Intraspecific polyploidy and cytogeography were clarified in the samples of Houttuynia cordata (Saururaceae) studied in the Sino-Japanese region of eastern Asia, ranging from Nepal, China, northern Thailand, Taiwan to Japan. Five chromosome numbers of 2n=72, 80, 96, 112 and 128 were detected, four of which were firstly recorded here. These chromosome numbers suggested that the basic chromosome number of Houttuynia could be x=8. The observed cytotypes were evaluated as 2n=72, 80, 96, 112 and 128, and represented 9x, 10x, 12x, 14x, and 16x, respectively. The continental part of east Asia harbored intraspecific polyploidy ranging from 9x to 16x, and only one cytotype of 12x or 2n=96 was found from the eastern edge of the Asian continent between Taiwan and Japan. The evolution of basic chromosome number was discussed based on a phylogenetic tree of the Saururaceae, suggesting that x=11 was an archaic basic chromosome number in this family. Houttuynia may have experienced a disploid reduction from x=11 to x=8, as an autoapomorphy and subsequent intraspecific polyploidization in continental eastern Asia.

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Genetic relationships among 16 accessions of Pinanga coronata (Blume ex Mart.) Blume from different sources both wild and cultivated individuals from botanical gardens (Indonesian Botanic Gardens and Montgomery Botanical Center) were studied using Random Amplified Polymorphic DNA (RAPD) markers. Thirty of fourty primers were reproducible among the 16 accessions of P. coronata. They revealed a total 243 bands, of which 238 were polymorphics. The genetic similarity according to Jaccard's coefficients among accessions ranged from 0.115 to 0.771, which was indicating that the accessions were genetically very diverse. Cluster analysis by UPGMA showed two clusters. Cluster A consisted of eight accessions from Sumatra (PC₁) and Java (PC₂, PC₄, PC₆, PC₇, PC₈, PC₉, and PC₁₀) in which genetic similarity varied between 0.50 to 0.63; and cluster B consisted of five accessions from Bali Isl. (PC₁₂, PC₁₃, and PC₁₄), Sumbawa Isl. (PC₁₅) and Timor Isl. (PC₁₆) in which genetic similarity varied between 0.56 and 0.77. Three accessions from Java (PC₃, and PC₅) and Bali Isl. (PC₁₁) did not belong to any clusters. Based on this study, cluster separation was not only depend on altitudes, but also geographical distribution as well.

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Commelina benghalensis L and C. caroliniana Walter, two allied weedy species of the Commelinaceae vary in their breeding and meiotic systems. The former is predominantly auto- and the latter facultatively xenogamous. Meiotic system of C. caroliniana also provides for higher recombination index, characterized as it is by high chromosome number and higher chiasmata frequency: On the contrary C. benghalensis has fewer chromosomes and closed breeding system for which reason it generates little genetic variability. This difference qualifies C. benghalensis as a “specialist” and C. caroliniana as a “generalist”

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Six species of Hylotelephium collected in Asian continent were karyologically studied. The somatic chromosome numbers were 2n=20 in H. tatarinowii, 2n=22 in H. ewersii, 2n=24 in H. viviparum and H. pallescens, 2n=48 in H. telephium, and 2n=46 in H. ussuriense var. ussuriense. The chromosome number of 2n=46 reported here was new to H. ussuriense var. ussuriense. The chromosome numbers of 2n=20 in H. tatarinowii, 2n=22 in H. ewersii, 2n=24 in H. viviparum and H. pallescens, and 2n=48 in H. telephium reported here verified the previous records. Their karyotypes were commonly mono-modal decreasing in length from the largest to the smallest chromosomes and showed similar chromosome sizes and chromosome complements in centromeric positions to each other expecting those of H. telephium had slightly large sized chromosomes.

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