The 10 South African species cur- rently assigned to Laurentia (an otherwise Mediter- ranean genus) are segregated here as the genus Wimmerella on the basis of their basal (vs. medial) bracteoles; larger flowers and fruits; and subglobose (vs. ellipsoid) seeds lacking a strophiole, which are sulcate with flattened (vs. keeled) walls. Laurentia Adanson, as circumscribed by Wim- mer (1953, 1968), was a genus of oddly discontin- uous distribution. Its 27 species were restricted to either the Mediterranean region (3 spp.), South Af- rica (10 spp.), Australia (10 spp.), western North America (3 spp.), or the West Indies (1 sp., spread in historic times throughout much of the tropics). Phytogeographic coherence of the infrageneric taxa recognized in Wimmer's treatment was no better. The Mediterranean and South African species and two of the species from North America were as- signed to section Laurentia; the remaining North American endemic to section Palmerella (A. Gray) E. Wimmer; and the Australian and West Indian species to section Isotoma (R. Brown) Endlicher. However, this very broadly construed Laurentia was something of an innovation with Wimmer. Many of the species had been assigned to smaller genera by earlier authors, and that is the classifi- cation preferred by most current workers (e.g., McVaugh, 1940a, 1943; Mason, 1957; Melville, 1960; McComb, 1970; Elliot & Jones, 1990; Chap- man, 1991; Skog, 1991; Lammers, 1993; Morin, 1993; Kartesz, 1994). Here, the Australian species comprise Isotoma (R. Brown) Lindley, the sole West Indian species is segregated as Hippobroma G. Don, and the North American species are assigned to Porterella Torrey and Palmerella A. Gray. As noted by Lammers (1997), this leaves only the Mediterranean and South African species in Lau- rentia. The present paper executes the final dis- memberment of Laurentia, by segregating the spe- cies of these two regions into separate genera. Evidence supporting the generic distinctness of the Mediterranean and South African species was provided in detail by Serra and Crespo (1997) and Crespo et al. (1998). These authors placed partic- ular emphasis on differences in seed morphology: seeds of the South African species are subglobose, lack a strophiole, and are sulcate with flattened walls; those of the Mediterranean species are ellip- soid, strophiolate, and sulcate with keeled walls. The extreme value of seed features in Lobelioideae was first stressed by McVaugh (1936, 1940b) and recently expanded upon by Murata (1992, 1995). The two groups of species were also distinguished by bracteole position (basal in South Africa, medial in the Mediterranean) and by the larger flowers and fruits of the former. Furthermore, in the Mediterranean species, the plants are erect and the flowers solitary in an axillary position (appearing terminal in rosulate species). In contrast, the South African species have decumbent stems with solitary axillary flowers; or if the stems are erect, then the flowers are borne in a 2-15-flowered terminal raceme. As these differences are consonant with differences used to distinguish genera in the subfamily, Serra and Crespo (1997) and Crespo et al. (1998) rec- ognized the Mediterranean and South African spe- cies as two distinct genera. But what names should these genera bear? Mei- kle (1979) published a brief note contending that he name Laurentia was a superfluous renaming of Lobelia. In its place, he adopted the name Solenop- sis C. Presl. Recently, however, Lammers (1997) presented evidence that Laurentia was not illegitimate, and formally proposed that the name be con- served to ensure stability. The type of Laurentia is NovoN 9: 414-418. 1999. This content downloaded from 207.46.13.92 on Wed, 30 Nov 2016 05:08:49 UTC All use subject to http://about.jstor.org/terms