Chapter 17, Problem 15TYK

SCIENTIFIC THINKING As you learned in Module 17.18, symbiotic relationships with mycorrhizal fungi are found in almost all present-day plant lineages. Mosses are a major exception—most mosses lack mycorrhizal associations. Assuming that mycorrhizae were a key factor in the colonization of land by plants, propose an explanation for the absence of mycorrhizae in present-day moss lineages.