Delgado-Ramírez, V., Camacho-Velázquez, A., & Vázquez-Santana, S. (2021). Reproductive biology of Thelocactus leucacanthus ssp. schmollii (Cactaceae), a microendemic cactus of Querétaro, Mexico. Botanical Sciences, 99(4), 791-806. https://doi.org/10.17129/botsci.2798