Abstract
Subterranean parts of shoots of Dawsonia superba [≡D. longifolia] are shown to increase in length in addition to elongation of the above ground shoot. This appears to be caused by geotropic growth of rhizoids and rhizoid bundles. New buds of aerial shoots formed on these subterranean rhozoidal shoot masses become positioned gradually deeper in the ground than those produced during the preceding growing season. Since a new shoot from a deeper place requires energy to grow and reach the ground surface, translocation of photoassimilates must actively occur among the shoots connected by rhizoid bundles, as previously demonstrated for Polytrichum commune. Such subterranean shoot or rhizoid-systems, hidden under the ground, especially in large moss species, have seldom been reported and they may play a significant role in perennation and survival under adverse conditions.
