From a single locality in the Lower Cretaceous (Albian) Cheyenne Sandstone of southwestern Kansas, twenty-six fossil plant megafossil species have been recognized, including three species of ferns, six species of conifers, fifteen species of angiosperms, and two forms of undetermined seeds and tree bark. The relative abundances of ferns, conifers, and angiosperms in the flora are 11.5%, 23%, and 57.6%, respectively. This indicates that angiosperms were the most diverse group in this basin of deposition during the Early Cretaceous. The discovery of a swollen, concave petiole base with attached stipules in one species of Sapindopsis suggests that Sapindopsis may have some relationship with Platanus. Two trends of angiosperm leaf evolution are proposed from an ancestral Sapindopsis complex. One line of evolution includes the palmately lobed palinactinodromous veined type leaves and palmately veined leaves, whereas the other line of evolution includes the true pinnately compound leaves.