Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Lovely Lady’s Tresses: Small Native Orchids Orchids are one of the largest plant families in the world with about 28,000 recognized species. Although we think of orchids as tropical, they can be found on all continents other than Antarctica. The best-known orchids are large and showy. But most orchids have small flowers and need to be closely examined to reveal their beauty. Late this summer a small orchid called the southern slender lady’s tresses was observed at the Huston-Brumbaugh Nature Center in southeastern Stark County. The scientific name of this species is Spiranthes lacera gracilis. The genus Spiranthes includes around 45 species worldwide and a dozen or so in the United States with nine species recorded for Ohio. The genus name is descriptive of the flower structure. The first part of the name, “Spir-“ refers to the fact that the many orchid flowers on a single flowerhead are twisted into a spiral. The –anthes part of the name means flower. So the genus name translates to twisted flower. This unusual structure makes the flower stalk look like a thin green twisted rope. There are two varieties of slender lady’s tresses, the northern and the southern. The northern variety (lacera) prefers damp soils and usually has a few leaves at its base when the flowers are present. The southern variety (gracilis) is found in drier locations and lack leaves when the flowers are blooming. The two varieties are not easily distinguished just as distinguishing among the nine species that can be found in Ohio can be a challenge. Orchids are insect pollinated, but they often require a very specific insect. Spiranthes orchids are usually pollinated by one of a few species of bumble bees. To avoid selffertilization the flowers, which contain both male and female parts, do not develop both parts at the same time. The male part develops first and the pollen is packaged in a structure found only in orchids called pollinia. The female parts of the flower develop later, so the bumble bee can only fertilize a flower if it moves from a young flower that is producing the pollinia to an older flower that has fertile female parts. Because of this life cycle strategy, orchid flowers usually remain open for days or even weeks to maximize the opportunities for pollination. Orchid flowers are very diverse in their structure and color, but there are a few characteristics shared by all orchid flowers. The flowers are all bilaterally symmetrical. Many flowers are radial. Think of a daisy with a clear center and points radiating out from that center. Orchids are bilaterally symmetrical meaning that they have two sides like humans do. Orchid flowers almost always have a petal that is modified into a lip that extends outward from the tube that forms the central part of the flower. Surrounding the petals are structures called sepals. These are the arms or wings that extend out around the central reproductive parts of the flower and sometimes they are very large and showy. In Spiranthes, their structure varies among the species but the sepals are usually similar in size to the central part of the flower. Although some species of showy orchids are at risk of extinction, many orchids are small and do not attract the attention of people. Perhaps if you look more carefully you too can find a lady’s tresses or another orchid. Many of them are in bloom from late July through early September. Photo. Southern slender lady’s tresses in bloom at the Huston- Brumbaugh Nature Center in late August 2011. Photo by C. McClaugherty