Archontophoenix alexandrae (F. Muell.) H. Wendl. & Drude
Archontophoenix alexandrae (F. Muell.) H.
Wendl. & Drude var. alexandrae
Archontophoenix
alexandrae (F. Muell.) H. Wendl. & Drude var. beatriceae (F.
Muell.) C.T. White ex L.H. Bailey
Archontophoenix alexandrae (F.
Muell.) H. Wendl. & Drude var. schizanthera H. Wendl. &
Drude
Archontophoenix beatriceae (F. Muell.) F.M.
Bailey
Archontophoenix veitchii H. Wendl. &
Drude
Jessenia glazioviana Dammer
Ptychosperma
alexandrae F. Muell.
Ptychosperma beatriceae F.
Muell.
Ptychosperma veitchii H. Wendl.
Arecaceae
Alex palm, Alexander palm, Alexandra palm, feather palm, king Alexander palm, king palm, northern bangalow palm
Native to northern and central Queensland (i.e. from Baffle Creek, just south of Gladstone, to Bathurst Bay on the Cape York Peninsula).
This species is becoming naturalised in the Moreton district in south-eastern Queensland.
It is possibly also becoming naturalised in the coastal districts of northern New South Wales.
In its native habitat, in northern Queensland, this species is generally confined to lowland swamps, drainage lines and riparian rainforest vegetation. It is an emerging weed of waterways and riparian vegetation in the wetter coastal districts of south-eastern Queensland.
A tall palm with a single trunk growing up to 30 m in height and with a crown that usually contains about 10-12 leaves.
The grey trunk is ringed with noticeable leaf scars, but is otherwise smooth. This trunk is up to 30 cm thick, but is frequently expanded at the base (up to 50-60 cm across).
The massive leaves (3.5-4.5 m long on mature trees) are alternately arranged, but are clustered at the top of the trunk. These leaves are usually not held flat, but instead are twisted laterally. Each of the leaves is borne on a thick stalk (i.e. petiole) up to 40 cm long and has 60-80 long and narrow leaflets (i.e. linear pinnae) on each side. The base of the leaf stalk forms a sheath-like structure around the trunk (i.e. crownshaft) that is up to 1 m long and bright green or light green in colour. The leaflets (up to 80 cm long and 3-5 cm wide) have dark green upper surfaces and paler whitish-green or silvery-grey undersides. They have entire margins and pointed tips (i.e. acuminate apices) and are all borne in the same plane.
The flower clusters (i.e. inflorescences) are produced just below the sheath-like leaf stalk bases (i.e. crownshaft). Young flower clusters are enclosed three large bracts (up to 80 cm long and 12 cm wide). These clusters (50-100 cm long and up to 50 cm wide) are borne on stalks (i.e. peduncles) up to 15 cm long and have numerous upright (i.e. erect) to drooping (i.e. pendulous) branches. The flowering branches and flowers are mostly white or cream in colour. Separate male and female flowers are present in these clusters. The stalkless (i.e. sessile) flowers are borne in threes (i.e. triads) along the flowering branches, each group having a single female (i.e. pistillate) flower and two male (i.e. staminate) flowers. The male flowers (6-9.5 mm long) have three small sepals (about 2 mm long) and three larger petals (6-7 mm long and 2-2.5 mm wide). They also have 9-16 stamens, each consisting of a short stalk (i.e. filament) about 2 mm long topped with a yellow anther (3.5-4 mm long). The smaller female flowers (about 4 mm long) have three tiny sepals, three petals, and an ovary topped with a short style and three stigmas.
The round or egg-shaped (i.e. ovoid) fruit (8-14 mm long and 6-11 mm wide) turn from green to bright red as they mature. These fruit lose their fleshy red outer covering as they age, exposing a fibrous brown under-surface. The seed itself is brown, round, and about 8 mm across.
This species reproduces only by seed. The relatively small fruit are presumably dispersed by birds, bats and other animals. They are probably also spread by water and in dumped garden waste.
This species is not currently declared under any state or local government legislation.
As this species is not a declared plant, its control is not required and there are no restrictions on its sale or cultivation. However, it is an emerging environmental weed and should be controlled in sensitive bushland and conservation areas.
Alexandra palm (Archontophoenix alexandrae) is very similar to the locally native bangalow palm (Archontophoenix cunninghamiana). These two species can be distinguished from each other by the following differences:
Alexandra palm (Archontophoenix alexandrae ) is widely cultivated as a garden and street tree in Australia. It is extremely common in cultivation in south-eastern Queensland, but has only been popular for a relatively short period of time. It has been widely promoted in recent times as a "native" replacement for the introduced cocos palm (Syagrus romanzoffiana ).
However, Alexandra palm (Archontophoenix alexandrae) is not native to south-eastern Queensland. It is spreading from cultivation and is beginning to invade waterways and riparian areas in this region. It is only in recent times that large numbers of fruiting specimens of Alexandra palm (Archontophoenix alexandrae) have been present in the region. Trees produce large quantities of seeds, which are spread by birds and other animals into natural areas, and readily germinate in wet environments. These seeds may also be washed down drains into suburban waterways.
Alexandra palm (Archontophoenix alexandrae) is already present along waterways in many parts of Brisbane and south-eastern Queensland, but is most common along wetter and more shaded creeks and in remnant rainforest areas. Most of the naturalised plants have not yet reached maturity, indicating that it is a relatively new addition to these waterways. However, the vast numbers of individuals at some locations indicate that the rate of invasion is quite rapid. One of the worst infestations is present at The Gap, in Brisbane, where hundreds of saplings and seedlings are growing along Enoggera Creek.
A similar pattern of invasion has also recently been reported in Hawaii, where Alexandra palm (Archontophoenix alexandrae) is invading roadsides, gullies, and streambeds in the wetter parts of Hawaii Island.