Buxus madagascarica subsp. xerophila H. Perrier, Fl. Madagascar 113: 4-5 (1952) Buxus madagascarica subsp. xerophila H. Perrier, Fl. Madagascar 113: 4-5 (1952) A synoptic revision of the genus Buxus L. (Buxaceae) in Madagascar and the Comoro Islands Schatz, George E. Lowry Ii, Porter P. Adansonia 2002 3 24 2 179 196 5X5TL G.E. Schatz & Lowry G. E. Schatz & Lowry 2002 [180,587,1523,1550] Magnoliopsida Buxaceae Buxus Plantae Buxales 4 183 Tracheophyta species calcarea sp. nov.     Buxus madagascaricasubsp. xerophilaH. Perrier, Fl.   Madagascar113: 4-5 (1952), nomen inval., non rite publ. sine Latin, pro parte“ fa. calcicolaH. Perrier”; syn. nov.  Haec species lamina foliari plerumque supra medium latiore ad congeneros madagascarienses nonnullos accedit, sed ab eis foliis minoribus (minus quam 35 mmlongis) rigidissimis venatione ut videtur carentibus juventute glaucis distinguitur.  TYPUS. — Service Forestier (Capuron) 11870 [= H. Humbert& R. Capuron 29315], Madagascar, Prov. Toliara, Sud-Ouest: bush (sur calcaire) sur les falaises des environs de Lavanono [falaise côtière nord- Fig. 3. — Distributions of  Buxus, mapped on the bioclimatic zones of Madagascar(after CORNET 1974; see SCHATZ 2000).  B. angustifolia(),  B. calcarea(❋),  B. capuronii(),  B. humbertii(✚),  B. itremoensis(),  B. macrocarpa( J),  B. madagascarica(*),  B. monticola(•),  B. moratii(Δ).  ouest du Cap Sainte-Marievers Lavanono], [ 25°28’S, 45°00’E],  1-150 m,  8 Mar. 1955, fr. (holo-, P!; iso-, K!, MO!, P!, TEF!). Shrubs to small trees to 4-5 m, young stems  1 mmdiam., glaucous with short, erect tri- chomes, internodes 7-11 mm. Leaves very stiff and thick coriaceous, glaucous when young, 0.7- 3.2 × 0.3-1.1 cm, oblanceolate to obovate or sometimes narrowly elliptic, usually broader above the middle, apex rounded to obtuse or rarely acute, base cuneate to attenuate, midrib invisible above, evident and slightly raised towards the base below, secondary venation absent; petioles 1-2 mmlong. Flowers solitary, axillary; male flowers subtended by 8-12, slightly keeled, minute bracts; sepals 4, 0.6-1 × 1-1.2 mm, broadly ovate, apex rounded; anthers 4, sessile, 1.5 × 1 mm; female flowers subtended by 8 slightly keeled, minute bracts; sepals 4, 1.2-1.6 × 0.9-1.8 mm, broadly ovate, keeled, apex obtuse to acute, styles 3, 3- 4 mmlong, apex strongly recurved, stigma borne along inside of upper 2/3. Fruits 6-8.5 × 5 mm, ellipsoid, stylar remnants 2 mm; seeds 5.5 × 3 mm. — Fig. 4.  Fig. 4. —  Buxus calcarea: A, fruiting branch; B, leaf, adaxial surface; C, leaf, abaxial surface. ( Service Forestier 11870).   Buxus calcareais known from subarid deciduous thicket on tertiary limestone in southwestern Madagascar, from the Mahafaly plateau to Angavo east of Antanimora (Fig. 3). Among the species with leaf blades usually broader above the middle,  B. calcareacan be distinguished from  B. capuroniiand  B. humbertiiby its small, very stiff coriaceous leaves lacking any visible venation, which are glaucous when young. CONSERVATION STATUS. —  Buxus calcareais known from only 4 localities, and has not been collected since 1963. With an Extent of Occurrence of c. 3,650 km 2, an Area of Occupancy of perhaps only 400 km 2, and only 4 sub-populations,  B. calcareais assigned a preliminary status of Endangered (EN B1ab2ab).   PARATYPES. — MADAGASCAR, Prov. Toliara:   Perrier de la Bâthie5989, plateau Mahafaly(Menarandra), [ 24°42’S, 45°03’E],  June 1910, fl. ( P, 2 sheets);  Service Forestier (Capuron) 8485, Sud-Ouest: bush, à l’est du Mandrare, sur la route d’Ambovombe à Ft. Dauphin, [ 25°01’S, 45°30’E],  22 Sep. 1953, fl. ( P, TEF);   Service Forestier(Capuron) 22484, Sud: crête du massif de l’Angavoà l’est d’Antanimora, [ 24°50’S, 45°48’E],  500 m,  23 Jan. 1963, fr. ( MO, P, TEF).  3.  Buxus capuroniiG.E. Schatz & Lowry,  sp. nov.  Haec species lamina foliari plerumque supra medium latiore ad congeneros madagascarienses nonnullos accedit, sed ab eis foliis majoribus (maximo plus quam 40 mmlongo) supra secus costam rubellam trichomatibus albis erectis brevibus obtectis distinguitur.   TYPUS. — Service Forestier (Capuron) 24212, Madagascar, Prov. Mahajanga, Ouest (Ambongo): forêt de Tsiombikibo[FC], à l’ouest de Mitsinjo, [ 16°00’S, 45°44’E],  19 Nov. 1965, fl. (holo-, P!; iso-, BR!, C!, G!, K!, MO!, P(2)!, PRE!, TEF!, US!, WAG!). Small tree, stems 1 mmdiam., reddish, prominently ridged, covered with sparse, short, erect, white trichomes, internodes 5-11 mm. Leaves coriaceous, 3-5.1 × 0.6-1.8 cm, narrowly obovate to obovate, apex rounded to obtuse, base cuneate to attenuate, midrib raised and rounded above, 0.2 mmbroad at apex broadening to 0.9 mmbroad at base, reddish, with short, erect, white trichomes becoming dense toward the base, slightly raised below, secondary veins 12-16 per side, barely visible on young leaves; petioles 1-2 mmlong. Flowers axillary; male flowers solitary or 3 per axil, subtended by 8 or 12, slightly keeled, minute bracts; sepals 4, 0.8 × 0.6-0.9 mm, broadly ovate, the apex rounded to acute; anthers 4, sessile, 1.6- 1.7 × 0.7-0.8 mm; female flowers solitary, or 2-3 per axil, or the central flower in bisexual inflorescences, subtended by 12 strongly keeled, minute bracts; sepals 4, 1.5 × 1.6 mm, triangular, strongly keeled, the apex acute, styles 3, exserted only 0.5 mmabove sepals. Fruits unknown. — Fig. 5.   Buxus capuroniiis known only from the typecollection, gathered by CAPURON in November, 1965, at the dry deciduous forêt de Tsiombikibo to the west of Mitsinjo in the Ambongo region (Fig. 3). Among the species with leaf blades broader above the middle,  B. capuroniican be distinguished from  B. calcareaand  B. humbertiiby its larger leaves with the midrib above bearing short, erect, white trichomes.  ETYMOLOGY. — This species is named in honor of René CAPURON, who contributed so much to our knowledge of Madagascar’s woody flora. CONSERVATION STATUS. — Because  Buxus capuroniiis known only from a single historical collection, the available data are insufficient to assess its conservation status. It must therefore be regarded as Data Deficient (DD). Tsiombikibo currently retains the status of a Forêt Classée, and thus there is hope that  B. capuroniistill persists there, or in nearby Baie de Baly PN.   4.  Buxus humbertiiG.E. Schatz & Lowry,  sp. nov.     Buxus madagascaricasubsp. xerophilaH. Perrier, Fl.   Madagascar113: 4-5 (1952), nomen inval., non rite publ. sine Latin, pro parte“ fa. silicicolaH. Perrier”; syn. nov.  H a e c s p e c i e s l a m i n a f o l i a r i p l e r u m q u e s u p r a medium latiore ad congeneros madagascarienses nonnullos accedit, sed ab eis foliis minoribus (minus quam 35 mmlongis) glabris venatione secundaria tertiariaque supra manifesta apice plerumque emarginatis distinguitur.  TYPUS. —   Humbert13695, Madagascar, Prov. Toliara, bassin de réception de la Mananara, affluent du Mandrare, pentes occidentales des montagnes entre l’Andohahelaet l’Elakelaka entre Ampahiso et Mahamavo(gneiss), vers  700 m, [ 24°45’S, 46°43’E],  Jan.-Feb. 1934, fr. (holo-, P!; iso-, MO!, P!). Shrubs to small trees, young stems < 1 mmdiam., glabrous, internodes 4-9(-20) mm. Leaves coriaceous, glabrous, greenish and somewhat glossy, 0.8-2.2 × 0.3-1 cm, oblanceolate to obovate, slightly convex, apex rounded and often emarginate, base attenuate and decurrent, midrib flat to slightly impressed along lower half above, slightly raised below, dense secondary and tertiary venation evident and slightly raised above; leaves subsessile, petioles < 1 mmlong. Flowers unknown, axillary; sepals of female flowers in fruit 2 × 1.5-1.8 mm, triangular, the apex acute to obtuse. Fruits 6-7 × 4.5-5 mm, ellipsoid, the stylar remnants 1 mmlong; seeds 3-3.5 × 2 mm. — Fig. 6.   Buxus humbertiiis known from three disjunct areas of dry to subarid deciduous thicket and forest in southern Madagascar, possibly associated with siliceous soils on gneiss (Fig. 3): the western slopes of Andohahela PN in the upper Mananara river basin; the Menarahaka river valley east of Ihosy; and Zombitsy PN near Sakaraha, where it was last collected in 1972. Among the species with leaf blades usually broader above the middle,  B. humbertiican be distinguished from  B. calcareaand  B. capuroniiby its small, somewhat convex leaves with distinct secondary and tertiary venation visible on the upper surface and with a usually emarginate apex.  ETYMOLOGY. — The species epithet honors Prof. Henri HUMBERT, who conducted extensive field work in Madagascarover five decades, and who contributed greatly to our understanding of the Malagasy flora and vegetation. CONSERVATION STATUS. —  Buxus humbertiiis known from only 3 localities, and has an Area of Occupancy of approximately 300 km 2within an Extent of Occurrence of c. 24,765 km 2. Thus, despite the fact that it may persist at two protected areas (Zombitsy PN and Andohahela PN),  B. humbertiiis assigned a preliminary status of Endangered (EN B2ab).    PARATYPES. — MADAGASCAR,  Prov. Toliara:  Debray1913, forêt du Zombitsy-Sakaraha, [ Zombitsy PN], [ 22°46’S, 44°42’30”E],  30 Nov. 1972, st. ( MO, P);   Guillaumet2438, forêt du Zombitsy-Sakaraha, [ Zombitsy PN], [ 22°46’S, 44°42’30”E],  Apr. 1969, st. ( P, TAN);   Service Forestier( Capuron) 20229, Ouest: forêt du Zombitsy, à l’est de Sakaraha, [ ZombitsyPN], [ 22°46’S, 44°42’30”E],  3-5 Apr. 1961, fr. ( K, MO, P, TEF);   Service Forestier96-R-10, forêt de Menarahaka, Dist. d’Ihosy, [ 22°32’S, 46°29’50”E],  Dec. 1951, st. ( MO, P, TEF);   Service Forestier46-R- 239, Menarahaka, Ihosy, [ 22°32’S, 46°29’50”E],  7 Feb. 1954, st. ( P, TEF);   Service Forestier207-R-239, forêt de Menarahaka, Dist. d’Ihosy, [ 22°32’S, 46°29’50”E],  25 Mar. 1956, st. ( P, TEF).  5.  Buxus itremoensisG.E. Schatz & Lowry,  sp. nov.  Haec species ab omnibus congeneris madagascariensibus foliis maturis linearibus distinguitur.   TYPUS. — Labat, Du Puy& Andriantiana2441, Madagascar, Prov. Fianarantsoa, Ambatofinandrahana, Itremo, juste à l’est du col d’Itremo, 20°34’13”S, 46°35’08”E,  1560 m,  26 Nov. 1993, fl., fr. (holo-,P!; iso-, K!, MO!, TAN!, TEF!, WAG). Rheophytic shrub 2 mtall growing amongst rocks in streambed, completely glabrous. Stems 0.6 mmdiam, distinctly 4-angled, internodes 4-10 mm. Leaves coriaceous, 1.4-3.7 × 0.09-0.3 cm, linear, sometimes slightly falcate, apex acute to acuminate, base attenuate and decurrent along stem, midrib flat to slightly raised above, raised below, secondary venation absent; leaves subsessile, petioles to 0.4 mm. Flowers solitary, axillary, subtended by several minute bracts; male flowers with 4 minute sepals less than 0.5 mmlong, anthers 4, sessile, fused at their base, 1 × 0.4 mm; female flowers with 4 minute sepals less than 0.5 mmlong, styles 3, sessile, 3 mmlong, the apex strongly recurved, stigma borne along inside of upper 2/3. Fruits 3-3.5 × 2-2.5 mm, ellipsoid, the stylar remnants 1.6 mmlong. — Fig. 7.  Fig. 6. —  Buxus humbertii: A, flowering branch; B, leaf, adaxial surface; C, leaf, abaxial surface. (  Humbert13695).  Fig. 7. —  Buxus itremoensis: A, flowering and fruiting branch; B, leaf, adaxial surface; C, leaf, abaxial surface. ( Labat et al. 2441).   Buxus itremoensisis a rheophytic shrub known only from the Itremo massif (Fig. 3). It can be easily distinguished from all other Malagasy  Buxusspeciesby its linear, slightly falcate leaves. Both  Buxus madagascaricaand  B. monticolaalso exhibit linear leaves during the juvenile seedling stage, as illustrated by PERRIER DE LA BÂTHIE (1952)in the Flore de Madagascar(undoubtedly based upon Perrier de la Bâthie 13275for  B. madagascarica). Thus,  Buxus itremoensispossi- bly represents a case of paedomorphism, with retention of juvenile leaves into the adult reproductive stage. CONSERVATION STATUS. — With only a single sub-population outside the current protected areas network, an Extent of Occurrence less than 100 km 2and an Area of Occupancy less than 10 km 2,  B. itremoensisshould be considered Critically Endangered (CR B1ab2ab). It joins numerous other plant species restricted to the Itremo massif, which is among the very highest priority areas for plant conservation in Madagascar.   PARATYPES. — MADAGASCAR,  Prov. Fianarantsoa:  Humbert30033, montagnes à l’ouest d’Itremo, bois des pentes occidentales sur gneiss et quartzites, [ 20°34’S, 46°34’E],  1500-1700 m, 17-22 Jan. And  18-22 Apr. 1955, fr. ( CAS, G, K, MO, P(3 sheets), WAG);  Lowry, Schatz, Andriamihajarivo, Hong-Wa, Rapanarivo& Rabarison5822, Itremo massif,  Wof Ambatofinandrahanaalong road to Col d’Itremo, just below bridge over Ambalorangolana river, wet creek bed, 20°34’40’’S, 46°35’11’’E,  1540 m,  9 Nov. 2002, fl. ( CAS, G, K, MO, P, TEF, WAG);  Randrianaivo, Birkinshaw, Rakotomamonjy, Andriatiana, Randrianasolo& Rasolomanana154, Itremo, 20°34’S, 46°34’E,  1630-1770 m,  6 Apr. 1998, fr. ( MO, P, TAN);  Schatz, Razafindrakoto, Andrianjafy& Rabenantoandro3980, Itremo, 20°34’21”S, 46°34’54”E,  1580 m,  11 Mar. 2000, fr. ( MO, P, TEF);  Service Forestier (Capuron) 11556, Mont Ambatomenaloha, Wd’Itremo, restes de forêts dans les thelwegs humides, [ 20°34’S, 46°34’E],  18 Jan. 1955, fl. ( G, K, MO, P(2 sheets), TEF);  Service Forestier (Capuron) 29041, berges et rochers encombrant le lit de l’Ambatorangotanadans le montée au col de l’Itremo, [ 20°34’S, 46°34’E],  1600 m,  21 Feb. 1970, fr. ( MO, P(2 sheets), TEF);   van der Werff& McPherson13585, massif d’Itremo, 20°37’S, 46°35’E,  1500 m,  27 Oct. 1994, fl., fr. ( MO, TAN). 1955-03-08 P, K, MO, TEF du Cap Sainte-Marie & Lavanono 76 -25.466667 1246 45.0 5 184 1 1910-06 P Perrier de la Bathie Madagascar -24.7 Mahafaly 1249 45.05 Perrier de la Bathie 7 186 1 Toliara paratype 1953-09-22 P, TEF du Mandrare & Ft. Dauphin Madagascar -25.016666 1248 45.5 7 186 1 paratype 1963-01-23 MO, P, TEF Service Forestier & Sud & de l'Angavo & d'Antanimora Madagascar 500 -24.833334 1249 45.8 7 186 1 paratype 1965-11-19 TYPUS, P, BR, C, G, K, MO, PRE, TEF, WAG de Tsiombikibo & de Mitsinjo Madagascar -16.0 Mahajanga 1283 45.733334 7 186 1 Mahajanga 1934-01 1934-02-31 1934-01 P, MO de la Mananara & du Mandrare Madagascar 700 -24.75 l'Andohahela 1249 46.716667 9 188 1 Toliara 1972-11-30 MO, P du Zombitsy-Sakaraha & Zombitsy PN Madagascar -22.766666 Debray 925 44.708336 Prov. 9 188 1 Toliara paratype 1969-04 P, TAN du Zombitsy-Sakaraha & Zombitsy PN Madagascar -22.766666 Guillaumet 925 44.708336 9 188 1 paratype 1961-04-03 1961-04-05 1961-04-03 K, MO, P, TEF du Zombitsy & de Sakaraha & Zombitsy Madagascar Service Forestier -22.766666 Ouest 925 44.708336 Capuron 9 188 1 paratype 1951-12 MO, P, TEF de Menarahaka & Dist. d'Ihosy Madagascar -22.533333 Service Forestier 925 46.497223 9 188 1 paratype 1954-02-07 P, TEF Madagascar -22.533333 Service Forestier 925 46.497223 9 188 1 paratype 1956-03-25 P, TEF de Menarahaka & Dist. d'Ihosy Madagascar -22.533333 Service Forestier 925 46.497223 9 188 1 paratype 1993-11-26 TYPUS Du Puy & Andriantiana Madagascar 1560 -20.570278 Ambatofinandrahana 21 46.585556 9 188 1 Fianarantsoa 1955-04-18 1955-04-22 1955-04-18 CAS, G, K, MO, P, WAG Madagascar Prov. 1600 -20.566668 Jan. And 1267 46.566666 d'Itremo 12 191 1 Fianarantsoa paratype 2002-11-09 W, CAS, G, K, MO, P, TEF, WAG Rapanarivo & Rabarison Madagascar 1540 -20.577778 Ambalorangolana river 21 46.586388 12 191 1 paratype 1998-04-06 MO, P, TAN Randrianasolo & Rasolomanana Madagascar 1700 -20.566668 1267 46.566666 12 191 1 paratype 2000-03-11 MO, P, TEF Andrianjafy & Rabenantoandro Madagascar 1580 -20.5725 21 46.581665 12 191 1 paratype 1955-01-18 W, G, K, MO, P, TEF Madagascar -20.566668 1267 46.566666 12 191 1 paratype 1970-02-21 MO, P, TEF de l'Ambatorangotana & de l'Itremo Madagascar 1600 -20.566668 1267 46.566666 12 191 1 paratype 1994-10-27 MO, TAN van der Werff & McPherson Madagascar 1500 -20.616667 1267 46.583332 12 191 1 paratype