Ptychosperma macarthurii (H.Wendl. ex H.J.Veitch) H.Wendl. ex Hook.f.

Arecaceae

Hooker, J.D. (1884) Report on the Progress and Condition of the Royal Gardens at Kew, during the year 1882 : 55.

MacArthur Palm; Macarthur's Palm; Palm, MacArthur

Grows up to 9 m tall but usually flowers and fruits when smaller. Multistemmed or stems often clumped and usually surrounded by suckers.

Leaves to 3 m long, pinnate with 15-40 leaflets on each side of midrib and to 56 cm long.

Inflorescence 20-45 cm long bearing flowers in groups of three consisting of two male and one female flower. Male flowers with sepals 3, c. 1.5-2.5 mm long, yellow-green to light green; petals 3, c. 7 mm long, yellow-green to light green; stamens 23-40 per flower; ovary, style and stigma always well developed but the ovules are absent in the male flowers. Female flowers with sepals 3, 2 x 3 mm, cream-green; petals 3, 3-4 x 2-3.5 mm, cream-green; 3-6 staminodes present; stigma 0.5 mm llong, recurved.

Fruits ovoid, 12-18 mm long x 8-12 mm diam.; red when mature. Seed 9-12 mm long, 5-angled.

Leaflets long and narrow, wider on older plants.

Occurs in NT and CYP. Altitudinal range quite small from near sea level to 400 m. Grows as an understory plant in lowland rain forest, monsoon forest and brackish mangrove. Also occurs in New Guinea.

A commonly cultivated palm in tropical gardens.

Distinguished by the clumping habit, number of pinnae 15-40 on each side of the rachis, and the homogeneous endosperm in seed.

Kentia macarthurii H.Wend. ex H.J.Veitch, Catalogue 1879 : 26(1879), Type: None cited, neo: Papua New Guinea, Daru Island, Brass 6376; holo: A. Ptychosperma julianettii Becc. ex Martelli, Atti della Societ~g Toscana di Scienze Naturali Residente in Pisa. Memorie 44 : 143(1934), Type: Raccolto da Amadeo Giulianetti in Hammond Island nello stretto di Torres il 22 Marzo 1891. Ptychosperma bleeseri Burret, Repertorium Specierum Novarum Regni Vegetabilis 24: 266(1928), Type: Nord Australien: Gebeit von Port Darwin, Koolpinyah, Bankers Jungle 15 Fuss hohe, schlanke Palm (F.A.K. Blesser No 430 27 Aug. 1925). Actinophloeus bleeseri (Burret) Burret, Repertorium Specierum Novarum Regni Vegetabilis 24 : 266(1927).