Trifolium constantinopolitanum Seringe (E-Medit.) – An exceptional and ephemeral alien. Recorded once but in quantity on a demolition site of a horse artillery in Gent in 1995, along with numerous other southern European Fabaceae (including many species of Trifolium; see Verloove & Heyneman 2012).
Trifolium constantinopolitanum much resembles T. alexandrinum (see above) and T. echinatum. According to Coombe (1968) it is possibly better placed under one of these species. From Trifolium echinatum it is best distinguished by its calyx that is constricted at throat (calyx tube urceolate) and its corollas that are always cream-coloured (more often pinkish in T. echinatum). Moreover, its longest (lowest) calyx tooth is hardly longer than the tube whereas in Trifolium echinatum the lowest calyx tooth is about twice as long as the tube.
The exact area of origin is usually given as rather disjunct. Coombe (1968) and Zohary & Heller (1984) cite Trifolium constantinopolitanum from Switserland and France. However, these findings surely refer to introduced plants. It is probably only native in the eastern Mediterranean region.
Selected literature:
Coombe D.E. (1968) Trifolium. In: Tutin T.G. & al. (eds.), Flora Europaea, vol. 2. Cambridge University Press, Cambridge: 157-172.
Verloove F. & Heyneman G. (2012) Merkwaardige plantencollecties van twee antropogene zaadbanken in Gent (Oost-Vlaanderen, België). Dumortiera 100: 19-24. [available online at: http://www.br.fgov.be/DUMORTIERA/DUM_100/Dum%20100_19-24_Zaadbanken%20Gent-Verloove%20en%20Heyneman.pdf]
Zohary M. & Heller D. (1984) The genus Trifolium. Israel Academy of Sciences and Humanities, Jerusalem: 606 p.