(First upload on April 11 2003. Last on February 12 2013) [ 日本語 | English ]

Senecio cannabifolius Less.

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

Senecio L. (キオン)
Hangonsou (ハンゴンソウ, 反魂草), Aleutian ragwort
Lifeform: tall perennial forb, often becoming 2 m high
Distribution: Sakhalin, Hokkaido, Honshu (above central Honshu), Korean Peninsula, China, eastern Siberia, Kamchatka
Habitat: forest floor

Flora on Mount Usu
HUSTEP: Plants and Plant communities in Japan (flora list)

Palatability: high for deer (on Nakajima Island)

Jacobaea cannabifolia (Less.) E. Wiebe

f. integrifolius (Koidz.) Kitag. (ヒトツバハンゴンソウ)
Note that Oh-hangonsou (オオハンゴンソウ) is Rudbeckia laciniata L.
It is a totally different species.

Senecio cannabifolius in Hokkaido

[1/2] near (the former) Muroran Marine Station, Hokkaido University, on August 20 2007. [3/4] in Tomakomai Experimental Forest, Hokkaido University, on September 10 2009. [5] in the crater basion of Mount Usu on July 26 2017. [6] on Nakajima Island located in the center of Lake Toya on July 21 2005. The population was decreased greatly by over-grazing of ezo-deer (Tsuyuzaki & Takahashi 2007). Discarded: on the northwest slope of Mount O-Usu, which is the highest peak on Mount Usu, in 1983. The plants suvived in the former topsoil and reproduced vegetatively soon after the 1977-1978 eruptions.