Vitex rabenantoandroi Callm. & Phillipson, 2021

Callmander, Martin W. & Phillipson, Peter B., 2021, Towards a Revision of the Genus Vitex (Lamiaceae) in Madagascar. II: Three New Species from the Littoral Forests, Novon: A Journal for Botanical Nomenclature 29, pp. 38-47 : 42-44

2. Vitex rabenantoandroi Callm. & Phillipson , sp. nov.

TYPE: Madagascar. Atsimo-Atsinanana [Fianarantsoa]: forêt à Iabomary , 40 km au SW de Farafangana, 23°03′34″S 47°40′23″E, 0–50 m, 6 Feb. 2001, J. Rabenantoandro, R. Rabevohitra & Ratiana 409 (holotype, G [bc] G00341873! ; isotypes, MO-6039865 image!, P [bc] P02866503! , TAN n.v.). Figures 2C , 3 .

Diagnosis. Vitex rabenantoandroi Callm. & Phillipson differs from V. chrysomallum Steud. by its (2- to)3(to 5)-flowered cymose inflorescence (vs.> 10-flowered), its long and large calyx (9–13 × 4–7 mm) covered by a very fine dense orange velutinous indument (vs. small, ca. 4 × 4 mm, with a scarce fawn puberulent indument), and its wide (6 mm) golden yellow corolla (vs. narrow [3 mm], bright yellow).

Tree up to 15 m tall. Young vegetative parts and inflorescence branches with a fine mid-brown pubescence, glabrescent. Leaves palmate, (2- to)5-foliolate; petiole 2–9 cm; leaflets obovate (sometimes narrowly so), petiolulate (petiolule 0.5–1.5 cm), subcoriaceous, the largest (median) leaflet 4–15 × 1.5–6 cm; blade dark brown above and mid-brown below in sicco; base attenuate; apex generally rounded, sometimes emarginate; margin entire, usually at least somewhat revolute; abaxial surface glabrous, with midrib prominent, and, together with secondary veins, with a brown pubescence when young, glabrescent; adaxial surface glabrous, with midrib impressed. Inflorescence axillary (generally in opposite pairs), a (2- to)3(to 5)-flowered cyme comprising a single terminal flower and 2 or more lateral flowers; peduncle 1.5–2 cm; terminal flower borne on an ebracteolate pedicel ca. 0.8 cm; lateral flowers subtended by small paired caducous bracteoles and borne on pedicels 0.2–0.4 cm; pedicels with a very fine dense orange velutinous indument that becomes brown in fruit (appearing glabrous without magnification), not elongating in fruit. Calyx campanulate, 9–13 × 4–7 mm, truncate but splitting at anthesis to form irregular lobes of a variable number, with an indument similar to that of the pedicel. Corolla tubular, slightly curved, ca. 20 × 6 mm, tapering to 3 mm diam. at base, golden yellow sericeous outside, yellow, glabrous inside (except the sericeous proximal part); lobes triangular, ca. 1 × 2 mm but their outline almost completely concealed by the indument. Stamens 4, slightly curved, exserted by ca. 6 mm; filaments ca. 26 mm, the portion within the tube villous; anthers ca. 1 mm. Style ca. 26 mm, shortly bifid. Fruit a drupe, globose-ellipsoidal, 15–20 × 10–12 mm, wrinkled when dried, cupped by the accrescent calyx for ca. 3/4 of its length.

Etymology. The species epithet honors our colleague Johny Rabenantoandro, who made more than 1100 plant collections working with Gordon McPherson on the littoral forest project (see above). Johny collected all three new species presented in this article, including the type material of both this eponymous species and Vitex zigzag .

Vernacular name. “Vombirimbarika” (Birkinshaw et al. 1649).

Distribution and ecology. Vitex rabenantoandroi is known mostly from littoral forests of the east coast of Madagascar, but a few collections are from lowland evergreen forest (e.g., at Ankarabolava). Its distribution spans more than 850 km along the east coast of Madagascar from the Anosy Region in the south to the Analanjirofo Region in the center. The new species grows from sea level to ca. 100 m. s.m.

Conservation status. Vitex rabenantoandroi is known from 18 subpopulations in littoral forests along the east coast of Madagascar and hasan EOO of ca. 11,600 km 2 and an AOO of 76 km 2. Seven subpopulations are encompassed in the protected area network (Agnalazaha, Agnakatrika, Analalava, two within Ankarabolava, Manombo, and Tsitongambarika) where they are at least afforded legal protection. At the other sites in which the species occurs it is threatened by forest clearance for grazing, agriculture, and urbanization ( Consiglio et al., 2006). With these threats and its restricted EOO and AOO, but with more than 10 known locations, V. rabenantoandroi is assigned a status of “Near Threatened” [NT] following IUCN Red List Categories and Criteria ( IUCN, 2012).

Notes. Vitex rabenantoandroi is clearly distinguished from other Malagasy Vitex species by its inflorescence with only two to five flowers borne on pedicels covered by a very fine, orange, velutinous indument, and with its golden yellow corolla that is sericeous outside. Specimens have frequently been identified in the past as V. chrysomallum . This species, which also occurs in littoral forests of Madagascar, can be easily distinguished from the new species by its bright yellow corolla andinflorescencesalwayswith> 10 flowers ( Fig. 2D ).

Paratypes. MADAGASCAR. Analanjirofo [Toamasina]: Fenerive, [17°17′S 49°23′E], 25 Sep. 1954, Service Forestier 10817bis (G, MO, P, TEF). Anosy [Toliara]: Iabakoho, Antsotso Avaratra , Ivohibe , 24°34′10″S 47°12′26″E, 105 m, 24 May 2006, Birkinshaw et al. 1649 (MO, P, TAN). Atsimo-Atsinanana [Fianarantsoa]: Mahabo, forêt de Analazaha Mananivo , 23°12′38″S 47°43′47″E, 25 m, 19 Feb. 2003, Ludovic et al. 253 (P, TAN); same loc., near village of Mahabo, 23°10′36″S 47°42′01″E, 3 Nov. 2001, McPherson & Rabenantoandro 18309 (MO, P); Mahabo-Mananivo , 23°10′20″S 47°42′23″E, 29 m, 23 Sep. 2002, Rabenantoandro et al. 966 (P, MO, TAN); Mahabo, 23°10′12″S 47°41′54″E, 5 Feb. 2001, Rabevohitra & Rabenantoandro 3795 (MO, P, TAN); Mahabo, forest block of Ampanasanay, along trail going to Anosiala, 23°10′58″S 47°41′44″E, 13 m, 19 June 2004, Randrianasolo et al. 861 (P); 1 km à l’E de Vohipaho, AP Ankarabolava , 23°31′16″S 47°29′55″E, 75 m, 18 Feb. 2016, Ratovoson 2179 (MO, P, TAN); 3 km Sde Tsianofana, AP Ankarabolava , 23°27′03″S 47°30′29″E, 95 m, 22 Feb. 2016, Ratovoson 2259 (MO, P, TAN); le long de la rte. entre Farafangana et Vangaindrano, 23°03′32″S 47°43′29″E, 14 Jan. 2009, Razafindraibe et al. 211 (MO, P, TAN); Mahabo- Mananivo, ca. 3 km à l’E du gîte MBG, 23°10′58″S 47°42′27″E, 12 m, 13 Aug. 2006, Razafitsalama & Tsimahely 959 (MO, P, TAN); forêt de Mahabo , 23°11′13″S 47°42′27″E, 22 m, 26 Aug. 2003, Razakamalala & Rabehevitra 706 (P); Manombo AP , parcelle II , 23°05′23″S 47°45′13″E, 20 m, 20 Sep. 2005, Razakamalala et al. 2154 (MO, P, TAN). Atsinanana [Toamasina]: forêt d’Analalava , à 6 km Wde Foulpointe, 17°41′33″S 49°27′29″E, 45 m, 9 Mar. 2005, Lehavana et al. 295 (MO, P, TAN); Fir. Ambodibonara , Fkt. Ambalavontaka , forêt de Nankinana , 20°21′15″S 48°36′26″E, 18 m, 10 Feb. 2004, Rabehevitra et al. 778 (MO, P, TAN); Antetezana, [17°47′S 49°28′E], 5–25 m, 21 June 1950, Service Forestier 1985 (P, TEF); forêt d’Analalava , àl’Wde Foulpointe, [17°41′30″S 49°27′30″E], 22 May 1969, Service Forestier 28881 (P, TEF). Vatovavy-Fitovinany [Fianarantsoa]: à 13 km env. au Nde Manakara, 22°01′41″S 48°04′10″E, 8 Feb. 2001, Rabevohitra & Rabenantoandro 3841 (MO, P, TAN); Nosy Varika, forêt d’Ambolo , 20°48′59″S 48°27′09″E, 16 June 2004, Ranaivojaona et al. 831 (MO, P, TEF); Fkt. Marohita , forêtlittoraled’Alimamba , 21°28′04″S 48°17′43″E, 13 m, Oct. 2004, Razakamalala et al. 1660 (MO, P, TAN); Belambo Manakara, [22°02′15″S 48°00′45″E], 14 Feb. 1955, Service Forestier 13599 (P, MO, TEF); forêt E du village Ambohitsara , Nosy Varika, 20°33′S 48°30′E, 20 May 1961, Service Forestier 19952 (P, TEF). S. loc.: s.d., Service Forestier 2120 (P, TEF).

Figures

Figure 2. Vitex L. from the littoral forests of Madagascar. ––A. Vitex bracteata Scott Elliot, Swenson 1710 (photo, U. Swenson). ––B. Vitex tristis Scott Elliot, Ratovoson 1742 (photo, F. Ratovoson). ––C. Vitex rabenantoandroi Callm. & Phillipson, Ratovoson 2179 (photo, F. Ratovoson). ––D. Vitex chrysomallum Steud., Miller 10454 (photo, P. Lowry).

Figure 3. Vitex rabenantoandroi Callm. & Phillipson. —A. Flower. ––B. Branch with inflorescence. ––C. Branch with infructescence. ––D. Detail of fruit. A, B based on Rabenantoandro et al. 409 (TAN). C, D based on Ludovic 1055 (TAN). Drawing: Roger Lala Andriamiarisoa.