Title
Liana structure, function and selection: a comparative study of xylem cylinders of tropical rainforest species in Africa and America
Document Type
Article
Publication Date
1993
Volume Number
113
Source Publication
Botanical Journal of the Linnaen Society
Abstract
Liana structure, function and selection: a comparative study of xylem cylinders of tropical rainforest species in Africa and America A general analysis of xylem cylinders is presented on the basis of intercontinental (Africa-America) comparisons of 448 species (35 families) of tropical forest lianas. Drawings of stem transverse sections are presented for 58 species. From an evolutionary point of view, the liana represents a woody plant form at the crossroads of two life-form types: either self-supporting or non-self-supporting. The interconnections between anatomy, life-form, and dynamics of forest space occupation are highly integrated. The American lianas show a distinct propensity to form a crown in the forest canopy constituted of multiple leafy units (small crowns) which grow apart with an increasing distance between each unit (expansion with a centrifugal tendency). Xylem cylinders associated into polystelic and multiple stems appear to facilitate this behaviour (nearly 80% of American species compared to less than 50% in Africa). Neotropical forests seem to show a comparatively higher range of sites exposed to light than African ones.