Botany Photo of the Day

Lindsay Bourque continues with the BPotD series on Biodiversity and Sports. The photograph today is by Dave Powell of the USDA Forest Service via forestryimages.org (in context on the site), while the public domain illustration is by Carl Lindman in "Bilder ur Nordens Flora". Sorry, I couldn't find a suitably-licensed version of a turfgrass image definitively identified as Poa pratensis, so you'll have to follow the links.

Lindsay writes:

Variously known as turf, pitch, field or green, turf grasses literally provide the staging for many of the world's most popular sports. What might fall from ubiquitous knowledge, however, is the co-evolution of sports turf and livestock. Hardy European species that were used for grazing livestock provided smooth surfaces ideal for playing surfaces. Indeed, the grounds of St. Andrews Links, Scotland, arguably one of the first golf courses in the world, was land originally granted by King David I in 1123 as public commons and was used for grazing. One theory has it that golf began with shepherds knocking stones into a rabbit hole while their sheep grazed. In fact, the origin of the term "lawn" refers to areas that were maintained in this way and are still retained in place names throughout the United Kingdom.

When European settlers arrived in North America, they brought not only their livestock but also seeds for grazing pastures. One of those species, Poa pratensis, commonly known as Kentucky bluegrass, is the parent species of some of the most commonly used cool season turf grasses today. This perennial groundcover is native to much of Europe, northern Asia and the mountains of Algeria and Morocco. It forms a dense sod when grown in pure stands--making it ideal for sport. Some First Nations groups in North America called it "white man's tracks" because almost everywhere European settlers went with their livestock and plows, they found Kentucky bluegrass. Today, there are hundreds of cultivars (PDF) of Kentucky bluegrass that cover playing fields for baseball, football, soccer, volleyball, softball, tennis, badminton, polo, lawn bowing greens, and croquet.

The high level of maintenance for turf areas has drawn a lot of criticism in recent years, for both the high volume of water used for irrigation as well as pesticide use. From a biodiversity standpoint, monocultures tend to be more vulnerable to disease. Seed mixtures are becoming more popular to help control the spread of pests. Overseeding bluegrass turf with another common turf grass, Lolium perenne, commonly known as perennial ryegrass, provides good suppression of fusarium blight. This fungal disease which causes severe root rot, resulting in patchy turf. Also native to Europe, Asia and northern Africa and widely cultivated and naturalized around the world, Lolium perenne, has been used exclusively since 1995 on the courts of Wimbledon, upon recommendation of the Sports Turf Research Institute.