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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