It is critical to gather biological information about rare and endangered plants to incorporate into conservation efforts. The secondary metabolism ofPityopsis ruthii, an endangered flowering plant that only occurs along limited sections of two rivers (Ocoee and Hiwassee) in Tennessee, USA was studied. Our long-term goal is to understand the mechanisms behindP.ruthii’s adaptation to restricted areas in Tennessee. Here, we profiled the secondary metabolites, specifically in flowers, with a focus on terpenes, aiming to uncover the genomic and molecular basis of terpene biosynthesis inP.ruthiiflowers using transcriptomic and biochemical approaches. By comparative profiling of the nonpolar portion of metabolites from various tissues,P.ruthiiflowers were rich in terpenes, which included 4 monoterpenes and 10 sesquiterpenes. These terpenes were emitted from flowers as volatiles with monoterpenes and sesquiterpenes accounting for almost 68% and 32% of total emission of terpenes, respectively. These findings suggested that floral terpenes play important roles for the biology and adaptation ofP.ruthiito its limited range. To investigate the biosynthesis of floral terpenes, transcriptome data for flowers were produced and analyzed. Genes involved in the terpene biosynthetic pathway were identified and their relative expressions determined. Using this approach, 67 putative terpene synthase (TPS) contigs were detected. TPSs in general are critical for terpene biosynthesis. Seven full-length TPS genes encoding putative monoterpene and sesquiterpene synthases were cloned and functionally characterized. Three catalyzed the biosynthesis of sesquiterpenes and four catalyzed the biosynthesis of monoterpenes. In conclusion,P.ruthiiplants employ multiple TPS genes for the biosynthesis of a mixture of floral monoterpenes and sesquiterpenes, which probably play roles in chemical defense and attracting insect pollinators alike.