Pleuroziales

Pleurozia is the only genus of liverworts in the family Pleuroziaceae, which is now classified in its own order Pleuroziales, but was previously included in a broader circumscription of the Jungermanniales. The genus includes twelve species, and as a whole is both physically distinctive and widely distributed. The lower leaf lobes of Pleurozia species are fused, forming a closed water sac covered by a movable lid similar in structure to those of the angiosperm genus Utricularia. These sacs were assumed to play a role in water storage, but a 2005 study on Pleurozia purpurea found that the sacs attract and trap ciliates, much in the same way as Utricularia. Observations of plants in situ also revealed a large number of trapped prey within the sacs, suggesting that the species in this genus obtain some benefit from a carnivorous habit. After Colura, this was the second report of zoophagy among the liverworts....read more on Wikipedia.