"Nature Guide Journal"

22 March 2001

Spring is in the air and many organisms are focusing their energy on sex—plants as well as animals. Red-flowering currant, trillium, violets, skunk cabbage...even the trees are flowering.

The diversity of plant flowers is a pretty good indication of the relative value of flowers in plant reproduction. Flowers are the means by which "higher plants" exchange or combine their genetic material. This mixing and combining of genes (sexual reproduction) fosters diversity of the genetic makeup of offspring, resulting in an explosion of variety within members of the species. Genetic variety is a great advantage to a species since any given threat is then unlikely to kill all the members: there is a heightened chance that some members of the population will be just different enough to survive.

By definition, "flowers" are the reproductive organs of higher plants, that have apparently evolved from specialized leaves. The most complex flowers house both male parts (that produce pollen) and female parts (that produce seeds).

The classic illustration of a plant flower shows a center pistil, with its stigma-topped route to the ovary (female aspect), surrounded by a number of stamens that support pollen-producing anthers (male aspect). These central organs are usually shown partially enclosed by petals, with sepals on the very outside of the assemblage.

The push toward diversity has resulted in some highly modified flowers, with appealing colors, elaborate shapes, or tempting scents. The higher plants are classified by the shape and arrangement of the various flower parts. Trillium, for example, is placed in the Lily Family because its flower parts are in multiples of three, and the petals and sepals are attached below the ovary. Iris has flower parts in multiples of three, but is placed in a different family (the Iris Family) because the petals and sepals are attached above the ovary.

Many familiar species produce male flowers and female flowers on separate plants, such as in English holly and kiwi. A third arrangement is the production of separate male and female flowers on a single plant, such as in red alder and shore pine.

Yes, the stubby strings of catkins now dangling on the red alders are flowers—actually, tightly spiraled clusters of (male) stamens. Female red alder flowers, later to become the seed-bearing cones, are also currently evident. Like most very plain flowers, red alders cast their pollen to the wind to land by chance on a receptive female.

By summer the male shore pine flowers will be ready to cast their pollen with each breeze and jostle, as we continue through the flowering season.