. Chromosomes and phylogeny in Crepis. II. The relationships of one hundred eight species. Crepis; Plants; Karyokinesis. 292 University of California Publications in Agricultural Sciences [Vol. 6 The basic numbers common to all three subgenera are 8 and 10, there being fifty-five species with eight, and nineteen species with ten chro- mosomes. In Catonia and Eucrepis there is a third basic number, namely, 12, and in Eucrepis, a fourth, namely, 14. But as will be shown, these "basic" numbers are not all equally primitive. Furthermore, the subgen- era may contain more than one phylogen
. Chromosomes and phylogeny in Crepis. II. The relationships of one hundred eight species. Crepis; Plants; Karyokinesis. 292 University of California Publications in Agricultural Sciences [Vol. 6 The basic numbers common to all three subgenera are 8 and 10, there being fifty-five species with eight, and nineteen species with ten chro- mosomes. In Catonia and Eucrepis there is a third basic number, namely, 12, and in Eucrepis, a fourth, namely, 14. But as will be shown, these "basic" numbers are not all equally primitive. Furthermore, the subgen- era may contain more than one phylogenetic line of a given basic number. CHROMOSOME NUMBER AMD PHYLOGENY IN CREPIS EUCREPIS 442 55? 88?2 225 (15-24) 40 CATONIA /402^ \l6/62 j63 ,43 ,27 706 825 |23 I03 88 BARKHAUSIA I62 ? (10-18). Fig. 2. Distribution of chromosome numbers in the subgenera in relation to phylogeny. The great predominance of 8-chromosome species has led to the erro- neous assumption by some writers that eight is the most primitive num- ber in Crepis. But frequency of occurrence is not a sufficient basis for such an inference. The important fact that some of the 8-chromosome species are more highly specialized than any 10-chromosome species has been overlooked. Of still greater significance is the fact that none of the 8-chromosome species, even in Catonia, are as primitive in morpho- logical aspects as are some of the 10-chromosome species, such as sibirica and pontana in Catonia, raulini and bithynica in Eucrepis, and albida. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Babcock, E. B. (Ernest Brown), 1877-1954; Cameron, Donald Ross, 1907-1984. Berkeley, Calif. , University of California Press
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