EPOW - Ecology Picture of the Week

left to right: Upper Amazon, Bolivia; Bobangi, Congo; Congo River Basin; South Africa 

Explanation:   So different, yet so much alike are these thorned tree trunks or boles.  Why would such different trees in different parts of the world have evolved such similar defenses?

Well, would you climb a thorned tree to seek its fruits?  Or chew a slab from its armed bark?

Many trees have thorned boles, particularly in thorn scrub woodlands (hmm, well named, eh?) and tropical forests.  The examples in this week's EPOW include a member of the kapok family (Bombacaceae) from Bolivia, South America (far left photo), and a member of the acacia family (Acacia nigrescens, Mimosaceae) from South Africa (far right photo).

Another example of a well-armed denizen of tropical forests is the shaving-brush tree (Pachira quinata, Bombacaceae) of subtropical deciduous forests of Central America.  This tree also has nasty thorns to thwart herbivores from devouring it.  

Thorns and spines are actually modified stems and leaves.