Nine species of the permineralized stems of Tempskya were investigated from the Lower Cretaceous Cedar Mountain and Burro Canyon Formations, and the lower Upper Cretaceous Dakota Formation in central and southeastern Utah. Tempskya jonesii, T. stichkae, and T. readii are new and are differentiated on the basis of the radial orientation of their dorsiventral stems, their internodal lengths, the lack of sclerenchyma in the inner cortex of T. jonesii, the three nearly continuous zones of sclerenchyma in the inner cortex off T. stichkae, and the completely sclerotic inner cortex of T. readii. Specimens of T. jonesii and T. minor were collected in growht position near Castle Dale, Utah, which is the first time Tempskya has been collected in this position in North America. Thin leaves were also observed for the first time in Tempskya in specimens of T. wyomingense. Tunnels containing three sizes of fecal pellects are common in tissues of stems, roots, petioles, and epidermal hairs of the false trunks of Tempskya, indicating that three different grazers fed upon these plants. Arbuscules of vesicular-arbuscular (V-A) mycorrhizal fungi occur in some roots of the false trunks of T. jonesii. Specific characters of Tempskya and possible environmental circumstances under which these plants grew are reviewed, and we conclude that they grew under relatively humid conditions in swamps on flood plains.