Pandanus (Malayan, pan-dang), the generic name of the screw pines, so called not because of their resemblance to the pines proper, but from the leaves, which are arranged spirally, somewhat like those of the pineapple. The genus is the principal one of the order panda-nacea, which as at present restricted consists of only three genera of arborescent plants, with simple or branched stems and simple leaves arranged .in three very close spirals; the flowers are dioecious, without calyx or corolla, and arranged very compactly upon a spadix; the fruit consists of numerous fibrous drupes closely crowded and cohering. The trunks in this family are supported by strong adventitious roots, and appear as if set upon a cone of props. The screw pines are natives of the East, especially the islands of the Indian archipelago, abounding along the banks of rivers and the littoral marshes, often occupying large tracts to the exclusion of other vegetation. There are 30 or more species, some being 20 or 30 ft. high, but the majority do not exceed 10 or 15 ft. One of the finest is pandanus candeladrum, the chandelier tree, so named on account of its manner of branching.
The most useful species, P. utilis, is the vacoa of Mauritius, where it grows wild, and is also cultivated to a great extent; its leaves are used in manufacturing the sacks in which sugar is exported, and in England the empty sacks are converted into fish bags. The flowers of P. odoratissimus are exceedingly fragrant, and the tree is cultivated in Japan for the sake of their perfume. A number of species and varieties are in cultivation ; their handsome and peculiarly arranged leaves make the plants conspicuous ornaments in a stove house; the leaves, from 3 to 6 ft. long, are generally gracefully recurved and pendulous, with their edges and the midrib upon the back armed with very sharp recurved prickles, which, while they render the plants troublesome to handle, add much to their beauty, as they are white, brown, or red, and in fine contrast with the green leaf; in some the leaf is marked with white longitudinal stripes. Small plants of screw pines are used for decorating tables and rooms.