What is a saguaro cactus thick round stem?
I’m not sure I understand the question. But, a saguaro cactus is a tall (up to about 20 feet) round cactus about 1 foot in diameter at its base. It grows branches (stems) about half-way up its trunk that resemble arms. These eventually get very long and thick, up to several inches in diameter and as high as the top of the cactus. I suppose a thick round stem of a saguaro cactus would be as opposed to a small spindly one.