PEEC Amateur Naturalist: Green Gentian, A Curious Geometric Flower

PEEC Amateur Naturalist
Green Gentian, a Curious Geometric Flower

A remarkable plant can be seen blooming in the open pine forest and meadows of the high country on the way to the Valles Caldera and in Canada Bonita.

Its popular name is green gentian but it is also called deer’s ears, monument plant, or elk weed. Its scientific name is Frasera speciosa.

Green gentian grows as a set of leaves on a single stem that is low to the ground. The soft, fuzzy leaves resemble the ear of a deer, as the popular name suggests. The cluster of leaves become more numerous and larger over a period of several years. Nothing unusual happens during this time.

Green gentian was thought to be a biennial plant until Dr. David Inouye in Colorado patiently monitored it and determined that a green gentian plant may live upwards of sixty years rather than two years. A remarkable event happens sometime during those years. Many of the plants in one particular area grow a tall spike.

The plants somehow synchronize with one another, starting to grow the spike at the same time during the summer. A spike may grow three to six feet high and then is covered with unusual looking flowers. The plants die after this one-time blooming event.

The flowers would bring joy to Euclid since there is so much geometry in their design. The photograph shows a base outlined with a purple-dotted square. A circular ovary is positioned at the middle of the base with four stamens around it. The stamens are shaped like acute triangles and also grow at right angles to one another. Another set of four acute triangular sepals appears directly below and in between the petals. The four petals are positioned at 45 degrees relative to the stamens.    

Green gentian: a geometric flower. Photo by Robert Dryja             

The flowers are unusual in being primarily shades of green. The colors of flowers usually are thought to attract insects. The insects pollinate the stigma (top part of the pistil, the female part of flowers) as they collect nectar.

Green gentian. Photo by Robert Dryja       

Many species of wild flowers are brightly colored red and yellow. What insects are attracted to the subdued patterns of a green gentian flower?  Flies and carrion-loving insects may be happy with pale-colored or even brown flowers, especially if they have a unpleasant smell. But could there be another reason that insects or birds would be attracted to green gentian?

Some species of insects perceive flowers differently than we do by being able to perceive ultraviolet light. The intensity of ultraviolet light increases with elevation and green gentians grow on high mountains. Perhaps the flowers of green gentian appear more brightly lit with contrasting colors when viewed with ultraviolet light.

The set of two photographs below shows the different appearance of flowers in normal and in ultraviolet light. What would a green gentian flower look like when seen with ultraviolet light?  Perhaps it is more inviting to pollinating insects.

Regular light. Photos by Bjørn Rørslett

The stigmas of potentilla flowers await pollination at the center of contrasting “bulls eyes” when viewed with ultraviolet light. Photographs by Bjørn Rørslett

Ultraviolet light. Photos by Bjørn Rørslett

Information from, Rachel Turiel, “Banner Blooms: Flowering Monument Plants Proliferate across Colorado,” The Durango Telegraph, vol. 2, no. 29, July 2003, articles by Dr. David Inouye and others, edited by Rebecca Shankland.