I took today's Botany Photos of the Day one morning a few weeks ago in our Physic Garden, an area that usually hums with the frenzied activity of elated honeybees. On this particular summer morning, when the sun took a rare break behind a blanket of cream-coloured cloud, things were somewhat more silent, serene, and, it seems, congenial to contemplation.
Acanthaceae is a family of 250 genera and about 2500 species that put forth perfect (bisexual) flowers along with alternately arranged leaves that are simple and decussate. Member species are typically herbs, shrubs, or vines that produce two-leaved (e.g. dicotyledonous) seeds. The family—which receives its scientific name from the Greek akantha (prickle or thorn) for its characteristically spiky leaves and flowers—is native to a broad variety of habitats throughout the tropical regions of Malaysia, Africa, Central America, and northern South America, though some genera and species are native to more temperate climate areas.
Acanthus, a genus of 30 species, is native to the Old World, where its distribution is centered around the Mediterranean Basin. One of these species, Acanthus spinosus or bear's breeches, is a self-sowing evergreen perennial hardy to climate zones 5 through 9. At altitudes below 800 metres, the plants grow to just over 1 metre in height, and they spread to about a ½ metre when sited in full sun or partial shade and exposed to moderate amounts of water. The species enjoys dryer soils, and is often found in olive groves and alongside roadways, though it is commonly cultivated as a garden ornamental as well. The hooded flowers, which bloom from June to August, are a deeply veined purplish grey.
The plant, whose somewhat mysterious common name derives from its broad and hairy leaf, is included in our Renaissance Physic Garden because, to use the words of the contemporary (16th century) English Botanist John Gerard, the plant was at one point thought "an excellent plaister against numbness in the hands and feet".