Owing to the arrangements already mentioned, the pollen has to be transported by the wind or insects to the female flowers. This is facilitated sometimes by the elastic movements of the stamens and anthers, which liber ate the pollen so freely at certain times that travellers speak of the date-palms of Egypt (Phoenix dactylifera) being at daybreak hidden in a mist of pollen grains.
In other cases fertilization is effected by the agency of man, who removes the male flowers and scatters the pollen over the fruit bearing trees. This practice has been followed in the case of the date from time immemorial.
The fruit is various in form, size and character ; sometimes, as in the common date, it is a berry with a fleshy rind enclosing a bard stony kernel, the true seed; the fruit of Areca is similar; sometimes it is a kind of drupe as in Acrocomia (fig. 5), or the sus flabellifer) have a wide distribution. With three exceptions Old and New World forms are distinct—the coconut (Cocos nucifera) is widely distributed on the coasts of tropical Africa, in India and the South Seas, the other species formerly included in the genus being confined to the western hemisphere. The oil palm (Elaeis guineensis) is a native of west tropical Africa. Raphia has species in both tropical Africa and tropical America.
The genera are arranged, according to Drude, in six tribes, distinguished by the nature of the foliage, the sexual conditions of the flower, the character of the seed, the position of the raphe, etc. Other characters serving to distinguish the minor groups are afforded by the habit, the position of the spathes, the "aestivation" of the flower, the nature of the stigma, the ovary, fruit, etc.
Palms are of the greatest economic importance. They furnish food, shelter, clothing, timber, fuel, building materials, sticks, fibre, paper, starch, sugar, oil, wax, wine, tannin, dyeing materials, resin and a host of minor products, which render them most valuable to the natives and to tropical agriculturists. The coco
Trachycarpus Fortunei, etc., and the Chilean Jubaea spectabilis. The date palm is commonly planted along the Mediterranean coast. There are several low growing palms, such as Rhapis flabelliformis, Chamaerops humilis, etc., which are suited for ordinary green-house culture, and many of which are enabled to resist the dry and often gas-laden atmosphere of living rooms.
For further details, see B. Seeman, History of the Palms_ (1856) ; A. Engler and K. Prantl, Die Natiirlichen Pflanzenfamilien (Leipzig, 1887-1902) ; A. B. Rendle, Classification of the Flowering Plants (Cambridge, 1925) ; E. Blatter, The Palms of British India and Ceylon; as well as such great works as Martius, Historia Naturalis . . . Palmarum in 3 vols., and Barbosa Rodrigues, Sertum Palmarum Brasiliensium in 2 vols. (V. H. B.) American Palms.—The palms native in the continental United States, to which reference has been made above, are 15 or more species; a number of them are as yet imperfectly under ' stood. Most of them are fan-leaved palms. In California one palm is native, the sturdy Washingtonia filifera; this plant occurs about the borders of the Colorado desert, in canyons along streams or in seepage places in the open ; it occurs also in south-western Arizona. In Texas one species is native near the mouth of the Rio Grande, this being the northern limit, as far as known, of its dis tribution. It is a striking fan palm, Sabal texana. In eastern Texas the dwarf palmetto or blue-stem palm, Sabal minor, but