Acanthaceae

Acanthus Family

Family Description

The Acanthus family consists of 250 genera and 2600 species of tropical herbs or sometimes shrubs with opposite, simple, mostly entire leaves and often, prominent venation in contrasting colors. The 5(4)-merous, zygomorphic, tubular flowers are borne in terminal spikes or racemes and usually subtended by showy imbricate (overlapping) bracts. When viewed from above the spikes or racemes are square. The ovary is superior and 2 celled with each cell containing 2-10 ovules. The fruit is a 2-celled capsule. Dried plant specimens have cystoliths (deposits of calcium carbonate) present in the vegetative portions of the plant as protuberances or streaks.

Key diagnostic features of this family are:

• opposite, simple, entire leaves with prominent venal marking
• flowers in terminal spikes or racemes subtended by showy bracts

Acanthus family members require organic media with good drainage. Plants should have uniform moisture, and if water is deficient, wilting is sudden and extreme. Plants often appear beyond recovery, but if water is administered before discoloration, recovery will follow. Propagation is by terminal cuttings or seeds with germination best above 70°F. Plants are grown as houseplants or flowering pot plants for medium to high light conditions. Mealybugs may be a problem, but are not usually serious.

Cultivated genera include Acanthus, Aphelandra, Asystasia, Barleria, Crossandra, Dicliptera, Duvernoia, Eranthemum, Fittonia, Hemigraphis, Hygrophila, Hypoestes, Justicia, Mackaya, Megaskepasma, Pachystachys, Peristrophe, Ruellia, Ruspolia, Ruttya, Sciaphyllum, Stenandrium, Thunbergia, and Xantheranthemum.

Representative Species

LSU Horticulture Department Julian C. Miller Hall Baton Rouge, LA 70803 225.578.2158