Plants on the perimeter of campus invite an assortment of pollinators to visit SF State’s native landscaping. We have strategically selected plants known to associate with pollinators native to this region. Cultivated plants found in conventional landscapes are often bred for traits that are attractive to humans and offer zero benefits to the local ecosystem. In addition, these plants may be endemic to a region that lacks anything in common with California and our native fauna. In essence, the cultivar is a misplaced ornament with traits that offer limited incentive for wildlife to revisit an already highly fragmented ecosystem. By encouraging pollinators to utilize resources present in the native garden, we improve land usage and habitat value while integrating our personal space into the surrounding ecosystem.
II. Floral Morphology
Most flowers share the same common theme with some variation on the generalized pattern. Flowers are divided up into whorls, or individual subunits of a flower. The outermost whorl, the calyx, protects the growing bud as it develops Interior to the calyx is corolla that is made up of individual petals. Inside of the corolla is the androecium that is made up of single units called stamens. Finally, the central unit to a flower is the gynoecium. The following table is a break down of the four whorls and their associated structures.
III. Pollination Syndromes
There is not a more palpable sense of evolution at work than the variation observed with floral morphology. The general four whorled morphological pattern has been presented. A seemingly endless combination of variations on this common theme occurs among flowering plants. Plants are immobile organisms. They do not interact with their environment in the ways that insects or animals do. Plants are forced to manipulate their environment through the evolution of specialized traits that encourage the surrounding environment to work for them. The following explores various pollen vectors and traits seen among the associated plants
-Beetles: flowers pollinated by these insects are either large and borne singly on a flowering stalk (peduncle) or small with numerous flowers on one head. These flowers are typically dull colored and possess a strong odor.
Eschscholzia californica receiving attention from a beetle
-Bees: bee pollinated flowers are generally yellow or blue and express distinct markings. Bees are able to perceive ultraviolet light and cannot see the color red. A flower that looks one way to humans will appear very different to a bee and will often have patterns invisible to our eyes.
-Butterflies & Moths: associated flowers generally possess a long corolla (see section II on floral morphology) and can emit a strong fragrance.
A butterfly’s proboscis reaches into the depth of the corolla tube
-Birds: associated flowers produce copious amounts of nectar to keep up with the bird’s energy demand. Plants that produce the most nectar are rewarded with more frequent visits, increasing the plant’s reproductive success.
-Wind: flowers pollinated by wind are relatively nondescript. These flowers need not devote the excess energy into florid traits, as wind is not selective like organismal vectors.
The spikelet of Festuca rubra showing dozens of flowers clustered on one inflorescence
-Pollen vector: The means by which the pollen of one plant reaches the flower of another.
-Whorl: Their single tier/subunit of a flower.
VI. Species on Display
- Peter Raven, Ray Evert, and Susan Eichhorn. Biology of Plants. Sixth. New York: W.H. Freeman and Company, 1999. Print.
-Calflora: Information on California plants for education, research and conservation.
[web application]. 2008. Berkeley, California: The Calflora Database [a non-profit organization].
Available: http://www.calflora.org/ (Accessed: Oct 20, 2008).
-All photographs: Creative Commons Attribution