(First upload on June 6 2009. Last on December 4 2017) [ 日本語 | English ]

Urtica platyphylla Wedd.

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

Urtica L. (イラクサ) in Japan

All native species are distributed in Hokkaido
U. thunbergiana Sieb. et Zucc. (イラクサ), 40-80 cm tall, temperate regions
U. platyphylla Wedd. (エゾイラクサ)
U. laetevirens Maxim. (コバノイラクサ)
U. angustifolia Fischer (ホソバイラクサ)

var. shikokiana (Makino) Ohwi (ナガバイラクサ)

U. dioica L. (セイヨウイラクサ) [exotic to Japan]
U. urens L. (ヒメイラクサ) [exotic to Japan]

Urtica platyphylla in Hokkaido

Ezo-irakusa (エゾイラクサ, 蝦夷刺草)
Lifeform: perennial forb, with 50-80 cm tall
Distribution: China- Japan
Habitat: woodlands - forests

Field training on integrated environmental research (統合環境調査法実習) (fauna and flora 種リスト)
HUSTEP: Plants and Plant communities in Japan (flora list)

Stem: dense, short hair
Poison: leaves and stems have stinging hairs, causing irritation to skin

[1-4] at Keiteki-no-Mori forest in the campus of Hokkaido University. [1] a grassland completely dominated by this species on May 15 2014, after a huge gap was developed by Typhoon 18 in 2004. [2/3] on July 23 2009. Just flowering. Do not touch! [4] at a forest edge near Akkeshi Marine Experimental Station, eastern Hokkaido, on July 1 2014. [5/6] near a transplanted forest of Fraxinus mandshurica in the Experimental Forest of the University of Tokyo, Furano, central Hokkaido, on June 28 2017. (6, see the diverse leaf shapes.)