Pleurozia Explained

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.^[1] The genus includes twelve species,^[2] and as a whole is both physically distinctive and widely distributed.^[3]

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.^[4]

Taxonomy

The genus Pleurozia has been subdivided into three subgenera:

• Pleurozia subg. Pleurozia
  • Pleurozia gigantea (Weber) Lindberg
• Pleurozia subg. Constantifolia Thiers
  • Pleurozia purpurea Lindberg
  • Pleurozia conchifolia (Hooker & Arnott) Austin
• Pleurozia subg. Diversifolia Thiers
  • Pleurozia acinosa (Mitten) Trevisan
  • Pleurozia articulata (Lindberg) Lindberg & Lackström
  • Pleurozia caledonica (Gottsche ex Jack) Stephani
  • Pleurozia curiosa Thiers
  • Pleurozia heterophylla Stephani ex Fulford
  • Pleurozia johannis-winkleri Herzog
  • Pleurozia paradoxa (Jack) Schiffner
  • Pleurozia subinflata (Austin) Austin
• Unplaced
  • Pleurozia pocsii Müller

Notes and References

1. Book: Schuster, Rudolf M. . 1966 . The Hepaticae and Anthocerotae of North America . I . 381–384 . New York . Columbia University Press .
2. Thiers . Barbara M. . 1993 . A Monograph of Pleurozia (Hepaticae; Pleuroziaceae) . The Bryologist . 96 . 4 . 517–554 . 10.2307/3243984. 3243984 .
3. Book: Jones, E. W. . 2004 . Liverwort and Hornwort Flora of West Africa . Scripta Botanica Belgica . 30 . Meise . National Botanic Garden (Belgium) . 90-72619-61-7 . 197–198 .
4. Hess . Sebastian . Frahm . Jan-Peter . Theisen . Inge . 2005 . Evidence of zoophagy in a second liverwort species, Pleurozia purpurea . The Bryologist . 108 . 2 . 212–218 . 10.1639/6. 85079354 .