About 2,854 taxa of vascular plants are known to occur in BC. Approximately 1,990 of these taxa are found in plant communities that are dominated by steppe vegetation, which includes our native Bunchgrass Zone. This wide diversity of plant species requires managers to have a thorough understanding of plant physiology and morphology. Plants are generally grouped into six classes: trees, shrubs, grasses, grass-like plants (sedges and rushes), forbs (broad-leaved herbaceous plants) and cryptogams (mosses and lichens).
Trees can be either coniferous or deciduous. Coniferous trees, including lodgepole and ponderosa pine, have needle-like leaves and seeds borne in cones. Coniferous trees are often referred to as “evergreens” because they retain their leaves throughout the year. Deciduous trees such as trembling aspen, on the other hand, generally have broad, net-veined leaves and seeds that are produced from flowers. The leaves of deciduous trees usually change colour before they are shed in the autumn.
Shrubs are woody plants that have shorter, bushier appearances than trees. Instead of having a main trunk, shrubs have more numerous smaller branches that extend out from the base of the plant. Shrubs can be either coniferous or deciduous. Junipers are coniferous shrubs, whereas Saskatoon, common snowberry and willows are examples of deciduous shrubs.
Grasses are herbaceous plants, which mean that they die back to ground level each year. Grasses have hollow, jointed stems and the leaves are slender, parallel-veined and two-ranked (meaning that they grow in alternate rows up the stem). The flowers and seeds of grasses can vary greatly and are used to distinguish between different grass species. Bluebunch wheatgrass (found in steppe vegetation of the Southern Interior), pinegrass (found beneath forest canopies throughout central and southern BC) and Altai fescue (found in northern BC) are some common grasses of BC’s rangelands.
Sedges and rushes are similar to grasses in that they have slender, parallel-veined leaves, but their stems are unjointed and solid. Rushes have round stems and sedges usually have three-sided stems. Leaf patterns also differ, leaves of sedges are three-ranked (occur in threes around the stem) and leaves of rushes are two-ranked. Both sedges and rushes are associated mainly with wetlands but a number of sedges are also found in grasslands, forests and alpine areas throughout BC’s rangelands.
Forbs are generally small plants that produce flowers. They flower at different times throughout the growing season and die back after flowering. Forbs are broad-leaved plants with fleshy stems and net-veined leaves. Yarrow, low pussytoes, lupines, arrow-leaved balsamroot and heart-leaved arnica are some of the common forbs in BC grasslands.
Cryptogams are rather complex and have both visible and microscopic components that grow over the surface of soils. The visible part includes lichens, mosses and liverworts, while the microscopic component is made up of algae, fungi and bacteria. Because of this complexity, cryptogams are more commonly referred to as the microbiotic crust of soil surfaces. Some common lichens and mosses on BC’s bunchgrass ranges include pixie-cup lichens and rusty steppe moss.
Photo:Larry Halverson (Aspen Forest, deciduous trees)Don Gayton (Rough fescue plant)Kristi Iverson (Arrow-leaved balsam root)
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