Water-spider Orchid, Habenaria repens

Tuesday, July 7, 2009

Nature Notes
by Bob Thomas

Our most common orchid is so non-descript and camouflaged in its aquatic habitat that it is seldom seen, even by avid naturalists.

The plant is the water-spider orchid, Habenaria repens. For years I've considered it a plant that thrives in acidic waters with loads of tannins, such as the lake at Percy Quin State Park in Mississippi. Although I've occasionally found it spottily distributed in Louisiana, I could always find it when my family spent time in Percy Quin. It ranges from Texas to North Carolina.

I was recently pleasantly surprised to find this orchid thriving in a small, yet very healthy, cypress swamp. It is abundant at the Jean Lafitte Nature Study Park, adjacent to Fisher Middle High School in the Town of Jean Lafitte, Louisiana.

This sensational nature area (replete with a 0.8 mile-long boardwalk) has cypress of all sizes, from seedlings to mature trees. Due to the presence of a thin canopy, the water surface sports a dense growth of many marsh plant species. In fact, the plants form a floating mat with the green water-spider orchids laced into the dense growth. You can easily follow the boardwalk and enjoy the cypress, heron rookery, the occasional alligator, and more, and not see the orchids at all.

The floating mat is perfect for water-spider orchids, because the species may set seeds and/or propagate by runners (stolons) that spread in all directions.

Water-spider orchids appear as one- to two-foot high stalks protruding from the surface. On close examination, the stalks are covered with greenish white orchid flowers that have the perianth (the sepals and petals together) divided into small elongated lobes that are reminiscent of spiders - thus the name. Their leaves are about ten inches long, and one inch wide.

In the evenings, the flowers emit a strong fragrance, which evidently attracts its pollinators - night-flying moths.

Habenariol is a chemical produced by water-spider orchids that deters feeding activities by red crawfish, Procambarus clarkii.

Joe Baucum, one of the founders of the nature study park and an avid local naturalist, introduced me to this gorgeous nature reserve. He and his colleagues maintain and monitor its health and well-being. Having water-spider orchids so common along the boardwalk is an added thrill.

DIRECTIONS TO THE JEAN LAFITTE NATURE STUDY PARK: On Jean Lafitte Boulevard (LA 45) in Lafitte (the town, not the national park), turn left on City Park Drive (the first street after you pass Fisher Middle High School). Drive the short distance to the levee, park, walk over the levee, and you are on the boardwalk.


Water-spider orchids, Habenaria repens,                                              Water-spider orchids.
growing densely in a floating marsh at Jean                                         Photo by Bob Thomas.
Lafitte Nature Study Park.
Photo by Bob Thomas.


Water-spider orchid flowers.                                                              Water-spider orchid spike (raceme)
Photo by Bob Thomas.                                                                     of flowers.
                                                                                                          Photo by Bob Thomas.


Habitat of water-spider orchids,                                                         Jean Joe Baucum at the entrance of the
Lafitte Nature Study Park.                                                                 Jean Lafitte Nature Study Park.
Photo by Bob Thomas.                                                                    Photo by Bob Thomas.