(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), less stimulose, in Korea and south to the Chubu District of Japan

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 (恵迪の森) 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.)