732 species of 132 families of vascular plants have been identified in Kaisho Forest so far. Plants distributing mainly in subtropical, warm temperate and cool temperate areas are found here. One species is rated as threatened species and seven, as vulnerable species in the Japanese Red Data Book.

Quercus mongolica Fischer ex Ledeb.(Fagaceae). Oak species are important components of the forest canopy of Kaisho Forest. Some oaks are deciduous and some are evergreen. Q. mongolicais a deciduous oak distributing mainly in China and Korea, and rare in Japan.

Alnus trabeculosa Hand.-Mazz.(Betulaceae). An alder species rated as 'vulnerable'. Grows in wet area. A population of more than a thousand individuals is found in Kaisho Forest

Magnolia stellata (Sieb. et Zucc.) Maxim. (Magnoliaceae). Vulnerable magnolia species. Grows in wet area. Endemic to the central part of Japan and found in restricted area. It flowers in early April preceding the leaf expansion.

Clematis patens Morr. et Decne. (Ranunculaceae). Vulnerable liana species growing at the edge of forests. The flowers are quite attractive. Unfortunately, it has attracted inconsiderate collectors, which must have been a threat to this species. A small population is found in Kaisho forest.

Swertia bimaculata (Sieb. et Zucc.) Hook. et Thoms. (Gentianaceae). Biennial species flowering in autumn. The flowers of 1.5 cm diameter are neat and elegant.

Cynanchum katoi Ohwi (Asclepiadaceae). Vulnerable species. The first described specimen of this species was from Seto city, where Kaisho Forest is. The habitat of the first specimen was destructed through development. Very small population of this species was found in Kaisho Forest. This is apparently the only population remained in Seto city.

Habenaria radiata (Thunb.) Spreng. (Orchidaceae). Vulnerable species of the orchid family growing in wetlands. Its vernacular name, "Sagi-So", means 'Heron plant'. The beautiful while flower really looks like a heron spreading wings. This is another victim of inconsiderate collectors.

Heterotropa kooyana (Makino) F.Maek. var. brachypodion (F. Maek.) F.Maek. (Aristolochiaceae). Abundant in Kaisho Forest. Larvae of a species of butterfly, Luehdorfia japonica , feeds exclusively on this group of plants.

Variation of Drosera spathulata Labill. (Droseraceae). An insectivorous plant growing in oligotrophic wetlands. Its sticky leaves are the traps to catch small insects.

Courtesy of Kaisho Naturalist Group