RUTACEZ. 409 
contain under their coats one or several fleshy embryoes, with 
cotyledons often unequal and irregular, and short superior radicle 
(figs. 457-459). More than thirty species of this genus have been 
described ; these are probably forms or varieties of four or five species,’ 
natives of the tropical regions of Asia. They are aromatic’ trees or 
Citrus Aurantium. 

Pigs, 457, 458, 459. 
Embryos (+). 
shrubs, with branches often thorny, leaves persistent, alternate only 
having one articulate foliole and a more or less dilated and winged 
petiole. The fragrant flowers are axillary and solitary, accom- 
panied by sterile bracts, or disposed in few-flowered cymes with 
centrifugal evolution. 

unequal faces. Their contents become modified ; 
in the interior is secreted the acid and sweet 
juice of oranges, lemons, &c. (Upon the forma- 
tion of this complementary layer of the fruit 
see TARGIONI, in Giorn. Tose. d, Sc., i, 575.— 
Zuce., in Abh. d. Bay. Akad., iv. p. i. 159 ; 
p. ii. 33, t. 66.—H. BN., Awrantiac., 42.— 
Can., Sull, Polp. che Invogl. i Semi (Firenz., 
1864), 7, t. 1. 
1 Monarp., De Citr. Aurant. et Lim. 
(Antwerp., 1561).—FERRAR., Hesperid. (Roma, 
1646),—Gattes., Tr. du Citrus (Par., 1811). 
D. Giard. di Firenze (1839); Gli Agrum.— 
Risso & Porr., Hist. Nat. des Orang. (Par., 
1818-19). — Rœm., Syn. Hesperid. (For the 
principal treatises on the genus, see PRITZEL, 
Thes., 444, 451..—Wient & Arn., Prodr., i. 
97.—Sirs. & Zuco. Fl. Jap., t. 15,—GRIsEB., 
Fl, Brit. W.-Ind,, 132.—Buntu., Fl. Austral., 
i, 371.—Miaq.,, Fl. Ind.-Bat., i. p. ii, 530.— 
Watp., Rep., i. 382; ii. 504; v. 140; Ann. 
vii, 535. 
* This is due to the numerous more or less 
prominent vesicles full of an essential oil scat- 
tered through most of the organs, leaves, flowers, 
pericarp, &e. We observed in 1855 that these 
reservoirs are formed first of a certain number 
of secretive cells constituting a yellowish mass 
embedded in the ambient tissues, and that later 
a large channel is produced at this level which 
crosses and forms a large lacuna, carpeted with 
the remains of fine compressed cells. MARTINET, 
who has studied the development of these 
glands (in Ann. Se. Nat., sér, 5, xiv. 199), does 
not admit this opinion; but it is easy to see that 
what he substitutes for it only differs in the 
mode of statement and the interpretation of 
facts, 
3 Equal in size to the limb itself in certain 
species of Citrus, especially ©. Hystrix DC. 
(Cat, Hort. Monsp., 97; Prodr., n. 7). In 
Pseudegle the leaves are trifoliolate. 
