Darkness inexorably yields to light, just as warmth will gently thaw the coldest days. Nowadays our small corner of earth begins to lean toward the sun and the landscape lifts her face gratefully to absorb a slow increase of its regenerative rays. The lengthening photoperiod and slow defrosting of soil sends chemical signals zinging through vascularized tissue, whispering with urgency; “grow!”
Before plants put their energy into the singular activity of unfurling leaves with which to fuel themselves, they reproduce. Flowers, in varying forms, are simply precursors to fruit. Those fruits will contain a seed, a fertilized embryo. To accomplish fertilization, flowers produce pollen on anthers. With luck or careful engineering, the pollen is received by stigmas. This “flowering” clade of plants is classified as angiosperms and is the most diverse group of terrestrial organisms, making up 90% of the plant life on earth. Each spring angiosperms brighten the world with colors, shapes and smells aimed to allure.
A single flower or cluster of flowers at the end of a stem is known as an inflorescence. The growth pattern of inflorescence is used to identify the type of plant. Grasses belong to a family in the plant kingdom called Poaceae. They have three types of inflorescence in which florets—which will become seeds if pollinated—are arranged. The flowers of Poaceae only appear briefly and are often overlooked, but close examination reveals an exquisite design. When grass flowers bloom, their colorful anthers and stigmas swell to erupt from minute green coverings like tiny fireworks. Grass flowers are so unique that their anatomy has an array of proprietary terms to describe them. Glumes, palea and lemma are each a type of modified leaf called bracts. They encase the tiny grass flower until the right time when the flowers erupt and flood the spring air with pollen.
Composite flowers, often known generically as “daisies” belong to the Asteraceae family. This cheerful, bright inflorescence pops with bold colors and often has a medicinal or nutritional value, thus encouraging its propagation. The flower head of this plant is made of many tiny flowers arranged in a circle. The “petals” of an aster consist of individual ray flowers. Ray flowers can have anthers or stigmas or both, but most are pistillate, which means they only contain a stigma and a style to receive pollen. The center of a composite inflorescence consists of disk flowers. The smaller disk flowers have tiny distinct petals, as opposed to a ray flower’s petals which are fused making them appear singular. Perhaps the most well-known example of the Asteraceae family is the sunflower. Local composites include the arrow leaf balsamroot, thistles, even sagebrush.
Trees and shrubs also flower with various unique shapes. Next time you walk by a willow whose silver buds have lengthened into speckled yellow shoots, listen. You will hear the buzz of hundreds of happy insects busily collecting the rich concentrations of pollen sprouting from little catkin flowers. Catkins are long, cylindrical groups of tiny flowers commonly employed by woody plants in the flowering game.
The genus Penstemon is one of the largest in the world with 270 different species—all of which are endemic (originated) to North America. Arguably some of the most beautiful flower types, Penstemons are recognized for their vibrant and unique colors and shapes. The petals of this flower are fused, creating a tubular covering for the anthers and stigma. They are sometimes called beardtongue, which refers to a common feature of this plant. The beardtongue is a sterile stamen that is modified to varying degrees to increase the likelihood of pollination by attracting insects or animals. Penstemons have speciated to take advantage of a variety of growing habitats from deserts to wetlands, high alpine soils to rocky cliff sides. Oregon has at least 46 native Penstemon plants.
Given the diversity of flowering plants, it should come as no surprise that flowers bloom in a mind-bending array of forms. All of them possess one thing in common: an ovary containing a seed which requires pollination to germinate. The process of pollination can be left to capricious breezes, as in the case of grasses or specifically facilitated by an animal or insect that many of our Penstemons rely on. Then the subject of seed dispersal begins.
Probably one of the reasons angiosperms are so successful is that their seed often confers some benefit to its distributor. Angiosperm seeds containing nutrient-rich ovaries are an essential diet item for most land-dwelling life forms, but that is a song for another season. This spring, enjoy the flowers, because after all, that’s what they were designed for!