Further Observations on Chromosomes in the Genus Indigofera L.

Root tip counts in a number of East- and South East African species of Indigofera, the seeds of which were made available by Kew Herbarium and of two more Asiatic species resulted in 2n = 14 for 2 species in the Latestipulatae section of the subgenus Indigofera and for 2 species in the subgenus Indigastrum. D e w The latter report is in accordance with the previous record of Hagerup for I. parviflora. _ __ All the other ones investigated have 2n = 16. A considerable difference in chromosome shape and magnitude is present. Two cultivars of Cyamopsis psoralioides (2n = 14) have been inserted: only the total chromosome length and shape of Indigofera ischnoclada (section Indigastrum) enters within the same order of Cyamopsis. A tentative division of the 16 chromosome species hitherto studied in three groups with small, medium and large chromosomes was made and the actual differences between the three mean total chromosome lengths of these groups could be proved to be statistically significant. A few implications as to the meaning of these differences in respect of the evolution and geographic distribution are worked out, but it is pointed out that these need be very preliminary and that further study of the Indigofera cytology is necessary.