Willdenow, the first to propose subdividing the large 
Linnean genus Mimosa, transferred the species under con- 
sideration to Acacia. He listed A.arabica, but for some 
reason revived an old epithet of Bauhin’s, vera, instead 
of accepting nilotica as the specific epithet. This treat- 
ment of Willdenow’s, recognizing Acacia arabica and 
Acacia vera, was generally followed by botanists until 
Bentham’s revision of the Mimosae appeared in 1842. 
In 1813, however, Delile in his Florae Aegyptiacae 
Illustratio published the combination Acacia nilotica 
based on Mimosa nilotica Linnaeus. 
In 1842, George Bentham contributed a series of 
papers to Hooker’s London Journal of Botany entitled 
**Notes on the Mimosae with a synopsis of the species. ”’ 
In this work the author maintains only one of the two 
species under discussion, Acacia arabica, stating (page 
500): 
“*This very variable species should probably include the Acacia 
Nilotica, and A.vera of different authors, if, as is maintained by many, 
the downy or smooth pod is not a specific distinction. ’”’ 
Bentham goes on to describe four varieties, based on 
the principal forms of the species which he had seen. 
These varieties are a tomentosa, 8B Kraussiana, y nilotica 
and 6 indica. 
Bentham further stated his position in regard to Aca- 
cia arabica in his ‘‘Revision of the Sub-order Mimosae’’ 
which appeared in 1875 in Vol. 380 of the Transactions 
of the Linnean Society of London. Here (page 506) he 
writes: 
““The specimens of this plant show so great a diversity in the in- 
dumentum, the spines, the number of pinnae, and even in the fruit, 
that I should readily have adopted its proposed division into at least 
four species could I have ascertained any consistency or correlation 
in the different characters. ’’ 
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