(First upload on February 5 2012. Last on September 20 2015) [ 日本語 | English ]

Dioscorea polystachya Turczaninow

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

Dioscoreaceae (ヤマノイモ科)

About 800 species in eight genera are recorded in the world ⇒ Engler's syllabus (エングラー体系)

mostly distributed in tropical regions

One genus is recorded from Japan

Dioscorea L. in Japan

D. batatas Dence.(ナガイモ) D. tokoro Makino (オニドコロ) D. nipponica Makino (ウチワドコロ)

Dioscorea polystachya in Hokkaido

Nagaimo (ナガイモ, 長芋), Chinese yam
Lifeform: perennial vine
Distribution: Native to eastern Asia, not included Japan (introduced to Japan in or before 17th century)
Habitat: moist, and disturbed sites
Tuber (and other organs): edible → wild vegetable (山菜)
Vine: twining clockwise

Dioscorea batatas Decne.
Dioscorea opposita Thunb., nom. illeg.

Viola1 Viola2 Viola3


Viola4 Viola5
[1] at the backyard of Japanese Archery Training Hall, Hokkaido University, on July 27 2015. [2-5] climing up a hedge at N28/E3, East Ward, Sapporo. [1-4] on August 18 2011. [5] on September 26 2014. Who transplanted this? I did not think this was Chinese yam when I saw this at the first time in fornt of the apartment.