Vitex barorum (Humbert) Callm. & Phillipson, 2018

Callmander, Martin W. & Phillipson, Peter B., 2018, New combinations and typifications in Vitex (Lamiaceae) from Madagascar, Candollea 73 (1), pp. 131-136 : 132-133

Vitex barorum (Humbert) Callm. & Phillipson , comb. et stat. nov.

Ξ Vitex betsiliensis subsp. barorum Humbert in Notul. Syst. (Paris) 8: 23. 1939 .

Lectotypus (designated here): MADAGASCAR. Prov. Fianarantsoa: vallée d’Ihosy , 850 m, 29.VII.1928, Humbert & Swingle 4908 ( P [ P00573440 ]! , isolectotype: B [ B100030550 ] image seen, BR [ BR0000005162642 ] image seen, G [ G00096014 ]!, K, MO-2160579 !, NY [ NY00138422 ] image seen, P [ P00440339 , P00440340 ]!, PRE, TAN, WAG [ WAG0251822 ] image seen) . Syntypi: MADAGASCAR. Prov. Fianarantsoa: env. d’Ihosy , [22°23’S 46°07’E], VI.1933, Perrier de la Bâthie 19267 ( P [ P04398730 , P04398731 , P00440341 , P00573443 ]!) . Prov. Toliara: vallée moyenne du Mandrare , près d’Anadabolava , Mont Vohirotsy , [24°16’S 46°43’E], 850 m, XII.1933, Humbert 12649 ( G [ G00341742 ]!, P [ P00440342 ]!) .

Notes. – HUMBERT (1939: 24) considered this taxon to be a subspecies of V. betsiliensis , distinct from the typical plant, stating: “…. adaptée à un climat plus chaud de moindre altitude [adapted to a hotter climate and lower altitude]”. Vitex barorum can be easily distinguished from V. betsiliensis by its smaller flowers - calyx 5-6 mm long (incl. 1 mm lobe) and corolla c. 10 mm long vs. calyx 8-12 mm incl. a 2 mm lobe and corolla 12-22 mm long; its white finely canescent indument on its lower leaf surface between the secondary veins and on the calyx between the nerves, and has a predominately salmon-pink papillate indument on the lower leaf midrib and secondary veins, petiole, inflorescence and young stem, while V. betsiliensis has a uniform, very dense, white, lanate indument covering the lower leaf surface, petiole, inflorescence and young stem. Vitex barorum is found on rocky slopes and inselbergs in the south and south-east of Madagascar while V. betsiliensis is endemic to the marble of Ibity and Itremo massifs.

All three available syntype collections are well representative of the species, however we select a sheet of Humbert & Swingle 4908 in Paris as the lectotype, since it has more duplicates distributed to different herbaria.

Conservation status. – Vitex barorum is known from 12 locations of which only one, the newly established VohidavaBetsimalaho Reserve, is encompassed by the protected area network. Here the species has been collected just once, in 2007 (Randriatsivery 270) ”. All of the other collections date back to the sixties or the seventies and come from fragmented midelevation forest patches on rock outcrops in southern highlands, that are now highly threatened by over-grazing, wild fires and over-exploitation. With an EOO of c. 15,000 km 2 and an AOO of 56 km 2, V. barorum is therefore assigned a preliminary IUCN conservation status of “Vulnerable” [VU B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v)].

Specimens examined. – MADAGASCAR. Prov. Fianarantsoa: premier étage de la Brioche ou “Fandrana” , PK 545 à 64 km d’Ihosy à Ambalavao, [22°01’S 46°22’E], 1200 m, 17.V.1971, Cremers 1545 ( P) ; Mont Vohipolaka au N de Betroka , versant NW , [23°08’S 46°05’E], XI.1933, Humbert 11632 ( G, MO, P [2 sheets], TEF) ; Haute Matsiatra, Ingaro [21°36’S 46°22’E], VI.1969, Morat 3321 ( MO, P, TAN) ; La Brioche: rocher entre Ihosy et Ambalavao , [22°01’45”S 46°22’10”E], 1200 m, VI.1969, Morat 3353 ( MO, P) ; Massif Ingaro , Ambalavao, [21°36’S 46°22’E], 900 m, 12.II.1955, Service Forestier 13743 ( P, TEF) ; Ambandroja, Ambandrozana , [21°59’30”S 46°36’30”E], 900- 1360 m, 22.VII.1954, Service Forestier 14490 ( G, MO, P, TEF) ; massif de l’Ifandana, entre Ankaramena et Ihosy , [22°01’00”S 46°22’30”E], 1300-1400 m, 7.X.1964, Service Forestier 23506 ( P, TEF) . Prov. Toliara: vallée moyenne du Mandrare , près d’Anadabolava , Mont Vohirotsy (sommet), [24°38’S 46°26’E], 800 m, XII.1933, Humbert 12648 ( P) ; Amboasary Sud, Mahaly, Anadabolava , 24°14’36”S 46°17’01”E, 813 m, 27.X.2007, Randriatsivery 270 ( MO, P, TEF) ; Anadabolava (Moyen Mandrare) , [24°12’S 46°19’E], IX.1953, Service Forestier 8538 ( P [2 sheets], TEF) ; Vohidava , près Anadabolava (Moyen Mandrare), [24°09’S 46°15’E], 700-900 m, 6.II.1963, Service Forestier 22598 ( MO, P, TEF) ; Lalanandro , [22°19’S 46°07’E], 6.XI.1967, Service Forestier 27873 ( G, MO, P, TEF) .