Botany Photo of the Day

Sparganiaceae (Bur-reed family), which is sometimes included in the Typhaceae, consists of a single genus of perennial aquatic and paludial (marsh-inhabiting) species. The family exhibits cauline (stem) and basal leaves as well as a single terminal inflorescence furnished with multiple tightly clustered racemose flower heads. Generally speaking, Sparganiaceae species inhabit the northern temperate zone, though a few species extend south to Mexico, New Zealand, and Australia.

Sparganiaceae's single genus, Sparganium, includes 14 species, and, like a number of plants recently featured here, it was first described by Linnaeus in the 1750s. Species exhibit strap-shaped leaves, and it is from this feature that Dioscorides, botanist and 'Father of Medicine', drew inspiration when he named these plants after sparganon, the Greek term for 'swaddling band'. Species produce odorless, monoecious flowers that bloom from late spring to late summer depending on altitude and latitude. In the image, the clusters of male flowers, now spent, are located above the females on the floral axis.

The species, S. emersum, commonly known as the European bur-reed, grows up to a metre in height in the still or slowly flowing waters of both North America and Eurasia. The plant is particularly abundant in the western half of North America, though less robust forms are found east of Manitoba and Minnesota. The species is perennial and rhizomatous, and it bears a variety of leaves, some of which stand stiff and erect while others float limply on the surface of the water below. The basal leaves, which are triangular in cross section, are often used to distinguish this from other Sparganium species.