Knowledge of Carex L. (true sedges) and Hypericum L. (St. John's wort) in the Neotropics is fragmentary. As a result of a fieldwork campaign in Ecuador and revision of herbarium collections (K, QCA and QCNE), we present here relevant records of twelve Carex (Cyperaceae) and four Hypericum (Hypericaceae) species. Regarding Carex, we present the novel report for South America of C. aztecica, as well as the first Ecuadorian records for C. brehmeri, C. collumanthus, C. fecunda, C. melanocystis and C. punicola. The three later records have additional biogeographical significance, as they represent the new northern limit of these species. We also include observations for another five species included in the Ecuadorian Red List of Endemic Plants. As a result, the list of native Carex reported for Ecuador would now include 52 taxa. With regard to Hypericum, we include the new report of H. sprucei for the province of Bolívar, and the confirmation of the presence of three rare species (H. acostanum, H. matangense, H. prietoi) in their type localities, although with extremely low population sizes. We discuss their conservation status and implications.