5. Pandanus tectorius Parkinson, J. Voy. South Seas. 46. 1773.
露兜树 lu dou shu
Pandanus fascicularis Lamarck; P. odoratissimus Linnaeus f. var. sinensis (Warburg) Kanehira; P. remotus H. St. John; P. sinensis (Warburg) Martelli; P. tectorius var. sinensis Warburg.
Trees or shrubs, 3-10 m. Stems erect or ascending, many branched, non-suckering; prop roots present or absent; numerous aerial roots often present. Leaves green, often glaucous abaxially, linear-ensiform, to 180 × 10 cm, spinose-serrate on margin and midvein abaxially, apex abruptly long acuminate. Male inflorescence to 60 cm, pedunculate, paniculately compound with ultimate spiciform branches; spathes 13-18, white, narrowly lanceolate, 10-60 × 1.5-4 cm, serrate on margin and midvein; spikes pendulous, 8-20 mm; stamens 10(-25), racemosely fasciculate; filaments connate below, 1-3 mm; anthers linear, ca. 3 × 0.6 mm, connective mucronate. Female inflorescence capitate, solitary, globose to ovoid-ellipsoid, 10-25 cm; spathes numerous, white, 15-30 × 1.4-2.5 cm, margin serrate; ovule 1 per locule. Syncarp pendulous, globose or cylindric, to 17 × 15 cm; phalanges 40-80 per aggregate-head, each phalange comprising 4-12 fused obconic carpels connate below and free above, fragrant, yellow to orange to yellowish brown from base to apex, 4-10 × 1-6.5 cm; carpel apices distinct, flattened or angled, tuberculate; persistent stigma subsessile, slightly protruded. Fl. Jan-May, fr. Oct.
Seashores, sandy beaches. Fujian, Guangdong, Guangxi, Guizhou, Hainan, Taiwan, Yunnan [SE Asia, tropical Australia, Pacific islands (Polynesia)].
Pandanus tectorius sometimes is used as a living fence, and the leaves are used for weaving.
According to FRPS (8: 20. 1992), Pandanus tectorius var. sinensis (a variety not accepted in this treatment on the authority of Stone, Fl. Cambodge, Laos & Vietnam 20: 24. 1983) occurs on seaside beaches in Guangdong, Guangxi, Hainan, and Taiwan and differs from the typical variety in having leaves narrower, attenuate into a long flagelliform apex, to 15 cm; ovary (4 or)5- or 6(or 7)-locular; and syncarp smaller, globose, ca. 8 × 8 cm, consisting of 50-60 phalanges, each phalange ca. 2.5 × 2 cm. Stone (loc. cit.) considered P. tectorius var. sinensis, with phalanges ca. 3.5 × 4 cm, to be a synonym of P. odoratissimus, with phalanges 3-8 × 2.5-4.5 cm. The correct name of this taxon has long been controversial (see Martelli, "Pandanus odoratissimus" o "Pandanus tectorius"? Nuovo Giorn. Bot. Ital., n.s. 36: 329-337. 1929). Stone (Bot. J. Linn. Soc. 97: 36-38. 1988) reinstated P. tectorius, reversing his former acceptance of P. odoratissimus (Fl. Cambodge, Laos & Vietnam 20: 23. 1983). The type specimen of P. remotus, a name synonymized by Stone (loc. cit.: 24), is from Hong Kong (Shek O).
Stone (Bot. J. Linn. Soc. 97: 46-47. 1988) noted that there are "variegated-leaf mutants of P. tectorius, known in horticulture variously as P. sanderi and P. veitchii. ..... (which can back-mutate to all green leaf forms)." The mutant (cultivar) P. sanderi Masters is cultivated as an ornamental in Hong Kong (see Check List Hong Kong Pl. 297. 2002). Its leaves have yellow or golden longitudinal marginal stripes. Pandanus veitchii Masters & T. Moore is cultivated at the Taiwan Forestry Research Institute. Its leaves have white or silvery marginal stripes.