Mesembryanthemum haeckelianum A. Berger

Raab-Straube, Eckhard von & Raus, Thomas, 2024, Euro + Med-Checklist Notulae, 17, Willdenowia 54 (1), pp. 5-45 : 7-8

Mesembryanthemum haeckelianum A. Berger

(≡ Aptenia haeckeliana (A. Berger) Bittrich ex Gerbaulet ≡ Platythyra haeckeliana (A. Berger) N. E. Br. ) – Fig. 1.

A Hs(S): Spain: Valencia, Paiporta, l’Horta, Sant Joaquim, camí de l’Hort de Colom, 39°25'8.72"N, 00°24'46.43"W, 17.5 m, nitrophilous grasslands on roadsides, 8 Dec 2020, Fos & Laguna (VAL 243737), det. G. F. Smith & F. Verloove.

– Mesembryanthemum haeckelianum , which is endemic to South Africa’s Eastern Cape province, is sometimes used as a groundcover in domestic horticulture and landscaping. However, as a groundcover, it is not as popular as the purple-flowered M. cordifolium L. f. and the red-flowered hybrid between these two species, M. ×vascosilvae (Gideon F. Sm. & al.) L. Sáez & Aymerich (see Smith & al. 2020; Sáez & Aymerich 2020), at least in the Valencian Community ( Spain) and other parts of the Iberian Peninsula. Nevertheless, both species and the hybrid between them are marketed for ornamental use and plants are sold onsite in nurseries and garden centres as well as online. Note though that material of all three taxa is often confusingly sold as varieties of M. cordifolium . Mesembryanthemum haeckelianum is reported here as a new alien plant for the flora of Spain and Europe. Beyond its natural geographical distribution range, it has been reported from Belgium and Germany, but these records clearly refer to living plants cultivated in the Botanical Gardens of Meise and Darmstadt, respectively. There is also a record from Lajares, Lanzarote (Canary Islands) reported by GBIF (2022), but without access to information on the origin of this material nor any evidence such as pictures or herbarium sheets to aid its identification, it could possibly be of cultivated plants. The specimens found in Valencia ( Fig. 1 ) cover a surface area of 3–4 m 2 with some branches scrambling to a height of about 2 m into a Cupressus sempervirens L. tree that grows nearby. Mesembryanthemum haeckelianum grows in nitrophilous plant communities on a roadside in association with Beta vulgaris subsp. maritima (L.) Thell., Cichorium intybus L., Crepis vesicaria subsp. taraxacifolia (Thuill.) Thell. , Diplotaxis erucoides (L.) DC., Emex spinosa (L.) Campd., Fumaria capreolata L., Malva parviflora L., Oxalis pes-caprae L., Euphorbia peplus L., E. terracina Lag. , Piptatherum miliaceum Coss. and Plantago lagopus L., among others. Because of its creeping and scrambling habit, it has not been possible to confirm the number of naturalized individuals, although the material could be derived from a single specimen. Plants flower sporadically throughout the year, as does M. ×vascosilvae , incidentally, although in winter the flowers are smaller and paler yellow to almost white. Fruits with well-developed seeds have also been observed. Mesembryanthemum L. and Aptenia N. E. Br. are often united by contemporary authors, as a result of molecular phylogenetic studies ( Klak & al. 2007, Klak & Bruyns 2013). Online databases such as the International Plant Names Index ( IPNI 2023), the World Flora Online ( WFO 2023) the Catalogue of Life ( Bánki & al. 2023), POWO (2023) but also the Euro+Med PlantBase (Raab-Straube 2018+a) adhere to this view. We have previously referred to this species under Aptenia ( Smith & al. 2020).

S. Fos, E. Laguna, G. F. Smith & F. Verloove

Figures

Fig. 1. Mesembryanthemum haeckelianum – A: flowering plant in nitrophilous grassland habitat; B: detail of plant with flowers; C: detail of fruits. – Spain, Valencia, Paiporta, Sant Joaquim, 1 May 2023 (A), 8 Dec 2020 (B, C), photographs by S. Fos.