In 1927, A. Chevalier (in Rev. Bot. Appl. 8: 125) 
questioned the validity of Acacia tortilis Hayne; dis- 
carded it on the ground that Mimosa tortilis Forskal was 
a nomen nudum; and adopted in its stead Acacia fasci- 
ulata Guillemin & Perrottet. 
In 1933, Maire (in Mém. Soc. Hist. Nat. Afr. Nord 
3: 118) pointed out that Acacia fasciculata Guillemin & 
Perrottet was itself untenable as it was a later homonym 
of both 4. fasciculata Kunth and 4 ,fasciculata R. Brown; 
and adopted Acacia Raddiana G. Savi with which to 
replace Acacia tortilis Hayne, a procedure which Chev- 
alier followed in 1984 (in Rev. Bot. Appl. 14: 881). 
Maire, however, did not discard Acacia tortilis Hayne 
for the same reason that Chevalier did. He did not con- 
sider that Mimosa tortilis Forskal was a nomen nudum in 
view of the fact that a description, even though a meagre 
one, accompanied the publication of the name. Maire’s 
action was prompted by his belief that Forskal’s name 
applied to a different species from the one Hayne had de- 
scribed, i.e. to A.spirocarpa Hochstetter ex A. Richard 
rather than to 4.tortilis Hayne; and further, that Hayne 
had erroneously applied the original epithet in its new 
position. This belief was based in part on Christensen’s 
‘‘Index to Forsskal: Flora Aegyptiaco-Arabica 1775, 
with a Revision of the Herbarium Forsskal,’’ and in part 
on a personal letter from Christensen in which the latter 
corroborated his published statement. 
Christensen’s published commentary (in Dansk Bot. 
Arkiv 4 (1922) 29) is not entirely clear: 
‘*g9, +Mimosa tortilis = Acacia tortilis (Forsk.) Hayne (A.spi- 
rocarpa Hochst. ; Schwf. Beitr. 207).”’ 
It is no wonder that Maire asked Christensen for 
further confirmation, which he received in a letter to 
which he refers (l.c. 118 im adnot): 
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