Archontophoenix alexandrae (F.Muell.) H.Wendl. & Drude

Arecaceae

Wendland, H.A. & Drude, C.G.O. (1875) Linnaea 39: 212.

Alexandra Palm

Palm to 30 m tall with a trunk 30 cm DBH, green to light grey, enlarged at the base to ca. 50 cm, becoming fissured with age. Leaf scars prominent.

Leaves 10-12, up to 4.5 m long, with a pronounced lateral twist, with 60-80 pinnae per side. Crownshaft to 100 (-130) cm long, elongate, light green to lime green with a waxy surface, swollen and tapered towards the base and the apex, irregularly bulging near attachment of petiole. Petiole up to 38 cm long, concave above and convex below. Rachis ridged above and convex below. Pinnae up to 75 x 3-5 cm, rigid, dark green on adaxial surface and silvery grey on abaxial surface. Midrib prominent on both surfaces, cream, with up to 12 prominent ribs on abaxial surface.

Inflorescence 50-100 x 40-50 cm, axis cream changing to green or brown. Prophyll up to 78 x 12 cm, dorsiventrally compressed, winged, fibrous, with black scales near the base. Peduncular bract to 44 x 6 cm, beaked, thickly fibrous and white on the inside. Peduncle up to 15 x 8 cm, green. Rachis erect up to 40 x 2.5 cm and 2 cm thick and angular at the base. Staminate flowers paired at the front part. Flowers white to cream. Staminate flowers 6-9.5 x 2-3 mm opening to 10 mm. Sepals to 2 mm long. Petals 6-7 x 2-2.6 mm, falcate and suffused light brown at the base. Stamens 9-16 with curved filaments up to 2 mm long. Pistillode equal to slightly longer than the stamens. Pistillate flower up to 4 x 3 mm.

Fruit ovoid/globose and 8-14 x 6-11 mm and bright red at maturity. Stigmatic remains prominent at the apex. Persistent calyx up to 3 mm long. Epicarp smooth and waxy to glossy. Mesocarp fibres up to 1 mm wide, flat and sparingly branched and remaining tight in the dried state. Endocarp brittle, lacking the imbedded mesocarp fibres. Seed globose and up to 8 mm diameter.

Features not available.

Occurs in NEQ and CEQ to as far south as Brisbane. Altitudinal range from near sea level to 1000 m. Grows in swampy areas and along drainage lines in rainforest, gallery forest along seasonally dry creeks, vine forest, Melaleuca forest and mixed Eucalypt forest.

A popular park and garden plant. Distinguished by: undersurface of pinnae with silver-grey scales, ramenta (large irregular scales on midrib) lacking; perianth white-cream, fruit ovoid-globose, 8-14 mm; mesocarp fruit fibres to 1 mm, flat, sparingly branched.

Ptychosperma alexandrae F.Muell., Fragmenta Phytographiae Australiae 5(32): 47, t. XLIII, XLIV.(1865), Type: In virgultis densis silvarum quam maxime umbrosarum ad flumen Fitzroys River Australiae capricornicae orientalis. Bowman.