Galium aparine L.
This is an annual, sprawling herb which has small hooks along the stems, at the tip and along the edges of the leaves and on the fruit. These hooks will catch (cleave) onto clothes, fur and feathers helping this plant to spread to new locations.
The stem is square in cross-section. It has hooked bristles mostly along the angles and may have long thin hairs at the nodes (place on the stem from where leaves arise).
Leaves are in whorls of 5-9. Leaves are lance-shaped with the apex or tip broadly rounded. The leaf margins, the upper surface of the leaf and the midvein on the lower surface all have small hooked hairs.
Flowers are small and appear on a short straight stem from the nodes and are in small clusters. Each small flower has 4 white petals.
Fruit is kidney-shaped, densely covered with hooked hairs on a straight pedicel (flower stalk).
Hooked hairs on leaves, stems and fruits will attach to passing animals or humans who brush against this plant to assist in plant and fruit dispersal.
Other plants easily confused with this plant
This plant may be confused with other weed species of Galium, especially Galium tricornutum and Galium divaricatum. G. aparine has 2-7 tiny white flowers on erect stems up to 2.5 cm long, G. tricornutum has usually only 3 drooping tiny white flowers on shorter stems, up to about 1.5 cm long, and G. divaricatum, a more erect plant, has 3-12 yellowish red flowers.
A native, which may be found in some parts of Australia, is Asperula, some species of which also have whorled leaves and stiff hairs, and all have square stems (in cross-section). Care should be taken before removing these plants, to check with a local plant expert, as to whether Asperula is known to be found in your area.
Sources & References
"Weeds - an illustrated botanical guide to weeds of Australia" by B. A. Auld and R. W. Medd
"Plantnet FloraOnline" (2005) http://plantnet.rbgsyd.nsw.gov.au/
Prepared by Justin KY Chu, July 2005
Checked by IEWF, July 2006, updated November 2006