In article , am=ray
wrote...

Can anyone identify a tree for me? It has 2cm thorns, pictured at:
http://members.iinet.net.au/~ray/thorn.jpg

Forked thorns just like that are characteristic of _Carissa macrocarpa_
"Natal plum", in the family Apocynaceae. Does it have smallish, rounded
leathery leaves, milky white sap, white flowers, and possibly red
edible fruits, such as shown in:

http://iris.plantsdatabase.com/fp.php?pid=430448
http://www.botany.hawaii.edu/faculty...r_mac_2246.jpg
http://www.botany.hawaii.edu/faculty...r_mac_2252.jpg
http://www.botany.hawaii.edu/faculty/carr/page5.htm
http://www.desert-tropicals.com/Plan...acrocarpa.html
http://waynesword.palomar.edu/ecoph20.htm
http://edis.ifas.ufl.edu/pdffiles/HE/HE61500.pdf
http://plantsdatabase.com/go/37046/
http://www.itis.usda.gov/servlet/Sin...h_value=501290
http://www.tradewindsfruit.com/natal_plum.htm

cheers