The upper and the lower lip are forming an ancle of about 90°. The corolla lobes do show at the base a pale violet veination. The spur is up to 1 cm long and of a green, sometimes brownish coloration.

According to the author of the first description of this species, P. gracilis appears in altitudes between 1000 and 1800 m. The dominating vegetation at the location of the species are cypress woods. In habitat plants are growing on shaded north facing calcerous cliffs.

You can cultivate this species as described in the cultural information for P. moranensis.

 

The summer rosettes of this tiny Mexican butterwort (found for the first time near Monterrey in the Central-Mexican Federal State Nuevo León) can reach a diameter of up to 3 cm, while the winter rosettes are with 2 cm in diameter smaller. The summer leaves have a characteristic brown to bronze coloured margin. The rest of the leaf is more light green to green-yellow. The summer rosette consists of 10 to 15 leaves. On the upper side the leaves are densely covered with segregating glands. The winter leaves are of a light green colour and instead of glands the upper surface is covered with white non-secretory hair. Flowers appear out of the winter rosette (In cultivation beginning of flowering was December/January).

The flower scapes as well as the calyx are of a red-brown colour. The corolla is two-lipped and the lobes are white. A characteristic feature of the corolla is the middle lobe of the lower lip, which is much larger in dimension in comparison to all other lobes. At the entry to the throat there is a light green elongated spot on the middle lobe. Also typical for the corolla of P. gracilis are the long white hair which densely cover the basal portion of the middle lobe.