|
The Joshua tree (Yucca brevifolia) is a highly branched yucca that can form a dominant tree-like "forest" over grassland zones in areas of the Mojave Desert. It is an "indicator species" of the Mojave Desert, insofar as it is restricted to this desert region and its distribution essentially defines the limits of the desert environment. The image above shows a well-developed stand of these plants image in the Joshua Tree National Park, USA. Although they look "woody", the stems of these trees do not have annual rings; instead they are fibrous and are coated with the remains of dead leaves.The leaves are short (about 30 cm long) and densely clustered near the tips of branches.
Some of the Joshua trees in this image have the remains of flower stalks. The growing point dies after flowering, and a new growing point emerges as a branch beneath this. Thus the trees become progressively more branched with age. Individual trees can live for perhaps 200 years or more. |
