Polemonium caeruleum subsp. yezoense

Family	Polemoniaceae
Subfamily	Polemonioideae
Scientific name	Polemonium caeruleum L. subsp. yezoense (Miyabe & Kudô) H. Hara
Synonyms	Polemonium caeruleum L. subsp. vulgare Brand var. yezoense Miyabe & Kudô; Polemonium caeruleum L. var. yezoense H. Hara; Polemonium yezoense (Miyabe & Kudô) Kitamura; Polemonium yezoense (Miyabe & Kudô) Kitamura var. hidakanum Koji Ito
Common name	(Japanese common name) ezo-no-hanashinobu (エゾノハナシノブ, 蝦夷花忍 [meaning: Ezo flowering ball fern (Ezo = an old name of Hokkaido)]), miyama-hanashinobu (ミヤマハナシノブ, 深山花忍 [meaning: high mountains hanashinobu]), hidaka-hanashinobu (ヒダカハナシノブ, 日高花忍 [meaning: Hidaka Mountains hanashinobu])
	(English common name) Japanese Jacob's ladder
Distribution	(Japan) Hokkaido, Honshu (Shirakami Mountains)
	(Other nations) none
Chromosomal number	2n=18
Description	Plants electing 35-80cm tall. Leaves 9-12 pairs leaflets. Flowers blue corollas 2-2.5cm long, flowering in May to August. Perennial plants.
Reference	Polemonium caeruleum L. var. nipponicum Kitamura
	Polemonium caeruleum L.
	Polemonium in Hokkaido, the Kuriles and Sakhalin
Note	Endemic to Japan.
	In general, Polemonium yezoense (Miyabe & Kudô) Kitamura var. hidakanum Koji Ito is a special form of Polemonium caeruleum L. subsp. yezoense (Miyabe & Kudô) H. Hara (often described as Polemonium caeruleum subsp. yezoense form hidakanum) in Japanese gardening field.
	Many authors wrote that Polemonium caeruleum L. var. nipponicum Kitamura (Syn. Polemonium acutiflorum Willdenow var. nipponicum (Kitamura) Ohwi; Polemonium caeruleum L. subsp. yezoense (Miyabe et Kudô) H. Hara var. nipponicum Makino; Polemonium nipponicum Kitamura) should be a synonym of Polemonium caeruleum L. subsp. yezoense (Miyabe et Kudô) H. Hara. There have been some discussions about the taxonomy.

May 2008 at Hokkaido University Botanical Garden	May 2008 at Hokkaido University Botanical Garden