Cushion Bush

The purple cushion found an almost empty landscape in Darwin's broad belt of taiga. It grew upward in this new environment, lifting its branches higher and more separately above the ground. Its branching pattern remains much like its ancestor's, but the overall shape is now bushier. It has a noticeable broad trunk above ground to support the many branches, which has developed from what was formerly the upper part of the taproot. This trunk contains a central channel for storage of water and nutrients, but there are smaller channels outside it for distribution up and down. Tissue remains fairly soft, and the cushion bush is prone to bending in the wind and may be blown over in a heavy gale or storm, which is the biggest limiting factor on their height and lifespan. It has, however, expanded the root system substantially, including more nodes for nitrogen fixers. The extended roots mostly reach downward, as they no longer have to contend with the permafrost of the tundra.

Reproduction is much as before, but now occurs exclusively at the tips of branches, mostly toward the top. Thin and hairlike reproductive structures form and detach in the wind. When they are blown onto another cushion bush, it becomes fertilized and grows a new appendage, which will then blow away to grow into a new bush. This grows fairly slowly, but more quickly than a purple cushion would, as the environment is not quite as harsh: It takes several years to mature and a few decades to reach full height.