Pavetta.
Family Rubiaceae > Subfamily Ixoroideae > Tribe Pavetteae.
There are 366 – 400 species known just as Pavetta or Christmas bush.
They are native to Africa, Asia and Australia.
Australia has 5 species with P. australiensis found in S. E. Queensland.
The following generalised description is based mainly on Australian species.
Many are shrubs 3 to 6 m high with some trees up to 10 m.
There are a few dwarf shrubs only 30 to 50 cm high.
The branches may be opposite and decussate.
The bark can be brown, grey, yellowish or whitish and smooth, corky or fissured.
Young twigs may have a few hairs but most have none.
The leaves are mostly opposite and decussate but some are in a whorl of 3.
They are frequently concentrated at the ends of the branches.
Petioles may be absent or up to 6 cm long.
The blade can be broad to narrowly elliptic or obovate.
The tips can be pointed or rounded and the base tapering or wedge-shaped.
The shape and size varies and is important in identifying species.
A single plant may have leaves that vary in size and shape depending on where they are.
The blades can be thin, leathery or semi-succulent and dull or glossy.
Many species have no hairs on the leaves but some do.
In the later hairs can be sparse on both surfaces up to dense and velvety underneath.
There may be hairs around the edges of the blade.
Many have bacterial nodules along the midrib or scattered on the blade.
They are round or elongated, black nodules.
There may be domatia in the axils of the nerves on the lower surface.
These are small pits covered by hairs or a fold of leaf tissue.
There are interpetiolar stipules that are fused at the base and sheath the stem.
They may be fused the whole way or there may be pointed lobes or a bristle.
They are only a few mms long and can be smooth or have a few hairs.
Inflorescences can be terminal on the main branches or on side branches.
They consist of a few to many flowers in loose or dense clusters.
The clusters can be branched or unbanched and round or flat-topped.
There may be leaf-like bracts and bracteoles and they can be free or fused.
The flowers are white, tubular, bisexual and with parts in 4’s.
The sepals, up to 10 mm long, can be free or with the bases totally or partly fused.
The lobes can be absent, linear, ovate, pointed or leaf-like.
There may or may not be hairs.
The stipules commonly persist in the fruit.
The corolla tube, up to 2 cm long, is tubular or funnel-shaped.
The 4 (5) lobes can be at right angles or curved backwards.
There may be some hairs inside the throat.
The corolla is commonly white or cream with green tips in the bud.
The 4 stamen filaments insert into the throat of the corolla tube between the lobes.
The dorsifixed anthers, initially straight and yellow, become dark and twisted.
The stamens can spread out or bend backwards between the corolla lobes.
There is a nectiferous disc on top of the inferior ovary.
The ovary is small with its 2 locules holding 1 ovule each.
The long style holds the green stigma well past the corolla tube.
The stigma can be ribbed and may have short hairs.
The fruit are roughly spherical with the calyx lobes attached at the tip.
They are 4 to 7 mm and commonly mature from green to black but occasionally they are white.
They have 1 or 2 seeds.
J.F.
