Bambusa.
Family Poaceae > Subfamily Bambusoideae > tribe Bambuseae.
Bambuseae has nearly 1000 species of tropical woody bamboos in 75 genera.
The Bambusa genus has around 120 (150) species with 3 native to Australia.
Available in Australia are at least 12 Bambusa species and 15 forms or cultivars.
They are perennial, woody bamboos with short sympodial rhizomes.
These are slow growing and form fairly dense clumps.
Culms are up to 25 or 35 m high and mostly 3 to 15 cm in diameter.
They are almost all erect with some having a drooping or arching top.
In most species the internodes are hollow but in a few they are solid.
The internodes are mainly smooth but some have hairs on part or all of them especially when young.
There are no hairs on the nodes.
Young culms are a bluish green with a waxy coating that wears off.
Mature culms are green, yellow, brown or black.
They may have green or yellow stripes and occasionally brown blotches that darken to black.
The culm sheaths at the nodes cover the emerging side branches and leaves.
The sheaths commonly have a large triangular blade but it can be narrow or ovate.
The sheaths may persist but if they fall off they may leave a scar around the culm.
There is a ligule with or without hairs and usually an external ligule as well.
They almost always have prominent auricles.
The mid culm nodes typically have 3 side branches with others having 1 to many.
Branches are present on the lower nodes.
They tend to be short although in some species they are up to 10 m long.
Each branch is tree-like and one primary branch usually becomes dominant.
The alternately arranged leaves have a short pseudopetiole.
Most blades are flat and lanceolate or oblong but a few species have fern-like leaves.
The blade can be up to 15 or 30 cm long and up to 5 cm or more in diameter.
Cross veins between the parallel ones are present in some species.
The leaf sheaths are hairy.
The long or short ligule may have hairs on the margin.
Auricles are almost always present and they may have setae (long hairs or bristles).
There is usually an external ligule as well.
The branched inflorescences are rarely, if ever, seen in cultivation.
In each spike the midrib or rachilla extends beyond the last spikelet.
Each spikelet has 1 or 2 (3) glumes, more than 2 (3- 20) fertile florets and usually some sterile ones.
The glumes at the base of each spikelet have no hairs or awns (terminal bristles).
The florets have a lemma with a blunt or notched end with no awn, and a palea.
There are 2 or 3 lodicules, 6 stamens and an ovary with hairs on the top.
The single style mostly has 3 stigmas.
(Spikelets and florets are typical of Poaceae and described in detail in Poaceae – grasses.)
J.F.
