A plant’s ability to withstand abiotic stress is important for their survival and reproductive success. Due to climate change and global warming, increasing temperature has become a major abiotic stress factor which can impact the stability of plant population dynamics, ecosystem functions, and agricultural productivity. The ability of plants to survive heat stress varies among and within species. Individuals within a species can vary because populations occur across a range of temperatures and are subjected to selection based on the temperature regimes they occur. While intraspecific variation in heat stress tolerance exists, it is rarely studied, and such studies can elucidate the underlying molecular mechanisms that can be used to improve crop thermotolerance and for in-situ and ex-situ species conservation. Here, we targeted a tropical liverwort, Marchantia inflexa growing in the island of Trinidad, the Republic of Trinidad and Tobago to examine the intraspecific variation of heat tolerance and sex differences in tolerance. Marchantia inflexa is an ideal candidate to study variation in heat tolerance across populations as they typically grow along cool, moist natural habitats along forested streams but are also found along novel habitats of exposed roadsides that are warm and dry. Multiple thallus tips were collected from four stream-sides and three roadside-sides, and their baseline physiologies were noted. Then the samples were subjected to a short high temperature stress (55 oC for 45 minutes). Percent recovery was calculated by measuring quantum efficiency of photosystem II over a period of ten days. Additionally, environmental data were recorded from the collection sites. By the fifth day in the recovery period, we detected a significantly higher recovery in the roadside collected plants than stream-side plants. Further, we noted a trend of higher recovery in male plants compared to female plants. We are under way with a common garden study to gain a more thorough understanding of the genetic and plastic effects of these varying heat stress responses. Identifying heat stress driven phenotypic variations within a species and their underlying molecular responses will contribute to the growing body of knowledge on thermotolerance.