XERXES

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XYLEM

in permanently dry regions is the organization of reservoirs which retain water and dole it out, according to the need. Such plants, therefore, usually are fleshy or succulent. The xerophytic societies are numerous, and among them may be mentioned rock societies, composed of plants living upon exposed rocks, walls etc.; sand societies, including beaches, dunes and sandy fields; shrubby heaths, in which species of the heath family abound; plains, the great dry areas in the interior of continents; cactus deserts of the southwestern states and Mexico; and tropical deserts, where the drouth conditions are extreme and the vegetation scanty.

Xerxes (zerks'ez) I, king of Persia, was the oldest son of Darius by Atossa, his second wife, and was appointed successor by his father in preference to Artabazanes, his oldest son by his first wife. Darius died in 485 B. C. in the midst of preparations for a third expedition against Greece; and Xerxes, as soon as he had subdued the rebellious Egyptians, gave his whole attention to the completion of his father's plans for the subjugation of the Hellenic states. A bridge of boats a mile in length was built across the Hellespont; and a canal was cut through Mt. Athos, near which the fleet of Mardonius had been wrecked in 492 B. C. In the spring of 480 B. C. the vast army, said to number 2,000,000, began to march toward the Hellespont; according to Herodotus it took this force seven days and nights to march across the bridge. Grote, who discredits the immense numbers given by Herodotus, nevertheless says: "We may well believe that the numbers of Xerxes were greater than were ever assembled in ancient times or perhaps at any known epoch of history. This immense force moved on without resistance till brought to a stand by Leonidas at Thermopylae; and, although the Greeks were defeated and slain, it was not without severe fighting and heavy loss on the part of the Persians. When Xerxes arrived at Athens, three months after crossing the Hellespont, he found the city deserted. Meantime the Persian and Greek fleets had taken their positions in the narrow strait between Salamis and the Attic coast, where the great naval battle of Salamis took place, in which the Persians were signally defeated, Xerxes himself fleeing in haste to the Hellespont. The bridge of boats having been destroyed in a storm, he crossed in a vessel, leaving Mardonius with 300,000 men to carry on operations in Greece. Next year that general was defeated by the Greeks in the famous battle of Platæa; and in 478 B. C. the Persians lost their last possession in Europe by the capture of Sestos in the Hellespont. Little more is known of the history of Xerxes, except that

he was murdered by Artabanus, who aspired to the throne, and was succeeded by Artaxerxes, his son, in 465 B. C. Herodotus commended him as a man and as a monarch. See Greece, Leonidas, Platæa, Salamis, Themistocles and Thermopylæ.

Ximenes (zï-me'nêz) De Cisneros, Francisco, in Spain commonly called Cisneros, a well-known statesman, archbishop and cardinal, was born at Torrelaguna in Castile in 1436. His great reputation for piety and iearning led Queen Isabella to choose him in 1492 for her confessor and three years after to appoint him archbishop of Toledo — a dignity which he refused to accept until he had received an express command from the pope. In 1507 he was promoted to the dignity of cardinal. During the lifetime of Isabella he was the guiding spirit in Spanish affairs; and on her death in 1504 he held the balance between the parties of Ferdinand and Philip of Burgundy, husband of Joanna, heiress of the crown. When Ferdinand died in 1516, he named Ximenes regent of Spain until the arrival of Charles his grandson; and, although the grandees formed a powerful combination against him, he was able to subdue them by his prompt and efficient measures and compelled them to submit to his authority. Scholars are indebted to him for the famous Complutensian edition (1502-18) of the Bible in several languages. He died at Roa on Nov. 8, 1517.

Ximenes de Quesada {zt-me'nez dă kâ-sa'da), Gonzalo, a Spanish explorer, was born in Granada in 1498, and came to America in 1535, when, under the orders of Governor Santa Marta, he took command of an expedition against the Chibcha Indians in New Granada. After enduring great privations and overcoming all obstacles, he conquered the cities of Tuna and Iraca, where he secured a vast quantity of treasure, which he divided among his soldiers. In 1538 Ximenes founded the city of Bogota m Colombia, and soon after sailed for Europe with Frederman from Venezuela and Benalcazar from Quito, in order to refer all matters in dispute between them to the king. Ximenes was at first fined and suspended from his offices by the king, but afterwards was sent to New Granada with the title of marshal. In 1561 he was appointed governor-in-chief, a position which he continued to hold until his death at Mariqueta, Feb. 16, 1579.

X=Ray. See Roentgen Rays.

Xylem [zl'lem), (in plants), that portion of a vascular bundle which contains the tracheary tissue and commonly is called the wood. The xylem is chiefly concerned in the ascent of sap, and in trees forms all of the trunk except the bark. See Vascular Bundle.