Over the past century in California, the invasive weed Salsola tragus (russianthistle) has become a widespread and troublesome pest plant. Early attempts at biological control of russianthistle achieved only partial success. Efforts to improve effectiveness of renewed biocontrol efforts revealed that two distinct, often sympatric, genetic entities comprise what has been called Salsola tragus: Salsola tragus and Salsola 'type B\ Efforts to identify and characterize 'type B' resulted in recognition of a third form, 'type C. We present a taxonomic and morphological examination of Salsola tragus, Salsola 'type B', Salsola 'type C and Salsola paulsenii using discriminant analysis with DNA sequence genotypes as the taxonomic framework. Salsola tragus and 'type B' were morphologically distinct; 'type C was morphologically intermediate between them and contained DNA sequence genotypes that were an additive mixture of haplotypes mostly exclusive to tetraploid 5". tragus and others exclusive to diploid 'type B'. 'Type C is a fertile allohexaploid that originated via hybridization between S. tragus and 'type B'. We provide a pre-existing name, Salsola australis, for 'type B', and propose Salsola ryanii sp. nov. for 'type C. Morphological variation, habitats, and dispersal behaviors among these Salsola taxa were examined in the herbarium and in the field. These are compared and discussed.

Various Salsola spp. have been introduced to the USA, and some of these are considered noxious or invasive in certain regions. The genus is taxonomically challenging, and recent morphological, cytological, and molecular work has shown that an unknown taxon, previously identified as S. tragus, but recently temporarily designated as Type B, with unknown origins, exists in California and Arizona. Type B's origins and identity are a point of concern for biological control efforts, as it is much less affected by fungal biological control agents than the sympatric invasive S. tragus. Initial studies in 2005 indicated that Type B is morphologically very similar to S. kali subsp. austroafricana which has been collected in southern Africa. Here we use DNA sequence data from a PEPC intron to compare USA and Old World specimens, and results indicate that S. kali subsp. austroafricana is genetically identical to Type B and distinct from S. tragus. It is unclear if 5'. kali subsp. austroafricana is native to southern Africa or to the northern hemisphere of the Old World, and further investigations in both regions are needed.

Nomenclatural and taxonomical considerations on Kali, a controversial genus recently segregated from the polyphyletic Salsola s. lat. (Chenopodiaceae), are provided. The Kali group includes annual plants with leaves ending in a spine and lacking hypodermis, having also a cortex alternate to longitudinal chlorenchymatous striae. The species belonging to this genus mainly have a paleotemperate distribution (Europe, Asia and North Africa), occurring as aliens in North America, Australia and South Africa. A new species collected on Mt. Etna (Sicily), and closely related to K. australe, is described and illustrated as K. basalticum Its morphological and molecular features, karyology (2n=54), ecology, distribution, phylogeny and conservation status are examined. In addition, a list of the currently known species of Kali is provided, with some new combinations: Kali nepalense (Grubov) comb. nov., Kali pellucidum (Litvinov) comb. nov., Kali sinkiangense (A.J. Li) comb. nov., Kali gobicolum (Iljin) comb. nov., and Kali ryanii (G.F. Hrusa & Gaskin) comb. nov.

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Morphological and isoenzyme variation among populations of western azalea. Rhododendron occidentale (Torr. & A. Gray) A. Gray, were examined. Three regional parapatric groups were revealed: 1 ) the northern California outer North Coast Ranges; 2) the northern California and southern Oregon Klamath Ranges; and 3) the central CaUfornia Sierra Nevada and southern California Peninsular Ranges. A highly variable but generally intermediate fourth group is restricted to ultrabasic substrates (serpentine) in the middle and inner North Coast Ranges of California. It is comprised of populations with recombined morphologies and alleles that were otherwise restricted to one or more of the three groups above. A revised intraspecific treatment is proposed, with the three regional groups above recognized as varieties. These are: R. occidentale (Torr. & A. Gray) A. Gray var. occidentale (outer North Coast Ranges), R. o. var. paludosum Jeps. (Klamath Ranges), and Rhododendron, occidentale var. californicum (Torr. & A. Gray) Hrusa comb, et stat. nov. (Sierra Nevada and Peninsular Ranges). Lectotypifications of Azalea occidentalis Torr. & A. Gray isotypes at PH and GH, Azalea californica Torr. & A. Gray in Durand, and Rhododendron sonomense Greene (NDG) are also provided.