Some observations of Pyrola elliptica and Pyrola chlorantha in northern Michigan.

Abstract

Pyrola elliptica and Pyrola chlorantha were found growing separately in nine sites, and together in one. At each site, the general habitat was remarkably similar, regardless of which species of Pyrola was present. These conditions, judging from site observations, plant associations, and literature habitat descriptions, showed well drained, sandy soil, likely ranging from slightly acidic to slightly calcareous, moderately well shaded in mixed forests. Despite the apparent abundance of similar habitat, P. elliptica and P. chlorantha appear to occur less frequently than might be expected, and where they do occur, they are usually found in a grouping. One possibility suggested for this is that there is a symbiotic relationship with another organism necessary for successful growth of Pyrola. And a lack of this symbiont prevents new growth from seed. Other possibilities suggested are infection or predation of seeds or young growth.