Caesar Weed ( Urena lobata )
Caesar Weed ( Urena lobata ) is a member of Malvaceae, the mallow family, which includes hibiscus, cotton, and okra. One of its common names is hibiscus burr, a reference to its burr-like seeds. It is a nonnative plant but is widespread all over Florida, it was introduced in this state about 1855.
In Florida, Caesar Weed is found throughout the entire peninsula and a few counties in the Panhandle. The Florida Exotic Plant Pest Council lists it as a category I invasive, meaning its footprint is spreading, but has yet to have done any serious damage to any habitats.
Erect, woody perennial herb or small shrub, up to 3 m tall, but usually around 1.5 m tall. Stems and leaves are covered with star-shaped (stellate) hairs; often many branched at the base. Leaves are simple, alternate, with the upper surface rough and the lower surface grayish, broadly ovate, often with 3-5 shallow, angular lobes at apex, up to 10 cm long; margins finely toothed, bases heart shaped; petioles up to 5 cm long; stipules tiny. Flowers are small, showy, hibiscus-like, solitary on short stalks in leaf axils, subtended by 5 basally united (involucral) bracts up to 0.7 cm; calyx 5-lobed, hairy; 5 petals, rose or pink, darker at the base, rounded, up to 1.5 cm long; stamens fused into an obvious pink column beneath a 5-lobed style. Fruits are small, barbed, spiny capsules, up to 1 cm across, with 5 prominent segments each containing 1 dark brown seed.
This species reproduces by seed. The hooked spines on its fruit readily attach to animal fur and clothing allowing for easy dispersal. Seeds may also be dispersed by water, soil or contaminated agricultural produce.
Caesar Weed is a traditional medicine that has the support of science. Extracts from either the roots or the leaves have broad antibacterial activity against both gram-positive and gram-negative bacterial, and it is anti-fungal as well. It has been reported that one extract was nearly as good aspirin. The roots are also diuretic and were used for stomach aches. Leaves are pasted and applied to skin problems. Medicines were made from fresh and dried parts.
