| Abstract: | ![]()
Reported in the present paper are chromosome numbers and karyotypes of threegenera of the Gesneriaceae, i.e. Ancylostemon Craib. , Briggsiopsis (Franch.) K. Y. Panand Lysionotus D. Don. The former two genera are endemic to China. The karyotype ofAncylostemon aureus (Franch.) Burtt is formulated as 2n = 34 = 20m(1sat) + 14sm, withthe same chromosome number as its allied species A. convexus Craib. This species is characterized by the interphase nucleus of complex chromocenter type and the proximal type ofchromosomes in the mitotic prophase. The chromosome number of the monospecific genusBriggsiopsis is 2n = 34, the same as the lowest chromosome number reported in Briggsia.The karyotype of Briggsiopsis, which is formulated as 2n = 25m + 6sm + 3st, also seems tobe primitive among the species of the two genera. Briggsiopsis is characterized by the interphase nucleus of simple-complex chromocenter type and the interstitial-gradient type of chromosomes in the mitotic prophase. The chromosome number of Lysionotus carnosus Hemsl. isthe lowest reported in this genus. Its karyotype is formulated as 2n= 30 = 21m + 5sm + 3st + lt. Lysionotus serratus var. pterocaulis, with the karyotype being formulated as 2n= 32 = 2lm + 10sm + lt, has the same chromosome number as var. serratus. These two speciesshow a remarkable differentiation of karyotypes and are characterized by the interphase nucleiof simple-complex chromocenter type and the gradient type of chromosomes in the mitoticprophase. _ . |
