kingdom Plantae - plants »  divisio Magnoliophyta - flowering plants »  class Rosopsida - eudicots » order Malpighiales »  family Violaceae »  tribus Violeae > genus Viola > Viola sect. Plagiostigma Godr.  > Viola subsect. Adnatae W. Becker 

Viola sieboldii Maxim.

| Bio Lib | GRIN | Wild plants in and around Shimane; Violet in Japan, Japanese Wild Flowers (Violaceae) 

Common Name:  Fumotosumire フモトスミレ ; 영월제비꽃 (yeong-woljebikkoch , Yeongwol violet)

Synon.: Viola pumilio W. Becker

Description: The rhizome is short. A stalkless violet, 4-6 cm high. Leaves 1-2.5cm length, 1-2cm width with a heart-shaped base and low serrations. The inferior surface is purple. The petiole is as long as 2-5 cm. The flowers are white, small, 7-10 mm in diameter. The lateral petals has normal hair and, in rare cases, hairless.  The sepal is lanceolate . The flowering season is April-May

Distributional Range:  Native Asia-Temperate EASTERN ASIA: Japan, [Honshu, Kyushu, Shikoku] Korea, South. Endemic species of Japan . It is distributed in Honshu (west of Iwate Prefecture ), Shikoku , and Kyushu . The northern limit on the Pacific side is Oshu , Iwate, and the northern limit on the Sea of Japan is Sakata, Yamagata .

Habitat: It grows in slightly dry forests and in grassy hills in sunny and warm lowlands

Notes: 

References:

1. Igari, M. 1996. Wild violets of Japan Note: book almost entirely in Japanese

2. Iwatsuki, K. et al. 1993-. Flora of Japan.

3. Ohwi, J. 1965. Flora of Japan (Engl. ed.). Note: mentions; possibly a form of Viola pumilio W. Becker