The morphology, taxonomy, ecology, distribution, and conservation status of the Oklahoma narrow endemics, Physaria angustifolia (Brassicaceae/Crucifereae) and Penstemon oklahomensis (Plantanginaceae), are reviewed and supplemented with original pollen morphological descriptions that include comparisons to taxa within their respective families. These descriptions are considered extensions of the original taxonomic descriptions, which lacked pollen morphology. Physaria angustifolia is an annual up to 4.0 dm in height found on limestone glades of southeastern Oklahoma and northeastern Texas. The taxon is considered imperiled in Oklahoma, with a state Natural Heritage rank of S2. The pollen has a reticulate surface and five apertures and is identical to most other members of the genus. Penstemon oklahomensis is a perennial herb 4.0–6.0 dm in height found throughout central Oklahoma and at a single site in Texas. The taxon is considered vulnerable, with a state Natural Heritage rank of S3. The pollen has a microreticulate surface with distinctive horizontal cracks across the colpal membrane, often isolating portions of the membrane. Although relatively uncommon in angiosperm pollen, such cracks are found in many members of the Lamiales.