authorities recognized page priority this was considered 
to be the earliest valid name for the arabica complex. 
W.F. Wight in 1905, and A. Chevalierin 1927, each pub- 
lished the combination Acacia scorpioides, and the latter 
made several varietal transfers. The International Rules 
as amended at Amsterdam in 1935 invalidate page pri- 
ority and the choice of epithets must be governed by 
Article 56. This states that when two groups of the same 
rank are united, and the names and epithets are of the 
same date, the author who first unites the two has the 
right of choosing one of the names and his choice must 
be followed. Linnaeus himself united scorpioides and ni- 
lotica (both 1753) under nilotica; consequently the latter 
epithet must be utilized. 
From all points of view it appears necessary to take 
up Acacia nilotica (L.) Delile in place of the more fa- 
miliar Acacia arabica (Lam.) Willdenow. This procedure 
has already been followed by some authorities. Among 
them may be mentioned Fiori, Boschi e piante legn. 
Eritrea (1912) 159—Fawcett and Rendle, FI. Jamaica 4 
(1920) 1389—Britton and Wilson, Sci. Survey Puerto 
Rico & Virgin Islands (1928) 354—Britton and Rose in 
No. Amer. FI. 23 (1928) 85—Chiovenda, Fl. Somal. 2 
(1982) 202. 
The correct nomenclature of this polymorphic species 
with the essential synonymy and necessary varietal trans- 
fers follows: 
Acacia nilotica (L.) Delile F\. Aegypt. Ill. (1813) 
53 
Mimosa nilotica Linnaeus Sp. Pl. (1758) 521. 
Mimosa scorpioides Linnaeus Sp. Pl. (1758) 521. 
Mimosa arabica Lamarck Encycl. 1 (1788) 19. 
Acacia arabica (Lam.) Willdenow Sp. Pl. 4 (1806) 
1085. 
[97 ] 
