(linearilobum transversale laciniata).
This is a most unusual and attractive form, in which the leaves are cut into very narrow, parallel sided lobes.
This gives a light, almost feathery appearance to the foliage, which is wonderfully decorative below the purple-violet flowers. This naturally has smaller tubers than many species, it is just the way that it is!
Sunny, well-drained spot with a dry summer rest.