Spruce broom rust of the broom. The main damage from the rust is simply overall volume and growth loss. The number of brooms as well as their proximity to the main stem can also play a role in determining the extent of the damage to the tree. "Chrysomyxa arctostaphyli" is an obligate parasite, and as with most other rust fungi diseases, spruce broom rust requires two different host plants to carry out its life cycle and is therefore referred to as heteroecious. The primary or aecial host of the rust is spruce ("Picea" spp.), and the secondary or telia host of the rust
Multicellular organism traits that are shared between distantly related lineages. The evolution of multicellularity could have occurred in a number of different ways, some of which are described below: This theory suggests that the first multicellular organisms occurred from symbiosis (cooperation) of different species of single-cell organisms, each with different roles. Over time these organisms would become so dependent on each other they would not be able to survive independently, eventually leading to the incorporation of their genomes into one multicellular organism. Each respective organism would become a separate lineage of differentiated cells within the newly created species. This kind of severely