Purple passion

Purple has come to symbolize richness or luxury, the color of royalty. In Los Angeles it also represents the L.A. Lakers, bringing pride to our town. But as I walk around the Santa Monica Mountains and see that most of the flowers presently blooming are purple, I realize that purple has significant meaning to many species other than humans. Many plant species have evolved to use this color and after hundreds of thousands of successful years this is surely not random.

Most prominent right now, displaying brilliant purples and pinks, are the clarkias. This genus of wildflower belongs to the family Onagraceae. This family is also known as the "evening primrose family" for the behavioral characteristic some species display of blooming in the evening and closing in the morning.

Flowers in this family have four petals, eight stamen, and a stigma that is ball shaped or four lobed with an inferior ovary. Two species highly visible right now are farewell to spring, Clarkia bottae, and elegant clarkia, Clarkia unguiculata.

Clarkia unguiculata

The lavender colors of farewell to spring are easily spotted while driving on Topanga Canyon just north of Top of Topanga or on Cornell Road just opposite Paramount Ranch. Stopping to get a better look at this plant will reveal lavender cupshaped flowers growing on stems 1- to 3-feet high. The interior of the flower is often flecked with red or purple spots sometimes fading to a white center. The leaves of this plant are alternate and lanceolate growing 1to 3-inches long.

Farewell to spring grows on dry open chaparral hillsides, often in disturbed areas. Through my research I have found no medicinal, practical or edible uses for this species.

Differing sharply in flower design is the elegant clarkia. These flowers have deep red/purple diamond shaped petals thinning to a "stem" where they connect to the corolla. Contrasting brilliantly to the purple petals are the orange and creamy white stamen. The unusual petal shape and striking color combinations create an image that is easy to identify.

This plant grows between 1and 6-feet high on sunny or shady slopes. The leaves are lanceolate, alternate, and grow up to 2.5-inches long. The seeds of this species can be eaten raw or cooked; however, the small size of the seeds makes harvesting difficult. The flowers of this plant can be processed to make a green or golden dye.

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Two other species of clarkia blooming right now are the purple clarkia, Clarkia purpurea, and the speckled clarkia, Clarkia cylindrical. Each flower displays various purples and elaborate patterns, conspicuous against the browns and greens of the chaparral, leading me again to wonder about the significance of the color purple. Walking around I see a plethora of purple: vetch, lupine, clarkias, phaecelias, vervain. Why the abundance of purple flowers?

In order to propagate, plants have developed different strategies for pollination (the movement of pollen from the anther to the stigma). One strategy uses animals as vectors, carrying pollen from one plant to another by providing some type of reward. Typically the reward is nectar, pollen, or possible breeding sites.

But in order to attract the pollinator, the plant must "advertise" its gifts. Advertising primarily occurs through color, shape, scent and/or nectar guides, those patterns on the flower that lead the animal to the nectar site. Often these guides are only visible to the pollinator.

Multiple audiences

Most flowers in the Onagraceae family are pollinated by insects, especially bees and butterflies. The nectar of these flowers accumulates at the base of the style or the lower part of the floral cup. When collecting the nectar the pollen adheres to the insect by a sticky substance called viscin which forms strands between the grains of pollen.

While butterflies and humans are attracted to the flashy purples and pinks inviting us to inspect further, bees' visual acuity differs greatly. While they are unable to detect the red spectrum, they do have a sensitivity to ultraviolet light. This UV detection often reveals patterns or nectar guides that are invisible to humans. In addition to nectar guides, bees are also attracted to shape, which explains why they are the main pollinators for the unusually shaped elegant clarkia.

The coevolution of flowers and their pollinators is magnificent. In the case of the clarkia, these planthave developed strategies that entice both bees and butterflies by appealing to multiple audiences. Whalooks purple and cup-shaped to humans takes on a very differenaesthetic through the eyes of a UVsensitive bee. Purple, the most obvious attractant to humans, becomes secondary; only one of many facets in the laws of attraction, reminding me that the earth is viewed through many perspectives and often through nonhuman eyes.