Taxonomic Note: I have annotated my photos (by AntMan01) as Epimedium koreanum, as a valid species separate from E. grandiflorum. A list of taxonomic references that support this taxon appear below. I am doing this because the National Garden Association plants Database utilizes the Catalog of Life as a singular guiding taxonomic reference, and it does not follow current 2017 references by RBG (Royal Botanic Garden), KEW Science, and Plants of the World Online.
Epimedium koreanum has long rhizomes and is a fast running species, E. grandiflorum has short rhizomes and is a "clumper". Epimedium koreanum has a few-flowered inflorescence from a pedicel attached to a naked leaf stalk, the flowers opening before the taller canopy of biternate leaves (3 sets of 3 leaflets), the individual leaflets are very large. The long spurs are incurved (arched downwards). Flowers are a noticeably large size. The growth pattern of E. koreanum is like a thicket of separate vertical leaf stalks, each stalk with a flower cluster attached at approximately the midpoint of the leaf stalk, completely different than E. grandiflorum which makes a dense woody pad of congested rhizomes/roots with many leaf stems arising from the rootstalk, and separate flower stems arising from the base.
Flora of China: Epimedium koreanum is from Korea, Japan, and several provinces of China
http://www.efloras.org/florata...
Flora of China: see note regarding grandiflorum not in China, under "insufficiently known species"
http://www.efloras.org/florata...
Flora of China: drawing of Epimedium koreanum, showing biternate leaf arrangement (3 sets of 3 leaflets) and flower stalk off the leaf stalk part way up.
http://www.efloras.org/object_...
Royal Botanic Garden, Kew Science, Plants of the World Online (2017)
http://powo.science.kew.org/ta...
Kew Names and Taxonomic Backbone
The International Plant Names Index and World Checklist of Selected Plant Families 2017. Published on the Internet at
http://www.ipni.org and
http://apps.kew.org/wcsp/
