Flowering plants have persisted through many climate shifts across the last 100 million years. Fossil leaf traits can provide valuable insight into plant adaptation in response to severe ecological changes, as they relate to plant functions (e.g., photosynthesis) and can correlate with their local ecosystem. While leaf functional traits, such as leaf mass area, have been empirically and extensively tested in extant and extinct woody dicots, monocot flowering plants are understudied in how functional leaf traits correlate with other environmental, physiological, and climatic variables. However, because monocots are highly diverse (~60,000 species), contribute significantly to global agriculture, and represent large carbon sinks in both terrestrial and marine ecosystems, they are worth studying further. Here, we focused on one family within monocots, Zingiberaceae (the gingers) because they have a good temporal and spatial fossil distribution and can potentially provide valuable information on how they adapted to shifts in climate. First, we first tested the validity of applying fossil dicot leaf area estimation (LAE) and leaf mass area (LMA) on living Zingiberaceae leaves. Neither the LAE nor LMA methods were applicable to living Zingiberaceae leaves, pointing to fundamental developmental differences in monocot and dicot leaves. Second, we measured leaf traits of 58 fossil Zingiberopsis specimens from the Cretaceous-Paleogene of North America; the leaf traits measured were vein length per area (VLA) of parallel, cross, and all venation (parallel, cross, and total VLA), leaf width, leaf vein packing, and average vein thickness. We compared the leaf trait data with paleoclimate data (mean annual temperature, mean annual precipitation, and [CO2]) to determine any statistically significant relationships and whether these leaf characteristics could be classified as leaf functional traits. Many mean values of the paleoclimate and fossil trait data (except for leaf width) were statistically and significantly different within each time period (Cretaceous-Paleocene-Eocene). In general, parallel vein traits had negative correlations with mean annual temperature and precipitation, while cross vein traits had positive correlations with those climate variables. All vein traits had statistically significant differences between time bins representing distinct [CO2]. Our findings suggest monocot venation is responding to local climate, with parallel vein architecture increasing in cool/dry climates in order to decrease the distance water needs to travel. Our study also illustrates the possible application of using monocot leaf traits for past plant-climate interactions, especially when fossil leaf material is fragmentary.