The abaca plant, which resembles in appearance the banana and plantain, to which it is closely related, is a perennial growing from short rootstocks. Numerous suckers grow from the rootstocks, forming a cluster of stalks 10 to 25 ft. in height. These stalks are formed by the broad, overlapping leaf items and bear at the top a crown of large, undivided leaves. The point of growth is at the base, and the fibre is obtained from the outer portion of each successive leaf stem. The flower stalk is pushed up through the centre of the plant, bearing at the top flowers that are followed by fruits similar to small bananas but filled with black seeds. Abaca plants grown from seeds do not come true to type, and this plant is propagated from suckers or from rootstocks.

The abaca plant flowers when about two years old, at which stage it is in the most favourable condition for the production of fibre. The stalk is then cut down, and the outer fibre-bearing layer of each successive leaf stem is stripped off in the form of ribbons, known as "tuxies." The tuxies are pulled under a knife that is pressed against a block of wood by means of a bamboo spring. This scraping process removes the pulp and other waste material, leaving the cleaned fibre in the hands of the operator. The fibre so cleaned has only to be hung up to dry in the open air, when, without further treatment, it is ready to be graded and baled for shipment. A small machine that is an adaptation of the hand cleaning process is used rather extensively in the Philippines. In operating this machine, the tuxie is looped around a revolving wooden spindle, which draws it under the stripping knife. Large automatic machines, of the same type as the sisal-cleaning machines, are used for cleaning abaca fibre in Indonesia and in countries of Latin America.

The quality or grade of abaca fibre is determined by the part of the stalk from which the fibre is obtained, by the amount of serration of the stripping knives and the degree of tension holding the knife against the block, and by prompt and careful drying of the fibre. The outer sheaths of the abaca stalk contain a rather short, strong but discoloured fibre; the middle sheaths produce a fibre of medium colour and good strength, the sheaths near the centre of the stalk have a very white, fine fibre of medium strength. In the process of cleaning abaca fibre, the use of coarsely serrated stripping knives and the lack of proper tension on the stripping knife result in the production of coarse low-grade fibre. Delay and carelessness in drying affect both the colour and the strength of the fibre.

The exceptional strength of abaca fibre and its quality of resistance to the action of salt water make it particularly suitable for marine cordage. It is also largely used for well-drilling cables. hoisting ropes and various other types of rope where strength and durability are required. Henequen and sisal have largely replaced abaca as a binder twine fibre. In the Philippines the superior grades of abaca are used for textile fabrics, hats, slippers rugs and various other articles. In Japan, large quantities of abaca fibre, and particularly the waste products, are used for the manufacture of paper. From the old and disintegrated ropes is made the well-known manila paper.

The abaca plant has been introduced into many different tropical regions, including Indonesia, India, the Andaman Islands, the West Indies and Central America, formerly the commercial production of this fibre was confined to the Philippine Islands. About 1921, shipments of abaca rootstocks were made from the Philippine Islands to Sumatra, where fairly large plantings were made. Despite some expansion of the industry there, it remained relatively unimportant. Small abaca plantings were also made in North Borneo. In 1925 a shipment of propagating material of the superior varieties of abaca was brought from the Philippine Islands to the republic of Panama by the United States department of agriculture. It was determined by experimental plantings that the climatic and soil conditions of this region are suitable for the abaca plant; that this plant is resistant to the more serious diseases of the banana plant and that abaca fibre of excellent quality can be produced in tropical America. In 1937 and 1939 these plantings were expanded to about 2,000 ac., and after 1942 there was a larger expansion in Costa Rica, Guatemala, Panama and other countries of Central America. (H. T. Es.)