Jensenia

Jensenia
Scientific classification
Kingdom: Plantae
Division: Marchantiophyta
Class: Jungermanniopsida
Order: Metzgeriales
Family: Pallaviciniaceae
Genus: Jensenia
Lindb. 1868
Species

Jensenia angulata
Jensenia canicruria
Jensenia decipiens
Jensenia difformis
Jensenia erythropus
Jensenia lewisi
Jensenia pisicolor
Jensenia spinosa

Synonyms
  • Makednothallus
  • Mittenia

Jensenia is a bryophyte plant genus in the liverwort family Pallaviciniaceae. It has been treated as a subgenus of Pallavicinia by several authors, though a set of features seems to set it apart as a genus.[1] The six[2] or seven[3] species of the genus belong to a southern, possibly Gondwana element.[1]

General characteristics

Jensenia liverworts are dioicous. Compared to Pallavicinia liverworts,[1][4] their thallus grows erect, and branches tree-like, rather than trailing the ground. The thallus is perched on an ascending stipe which grows from a creeping rhizome. Slime papillae are absent from the thallus margin, though locally present elsewhere. The midrib of the thallus is broad but ill-defined.

Reproductive morphology

Male reproductive organs are scattered over the thallus's dorsal surface, while female organs are specifically placed near a bifurcation of the frond. The pseudoperianth, a tube of thallus tissue protecting the archegonia, is basally fused with the calyptra. Following fertilization, the sporophyte is enveloped by three structures: the cup-shaped involucre, cylindrical pseudoperianth and the calyptra. The spore surfaces are irregularly fasciated.

References

  1. 1 2 3 Perold, S. M. (1993). "The hepatic, Jensenia spinosa (= Pallavicinia stephanii: Pallaviciniaceae), in southern Africa". Bothalia 23 (2): 223–229. Retrieved 12 March 2015.
  2. ↑ Grolle, R. (1964). "Jensenia statt Makednothallus, Revue bryologique et lichénologique". Notulae hepaticologicae 33: 227–229.
  3. ↑ Engel, J. J. (1990). "Falkland Islands (Islas Malvinas). Hepaticae and Anthocerotophyta. A taxonomic and phytogeographic study.". Fieldiana, Botany 25: 1–209.
  4. ↑ Grolle, R.; Piippo, S. (1986). "Bryophyte flora of the Huon Peninsula, Papua New Guinea. XVI". Acta Botanica Fennica 133: 59–79.
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