Vitex mcphersonii 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 : 38-40

1. Vitex mcphersonii Callm. & Phillipson , sp. nov.

TYPE: Madagascar. Analanjirofo Region [Toamasina]: Nof Soanierana-Ivongo, near village of Antanambao-Ambodimanga, 16°45′28″S 49°42′59″E, 19 May 2003, G. McPherson 18970 (holotype, G [bc] G00341881! ; isotypes, MO- 6481571 image!, P [bc] P04398085! , TAN n.v.). Figure 1 .

Diagnosis. Vitex mcphersonii Callm. & Phillipson differs from V. oscitans Moldenke by its smaller unifoliolate leaves (4–12 × 1–5 cm vs.11–14 × 6–8 cm), dark brown to mid-brown on both surfaces in sicco and not shiny (vs. bright green, very shiny below); smaller, tubular calyx, 3–5 × 2–3 mm, with short, straight lobes ca. 0.5 × 1 mm (vs. broadly campanulate, 5–7 × 3–4 mm, with larger, spreading lobes, ca. 1 × 3 mm); and tubular, curved corolla, densely pubescent in bud becoming sparsely pubescent at anthesis (vs. short, broad infundibular corolla, densely villous-hirsute outside, more densely so toward the apex, with long dull-brownish hairs).

Tree up to 20 m tall. Young vegetative parts and the inflorescence branches generally with a somewhat obscure, puberulous, gray indument. Leaves unifoliolate; petiole 0.5–2 cm; blade obovate to elliptic, coriaceous, 4–12 × 1–5 cm; dark brown to mid-brown on both surfaces in sicco; base attenuate; apex generally rounded, sometimes emarginate or occasionally acute; margin entire, revolute; both surfaces glabrous, abaxial surface with midrib, secondary, and tertiary venation prominent, adaxial surface with midrib impressed and venation obscure. Inflorescence axillary (generally in opposite pairs), a divaricating, 2- to 4-times branching dichasium or sometimes reduced to a monochasium, and sometimes having a sterile basal portion; bracteoles paired, conspicuous, elliptic to lanceolate, 6–15 × 2–6 mm, somewhat naviculate and wrapping around the pedicel of the subtended flower; with terminal flower usually present; peduncle 5–10 mm; branches 3–8 mm, <1 mm diam.; pedicels 2–5 mm, not elongating in fruit, puberulent. Calyx campanulate, 3–5 × 2–3 mm, 5-lobed, lobes triangular, ca. 1 × 1 mm, covered by a similar indument as the pedicel, enlarging in the fruit and splitting irregularly. Corolla tubular, curved, ca. 15 × 4 mm, tapering to 2 mm diam. at base, densely pubescent in bud becoming sparsely pubescent at anthesis, bright orange-red, zygomorphic with the lowest lobe ca. 3 mm, the lateral lobes ca. 2 mm, the upper lobes separated by a 1-mm-deep sinus. Stamens 4, curved, exserted by ca. 5 mm; filaments ca. 20 mm, the portion within the tube with scattered patent trichomes; anthers <1 mm. Style ca. 20 mm, shortly bifid. Fruit a drupe, globose-subcylindric, maroon, ca. 8 × 6 mm, wrinkled when dried, cupped by the accrescent calyx for ca. 1/4 of its length.

Etymology. The species epithet honors our colleague Gordon McPherson, who made more than 2300 plant collections in Madagascar during his eight visits between 1989 and 2003. Gordon was the Principal Investigator on the Missouri Botanical Garden project “A Botanical Survey of Madagascar’s Endangered Littoral Forest” between 2001 and 2005 supported by the National Science Foundation. This project provided an important leap forward in our understanding of the rich biodiversity of threatened littoral forests of Madagascar, and eventually the measures to protect them ( Consiglio et al., 2006).

Vernacular names. “Sakondranto” (Service Forestier 16198).

Distribution and ecology. Vitex mcphersonii is known from littoral forests on sands of the east coast of Madagascar from Manombo in the Atsimo-Atsinanana Region in the south to the Masoala Peninsula in the SAVA Region in the north. The new species grows from sea level to 50 m. s.m.

Conservation status. Vitex mcphersonii is known from eight subpopulations in littoral forest along the east coast of Madagascar, three of which are encompassed in the protected area network (Agnalazaha, Manombo, and Tampolo). At the five other sites (more than 60% of its AOO), the species is subject to threat from deforestation ( Consiglio et al., 2006), and the populations of the species are severely fragmented. On the basis of its AOO of just 52 km 2, V. mcphersonii would easily qualify as “Endangered” on this criterion; however, since it is known from more than five locations it is correctly assigned a status of “Vulnerable” [VU B2ab(iii)] following IUCN Red List Categories and Criteria ( IUCN, 2012). The two northernmost populations on the Masoala Peninsula are not protected and if these were extirpated, this would lower the AOO and drastically reduce the EOO of this new species and the number of localities, and the species would then be assessed as “Endangered.”

Notes. Vitex mcphersonii is similar to V. oscitans in having unifoliolate leaves and a pair of bracteoles wrapping around the pedicel of the subtended flower. The latter species has larger leaves, which are green and shiny below in sicco. As indicated in the diagnosis above, the flowers of the two species also differ in several respects. Unfortunately, the corolla color of V. oscitans is not known for certain, but we suspect that it may be pale pink or yellow, whereas the corolla of V. mcphersonii is bright red.

Other species from the eastern littoral forests in Madagascar have unifoliolate leaves and bracteoles wrapping around the pedicel of the subtended flower. Vitex bracteata Scott Elliot and V. tristis Scott Elliot , both endemic to the southeastern region, show this morphological character. Vitex bracteata can be easily recognized by its pubescent leaves, its pauciflorous inflorescences borne on a long (ca. 3–5 cm), narrow peduncle, and its long (ca. 1 cm), thin-textured calyx ( Fig. 2A ). Vitex tristis is distinctive in having a long (ca. 2 cm), red, tubular, membranaceous calyx with five ovate lobes ca. 2–3 mm long ( Fig. 2B ).

Paratypes. MADAGASCAR. Analanjirofo [Toamasina]: Nof Manompana, forêt d’Antanambao-Ambodimanga, 16°45′03″S 49°42′26″E, 16 m, 6 Oct. 2003, Andrianarivelo et al. 46 (G, MO, P, TEF) ; Tampolo AP , à 10 km au Nde Fénérive Est, 17°17′S 49°25′E, 0–5 m, 12 May 1997, R. Randrianaivo et al. 89 (MO, P, TAN) ; Distr. Soanierana-Ivongo, forêt de Menagisa-Pointalare , à 3 km vol d’oiseau au Sde Tanambao-Ambodimanga, 16°46′39″S 49°41′42″E, 12 May 2011, Randrianaivo et al. 1840 (CNARP, MO, P, TAN) ; Tampolo PA , along the “Grand Layon” towards the ocean, 17°17′05″S 49°25′22″E, 5 m, 31 June 1996, A. Randrianasolo 453 (MO, P, TAN) ; Baie d’Antongil , env. du village de Tenina (au Sde Rantabe), [15°44′00″ 49°39′30″], Mar. 1954, Service Forestier 9174 (G, K, MO, P [2 sheets], TAN, TEF) ; Tampolo AP , [17°17′05″S 49°25′22″E], 1954, Service Forestier 9199 (P [2 sheets], TEF); same loc.[17°17′05″S 49°25′22″E], 24 Mar. 1954, Service Forestier 9598 (P, TEF) ; same loc. [17°17′05″S 49°25′22″E], 10 May 1954, Service Forestier 10071 (G,P,TEF) ; Tampolo-Fénérive ,[17°17′05″S 49°25′22″E], 10 Aug. 1955, Service Forestier 15161 (G, P, MO, TAN) ; Tampolo AP , 17°17′05″S 49°25′22″E], 21 Mar. 1957, Service Forestier 16895 (P, TEF) ; Tampolo SF , 10 km Nof Fenoarivo, Station Forestière de Tampolo , 17°17′S 49°25′E, 10 m, 11 May 1991, Zarucchi et al. 737 6 (MO, P, TAN) . Atsimo- Atsinanana [Fianarantsoa]: Manombo AP , plage de Tsaratanana , 23°02′53″S 47°46′11″E, 12 Jan. 2001, Rabenantoandro et al. 755 (MO, P [2 sheets], TAN) ; Mahabo-Mananivo , 23°10′37″S 47°43′00″E, 10 m, 25 Sep. 2002, Rabenantoan- dro et al. 985 (G, P, MO, TAN) ; Manombo, [23°02′S 47°46′E], 27 July 1955, Service Forestier 13989 (P, TEF) ; Analazaha, [23°02″S 47°46″E], 19 July 1956, Service Forestier 16198 (G, MO, P, TEF) ; Manombo, [23°02′S 47°46′E], 21 June 1956, Service Forestier 16221 (P, TEF) ; same loc., 23 June 1956, Service Forestier 16272 (P, TEF) ; Manombo AP , Antakohandra , parcelle II , forêtlittorale d’Analazaha , 23°02′21″S 47°46′11″E, 23 Sep.2005, Razakamalala et al. 2240 (MO, P, TAN) ; Mahabo-Mananivo, 23°11′13″S 47°42′27″E, 22 m, 26 Aug. 2003, Razakamalala & Rabehevitra 719 (K, P, MO, TAN) . Atsinanana [Toamasina]: Ambila-Lemaitso, [18°49′S 49°08′E], 28 Aug. 1954, Service Forestier 12594 (P, TEF) ; same loc., 4. Dec. 1954, Service Forestier 16857 (P, TEF) ; same loc., 17 Aug. 1963, Service Forestier 21216 (P [2 sheets], TEF) . SAVA [Antsiranana]: Fiv. Antalaha , Com. Ambohitralanana , 15°17′30″S 50°17′00″E, [90 m], 21 May 2001, fl., Antilahimena et al. 731 (G, MO, P, TAN) . Vatovavy-Fitovinany [Fianarantsoa]: Manampana, [21°23′S 48°19′E], 18 June 1955, Service Forestier 14838 (P, TEF). S. loc.: forêts côtières de l’E, s.d., Louvel 88 (P).

Figures

Figure 1. Vitex mcphersonii Callm. & Phillipson. ––A. Branch with inflorescence and fruits. ––B. Fruit. Based on Service Forestier 9174 (P). Drawing: Roger Lala Andriamiarisoa.

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).