There are over 500 different species of sagebrush (genus = Artemisia) in the world, and somewhere around 20 in
But in plants the splitting part of meiosis sometimes doesn’t happen right and sex cells are created that are fully diploid. These new sex cells can sometimes combine with other diploid sex cells and create viable plants that are chromosomally tetraploid, with four sets of chromosomes. And other combinations can occur, resulting in plants that are chromosomally hexaploid (6 sets), octaploid (8 sets) or even triploid (3 sets). The two weird things about polyploidy are that often times the polyploid versions of plants exhibit traits or capabilities or hardiness not found in the diploid parent version, and that often times the polyploid versions can’t breed with the old diploid types and hence develop as separate species.
This may all sound rather esoteric, but it affects all of us every day. “Normal” wheat is diploid, but macaroni wheat is tetraploid and bread wheat is hexaploid. The bananas we buy in the supermarket are sterile triploids which can only reproduce through cuttings. In the natural world, plant polyploidy occurs all the time. All Coast Redwoods for example are chromosomally hexaploid.
Normal diploid sagebrush has 18 chromosomes, arranged in 9 pairs. But about a third of all Big Sagebrushes have 36 chromosomes, making them tetraploid. With Black Sagebrush, over 80% of the plants are tetraploid.
Sagebrush is wind-pollinated and its small seeds wind-dispersed. It self-pollinates easily. Its three-toothed leaves (hence the “tri-dentata” in the name) are covered with fine white hairs, which give sagebrush foliage its distinctive grayish tone. The little hairs act as teeny-tiny windbreaks and significantly reduce the amount of water lost by the leaves in high-wind conditions. Sagebrush is an adaptable survivor, and it’s been doing even better since Europeans started showing up. Domestic livestock generally find sagebrush unpalatable, due mainly to a series of organic chemicals in the leaves called terpenoids. (These chemicals are also what give sagebrush its wonderful scent, which is especially strong following a rain.) As a result, in heavily grazed areas, cattle will munch on grass and other shrubs, removing competition for space from sagebrush, which allows it to expand its coverage. Many of the sage-covered plains and hillsides you see across Western Utah and
Speaking of cattle, one of the absolutely most wonderful things about the
Tangent: The summit register, composed of several sheets of TRW company note sheets stapled together, was left by a John Vitz from
In October 2005, my friend Steve and I climbed
Next up: More Shrubs!