Updated June 6, 2012 @ 10:35am Vancouver time
Bryant wrote today’s entry:
I would like to thank Hugh and Carol Nourse for this wonderful photo of Sarracenia oreophila, showing both the flower and the pitcher (via the Botany Photo of the Day Flickr Pool). Pitcher plants, especially members of Sarracenia, are among my favourite living organisms due their unique and highly evolved physiology. Sarracenia oreophila is native to a handful of sites in Alabama, Georgia, North Carolina (and extirpated from Tennessee) (distribution map).
Sarracenia oreophila has pitchers that emerge in the early spring and can grow up to 75cm high. The pitchers are mostly a bright green with mild purple venation; the operculum (or flap) at the top of the pitcher is immobile and arches over the pitcher to prevent excess rainwater from filling the trap. The pitchers of Sarracenia oreophila wither and dry out during the hottest months of summer, while the non-pitcher form leaves known as
phyllogia phyllodia (see comments below) or “winter leaves” remain photosynthetically active throughout the year. The seeds of Sarracenia oreophila require contact with bare/open ground to germinate, which makes this species largely dependent on fire to propagate.
all many (see comments below) carnivorous pitcher plants, Sarracenia oreophila has highly modified leaves that form tall tubes that fill partially with rainwater. This provides the basic structure of a pitfall trap for insects, which are lured into the pitcher by a scent trail that is emitted from the flap above the opening to the pitcher. The inside of the pitcher is lined with very small and stiff downward facing hairs, which further direct insects downward. Once down inside the pitcher, the prey encounters a zone of epicuticular waxes and glands which prevent insects from gaining traction and exiting the trap. Once the insect has made contact with the water at the base of the pitcher, it is usually game over. Most Sarracenia species excrete a “wetting agent” into the water, which helps it stick to the wings and legs of insects making it nearly impossible to escape back up and out of the pitcher.
Once drowned in the fluid, the insects are then broken down and digested with the aid of enzymes, bacteria and fungi. Some pitcher plants have specialized glands that secrete enzymes into the fluid and others rely on bacteria and fungi that are introduced by prey into the aquatic environment within the pitcher. Some prey provide further digestive agents to the water, such as the formic acid found in ants. These acids can lower the pH of the water inside the pitcher to increase to rate of decay and digestion of prey insects.
Sarracenia oreophila is the most rare and endangered member of its genus, and it is listed as imperilled G2/N2 (Globally/Nationally). Threats to Sarracenia oreophila mainly come from development, fire suppression, encroachment, hydrological and soil disturbances. This photo was taken at the Reed Branch Wet Meadow Preserve in Georgia, which happens to be the last remaining site for this species in that state.