Mycorrhizae in recent volcanic substrates in Hawaii

Plants colonizing 8- and 14-yr-old lava flows, a 28-yr-old cinder fall, a 137-yr-old volcanic soil, and a geothermic volcanic soil were sampled for mycorrhizae. Vesicular arbuscular mycorrhizae were present in all sites, and the frequency of occurrence and intensity of root colonization increased with increasing age of the site. Orchid and ericoid mycorrhizae also were present in some sites. Native Hawaiian species tended to more frequently form mycorrhizae and have more intense mycorrhizal infection than did alien species. Plant succession on the Hawaiian volcanic sites showed a lack of dominance by nonmycotrophic species in the early seral stages. -from Author