Botany Lesson #1: Heterostyly

Oslo Riverfront Conservation Area

Dr. George Rogers, Botany Department Chair at Palm Beach State College, led a marvelous botany walk/talk on Saturday, November 18, for volunteers for the Oslo Riverfront Conservation Area (ORCA).  After a wonderful whirlwind “tour” of botany basics, we headed out in to the field, where Dr. Rogers regaled us with delightful botanical stories appropriate for leading a nature walk.

Our first stop: The ditch just to the west of the exit driveway of the Florida Medical Entomology Laboratory (FMEL) to check out the native aquatic plant, pickerelweed (Pontederia cordata).  This plant exhibits heterostyly; It has flowers with different length styles (female parts) relative to the stamens (male parts).  This arrangements facilitates cross-pollination.

Our next stop was a shortleaf wild coffee (Psychotria sulzneri), the only wild coffee that Dr. Rogers had found with it flowers on it. Dull leaf wild coffee is another name for this plant, with leaves which sport an attractive metal sheen.

This plant also exhibits heterostyly, a feature common in the large Rubiaceae family. Read more about the wild coffees, “real” coffee, Rubiaceae, and heterostyly on his informative blog called Treasure Coast Natives.

Below is a photo of the flowers on the more common shiny-leaved wild coffee (Psychotria nervosa) or just plain wild coffee.  This species of wild coffee generally flowers a bit earlier than shortleaf wild coffee.  Compare the flowers in the lower right hand corner with the short stamens with the other flowers with long, protruding stamens.  Wild coffees are heterostylus.

Dr. Rogers inspired us to better understand the magic of plants.