Local variation and population diversity of Hibiscus hamabo (Malvaceae)

Abstract

Flower and fruit morphologies of Hibiscus hamabo Siebold et Zucc. were investigated in nine populations, five on the Omura Bay side and four on the ocean side of the Nishisonogi Peninsula in Nagasaki Prefecture, southwestern Japan, and were compared among populations. The morphological characters investigated were petal length, petal width, style length, anther-stigma distance, anther-anther distance, number of stamens, fruit length, fruit diameter and potential number of seeds per fruit. Observed variations were mainly among populations, and each population had specific characters in flower and fruit morphologies. Population diversity is important for conservation and restoration in Hibiscus hamabo communities. Petal length, petal width, anther-anther distance, number of stamens, fruit length, fruit diameter and number of seeds in populations on the Omura Bay side were significantly smaller than each of those characters on the ocean side, but anther-stigma distance was longer. These characters may indicate that the populations on the bay side had evolved in the pollinator-rich environment and become to avoid self-pollination.