Xerochlamys villosa F.Gérard

Hong-Wa, Cynthia, 2009, Endemic families of Madagascar. XII. Resurrection and taxonomic revision of the genera Mediusella (Cavaco) Hutchinson and Xerochlamys Baker (Sarcolaenaceae), Adansonia (3) 31 (2), pp. 311-339 : 336-337

10. Xerochlamys villosa F.Gérard

Comptes rendus de l’Association française pour l’Avancement des Sciences 1914 (sess.43): 408 (1915). — Type: Madagascar, Prov. Toliara, massifs gréseux du mont Vohibasia , dans le bassin du Mangoky, dans le sud-ouest de l’île, 500 m, [21°41’S, 45°20’E], VIII.1910, fr., Perrier de la Bâthie 3011 (holo-, P! [ P00389140 ]; iso-, P! [ P00389141 ]) .

Xerochlamys luteola H.Perrier , Bulletin de la Société botanique de France 128: 57 (1931). — Type: Madagascar, Prov. Fianarantsoa, Isalo , près de Ranohira, grès, [22°11’S, 45°10’E], 800 m, X.1924, fr., Perrier de la Bâthie 16694 (holo-, P! [ P00389142 ]; iso-, MO!, P! [2 sheets: P00389143-44 ]).

ADDITIONAL MATERIAL EXAMINED. — Madagascar. Prov. Fianarantsoa, between Tametsoa and Sahanafo , [22°18’S, 45°22’E], 700-1100 m, 30. I.1955, Cours 5045 ( K, MO, P) . — Parc national d’Isalo , [22°33’S, 45°25’E], II.1963, Bosser 17245 ( MO, P, TAN) . — Idem , rebords est de l’Isalo à l’ouest de Ranohira, [22°36’S, 45°23’E], 31.XII.1962, Chauvet 393 ( K, MO, P, TEF) . — Idem , 800 m, 29. I.1955, Cours 5041 ( K, MO, P) . — Idem, 10 km west of Ranohira , [23°16’S, 45°11’E], 810 m, 3.II.1975, Croat 30570 ( MO, TAN) . — Idem, 10 km southwest of Ranohira , [22°30’S, 45°15’E], 800-900 m, 27.III.1985, Dorr et al. 4182 ( K, MO, P) . — Idem, northwest of Ranohira , [22°33’S, 45°19’E], 800 m, 14.II.1990, Du Puy et al. MB659 ( P, TAN) ; Homolle 1341 ( P) ; Homolle s. n. ( P) . — Parc national de l’Isalo forêt d’Ampandrabe , 22°36’51”S, 45°20’45”E, 905 m, 19.XII.2001, Hong-Wa & Ludovic 38 ( MO, P, TAN, TEF) . — Idem, ouest de Ranohira , [22°11’S, 45°10’E], 800-1250 m, 29.I-10.IV.1955, Humbert 28698 ( P) . — 30.VII.1928, Humbert & Swingle 4992 ( MO, P) . — Idem , falaise au nord de Sakamalio, [22°26’S, 45°17’E], 21.IV.1967, Jacquemin 334 ( P) . — Idem, Ranohira-Sakaraha , [22°39’S, 45°21’E], 900 m, 8.VIII.1995, Leeuwenberg & Rapanarivo 14620 ( K, MO, P, TAN) . — Idem, 15 km southwest of Ranohira , [22°41’S, 45°16’E], 800 m, 1.II.1990, Phillipson 3408 ( K, MO, P, TAN) . — Idem, 34 km west of Ranohira along the Sahanafa trail, 1200-1500 m, 6.VII.1992, A. Randrianasolo 239 ( MO) . — Idem, à l’ouest de Ranohira , [22°11’S, 45°10’E], 514-1268 m, 24. I.1955, Service Forestier 11672 ( K, MO, P, TEF) . — 17-18. VI.1958, Service Forestier 18574 ( K, MO, P, TEF) . — Ranohira , 22°37’04”S, 45°21’45”E, 871 m, 27. VI.2005, Hong-Wa et al. 380 ( MO, P, TAN) . — [22°33’S, 45°25’E], 800 m, 13.VII.1954, Service Forestier 14325 ( P, TEF) .

DESCRIPTION

Trees 4-8 m tall, trunk to 20 cm dbh; young twigs yellow-tomentose, older twigs glabrous. Leaf blades glossy bright green above, dull green beneath, broadly ovate or sometimes elliptic, 4-8 × 2-4 cm, chartaceous, with scattered trichomes on the abaxial midvein only when young, glabrous at maturity, base cordate to rounded, margin plane, apex rounded to emarginate, midrib yellow, slightly raised above, distinctly raised beneath, secondary veins prominent, 6-14 per side, 5-6 mm apart, looping 1-4 mm from the margin; petiole 4.5- 11 mm long, glabrous. Flowers solitary, axillary, or rarely inflorescences axillary or terminal, with 2 flowers; peduncle 1-3 mm long, glabrous, pedicel absent to 1 mm long, glabrous. Involucre light brown, urceolate, 3-10 × 4-10, yellow tomentose with scattered white trichomes, teeth 12-20, 0.5- 2.8 mm long; flowers 20-37 mm long at anthesis from apex of pedicel to apex of petals; sepals obovate, 5-12.5 × 4-9 mm, deeply emarginate, exserted 3-5 mm beyond the involucre; petals white, obovate, 17-27 × 8-15 mm, exceeding the involucre by 14-17 mm; disc 2-3.5 mm tall; stamens 24-47, 8- 18 mm long; ovary ovoid, 3-4 mm high, style 7-17 mm long, basally pubescent, stigma 2-3 mm wide. Fruits ovoid to subglobose, 7-11 × 5.5-12 mm, exceeding the accrescent involucre by 2-7 mm; seeds black, ovoid, 2-4 mm long, 3-6 per fruit.

PHENOLOGY

Flowering and fruiting from December to July.

VERNACULAR NAME

Foto.

HABITAT

On sandstone in evergreen sclerophyllous Uapaca bojeri (tapia) woodland from 800-1200 m in subhumid and subarid bioclimatic zones.

DISTRIBUTION

From Mt. Vohibasia to Isalo National Park in SW Madagascar ( Fig. 4 ).

REMARKS

This species can be distinguished by its large (> 4 cm long) and broadly ovate, glabrous leaf blades that are glossy bright green above and dull green beneath, its distinct leaf venation, and its large white flowers subtended by a yellow-tomentose, urceolate involucre. Both Xerochlamys villosa and X. undulata are found around the Isalo massif, but field observations indicate that the former is abundant on rocky substrates whereas the latter grows in sandy areas. The two species clearly differ from each other by the length (≥ 4 cm long in X. villosa vs. <4 cm long in X. undulata ) and the shape (ovate vs. elliptic) of their leaf blades, the absence (vs. presence) of trichomes, the colour of the petals (white vs. pale yellow to white) and of the indumentum on the involucre (yellow vs. red).

Perrier de la Bâthie (1931) described Xerochlamys luteola , failing to recognize that it represented the same entity as X. villosa , which he erroneously placed in synonymy under L. bojeriana . Indeed, the type of X. villosa (Perrier 3011, the only material available to him at the time) differs from X. bojeriana in several notable ways, including leaf blade shape and size, petiole length, and the shape and size of the involucre. Although no additional material of X. villosa s.s. has been collected since the type was made, X. luteola is clearly the same taxon.

CONSERVATION STATUS

Xerochlamys villosa has only been recorded in less than five locations within and around the Isalo and Vohibasia National Parks. With an extent of occurrence of 938 km 2, an area of occupancy of 90 km 2, this species is provisionally considered Endangered [EN B1ab(i,ii,iii,iv)+2ab(i,ii,iii,iv)].

UNPLACED MATERIAL

Madagascar. Prov. Fianarantsoa: Ambatofinandrahana , 20°30’43”S, 46°46’31”E , 1475 m, 31.VII.2001, Andriamihajarivo et al. 11 ( MO, P, TAN, TEF). — [20°33’S, 46°48’E] , 1600-1800 m, 9.II.1938, Decary 13081 ( MO,

P). — Andranofimoritra, bassin supérieur de l’Onilahy, [23°53’S, 46°31’E], 1000-1200 m, 19.XII.1928, Humbert 7047 ( P). — Itremo, eastern margin of the Itremo Massif, c. 19 km west of Ambatofinandrahana , 20°34’21”S, 46°34’54”E, 1580-1700 m, 10.III.2000, Schatz et al. 3963 ( MO) .

REMARKS

The four specimens listed above could not be placed in any of the species recognized here because of their unusual morphology.The material represented by Andriamihajarivo et al. 11 may be a hybrid between Xerochlamys diospyroidea and X. bojeriana , and likewise Humbert 7047 may be the result of hybridization involving X. diospyroidea and X. coriacea , or they may be completely distinct entities that could be recognizable with additional collections. By contrast, material of Decary 13081 appears to be related to X. elliptica , but cannot be accommodated therein because the leaf blades are broadly elliptic, deeply emarginate and lack the whitish coloration beneath, the secondary veins are not prominent and the specimen is described to be a small bush with pink flowers, whereas X. elliptica is a small tree generally with white flowers. The fourth specimen (Schatz et al. 3963) seems to represent nothing more than a variant of X. bojeriana as it has the same pubescent and elliptic (albeit almost cuneiform) leaf blade, which is also larger than usual; but these odd features, as well as the absence of reproductive organs on this specimen, preclude the confident assignment of a name.

Figures

FIG. 4. — Distributions of Xerochlamys elliptica F.Gérard (Å), X. diospyroidea (Baill.) Baker (▲), X. tampoketsensis F.Gérard (■) and X. villosa F.Gérard (●) mapped on the bioclimatic zones of Madagascar (after Cornet [1974], simplified by Schatz [2000]).