Eastern Arc moist forest flora - Biogeography and Ecology of the Rain Forests of Eastern Africa - page 49

Table 4.6. Endemic or near endemic genera of the Easten Arc with distribution, habitat and habit notes

Aeisilvaea A.R.-Sm. (Euphorbiaceae) - 1 species, Uluguru lowland forest on limestone. Shrub.
Cphalosphaera Warb. (Myrsticaceae) - 1 species throughout the Easten Arc in submontane orests. Large
canopy ree.
Dionychastrum A. & R. Fenandes (Melastomataceae) - 1 species, Uluguru, upper montane forest edge,
subalpine scrub. Related to the Madagascan Dionycha Naud. Small shrub.
Dolichometra K. Schum. (Rubiaceae) - 1 species, East Usambara submontane orest. Prosrate herb.
Englerodendron Harms (Leguminosae: Caesalpinioideae) - 1 species, East and West Usambara submontane
forest. Midstorey tree.
Linnaeopsis Engl. (Gesneriaceae) - 4 species, Uluguru montane forest. Herbs.
Neobenthamia Rolfe (Orchidaceae) - 1 species, Uluguru and Nguru forest edge. Herb.

Plapterocapus Dunkley & Brenan (Celastraceae) - 1 species, West Usambara dry upper montane forest. Tree.
Pseuonesohedyotis Tennant (Rubiaceae) - 1 species, Uluguru montane and upper montane forest. Small scrub.
Rhipidiantha Bremek. (Rubiaceae) - 1 species, Uluguru montane forest. Shrub.

Saintpaulia H. Wendi. (Gesneriaceae) - 20 species throughout the Eastern Arc and easten coastal moist forests
from lowland to upper montane forests. Related to some Madagascan Strptocapus. Herbs.
Th ulinia Cribb (Orchidaceae) - 1 species, Nguru subalpine grassland. Herb.

Urogentias Gilg & C. Benedict (Gentianaceae) - 1 species, Uluguru and Nguru subalpine scrub. Herb.
Zimmermannia Pax (Euphorbiaceae) - 7 species, 6 throughout the Easten Arc (1 also upper moist coastal
forest), 1 on Madagascar, submontane, montane and dry montane forest. Shrubs to small trees.

Zimmermanniopsis A.R.-Sm. (Euphorbiaceae) - 1 species, Uzungwa montane forest. Shrub.
Gen. nov. aff. Sideroylon sensu FTEA (Sapotaceae) - 1 species, Usambara and Nguru montane forest.
Midstorey to canopy tree.

Table 4. 7. Examples of genera with enemic species
in the Easten Arc which app ear to be palaeoenemics

compleity and origin of some neoendemics. For
example, Grey-Wilson (1980) cites a number of
present-day hybrid swarms of Impatiens at forest
edges or disturbed areas in forest, and suggests
that apparently stable species such as the Uluguru
endemics /. barbulata and . cinnabrina may have
arisen through hybridisaion. Hybridisaion
between the forest ree um guineense subsp.
af romontanum and the riparian or swamp ree S.
coratum may give rise to S. masukuense (White,
1978b; Lovett & Congdon, 1992), and may also
account for the Easten Arc endemic . slerophyl-
lum. The origin of stable species through
hybridisaion has been suggested or Eythina in
Meico (Neill, 1988), and Strptocarpus in Natal
(Hilliard & Burtt, 1971).
Other endemics may have originated from

Number of Number of Number
Easten Arc Eastern Arc of westen

Genus species species

endemics

Allanblackia 2
Anylocalyx 1
Enantia 1
Mammea 1
Oaoknema 1
Placodisus 1
Poyceratocapus 1
Sibangea

2 8

5
10
1
4
14
6
2
11
1

1

Uvariopsis 1

Zenkerella 4 4