concealed by persistent petiole bases or adventitious roots, 2.5-3.5 × 4-6 cm, elliptic to rhombic, about 3-7 orifices on their lower rim; spirally arranged.

Crown: large, more or less umbrella-shaped.

Trunk apex: densely covered with brown scales, concealed among the more or less close standing petioles; some dead leaves persistent and hanging from the apex, occasionally forming a dense skirt.

Lamina: elliptic to ovate; LL (120-)160-260(-310) cm, WL 120-155 cm, FW (40-) 50-100 cm, NP (10-)12-17.

DESCRIPTION

Petiole:(25-)35-80(-90) cm long, 2.5-4 cm in diameter; green, abaxial face violaceous to dark brown; distantly and coarsely muricate; with a thin and caducous tomentum of brown squamules; never with a reduced pinna near the base.

Lamina: bipinnate-pinnatisect to tripinnate, subcoriaceous to coriaceous, fertile-sterile dimorphism absent; shiny light to dark green above, distinctly glaucous to whitish below, more strongly so in young leaves, alcohol treated specimens usually pale green below; lamina base shortly attenuate to truncate, basal pinnae reflexed or patent, sometimes slightly conduplicate; rachis of the same colour as the petiole.

Largest pinnae: (43-) 55-78 cm long, distant by (10-) 14-17 cm, adjacent pinnae contiguous to overlapping; costae and costulae green.

Largest pinnules: 8-11(-13.5) × 1.5-2.5(-3) cm, adjacent pinnules spaced by less than to about their width, linear-oblong to triangular, their apex shortly caudate to acute, divided down to the costula into broadly adnate segments, the first (rarely up to 4) proximal segment pair sessile, the bases of adjacent segments confluent from the middle or upper third of the pinnule, rarely below; pinnule segments (0.1-) 0.2-0.3 cm wide, spaced by less than their width, more or less falciform, their margin entire to crenulate, rarely profoundly serrate, not or slightly revolute, their apex rounded to obtuse, rarely acute, the proximal segment pairs sometimes deeply crenate; lateral veins in the segments once to rarely twice furcate, but up to three times in deeply crenate forms.

Scales and hairs: scales present from the petiole base upwards to (30-) 50-60 cm on the petiole and rachis, at the petiole base moderately dense and overlapping, persistent, usually reaching the first pinnae both on the abaxial and adaxial face of the petiole, rarely caducous in the upper part of the petiole, narrowly triangular, (2-)3.5-5 × (0.1-) 0.2-0.4 cm, straight, more or less contorted further up on the petiole, with a twisted and crispate apex, shiny light to dark brown with a distinct lighter margin, not appressed to the petiole, not indurated; adaxial face of the costae and costulae moderately tomentose with brown, crispate, soft, multicellular hairs and bearing scattered, brown, filiform scales; adaxial face of the rachis with scattered,caducous, shiny brown, filiform scales, up to 1.5 cm long; abundant appressed, hyaline to black, glandular trichomidia on the abaxial face of the lamina; very caducous, blackish, short deltoid scales, about 0.1 cm long, on the abaxial face of the costulae; leaf otherwise glabrous.

Sori: very close to the midvein, contiguous to rarely spaced by less than their width, about 0.1 cm in diameter, covering up to three quarters of the segment, but often only 1-3 pairs of sori near the segment base; indusia always globular, light to dark brown, subcoriaceous to coriaceous, at maturity dehiscing in 2 or 3 persistent lobes, connivent in coriaceous forms after the sporangia are shed; receptacle capitate to slightly elongate, shorter than the rim of mature indusia, with inconspicuous filiform paraphyses shorter than the sporangia.

DISTRIBUTION

Northern (Manongarivo, Tsaratanana) to southern Central (Ranomafana) Madagascar; endemic.

ECOLOGY

(500-)1000-1600(-2500) m. Dense evergreen rainforests.

REMARKS

Cyathea similis differs from C. boivinii by its globular indusia, a lack of lamina dimorphism, the petiole

A D E H

B

F

C

G I

scales being less dense and usually ascending to the first pinna pair, an always distinctly glaucous abaxial face of the lamina and complete absence of a loose indument of crispate, branched hairs. Cyathea similis differs from the Mascarene C. excelsa by its ascending petiole scales, rounded to obtuse, subentire apices of the pinnule segments and an abaxially distinctly glaucous lamina. See under C. boivinii for further discussion of the closely related tripinnate Madagascan species.

Like in C. glauca from la Réunion, distinct by its dense axial indument of intricate branched hairs and the narrowly triangular, very dense scales restricted to the petiole base, the abaxial face of the lamina of C. similis is covered with dense branched, rod-like wax particles that cause the glaucous colour. Such structures are also present in other Madagascan tripinnate species, but never as well-developed as in C. similis .

Juvenile plants have pinnate-pinnatifid laminas, which are distinctly glaucous below (cf. Janssen et al. 2835). Petiole scales are comparatively narrow and dark in specimens from the Manongarivo and Tsaratanana massifs, but transition to the typical form is gradual and all specimens have the typical indusia of C. similis and their lamina is strongly glaucous below. Rabarimanarivo 186 from Ranomafana has thin, but globular and persistent light brown indusia and pinnule segments with a strongly serrate margin. As serrate forms occasionally occur and do not have been admitted varietal status in other species, they are not recognized for C. similis either. The scales of Rakotondrainibe 4845, 5162 and Rasolohery 128 are more or less restricted to the base of the petiole and do not ascend to the first pinna pair, but indusia are globular and the lamina is distinctly glaucous below. Either this is an artefact of the collection process or scales may be more rapidly caducous in some plants of C. similis .

TYPIFICATION AND SYNONYMY

Two sheets of Pool s.n. are present at K, respectively carrying a sterile leaf apex and sterile pinnae taken near the leaf apex together with fertile pinnules presumably from the middle of the leaf. Both labels include the name C. discolor in Baker’s writing. The tripinnate Madagascan species being closely related, we designate an epitype including petiole scales to provide a full set of differential characters for this species, i.e. ascending persistent scales, globular indusia and glaucous abaxial lamina surface.

The serrate pinnule segments with somewhat distant sori dehisced in dark and very coriaceous, connivent lobes of Gautier 3640 from Manongarivo ( Fig. 41A, F) are virtually identical to those of the type of C. albida Tardieu. The same collection includes a pinna with close sori and subentire margins illustrating transition to typical C. similis var. similis . Based on this evidence, we establish synonymy between C. albida and C. similis interpreting C. albida as an extreme morphotype linked to the species by gradual transition.

41b. Cyathea similis C.Chr. var. leptoderma Rakotondr. & Janssen , var. nov. ( Figs 42 A-C; 46G)

A typo differt indusiis membranaceis, dilute brunneis vel hyalinis, in statu juvenili globularibus, sed cito emarcidis, in soris maturis solum rudimentos exhibentibus (lobi lacerati vel collum basi receptaculi). Apex segmentorum pinnulorum obtusus vel acutus.

TYPUS. — Madagascar, Fianarantsoa, RNI d’Andringitra, 40 km au sud d’Ambalavao, sur les berges d’un affluent de la rivière Sahavatoy , 22°13’22’’S, 46°58’18’’E, 1250 m, 24.V.1995, Rakotondrainibe 2703 (holo-, P! [3 sheets: P0059908-10]) .

ADDITIONAL MATERIAL EXAMINED. — Madagascar. Cowan s.n. (BM). — Toamasina, Andasibe, RS d’Analamazaotra, Lac Vert, 18°56’S, 48°26’E, 930-950 m, 11.XI.2004, Janssen et al. 2571 (MO, P, TAN). — Fianarantsoa, PN Ranomafana, forêt de Talatakely, Ambanjapala, 21°15’54’’S, 47°25’36’’E, 1010 m, 26.IV.2005, Janssen et al. 2832 (MO, P, TAN). — Idem, forêt de Vohiparara, 21°14’10’’S, 47°23’43’’E, 1150 m, 27.IV.2005, Janssen et al. 2842 (MO, P, TAN). — Idem, N de Ranomafana, 21°12’S, 47°27’E, 1010 m, 3.XII.2000, Rabarimanarivo et al. 183 (P). — Fianarantsoa, RNI d’Andringitra, affluent de la rivière Sahavatoy, 22°13’22’’S, 46°58’18’’E, 1240- 1280 m, 29.V.1995, Rakotondrainibe 2724 (P, TAN). — Toliara,Tolanaro, RNI d’Andohahela, NW d’Eminiminy, 24°34’15’’S, 46°43’58’’E, 1450 m, 19.XI.1995, Rakotondrainibe 3122 (MO, P, TAN). — Antananarivo, forêt d’Andranomay, SE d’Anjozorobe, 18°28’48’’S, 47°57’18’’E, 1300-1450 m, 15.XII.1996, Rakotondrainibe 3723 (P). — Fianarantsoa, Corridor reliant les réserves d’Andringitra et d’Ivohibe, ESE d’Angodongodona, 22°25’18’’S, 46°53’54’’E, 1150-1300 m, 3.XI.1997, Rakotondrainibe et al. 4279 (P, TAN). — Fianarantsoa, PN de Ranomafana, forêt de Vatoharanana, 21°17’24’’S, 47°26’E, 1000-1100 m, 8.X.2000, Rakotondrainibe et al. 5957 (K, MO, P). — Forêt d’Andrambovato, bord de la rivière Tatamaly, 21°30’42’’S, 47°24’36’’E, 1000-1100 m, 13.X.2000, Rakotondrainibe et al. 5975 (K, P). — Forêt de Vinanitelo, SE de Vohitrafeno, 21°46’36’’S, 47°20’48’’E, 1000-1100 m, 29.X.2000, Rakotondrainibe et al. 6155 (P). — Toamasina, PN de Zahamena, Ambodivoahangy, 17°39’20’’S, 48°54’22’’E, 750 m, 4.X.2001, Ratovoson et al. 562 (MO, P). — Fianarantsoa, Ranomafana, 21°13’S, 47°27’E, 900 m, 10.X.1992, van der Werff et al. 12629 (MO, P). — Idem, 21°14’S, 47°24’E, 900 m, 11.X.1992, van der Werff et al. 12694 (MO, P).

DIFFERENTIAL FIELD OBSERVATIONS. — Trunk: HT up to 4 m.

DIFFERENTIAL DESCRIPTION

Indusia are globular when young, but light brown and membranous.Upon maturity of the sorus, they open with more or less irregular lobes and wither quickly, becoming translucent, light brown to whitish and reduced to lacerate lobes or a collar like structure surrounding the base of the receptacle.Th e receptacle is consequently slightly shorter to often longer than the rim of the mature indusium. Th e apex of the pinnule segments is obtuse to acute, not rounded.

DISTRIBUTION

Central (Andasibe) to Southern (Andohahela) Madagascar; endemic.

ECOLOGY

900-1300 m. Dense evergreen rainforests.

REMARKS

This variety has been established based on its membranous indusium as opposed to an at least subcoriaceous indusium with persistent erect lobes after dehiscence in var. similis . It is furthermore characterized by a southern distribution.

ETYMOLOGY

The epithet leptoderma refers to the very thin and quickly withering indusium of this taxon.

Figures

FIG. 1. — Spores of Cyathea sect. Alsophila in Madagascar and on the Comoros: A-C, spores of taxa belonging to the bipinnate clade (Janssen et al. 2008) have a perispore formed by dense slender rodlets; D-F, spores of taxa belonging to the tripinnate clade (Janssen et al. 2008) have a perispore with prominent crests; A, C. approximata Bonap.; B, C. kirkii Hook.; C, C. serratifolia Baker; D, C. boivinii Mett.ex Kuhn var.boivinii; E, C. melleri (Baker) Domin;F, C. similis C.Chr.,a young spore with a distantly verrucose perispore (Janssen & Rakotondrainibe 2006; Gastony & Tryon 1976). A, Janssen et al. 2449 (P); B, Rakotondrainibe et al. 6751 (P); C, Rakotondrainibe et al. 6230 (P); D, Janssen et al. 2481 (P); E, Janssen et al. 2536 (P); F, Janssen et al. 2576 (P). Scale bars: 10 μm.

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

FIG. 53. — Photographic documentation of field characters in Cyathea: A-D, habit; A’-D’, trunk apex; A”-D”, trunk surface at breast height; A-A”, Cyathea melleri (Baker) Domin; B-B”, C. sechellarum Mett.; C-C”, C. similis C.Chr.; D-D”, C. valdesquamata Janssen & Rakotondr. A, A’, B’, B”, uncollected; A”, Janssen et al. 2569; B, Janssen et al. 3247; C, Janssen et al. 2402; C’, Janssen et al. 2576; C”, Janssen et al. 2393; D, D”, Janssen et al. 2907; D’, Janssen et al. 2904. Vouchers at P. Photos A’-A”, C’ by G. Rouhan (MNHN); all other photos by T. Janssen. Scale bars: A-D, 1 m; A’-D’, A”-D”, 10 cm.

FIG. 42. — A-C, Cyathea similis var. leptoderma Rakotondr. & Janssen; A, young sori with a membranous, globular indusium; B, mature sori with a rudimentary indusium forming a collar-like structure at the base of the receptacle; C, pinnule segments abaxially with a fragment of the costula; D-G, Cyathea similis var. montana Janssen & Rakotondr.; D, pinnule segments abaxially with a fragment of the costula, common form; E, pinnule segments abaxially with a fragment of the costula, large and strongly crenate form; F, pinnules adaxially with a fragment of the costa; G, scale from the base of the petiole. A-C, Rakotondrainibe 2703 (P); D, F, G, Guillaumet 4063 (P); E, Rakotondrainibe 3615 (P). Scale bars: A, B, 0.5 mm; C-E, G, 0.1 cm; F, 1 cm.