A "tumbleweed-type plant" was one of the native life forms of the planet K-G. They were used by the plant species to herd the cattle beasts to them so that they could consume them.
In 2266, a USS Enterprise landing party observed the cattle beasts being herded by the tumbleweed plants to the plant species which then consumed them, and realized that this was the intended fate for the captured Janice Rand. After they rescued her, the tumbleweed plants tried to attack them, but they used their phasers to fend them off. (TOS comic: "The Planet of No Return")