Copyright 1998-2022 Yoshiaki Yoneda

While the morning glories belong to the tribe Ipomoeeae, genus Calystegia is classified in a different tribe, Conovolvuleae. We can find Calystegia japonica and C. soldanella nearby, which continue blooming in hot sunlight, whereas the flowers of the morning glories wither up early in the morning. We are very much interested in the contrastive character of the flower petals. From this flower petal withering point of view,, the author took up genus Calystegia as a member of the same Convolvulaceae. Furthermore, we were able to produce interspecific hybrids among Calystegia species, so these results were presented. The author hopes these plants will be useful as study materials.

As for the genus Calystegia, about 25 species are distributed over temperate to tropical zones throughout the world, among which four species grow wild in Japan. I introduced three species among the plants of Convolvulaceae already. These plants are perennial, have vines and prostrate stems, and their underground stems are very well developed. A remarkable characteristic of Calystegia is its two pieces of big bracts, which cover the calyx.

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References

1. Yoneda, Y. (1989) Genus Calystegia In: Yotarou Tsukamoto (ed.) Grand dictionary of horticultural plants. Vol. 4 p.151-152 Shougakkan.
   
2. Yoneda, Y., Nakamura, N. and Tamaki, S. (1989) Interspecific hybrids of Calystegia hederacea and C. soldanella. Rep.Fac. Lib. Arts, Shizuoka Univ.(Sci.) 25: 19-25.
   
3. Yoneda, Y., Imoto, M. and Tamaki, S. (1995) Studies on interspecific hybrids in four species of Calystegia in Japan. Rep. Fac. Lib. Arts, Shizuoka Univ. (Sci.) 31: 29-43.
   
4. Nakamura, N., Yoneda, Y. (1993) Use of Calystegia plants for teaching materials. Interspecific hybrid of C. hederacea x C. soldanella. 55th meeting of Society of Bioeducation, Department of Education, Hiroshima University.
   
5. Nakamura, N., Tamaoki, S., Imoto, M. and Yoneda, Y. (1994) Use of Calystegia plants for teaching materials. Interspecific hybrid of C. sepium x C. soldanella. 57th meeting of Society of Bioeducation, Sendai-shi.