Bismarckia nobilis, from Madagascar is the only species in the genus.
The solitary Bismarck palms are very occasionally seen in gardens in Brisbane.
Usually seen up to 10 or 12 m high they can be nearly twice that in the wild.
Cylindrical trunks are 30 to 40 cm across but up to 80 cm at the base.
Young trunks are covered in old leaf bases while older sections are bare.
The grey to brown trunks have close to very close ring scars.
On old palms the trunk has vertical fissures.
On mature palms the crown can be over 7 m wide and nearly as high.
The up to 30 leaves, on a petiole 2 to 3 m long have blades up to 3 m across.
Petioles are over 10 cm wide at the base which is concave above and rounded underneath.
The grey-green petioles have a waxy white coating and red-brown scales.
At the base the sharp petiole edges may have minute teeth.
The leaf sheaths, up to 80 cm long are split at the base and covered with scales .
Blades are costapalmate with a midrib or costa that can be over 40 cm long.
On the upper junction of the petiole and blade is a wedge shaped flap of tissue – the hastula.
The lower surface has no hastula.
Blades, attached to the costa are almost round and flat when young.
One side of the blade is attached up to 10 cm lower down on the costa.
Blades are partially divided into 20 to more than 70 stiff segments.
The undivided section is longer on the centre of the blade than the sides.
Segments are up to 5 cm wide and the tips are split for a short distance.
The edges of each segment are folded up (induplicate).
Many of the sinuses between the segment bases have a long filament.
Blades are blue-green but the waxy white coating makes them grey-green.
The lower surface has a thinner waxy layer and scales along the leaflet midribs.
The large feathery grey to red-brown scales eventually fall off.
Male and female flowers are on separate palms.
Erect inflorescences, among the leaves can be over 1 m long.
The peduncle, around 30 cm long has a keeled prophyll.
The few peduncular bracts, around 45 cm long are covered in scales.
Inflorescences, with 2 orders of branching have bracts at the base of each branch.
The midrib (rachis) has branches around 30 to 45 cm long.
From the tips of these are radiating branches (digitate rachillae).
Male inflorescences have up to 9 rachillae from each primary branch and females 2 to 5.
Rachillae, around 20 cm long have spirally arranged flowers among densely hairy bracts.
Male flowers are in groups or 3 while female flowers, on a short stalk are solitary.
Brown flowers, with bracteoles at the base have 3 sepals and 3 petals.
On male flowers the petals are the longer; in females the sepals are the longer.
Male flowers have 6 stamens with long filaments and dorsifixed anthers opening sideways.
There is a rudimentary ovary.
Female flowers have a ring of staminodes with 6 empty anthers.
The ovary has 3 locules each with 1 ovule and 3 stigmas that are slightly curved back.
Typically only 1 locule develops with remnants of the other 2 remaining at the base.
There are nectaries at the base of the ovary.
The fruit are ovoid to round drupes around 45 mm long.
If 2 or 3 carpels develop the fruit are lobed.
Dark brown with paler spots they have 1 longitudinally grooved seed.
J.F.
