Rubiaceae, commonly known as the madder or coffee family, consists of about 650 genera and 13000 species of (mostly) herbaceous flowering plants. The family, which includes the genus Gardenia, is commonly divided into the three subfamilies of Rubioideae, Cinchonoideae, and Ixoroideae, though a fourth subfamily, Antirheoideae, is sometimes used as well.
Cephalanthus—which, due to its tightly clustered, globose, and terminal inflorescences derives its name from the ancient Greek for 'head flower'—is a genus that counts between 6 and 15 species among its ranks. Commonly known as buttonbush, these species tend to bear their simple leaves either oppositely arranged or in whorls of three. They are native to the temperate and tropical climate zones of Asia, the Americas, and Africa.
The plant featured in today’s photo, Cephalanthus occidentalis, is a deciduous shrub that reaches to between 2 and, rarely, 15 metres in height. It generally grows multiple, glabrous, woody stems, and it thrives in wetland habitats and moist, well-shaded, loamy soils. From June to August, the plant puts forth the tightly packed orb of a flower typical of Cephalanthus species, which in this case boasts a fused, four-lobed corolla, and rests elegantly upon a short peduncle. Distributed throughout most of the eastern half of North America, buttonbush provides sensuous pleasure to humans and building materials to the Wood Duck (Aix sponsa), while its seed and nut-cluster of a fruit variously offer sustenance to deer, insects, and hummingbirds. Historically, humans have used an extract from the plant for medicinal purposes, but readers should note that the plant’s cephalatin content renders it toxic if not properly treated.
Should you like to see a previous entry on this flower, click here.