In western Cuba, there is a flat swampy savannah like area at sea level which is called Las Ovas, containing a large number of ponds and lakes. This is the home of P. filifolia, where it grows amongst tall grasses. The soil is damp, covered with white sand, but with plenty of organic material in deeper layers. While most Pinguicula species are growing in semi-shade areas, P. filifolia is growing in full sunlight, little protected by the surrounding grasses. The strong sunlight is even intensified by the reflections of the white sand. Humidity is high all the year round and temperatures are about 30° C, little lower at night.

At first glance leaves of P. filifolia are similar to those of the north-American sundew Drosera filiformis, but after the appearance of the flowers there is no doubt that it is a butterwort. Colour of the corolla lobes varies from white to pale violet, even a rare yellow flower form exists. The corolla has 5 equal lobes. Growth type is tropical homophyllous, meaning that the plants do produce only one set of leaves. Seed is produced by cross pollination, normally by small insects. So to obtain seed it is necessary to pollinate the flowers. Best would be if pollen of a second clone is used. Germination should occur after 10 to 14 days.