Cactus
Fungi, bacteria and viruses attack cacti, the first two particularly when plants are over-watered. Fusarium rot can gain entry through a wound and cause rotting accompanied by red-violet mold. ""Helminosporium" rot" is caused by "Bipolaris cactivora" ( "Helminosporium cactivorum"); "Phytophthora" species also cause similar rotting in cacti. Fungicides may be of limited value in combating these diseases. Several viruses have been found in cacti, including cactus virus X. These appear to cause only limited visible symptoms, such as chlorotic (pale green) spots and mosaic effects (streaks and patches of paler color). However, in an "Agave" species, cactus virus X has been shown to reduce growth, particularly when the roots are dry. There are no treatments for virus diseases.
List of ecoregions in North America (CEC)
With its shallow roots, it is able to take in a large quantity of water and store it in its pedals for extended periods of time. The Ocotillo (Fouquieria splendens) is another plant frequently found in this area, which is a very unusually shaped plant. Because of this, it is often referred to as a "vine cactus." This plant has an adaptive ability to photosynthesize during very dry conditions and gather large quantities of water when it is available. The Great Basin is also home to the oldest species in the world, the bristlecone pine ("Pinus longaeva"). Its needles allow it to retain water and use very little of it during its lifetime. It is able to grow on exposed rocky surfaces in higher elevations about forested areas. With these advantages come some drawbacks, including its very slow growth rate, which leaves it vulnerable to being out-competed by faster growing trees.