NSW Bitou Bush Threat Abatement Plan - Department of ...

Threat Abatement Plan - Invasion of native plant communities by Chrysanthemoides monilifera
3 The biology and ecology of bitou bush and boneseed
3.1 Plant descriptions and biology
The genus Chrysanthemoides (Asteraceae) has two species, both of which are endemic to South
Africa. The species C. monilifera has six subspecies, all described on the basis of fruit shape. Two
of these, subsp. rotundata (DC.) T. Norl. (bitou bush) and subsp. monilifera (L.) T. Norl.
(boneseed), were introduced to Australia, where they have subsequently become major
environmental weeds (Weiss et al. 1998). The two subspecies are capable of hybridising to
produce fertile plants with intermediate characteristics (Weiss et al. 1998). The fruit of
Chrysanthemoides is different from that of other members of the Asteraceae, being a fleshy drupe
which is readily dispersed by animals, in contrast to other members of the Asteraceae which are
dispersed by wind (Gosper 2004a). Dispersal of fruits by animals can lead to greater dispersal
distances than wind alone and faster dispersal/invasion rates (Smith 2000).
3.1.1 Bitou bush (Chrysanthemoides monilifera subsp. rotundata)
Bitou bush is a perennial, fast growing semi-succulent, spreading or somewhat prostrate woody
shrub, 1–3 m high and 2–6 m wide, with long stems that lie along the ground or over other
vegetation. These almost prostrate stems have erect ends. This decumbent habit is accentuated if a
plant grows under shade, where stems may reach more than 10 m, giving it the appearance of a
creeper rather than a shrub. The leaves are entire or slightly toothed, bright green, glossy, broadly
oval shaped, 3–8 cm long. The leaves and stems of juvenile plants are typically covered with
cobweb like hairs. The inflorescences are a compound head of tiny male and female flowers,
surrounded by 11–13 bright yellow floral bracts, or ligulate (see photo on the cover). The fruits
when mature are black,