''Pellia epiphylla'' (sometimes known as overleaf pellia or common pellia) is a species of thallose

liverwort The Marchantiophyta () are a division of non-vascular land plants commonly referred to as hepatics or liverworts. Like mosses and hornworts, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of ...

. It occurs in North America, Europe, North Africa and parts of Asia.Smith, A. J. E. (1989) ''The Liverworts of Britain and Ireland'', Cambridge University Press. It grows in patches in damp, sheltered places on neutral or acidic substrates. It is common on the banks of rivers, streams and ditches and also grows in wet woodland, marshes and on wet rocks.Atherton, Ian; Sam Bosanquet & Mark Lawley, ''eds.'' (2010) ''Mosses and Liverworts of Britain and Ireland: a field guide'', British Bryological Society.

Description

The thalli are irregularly branched and are fairly large, growing to over 1 cm wide and several centimetres long.Watson, E. V. (1981) ''British Mosses and Liverworts'', Cambridge University Press. They are green, sometimes with a red or purple tinge. They are fairly featureless with an ill-defined midrib and no visible network of cells on the surface. There are many long

rhizoid Rhizoids are protuberances that extend from the lower epidermal cells of bryophytes and algae. They are similar in structure and function to the root hairs of vascular land plants. Similar structures are formed by some fungi. Rhizoids may be uni ...

s on the underside of the thallus but no ventral scales. ''Pellia epiphylla'' is

monoicous Monoicy () is a sexual system in haploid plants (mainly bryophytes) where both sperm and eggs are produced on the same gametophyte, in contrast with dioicy, where each gametophyte produces only sperm or eggs but never both.Crandall-Stotler, B.J ...

, with both male and female sex organs on the same thallus. The small male organs are scattered along the midrib while the female organs grow near the tip of the thallus and are surrounded by a flap. The plant produces spherical, greenish-black capsules which are borne on stalks known as

seta In biology, setae (singular seta ; from the Latin word for " bristle") are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Annelid setae are stiff bristles present on the body. ...

e. These are pale green and up to 5 cm long.

Reproduction

Fertilisation takes place when the thallus is wet. The male sex organs (

antheridia An antheridium is a haploid structure or organ producing and containing male gametes (called ''antherozoids'' or sperm). The plural form is antheridia, and a structure containing one or more antheridia is called an androecium. Androecium is also ...

) absorb moisture and burst, releasing sperm. The sperm swim towards the female sex organs ( archegonia) and fertilise the

ova , abbreviated as OVA and sometimes as OAV (original animation video), are Japanese animated films and series made specially for release in home video formats without prior showings on television or in theaters, though the first part of an OVA s ...

. The fertilised ovum develops into a small sporophyte plant which remains attached to the larger

gametophyte A gametophyte () is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the ...

plant. The sporophyte contains spores inside a capsule which are released when the capsule becomes mature and splits. The spores

germinate Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, fer ...

to produce new gametophytes.Brooks, F. T. & Scott, D. H. (2003)
Fundamentals of Modern Botany
', Anmol.

Gallery

file:Pellia epiphylla IMG 1610.jpg file:Pellia epiphylla IMG 1631.jpg file:Pellia epiphylla with setae.JPG file:A liverwort - Pellia epiphylla - geograph.org.uk - 930744.jpg

References

External links

{{Taxonbar, from=Q1247948 Pelliales Taxa named by Carl Linnaeus