The massif of Jebel Marra lies in the western part of Sudan; it is a volcanic complex reaching
more than 3000m above sea level. The study area comprises three regions namely Zalingei, Wadi
Salih and Nerttiti. This study was designed to study the distribution of plant communities along
the altitudinal gradient. A total of 274 species, belonging to 34 families were recorded; the
nitrogen-fixing Fabaceae contributed 18.6% and grasses (Poaceae) contributed 16.4% of the
species present. The Sudano-Zambezian elements are the highest among the monoregional
species (28.6%) followed by Palaeotropical (19%) and Pantropical (17%) bioregions. A total of
17 species, belonging to 10 families, were found that had not previously been reported from the
Jebel Marra region. Plant communities were clustered using TWINSPAN; they fell into eight
distinct categories. A Canonical Correspondence Analysis separated the communities and the
species along the first axis. This axis was positively associated with finer soil textures and higher
iron content, and negatively associated with elevation, a transition to clay-loam, and sandy soil.
The second axis was associated with communities and species that were positively associated
with sandy soils and elevated levels of phosphate, and negatively correlated with sandy-loam soil
Keywords: Sudan, biogeographic affinities, plant communities, altitudinal gradient, Ordination