Petrocoptis pseudoviscosa

Petrocoptis pseudoviscosa is known from a single valley on the Spanish side of the Pyrenees Mountains. The total area of occupancy of the plant is about 11 km2 (4 mi2) with locations scattered along about 20 km (12 mi) of the valley at altitudes varying between 700 and 1,600 m (2,300 and 5,200 ft). The plants grow in crevices in inaccessible rocky outcrops, cliffs and caves. There are five populations, varying in size from about a hundred plants to a few thousands.

Although cross pollination is normal in this species, the flowers can self-pollinate, and the seeds produced by this process have been found to germinate equally well as those from cross-fertilised flowers. Other plants growing in close vicinity to Petrocoptis pseudoviscosa include the ferns Cystopteris fragilis, Asplenium ruta-muraria, Asplenium fontanum and Asplenium csikii, as well as the herbs Lonicera pyrenaica, Saxifraga longifolia, Chaenorhinum origanifolium, Sarcocapnos enneaphylla, Hieracium phlomoides and Bupleurum angulosum.