P. fragilis

P. fragilis may refer to:
 * Pentachaeta gracilis, a plant species in the genus Pentachaeta endemic to California
 * Polysiphonia fragilis, a red alga species
 * Phreatogammarus fragilis, an amphipod species found only in New Zealand's South Island

Synonyms

 * Pleurothallis fragilis, a synonym for Acianthera luteola, an orchid species