Tall, with numerous linear alternate lvs and usually one erect fl; tep widely spreading, clawed, conspicuously papillose toward the base within; 2n=24. Native of Europe, occasionally escaped from cult. in the ne. part of our range. June, July.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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