Riccia

Last updated

Riccia
Riccia huebeneriana Lindenb. Kohatakegoke.JPG
Riccia huebeneriana
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Division: Marchantiophyta
Class: Marchantiopsida
Order: Marchantiales
Family: Ricciaceae
Genus: Riccia
L., 1753
Species

Riccia is a genus of liverworts in the order Marchantiales. [1]

These plants are small and thalloid, i.e. not differentiated into root, stem and leaf. Depending on species, the thallus may be strap-shaped and about 0.5 to 4 mm wide with dichotomous branches or may form rosettes or hemirosettes up to 3 cm in diameter, that may be gregarious and form intricate mats. [1] [2]

The thallus is dorsiventrally differentiated. Its upper (dorsal) surface is green and chlorophyll-bearing, with a mid-dorsal longitudinal sulcus (furrow or groove). Air pores occasionally break through the dorsal surface, giving the thallus a dimpled appearance. In exceptional members such as Riccia caroliniana [3] [4] of Northern Australia and Riccia sahyadrica [5] of Western Ghats, the photosynthetic region is confined to the lower half of the thallus. [6]

The lower (ventral) surface has a mid-ventral ridge bearing multicellular scales that originate as a single row but normally separate into two rows as the thallus widens. The scales are multicellular and hyaline (glassy) in appearance, or violet due to the pigment anthocyanin. [1]

Rhizoids are nearly lacking in aquatic forms, but there are usually numerous unicellular rhizoids of two types on the ventral surface. [1] One type is called smooth and the other type is the pegged or tuberculated rhizoids; these help in anchorage and absorption. The inner surface of the smooth rhizoids is smooth while that of the tuberculate rhizoid will have internal cell wall projections.

Plants are usually monoicous, and sexual reproduction is by antheridia and archegonia. Asexual reproduction occurs by spores, by fragmentation of the rosettes, and by formation of apical tubers. Spores are large (45 to 200 µ) and formed in tetrads. [1]

One of the more than 100 species in this genus is the "slender riccia" ( Riccia fluitans ), which grows on damp soil or, less commonly, floating in ponds, [6] and is sometimes used in aquariums.

The sporophyte of Riccia is the simplest amongst bryophytes. It consist of only a capsule, missing both foot and seta, and does not perform photosynthesis. [7]

Related Research Articles

<span class="mw-page-title-main">Marchantiophyta</span> Botanical division of non-vascular land plants

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 genetic information.

<span class="mw-page-title-main">Hornwort</span> Division of non-vascular land plants with horn-shaped sporophytes

Hornworts are a group of non-vascular Embryophytes constituting the division Anthocerotophyta. The common name refers to the elongated horn-like structure, which is the sporophyte. As in mosses and liverworts, hornworts have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information; the flattened, green plant body of a hornwort is the gametophyte stage of the plant.

<span class="mw-page-title-main">Gemma (botany)</span>

A gemma is a single cell, or a mass of cells, or a modified bud of tissue, that detaches from the parent and develops into a new individual. This type of asexual reproduction is referred to as fragmentation. It is a means of asexual propagation in plants. These structures are commonly found in fungi, algae, liverworts and mosses, but also in some flowering plants such as pygmy sundews and some species of butterworts. Vascular plants have many other methods of asexual reproduction including bulbils and turions.

<i>Marchantia</i> Genus of plants in the liverwort family Marchantiaceae

Marchantia is a genus of liverworts in the family Marchantiaceae and the order Marchantiales.

<span class="mw-page-title-main">Metzgeriales</span> Order of liverwort plants

Metzgeriales is an order of liverworts. The group is sometimes called the simple thalloid liverworts: "thalloid" because the members lack structures resembling stems or leaves, and "simple" because their tissues are thin and relatively undifferentiated. All species in the order have a small gametophyte stage and a smaller, relatively short-lived, spore-bearing stage. Although these plants are almost entirely restricted to regions with high humidity or readily available moisture, the group as a whole is widely distributed, and occurs on every continent except Antarctica.

<i>Conocephalum</i> Genus of plants

Conocephalum is a genus of complex thalloid liverworts in the order Marchantiales and is the only extant genus in the family Conocephalaceae. Some species of Conocephalum are assigned to the Conocephalum conicum complex, which includes several cryptic species. Conocephalum species are large liverworts with distinct patterns on the upper thallus, giving the appearance of snakeskin. The species Conocephalum conicum is named for its cone-shaped reproductive structures, called archegoniophores. Common names include snakeskin liverwort, great scented liverwort and cat-tongue liverwort.

<i>Anthoceros</i> Genus of hornworts

Anthoceros is a genus of hornworts in the family Anthocerotaceae. It is distributed globally. Species of Anthoceros are characterized by having a small to medium-sized, green thallus that is more or less lobed along the margins.

<span class="mw-page-title-main">Prothallus</span> Gametophyte stage in the fern life cycle

A prothallus, or prothallium, is usually the gametophyte stage in the life of a fern or other pteridophyte. Occasionally the term is also used to describe the young gametophyte of a liverwort or peat moss as well. In lichens it refers to the region of the thallus that is free of algae.

<i>Cavicularia</i> Genus of liverworts

Cavicularia densa is the only species in the liverwort genus Cavicularia. The species was first described in 1897 by Franz Stephani, and is endemic to Japan, where it grows on fine moist soil.

<i>Jensenia</i> Genus of liverworts

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. The six or seven species of the genus belong to a southern, possibly Gondwana element.

<i>Pellia epiphylla</i> Species of liverworts in the family Pelliaceae

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 acidic substrates. It is common on the banks of rivers, streams and ditches and also grows in wet woodland, marshes and on wet rocks.

Petalophyllum, or petalwort, is a genus of liverworts in the order Fossombroniales.

Petalophyllum americanum, common name petalwort, is a species of liverwort in the order Fossombroniales. It is endemic to the Gulf Coast of the United States in Arkansas, Louisiana, Mississippi, and Texas. It was first described as the European species Petalophyllum ralfsii in 1919, but a detailed study later showed that the North American form is a distinct species.

<i>Ricciocarpos</i> Genus of liverworts

Ricciocarpos natans is the only species in the genus Ricciocarpos, a genus of liverworts in the family Ricciaceae. It was formerly listed in 1759 as a species of Riccia by Linnaeus, but then assigned to a new genus of its own in 1829 by August Carl Joseph Corda.

<i>Asterella californica</i> Species of plant

Asterella californica is a complex thallic liverwort in the phylum Marchantiophyta. A. californica often grows as colonies of flat rosettes of light green, rigid thalli, with undersides dark wine-red to nearly black. The receptacles are rounded, with four lobes each bearing a single sporangium sheathed by a white tattered skirt. A. californica is dioecious with separate male plants often intermingled with female plants. This species is found throughout California from San Francisco southward to San Diego and Guadalupe Island. Asterella californica is the commonest species of the three species of Asterella occurring in California; the other two species are A. bolanderi and A. palmeri.

<i>Cryptomitrium tenerum</i> Species of liverwort

Cryptomitrium tenerum is a species of liverwort native to North America. It is the only representative of its genus on the continent.

Riccia sahyadrica is a species of liverwort described from the Western Ghats of Peechi-Vazhani Wildlife Sanctuary of Kerala. Its name is derived from the Malayalam word Sahyadri for the Western Ghats. It is characterized by the photosynthetic region confined to the lower half of the thallus. In Riccia members, the photosynthetic region is on the upper half of the thallus. Only one other species, R. caroliniana from northern Australia, is known with this feature.

<i>Asterella drummondii</i> Species of plant

Asterella drummondii is a liverwort in the family Aytoniaceae, which was first described as Fimbraria drummondii by Taylor in 1846, from material collected by Ronald Gunn in Tasmania, and James Drummond in Western Australia from the Swan River. It is found in all states of Australia, in semi-arid areas.

<i>Podomitrium phyllanthus</i> Species of liverwort

Podomitrium phyllanthus is a thalloid liverwort in the Pallaviciniaceae family. It is found in wet forests and rainforests of Australia, New Zealand and New Caledonia.

<i>Monoclea forsteri</i> Species of liverwort

Monoclea forsteri is one of the two species in the thallose liverwort family Monocleaceae. It is dioicous with the capsule dehiscing with a single longitudinal slit. Endemic and widely distributed throughout New Zealand, it is also the country's largest thalloid liverwort. Hooker described the species in 1820. The holotype is in the British Museum.

References

  1. 1 2 3 4 5 Schuster, Rudolf M. (1992). The Hepaticae and Anthocerotae of North America. Vol. VI. Chicago: Field Museum of Natural History. pp. 421–440. ISBN   0-914868-21-7.
  2. Atherton, Ian; Bosanquet, Sam; Lawley, Mark, eds. (2010). Mosses and liverworts of Britain and Ireland: a field guide. UK: British Bryological Society. pp. 261–270. ISBN   978-0956131010.
  3. Na-Thalang, O., 1980. A revision of the genus Riccia (Hepaticae) in Australia. Brunonia, 3(1), pp.61-140.
  4. Cargill, D.C., Neal, W.C., Sharma, I. and Gueidan, C., 2016. A preliminary molecular phylogeny of the genus Riccia L.(Ricciaceae) in Australia. Australian Systematic Botany, 29(3), pp.197-217.
  5. Cargill, D.C., Manju, C.N., Deepa, K.M., Chandini, V.K. and Rajesh, K.P. 2019. A New Indian Species of Riccia with connections to Northern Australia. Journal of Bryology 42, DOI. https://doi.org/10.1080/03736687.2019.1611249
  6. 1 2 MacVicar, Symers M. 1971. The student's handbook of British hepatics, p. 12-13. Hitchen Whelden & Wesley, Ltd.; Authorized reprint of the 1926 edition published by Sumfield & Day, Ltd.
  7. Text Book Of Botany Diversity Of Microbes And Cryptogams