Sesuvium congense Welw. in Oliver, Fl. Trop. Afr. 2: 586 (1871)

Sukhorukov, Alexander P., Nilova, Maya V., Erst, Andrey S., Kushunina, Maria, Baider, Claudia, Verloove, Filip, Salas-Pascual, Marcos, Belyaeva, Irina V., Krinitsina, Anastasiya A., Bruyns, Peter V. & Klak, Cornelia, 2018, Diagnostics, taxonomy, nomenclature and distribution of perennial Sesuvium (Aizoaceae) in Africa, PhytoKeys 92, pp. 45-88 : 57-58

Sesuvium congense Welw. in Oliver, Fl. Trop. Afr. 2: 586 (1871)

Lectotype

( Gonçalves 1965): [ANGOLA, Bengo Province] Dist. Ambriz, Habit. freq.[ent] in rupestribus et glareosis ad ostia flum. Onço in Mossul [Ambriz Municipality, frequent in mountainous and gravelly places along the estuary of the river Onço in Mosul] fl. & fr. Nov 1853, Welwitsch 2382 (LISU214650 - photo! isolectotypes - BM000839899!, BM001209754! K000076293! LE!, P04602200!)

Nomenclatural notes.

A specimen in LISU has been wrongly stated to be the holotype by Gonçalves (1965) and then by Bohley et al. (2017). Indeed, the sheets of S. congense with the same label and collection number are present in several herbaria, as are many other specimens of Welwitsch’s material from Angola ( Albuquerque et al. 2009). No specimens and herbarium were cited in the protologue (Welwitsch in Oliver 1871) except the location "Lower Guinea, Congo [Angola as a part of Kongo Kingdom], Ambriz". The lectotype selected here is in accordance with Art. 9.9 of ICN ( McNeill et al. 2012). The synonymisation of S. congense with S. portulacastrum ( Adamson 1962) is incorrect.

The epithet " Sesuvium congense " probably refers to the "Kingdom of Kongo", a West African kingdom that united the territories of northern Angola (incl. Bengo and Zaire provinces) and the western part of DR Congo, as well as portions of Republic of Congo and Gabon.

Description.

The morphological description of the species is provided in Oliver (1871), Gonçalves (1970) and Bohley et al. (2017). This species is sometimes confused with branched S. sesuvioides (especially when the upper parts of the branches are collected) with similar smooth seeds. In contrast to S. congense or related S. crithmoides , S. sesuvioides is glabrous, with turbinate or balustriform flowers (without a rounded perianth cup).

Additional specimens examined.

ANGOLA: Benguela prov.: Lengue, 19 Dec 1932, Grossweiler 9715 (BM); 20 km W of Benguela, Baia Azul , 1 Apr 1973, P. Bamps & S. Martins 4372 (BR0000013827366); 74 km S of Benguela along road to Cuio , 74 m alt., 25 Dec 2016, C. Klak 2557 (BOL) ; Namibe prov.: Maiombo river, Oct 1859, Welwitsch 2395 (BM); Mossamedes [Namibe], valley of Rio Mukungo , Aug 1937, H. Humbert 16407 (BM); Mossamedes [Namibe], Porto Alexandre , 26 May 1937, A.W. Exell & F.A. Mendonça 2294 (BM); Mossamedes [Namibe], Porto Alexandre , Aug 1937, H. Humbert 16375 (BM); ca. 22 km NE of Namibe, 18 Jan 2009, Winter 7683 (PRE); road to Baba from Lucira road, 23 Jan 2009, Winter 7779 (PRE); Namibe , 9.7 km S of airport turn-off, 23 Jan 2009, Winter 7762 & 7766 (PRE); 27 km E of Namibe, 252 m, 19 Dec 2016, C. Klak 2554 (BOL) .

General distribution

(Fig. 9 ). Coastal sandy areas in Angola, from Bengo to Namibe provinces, recorded at altitudes between 74 and 252 m a.s.l. ( Gonçalves 1965).

Conservation status.

Sesuvium congense has an estimated EOO of 54,340 km2 (which would place the species in LC) and AOO of 36 km2 (which would place it in EN). However, it is unknown if the species persists in some of these localities. The size of its populations and their threats are little known, but the populations on the seashore and near rivers are probably impacted by development and agriculture. Therefore, the species, at this point in time, should be considered Data Deficient (DD) according to the IUCN Red List Criteria ( IUCN 2017).

Figures

Figure 9. Distribution map of Sesuvium congense.