Agnote 799 No. F92 July 2001 Agdex No: 642 ISSN No: 0157-8243 Fringed Spider Flower (Cleome rutidosperma) M. P. Schmid, Weeds Branch, Darwin Family: Capparaceae Class of Declared Weed: A (to be eradicated) and C (not to be introduced to the Territory) INTRODUCTION Fringed Spider Flower (Cleome rutidosperma) is native to tropical Africa, and occurs in Central America, Southeast Asia, including Timor (Soerjani et al. 1987). It is recognised as a significant weed that causes problems in cropping areas and natural ecosystems. It has been recorded on Christmas Island, an Australian territory, however the first Australian mainland incursion was discovered in August 2000, near Darwin's Fort Hill wharf. It has subsequently been discovered at 16 sites in suburban and rural Darwin. At the time of publication, all mainland sites were subject to eradication programs. DESCRIPTION Fringed spider flower can be clearly identified by the following characteristics: • Prostrate spreading herb, occasionally erect when growing with competing species such as gamba grass and spiny head sida. • Angular stems with longitudinal grooves; colour of mature stems is maroon with younger stems being a light green. • Trifoliate leaves with ovate to lanceolate leaflets 2.5 cm long and 1 cm wide. • The flowers are borne on a long (25 mm) pedicel (stem) and are blue to mauve in colour with four petals, six stamens and approximately 6 mm in size. • Fruit is identified by its elongate-linear capsule with an average length of 60 mm and diameter of 4-5 mm. The fruit is light green in colour and each capsule contains an average of 100 tiny black seeds when mature. • Seeds are 1.8-2.0 mm in diameter, ribbed with a white elaiosome. 2 Plants can grow rapidly and a seedling can germinate and set flower within six weeks under ideal growing conditions, such as those experienced during the Top End wet season. IMPORTANCE Fringed spider flower is on the North Australian Quarantine Service weeds target list as a category one weed “weeds posing a very serious threat”. In Asia, fringed spider flower is considered an agricultural weed, (Soerjani et al. 1987) which can reduce crop yields and increase production costs. It also invades disturbed areas and has negative impact on biodiversity (Bayley 2000, Du Puy and Telford 1993). Anecdotal evidence indicates that seed production of fringed spider flower is prolific, giving it an advantage as a competitive species. CONTROL The Department of Infrastructure, Planning and Environment weeds officers conduct regular surveys of known outbreaks. At these locations, control is by hand pulling or herbicide treatment, depending on the size of the infestation. It is important that any known sightings of this weed are reported immediately to DIPE. Through vigilance of people involved in the horticultural and nursery industries, along with the home gardener, eradication of this weed is achievable. If you find a plant fitting the description of Fringed Spider Flower, please report it to DIPE Weeds Branch Darwin, Jabiru, Katherine, Timber Creek, Borroloola, Tennant Creek or Alice Springs. REFERENCES Bayley, D. (2000). Efficient Weed Management. State of New South Wales. NSW Agriculture pp. 5. Du Puy, D.J. and Telford, I.R.H. (1993). Capparaceae Flora of Australia 50: 169-170. Soerjani, M., Kostermans, A.J.G.H., and Tjitrosoepomo, G. (1987). Weeds of Rice in Indonesia. Balai Pustaka, Jakarta. Please visit us on our website at www.primaryindustry.nt.gov.au Published: Tuesday 24 July 2001. 3 Drawing courtesy of Weeds of Rice in Indonesia. M. Soerjani et al. (1987). While all care has been taken to ensure that information contained in this Agnote is true and correct at the time of publication, the Northern Territory of Australia gives no warranty or assurance, and makes no representation as to the accuracy of any information or advice contained in this publication, or that it is suitable for your intended use. No serious, business or investment decisions should be made in reliance on this information without obtaining independent/or professional advice in relation to your particular situation.