In the previous paper, one of the writers (Matsuura) gave three different chromosome counts, n=21, 35 and 42, in three different plant groups of Phacellanthus tubiflorus, a parasitic herb. That this species is highly polymorphic from the karyological view was further ascertained in the present paper by the discovery of several other karyotypes, 19II (Fig. B. 2), 38II, (Fig. B. 3), 19III (Fig. D) (which is presumed as formed by the natural hybridization between the former two types), 38II+1I (Fig. B. 5) and 39II (Fig. B. 4). The material was obtained from roots of several different plant species, such as Ulmus lacinata, Cornus controversa, Morus bombycis, Kalopanax ricinifolium var. typicum and Picrasma quassioides.
The characteristic features of the meiotic metaphase of these types are (i) that no multivalents are formed, (ii) that the secondary association of bivalents occurs in a marked fashion (Fig. E) and (iii) that non-disjunction and non-conjugation (Fig. D. 9, B. 2) of certain bivalents are frequently met with. The last feature is considered as related with the formation of the aneuploid forms.
The meiotic metaphase of the 19III type is characterized by the occurrence of bivalents and univalents, no trivalents being formed, the combinations of them ranging from 19II+19I to 26II+5I (Table II), thus indicating the possibility of autosyndesis in the members of the haploid set. This suggests together with evidences from the secondary association of bivalents and also from the morphological comparison of the chromosomes in the haploid set (Fig. C. 6) that the basic number 7 which was inferred from the numerical consideration on the 21-35-42 series is also applicable to the present 19-38 series.
The comparison of morphological characters in these several karyotypes reveals only differences with minor importance, which may be ascribed to the limited habit of living of this plant, i. e. parasitism.
