CHROMOSOME NUMBERS OF SOME NORTH AMERICAN SCROPHULARIACEAE, MOSTLY CALIFORNIAN

Chromosome counts are reported for 55 collections of 38 species representing eight genera in Scrophulariaceae, mostly from California. Chromosome numbers of 17 species are reported here for the first time, including Collinsia linearis, Lamarouxia dasyantha, Mimulus arenarius, M. bicolor, M. bolanderi, M. breweri, M. filicaulis, M.layneae, M. latidens, M. pictus, M. pilosellus, M. pygmaeus, M. torreyi, M. tricolor, Pedicularis attolens, P. semibarbata, and Penstemon purpusii. The species of Lamarouxia do not appear to be cytologically uniform as haploid numbers of n = 7, 14, 15, and 16 have been recorded. The counts of n= 9, 18 for Mimulusprimuloides differ from a previous report of n = 17. Consistency of chromosome number appears to be characteristic of certain genera of Scrophulariaceae whereas variation due to polyploidy and aneuploidy occurs in others, especially the large, polymorphic genera Mimulus and Veronica.