Sesuvium verrucosum Raf., New Fl. [Rafinesque] 4: 16 (1836).

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 : 74-75

Sesuvium verrucosum Raf., New Fl. [Rafinesque] 4: 16 (1836).

Neotype

( Bohley et al. 2017). [USA] "Salt River", leg. Nutt.[all] (P00680440!); epitype (" A.C. Sanders 23186 ", BRIT, n.v.)

Nomenclatural notes.

It is still doubted whether Sesuvium verrucosum ( Rafinesque 1836) is the oldest name for this taxon. Three older names- Sesuvium revolutifolium Ortega from Cuba ( Ortega 1797), S. revolutum Pers. and S. sessile Pers. ( Persoon 1806), both of unknown origin-may be conspecific with S. verrucosum . However, the description of both S. revolutum and S. sessile is very short and poor and no original material could be traced. The protologue of S. revolutifolium completely matches the habit of S. verrucosum , but it is not sure whether the plants from North America are identical to those from Cuba. Sesuvium revolutifolium , S. sessile and S. revolutum have been synonymised with S. portulacastrum by Bohley et al. (2017), but the nomenclature of all three species needs further study.

Description.

The most indicative characters of this species are: 1) perennial life history, 2) presence of abundant papillae on stems and leaves, 3) Sesuvium sessile turbinate flower buds and capsules and 4) clearly expressed detachments of the aril from the seed coat. Usually, the stems are rooting; however Ferren (2003) and Baldwin et al. (2012) described S. verrucosum as a non-rooting plant (probably applicable to younger plants, as observed in the specimen from Cape Verde listed below). For detailed morphological description, see Fadaie et al. (2006) and Bohley et al. (2017).

Examined specimens.

CAPE VERDE: São Vicente Island, near Baia das Gatas, 6 Sep 1986, W.F. Prud’homme van Reine SV3 (L1693699); SPAIN (CANARY ISLANDS): Gran Canaria (selected specimens): San Bartolomé de Tirajana, Cauce del Barranco del Toro, Junto a la depuradora, 11 Dec 2003, B. Navarro, J. Naranjo, B. Vilches, I. Santana, M. Soto, O. Saturno s.n. (LPA20044; sub S. portulacastrum ); San Agustín, Barranco del Toro near the beach, dry riverbed and beach, very common, 30 Mar 2017, F. Verloove 12825 (BR, LPA, MW).

General distribution.

Sesuvium verrucosum is widely distributed in North Mexico and the southern part of the USA ( Ferren 2003). Outside of its native range in the New World, it is reported as an introduced species in South-West Asia: Bahrain ( Verdcourt 1985; see also specimens at BM! E! and K!), the eastern part of Saudi Arabia ( Miller 1996; specimens at E!, K!), Iran ( Fadaie et al. 2006) and United Arab Emirates (collections from Sharjah, 2009, K!). As indicated on the sheets from Bahrain (collected by M. Cornes and A.M. Alder, 1983-1985, E!), S. verrucosum is a widespread species in irrigated areas and loamy sands. In Saudi Arabia, it is invasive in diverse inland plant communities including wastelands and salt pans ( Miller 1996).

One record has to be added for Syria: small young plants with only a few flowers and flower buds (Syria, Adra, desert, 27 Mar 1931, R. Gombault 1998, P04583848!), previously reported as S. mesembryanthemoides ( Bohley et al. 2017). Surprisingly, S. verrucosum was found in other regions of the world as well (re-identifications of AS): (1) North Vietnam (Tonkin, Hải Phòng, sandy seashores, Jul 1908, Ch. D’Alleizette 2723, L1693583!, a new record for Southeast Asia) and (2) Hawaii [USA], Oahu, 10 Aug 1967, D. Herbst 523 (L0717044!). Both specimens were initially identified by the collectors as S. portulacastrum .

Here, neophytic S. verrucosum is reported for the first time from Macaronesia (Fig. 17 ), i.e. from São Vicente (Cape Verde) and Gran Canaria (Canary Islands, Spain). In Gran Canaria, the species is well-established and dominant in a dried-out riverbed and extends to the beach and young dunes (Fig. 20 ). So far, S. verrucosum has not been recorded in other suitable habitats in the area (pers. obs. by Marcos Salas-Pascual in 2016 and Filip Verloove in March and April 2017) and it remains unknown how the species was introduced. Due to the evident invasive character of this species, it may be found in other African countries.

Figures

Figure 17. Distribution map of Sesuvium portulacastrum subsp. persoonii (circles) and S. verrucosum (stars).

Figure 20. Sesuvium verrucosum: A green-leaved plants, B red-leaved plants. Photographs by F. Verloove (Gran Canaria, Canary Islands, Spain, spring 2017).