Pellia epiphylla
Encyclopedia
Pellia epiphylla is a species of thallose liverwort
. It occurs in North America, Europe, North Africa and parts of Asia. It grows in patches in damp, sheltered places on neutral or acid
ic substrates
. It is common on the banks of rivers, streams and ditches and also grows in wet woodland, marshes and on wet rocks.
s on the underside of the thallus but no ventral scales.
Pellia epiphylla is monoicous
, 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
e. These are pale green and up to 5 cm long.
takes place when the thallus is wet. The male sex organs (antheridia
) absorb moisture and burst, releasing sperm
. The sperm swim towards the female sex organs (archegonia
) and fertilise the ova
. The fertilised ovum develops into a small sporophyte
plant which remains attached to the larger gametophyte
plant. The sporophyte contains spores inside a capsule which are released when the capsule becomes mature and splits. The spores germinate to produce new gametophytes.
Marchantiophyta
The Marchantiophyta are a division of bryophyte plants commonly referred to as hepatics or liverworts. Like other bryophytes, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information....
. It occurs in North America, Europe, North Africa and parts of Asia. It grows in patches in damp, sheltered places on neutral or acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...
ic substrates
Substrate (biology)
In biology a substrate is the surface a plant or animal lives upon and grows on. A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock can be substrate for another animal that lives on top of the algae. See also substrate .-External...
. It is common on the banks of rivers, streams and ditches and also grows in wet woodland, marshes and on wet rocks.
Description
The thalli are irregularly branched and are fairly large, growing to over 1 cm wide and several centimetres long. 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 rhizoidRhizoid
Rhizoids are thread-like growths from the base or bottom of a plant, found mainly in lower groups such as algae, fungi, bryophytes and pteridophytes, that function like roots of higher plants ....
s on the underside of the thallus but no ventral scales.
Pellia epiphylla is monoicous
Monoicous
Monoicous is a botanical term used to describe plants which bear both sperm and eggs on the same gametophyte. Dioicous is the complementary term describing species in which gametophytes produce only sperm or eggs but never both. The terms are used largely but not exclusively in the context of...
, 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
Sporangium
A sporangium is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. All plants, fungi, and many other lineages form sporangia at some point in their life cycle...
which are borne on stalks known as seta
Seta
Seta is a biological term derived from the Latin word for "bristle". It refers to a number of different bristle- or hair-like structures on living organisms.-Animal setae:In zoology, most "setae" occur in invertebrates....
e. These are pale green and up to 5 cm long.
Reproduction
FertilisationFertilisation
Fertilisation is the fusion of gametes to produce a new organism. In animals, the process involves the fusion of an ovum with a sperm, which eventually leads to the development of an embryo...
takes place when the thallus is wet. The male sex organs (antheridia
Antheridium
An antheridium or antherida is a haploid structure or organ producing and containing male gametes . It is present in the gametophyte phase of lower plants like mosses and ferns, and also in the primitive vascular psilotophytes...
) absorb moisture and burst, releasing sperm
Sperm
The term sperm is derived from the Greek word sperma and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell...
. The sperm swim towards the female sex organs (archegonia
Archegonium
An archegonium , from the ancient Greek ἀρχή and γόνος , is a multicellular structure or organ of the gametophyte phase of certain plants, producing and containing the ovum or female gamete. The archegonium has a long neck canal and a swollen base...
) and fertilise the ova
Ovum
An ovum is a haploid female reproductive cell or gamete. Both animals and embryophytes have ova. The term ovule is used for the young ovum of an animal, as well as the plant structure that carries the female gametophyte and egg cell and develops into a seed after fertilization...
. The fertilised ovum develops into a small sporophyte
Sporophyte
All land plants, and some algae, have life cycles in which a haploid gametophyte generation alternates with a diploid sporophyte, the generation of a plant or algae that has a double set of chromosomes. A multicellular sporophyte generation or phase is present in the life cycle of all land plants...
plant which remains attached to the larger gametophyte
Gametophyte
A gametophyte is the haploid, multicellular phase of plants and algae that undergo alternation of generations, with each of its cells containing only a single set of chromosomes....
plant. The sporophyte contains spores inside a capsule which are released when the capsule becomes mature and splits. The spores germinate to produce new gametophytes.