40 NATURAL HISTORY OF PLANTS. 
phyllode (figs. 32, 33), while the leaflets abort more or less completely. 
The petiole often bears one or several glands. The stipules may be 
membranous, absent, ill-developed, or transformed into spines of 
sometimes considerable length (fig. 28). The flowers are generally 
small, forming globular capitula (figs. 28-32) or cylindrical cymes 
(fig. 31), each axillary to a bract, and sometimes articulated at the 
base. The spikes and capitula are solitary axillary, collected into 
racemes, or forming more or less ramified inflorescences terminating 
the branches. About four hundred species have been described in 
this genus; they have been grouped into more or less natural sec- 
tions, based on the habit and inflorescence ; for the characters of the 
fruits have been found inadequate to found well-defined subdivisions. 
Acacias are especially abundant in Australia and Africa, but species 
are also found in warm countries all over the world.' 
1 It was found impossible to divide the known 
species, upwards of four hundred in number, into 
subgenera or sections founded on the pod, for 
that is polymorphous, and every possible transi- 
tion between the various forms is found. BzEn- 
THAM, who has so long occupied himself in the 
study of this genus, has divided it into six 
secondary series based on the habit and inflo- 
rescence. ‘These are as follows :— 
I. Phyllodinea.—Species with laterally flat- 
tened or rounded phyllodes, the leaflets abortive, 
except in the first leaves of the plant, or on some 
adult branches (fig. 33). Sometimes the leaves 
are replaced by short scales or bracts. ‘To this 
group belong the genera Chithonanthus and Te- 
tracheilos of LuuMann (Plant, Preiss., ii. 
368), founded only on the form of the fruit. 
This genus contains nearly three hundred 
Australian species, besides five or six from the 
islands of the Pacific. (LaMK., in Journ, Hist. 
Nat., i. t. 15.—Lazsitn., Sert. Austr.-Caled., 
t. 88, 89.—A. Gray, Bot. Unit. States Erol. 
Exped. t. 53-—R. Br, in Ait. Hort. Kew., 
ed. 3, v. 464,—LinDL., Swan Riv., App., 15.— 
Meissy., in Pl. Preiss., ii. 199.—A. Cunn., in 
Field N. S. Wales, 348.—BeEnru., in Hook. 
Jowrn., i. 323; Fl. Austral, ii. 319.—F. 
MUvELL., Fragm., iii. 127, 151.) 
II. Botrycephale.—Australian species, ten in 
number, with flowers forming globular capitula 
collected into simple or ramified axillary or 
terminal racemes. Leaves bipinnate, stipules 
absent or ill-developed. (VeEnt., Jard. Cels., 
t. 1; Jard. Malimais., t. 21, 61.—ANDR., in 
Bot. Repos., t. 235.—Swxrr, Fl. Austral., 
t. 12.—Hook., in Bot. Mag., t. 1263, 1750.— 
Bot. Reg. (1848), t. 46.—Raicus., Icon. et 
Descr.gPlant., t. 73.—Link., Enum. Hort. 
Berol., 445.—R. Bx., in Ait. Hort. Kew., ed. 3, 
v. 467.—BEntH., in Hook. Journ., i. 383; Fl. 
Austral., ii. 418.) 
Il]. Pulchelle.—Low trees, much branched 
unarmed, rarely possessing axillary spines; 
leaves bipinnate; stipules absent or ill-developed. 
Flowers in globular capitula, rarely spicate ; 
peduncles axillary, splitary or fascicled. Species 
Australian, numerous. (Lapiz, Nowv.-Holl., 
ii. 88, t. 238.—A. DC., Pl. Bar. du Jard. de 
Geneve, note 6, t. 3.—Hoox., in Bot. Mag., 
t. 2188, 4588, 4653, 5191.— Bot. Reg., t. 1521. 
—F. Murtz., Pl. Victor. ii. t. Suppl. 12,— 
Linpt., Swan Riv., App., 15.—Link., Enum. 
Hort. Berol., ii, 444.—Mrtssn., in Pl. Preiss., 
ii, 204.—Benru., in Hook, Journ,, i. 387; Fl. 
Austral., ti. 416.) 
IV. Gummifere.—tTrees and shrubs with bi- 
pinnate leaves, and stipules all or part transformed 
into spines, sometimes of enormous size; other- 
wise unarmed. Flowers in axillary capitula or 
spikes, fascicled or united into simple or com- 
pound racemes towards the ends of the branches. 
Species especially American and African, some 
Asiatic, few Australian ; about fifty in number. 
(K., Mimos., t. 28, 29—Jacq., Hort. Schen- 
brun., t. 393.—VELLOZ., Fl. Flum., xi. t. 39.— 
Roxs., Plant. Coromand., t. 149, 150, 199.— 
Dewitz, Fl. Ayypt., t. 52, fig. 2—Wreur, 
Icon., t. 1157.—Nuzs v’Esrns., Plant. Offc., 
n. 332-836.—Bot. Reg., t. 1317.—F. Murtu., 
in Journ. Linn. Soe, iii. 147.—Brntu., in 
Hook. Journ., i. 499; in Linnea, xxvi. 629 ; 
Fl. Austral., ii, 419.—Borou., Trav., ii. 240, 
t. 6—E. Mry., Comm., 167.—Hanry. & Soyp., 
Fil. Cap., si. 280.) 
V. Vulgares.—Lofty trees or shrubs, often 
climbing, American, African or Asiatic, rarely 
unarmed, usually covered with prickles dissemi- 
nated over the branches or planted in the pul- 
