The structure and rate of growth of the rhizomes of some forest herbs and dwarf shrubs of the New Brunswick - Nova Scotia border region

Abstract

Rhizome growth was examined in 41 herbs and dwarf shrubs of hardwood and mixed forests in the New Brunswick-Nova Scotia border region of Canada. For each species the morphology of rhizome growth was examined and the rate of growth (cm/yr) was estimated. Thirty-four of the species had either surface or underground rhizomes and in 32 of these ramification or division of plants was observed. Two of the species that lacked rhizomes were able to spread by means of horizontal roots on which adventitious buds developed. The maximum rates of rhizome or root growth varied from almost nil for some species to rates approaching 1 m/yr for others. The frequency of branching also varied although this was not precisely determined for many species. Examination of the results indicated that most of the species of slower rhizome growth were characteristic of the climatic climax fern-herb forests of the region, whereas many of the species of faster rhizome growth were more characteristic of the successional stages after fire, logging, or other disturbances. The adaptive significance of these findings was discussed.