The shruem split of from the turretshroom. It evolved quite a different way to spread its spores. Due to its size it no longer needed the cap for protection against rain, so therefore it has evolved it to become very sporadeous and useless to use up less energy. It no longer has bright colours since the shruem wants it to be eaten, since the spores are placed on the cap. If an animal wants to eat the cap then it has to eat the spores, thereby spreading them for sure. When the Shruem is capless it just grows a new one very quick, however it needs the trunk as much as its ancestor, so it has evolved it to be bright colors instead so that it wont be eaten.