Wiley, Nordic Journal of Botany, 5(29), p. 518-533, 2011
DOI: 10.1111/j.1756-1051.2011.01104.x
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The taxonomic position of Astragalus raphaelis, a rare and misappreciated species endemic to Sicily, has been examined. In addition, its geographical distribution, ecology and conservation status, diagnostic morphological characters, pod and seed micro-morphology and relationship with A. stella are provided. Phenetic and phylogenetic trees (based on morphological data) for A. sect Sesamei shows that A. raphaelis is a taxonomically quite isolated species, with some relationships to A. sesamoides. The aim of this study is to taxonomically investigate Astragalus raphaelis G. Ferro, a critical species that is endemic to Sicily. It was described by Ferro (1978) from a population in Butera (south Sicily), that grow on steep and heavily eroded clayey badlands. Later, new records of this therophyte from other Sicilian localities were reported by Romano et al. (1994), Raimondo et al. (1994, 1995, 2004) and Minissale et al. (2009). Astragalus raphaelis belongs to A. sect. Sesamei DC., in which several annual species usually found in xeric environments are included, such as A. sesameus L., A. sinaicus Boiss., A. stella L., etc. (Gazer 1993). Ferro (1978) considered A. raphaelis to be closely related to A. sinaicus, from which it chiefly differs in having long pedunculate inflorescence, and different shape and arrangement of the legumes. Neither Pignatti (1982) nor Gazer (1993) re-ported A. raphaelis in their lists, while it was included by Conti et al. (2005) and Giardina et al. (2007). Recently, Podlech (2008) treated A. raphaelis as a synonym of A. stella, probably because of its long pedunculate inflores-cence. In order to clarify the taxonomic position and phyloge-netic relationships of A. raphaelis within A. sect. Sesamei, we did an in-depth survey focused on the macro-and micro-morphological characters of this species. In particular, we compared A. raphaelis with closely allied species belonging to this section, and especially with A. stella.