Karyomorphology and relationships in some genera of Saururaceae and piperaceae

Karyomorphological observations were carried out on three genera belonging to the Saururaceae and four genera of the Piperacea. All of the genera of Saururaceae show the same karyomorphological characteristics from interphase to metaphase in the somatic cell divisions. However there are two types of the karyomorphology in Piperaceae, i) the first type observed inPiper, Pothomorphe andZippelia, and ii) the second type inPeperomia. Each group corresponds to Thorne's two subfamilies (1974, 1976), Piperoideae and Peperomioideae. The basic chromosome numbers of the genera are confirmed or newly proposed as follows:Saururus x=11,Houttuynia x=12,Anemopsis x=22 (Saururaceae),Peperomia x=11,Piper andPothomorphe (=Heckeria) x=13,Zippelia x=19 (Piperaceae). The relationships of these basic chromosome numbers are presumed to be as shown schematically in Fig. 4. The original basic chromosome number of the common ancestral stock of Saururaceae and Piperaceae is presumed to be x=11.