Vepris welwitschii (Hiern) Exell

Lachenaud, Olivier & Onana, Jean-Michel, 2021, The West and Central African species of Vepris Comm. ex A. Juss. (Rutaceae) with simple or unifoliolate leaves, including two new combinations, Adansonia (3) 43 (10), pp. 107-116 : 114-115

Vepris welwitschii (Hiern) Exell

Glycosmis welwitschii Hiern , Catalogue of the African Plants collected by Dr Friedrich Welwitsch. Dicotyledons, Part 1: 115 ( Hiern 1896). — Vepris welwitschii (Hiern) Exell, The Journal of Botany 67: 148 ( Exell 1929). —

Type: Angola. in montibus petrosis supra Tandambando, IX.1854 (fr.), Welwitsch 471 (lecto-, LISU [ LISU206243 ], here designated).— Syntypes: Angola. inter Camutamba et Quicando, IX.1857 (fr. imm.), Welwitsch 471 (syn-, LISU [ LISU206244 ]); locality and date unclear (see notes), Welwitsch 471 (syn-, BM[BM000798355]); “Zenza do Golungo“, IX.1854 (fr. imm.), Welwitsch 471 (syn-, PRE [PRE0601859-0]); no locality or date (fr. imm.), Welwitsch 471 (syn-, COI[COI00097048]).

Vepris gossweileri I.Verd. , Bulletin of Miscellaneous Information , Kew 9: 399 ( Verdoorn 1926). —

Type: Angola. Serra do Socollo-Undui between Ambriz and Lifuni river, 11.XII.1907 (fr.), Gossweiler 4895 (lecto-, K [ K000199522 , K000199523 ], here designated; isolecto-, BM, COI[ COI00040965 ]).

DISTRIBUTION. — Endemic to northern Angola ( Fig. 2 ).

HABITAT. — Xerophytic vegetation on limestone outcrops, up to 800 m in altitude.

PHENOLOGY. — Flower buds in September; fruits in September (immature) and October.

PRELIMINARY CONSERVATION ASSESSMENT. — Endangered [EN B2ab(iii)]. Vepris welwitschii is a shrub endemic to Angola and occurring in xerophytic vegetation on limestone outcrops. It is known from seven specimens collected between 1854 and 1929, four of which were not considered for this assessment since their localities are either too vague or not traceable. Based on the remaining three collections, its extent of occurrence (EOO) is estimated to be 14 092 km² (within the limit for Vulnerable status under criterion B1) and its area of occupancy (AOO) to be 12 km ², within the limit for Endangered status under criterion B2. These collections represent three unique occurrences, three subpopulations, and three locations in the sense of IUCN. None of these occur in protected areas, and most are threatened by deforestation for agriculture and/ or charcoal production (apparent from satellite images), leading to an expected decline in the extent and quality of the habitat. Because of this decline, and the small number of locations (three), the species qualifies for Endangered status under the conditions B2ab(iii). Since the area where it occurs has not been explored botanically in recent times, field work is critical for more precise information about the species’ range and state of conservation.

OTHER STUDIED MATERIAL. — Angola. Vale de Cao , 26.X.1903 (fr.), Gossweiler 1493 ( BM, P06600651 ) ; Cuanza Norte, without precise locality, no date (fr.), Gossweiler 4799 ( COI p.p., see notes above); Vale do Zando, Cazengo , 800 m, 22.IX.1921 (fl. buds), Gossweiler 8915 ( BM) ; Catete, 1929 (fr.), Gossweiler 9173 ( BM, COI).

REMARKS

This species is still known from incomplete material only, no mature flowers having been collected; according to Welwitsch the fruits are black, which is unusual in the genus (they are more commonly red or orange), and the leaves are dry even in the fresh state. It is not to be confused with Teclea welwitschii (Hiern) I.Verd.( Verdoorn 1926: 408) [basionym: Zanthoxylum welwitschii Hiern (1896: 114) ], which is a synonym of Vepris grandifolia (Engl.) Mziray , a trifoliolate species.

The original description of Glycosmis welwitschii mentions a single collection, Welwitsch 471, but two different localities and dates: “on dry bushy rocky hills between Camutanda [Camutamba] and Quicanda, in young fr. Sept. 1857; also in mountainous rocky situations above Tandambondo, in young fr. Sept.1854 ”. It is known that Welwitsch commonly grouped under the same number collections from different places that he considered conspecific ( Albuquerque et al. 2009). One of the sheets in LISU, which has fruits better developed than the other and an unequivocal indication of locality in Welwitsch’s handwriting, is here selected as lectotype; other sheets of the same number should be regarded as syntypes. The sheet in BM bears two contradictory indications of localities and dates – corresponding to those given in the protologue – so its exact origin is unclear.

Exell’s (1929) transfer of Glycosmis welwitschii Hiern to the genus Vepris was overlooked by Stone (1985: 23) who in his monograph of Glycosmis treated this species as imperfectly known and commented “this is almost certainly G. parviflora run wild as a naturalized plant here as in São Tomé island”. This is actually not the case: while the Asian Glycosmis parviflora (Sims) Little is occasionally cultivated in Africa – Stone (1985: 15) cites one collection from Angola and the first author has seen two from the Democratic Republic of Congo – it does not seem to have naturalised anywhere, has never been recorded from São Tomé (as far as we know) and is in any way quite different from Vepris welwitschii , which is certainly a native African species.

The original description of V. gossweileri I.Verd. ( Verdoorn 1926) does not specify the herbarium of deposit of the type, Gossweiler 4895, but the locality cited, “Loanda: Cazengo”, is a strong indication that the specimen in Kew (consisting of two parts labelled Sheet I and Sheet II) was the one studied; the sheets in BM and COI bear a more precise indication of locality. Accordingly the Kew specimen is here designated as lectotype.

The specimen Gossweiler 4799 is a mixture of two different species. One sheet in BM and two in COI [COI00040957, COI00040958] represent the trifoliolate species V. grandifolia (Engl.) Mziray , to which they were correctly referred by Exell & Mendonça (1951: 270, as Teclea grandifolia Engl. ). A single sheet of the same number in COI [COI00040963], with unifoliolate leaves, was cited as Teclea gossweileri by Exell & Mendonça (1951: 271) but actually represents V. welwitschii .

Figures

FIG. 2. — Distribution map of Vepris africana (Hook.f.) O.Lachenaud & Onana, comb. nov. (·), V. laurifolia (Hutch. & Dalziel) O.Lachenaud, comb. nov. (●) and V. welwitschii (Hiern) Exell (▲).