2 _ BULLETIN 9, U. S. DEPARTMENT OF AGRICULTURE. 
Besides the 450 species there are many varieties developed through 
cultivation. Further, much confusion exists as to the proper identi- 
fication, not only of the acacias but of closely related genera, which 
are sometimes confused with the true acacias. An example of this 
is found in the so-called Acacia lophantha, which is an albizzia, as is 
the pink-flowered ‘Constantinople acacia.’’ The flowers of the true 
acacias are usually yellow, and are produced in globose heads vari- 
ously arranged; those of the albizzias are generally borne as spikes, 
similar to those of the Australian “bottle brush” ( Melaleucas), and 
are seldom yellow, though some are a greenish white. 
NOMENCLATURE. 
The difficulties of identification have led to equal difficulties of 
nomenclature, or, rather, the confusion in either case has led to 
confusion in the other. Except for the species of greatest economic 
value, which have been longest in cultivation, the nomenclature is 
so mixed in California that acacias are still being sent to Dr. Maiden, 
director of the Sydney Botanic Garden, for identification. 
Mr. Ernest Braunton, of Los Angeles, has done much in recent 
years to secure the correct identification of the acacias planted for 
ornament in southern California. Dr. Franceschi and Mr. P. Reidel, of 
Santa Barbara, and Miss Katherine Jones, of the University of Cali- 
fornia, at Berkeley, have worked with the acacias to the end that the 
synonyms may be all weeded out, and that the various species grown 
in California, where acacias have been most extensively planted in 
this country, may be accurately known. 
The chief difficulty has been with the so-called decurrens group, 
and the problem has been to distinguish between species and mere 
varieties. 
The classification made by Dr. J. H. Maiden* seems to be both 
culturally and scientifically correct, and its general adoption offers 
the best escape from present confusion in American nomenclature. 
According to this (1) Acacia decurrens, or decurrens var. normalis 
(Willd. and Benth.), is the “‘ black wattle”; (2) Acacia decurrens var. 
mollis (Benth.) is the Acacia mollissuma (Willd.), and is the leading 
‘“‘oreen wattle”; (3) Acacia decurrens var. pauciglandulosa (F. von 
M.) also is known usually as “green wattle’; (4) Acacia decurrens 
var. dealbata (F. von M.) is the leading “‘silver wattle.” 
These four wattles and two or three others of lesser importance 
pass into each other by successive gradations. They show cultural 
differences, however, and marked variations in yield of tan bark. 
The nurseryman naturally chooses the more floriferous and shapely 
form of Acacia decurrens, but the commercial planter must consider 
bark yields and proportion of tannin. 
1** Wattles and. Wattle Barks,” third edition, pp. 103, Sydney, 1906. 
