In central Spain N. triandrus subsp. pallidulus and N. rupicola grow together in a number of locations and hybridise producing N. rupidulus

N. triandrus subsp. pallidulus growing with N. rupicola at Navacarrada

N. triandrus subsp. pallidulus and N. rupicola in close proximity at Navacarrada

N. x rupidulus the resulting hybrid at Navacarrada