Hornwort
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== Introduction == | == Introduction == | ||
| - | Hornworts have a close distinction to another bryophyte plant called a Liverwort. There are 100 known species of hornworts and liverworts.Hornworts are similar to mosses, which people are much more fond of | + | Hornworts have a close distinction to another bryophyte plant called a Liverwort. There are 100 known species of hornworts and liverworts.Hornworts are similar to mosses, which people are much more fond of as opposed to liverwort or hornworts.[http://www.madsci.org/posts/archives/2000-04/955857807.Bt.r.html] The hornwort is a non-vascular plant. In this order there are three different familes and four different species, that catagorize these plants. Asexual, Hornwort reproduction occurs by self engenderation. |
== Anatomy == | == Anatomy == | ||
| - | + | The Thallus is one of the main destinctions between liverworts and mosses. Therefore the thallus' rhizoids are described as plain and simple, which discludes ventral scales. The rhizoids attach this plant to the ground. The sporophyte is seen as long and narrow, and has a central columella. The central columella is made up of sterile tissue as well as basal meristem. In some anthoceros, the hornwort presents pores in the capsule walls or lacks them. In dendroceros, the thallus is strap shaped, the midbrid is strongly noticeable and quite defined. In megaceros, there are usually more than one chloroplast in just one epidermal cell. It grows to about 1-3 cm wide, as a dark-green hue. This plant is perennial, and tends to grow in clusters; this is considered a social-plantae. Archegonia are found and embedded in the surface of the dorsal, behind the apices. The compact ground tissue is measured as 5-8 layers deep. Close to the thallus, is the pores that arise, are similarly distiguished to the stomata. Behind this, the aperature sometimes becomes more round. Hornwort sporophytes tend to be about 3-7cm tall and range from 0.7-9cm. The pseudoelaters, is often unbranched or has somewhat branched filaments.[http://www.nzetc.org/tm/scholarly/tei-Bio25Tuat01-t1-body-d2.html]In the hornwort the thalloid holds one cell each with a single chloroplast. Therefore, the bottom and basal growth of the sporophyte is needle-like. The capsule and stomata are columnar.[http://home.manhattan.edu/~frances.cardillo/plants/nonvas/antocero.html] | |
== Reproduction == | == Reproduction == | ||
=== Sexually === | === Sexually === | ||
[[File:538px-Hornwort structures.jpg|thumb|200px|right|The image shows the main parts of a hornwort, a plant taxa related to mosses.]] | [[File:538px-Hornwort structures.jpg|thumb|200px|right|The image shows the main parts of a hornwort, a plant taxa related to mosses.]] | ||
| - | Hornworts can reproduce in two ways, either | + | Hornworts can reproduce in two ways, either asexually or sexually. The hornwort plant, is very distinctive and similar to many other bryophyte plants in the way they reproduce. In a few types of species, the male and female, may either grow on just one single plant, however, the female and male organs may be seperated onto two different plants. The archegonia which is the female organ, and antheridia which is the male organ, are encapsulated. They are located at the center region on the upper portion of the thallus. During the growth of the antheridia; the archegonia tends to break down from a result of water. Many multiple sperms become chemically attracted to the female eggs, these eggs are located at the bottom. The female eggs are chemically attracted to the the base of the archegonia. These then make their way through to become fertalized eggs through water. A fertilized egg is also called a [gamete]. And so, the zygotes are spread through out the plant, they can than grow into the next generation. Sporophytes are horn-shaped and grow from the bottom of sheath under the surface of the gametophyte [thallus]. These hornworts [germinate] exactly from the spores.[http://www.hiddenforest.co.nz/bryophytes/hornworts/reproduction.htm] |
=== Asexually === | === Asexually === | ||
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===Gametophyte=== | ===Gametophyte=== | ||
| - | During the reproduction of a Hornwort, there is a flat greensheet called the [gametophyte] or [thallus]. The gametophyte in | + | During the reproduction of a Hornwort, there is a flat greensheet called, the[gametophyte] or [thallus]. The gametophyte in a hornwort is seen as wrinkled and green, as well as spiral-like. The color varies from dark green, light green, and even green-yellow. A hornwort[gametophyte] is usually portrayed as lobed or even sometimes wrinkled, this has a greenish colored sheet this is the [thallus]. The gametophye, depending upon the type of genus, can grow spiral-like. The thallus' color is dark green, light green, even yellowish in ''Notothylas''. The thallus can be many cells thick. In the genus ''Dendroceros'' the thallus is strap-like. Each tend to have a thick and central [midrib] with delicate lateral wings. The lateral wings are wavy and ruffle-like. Also, the thallus is connected to hook structures, the smooth rhizoids. Which bloom at the underside of the thallus.[http://www.anbg.gov.au/bryophyte/what-is-hornwort.html] |
=== Sporophyte === | === Sporophyte === | ||
| - | Hornwort plants contrast in shape of the sporophyte generation.The hornworts generate spores inside of a greenish, horn-like stalk, instead | + | Hornwort plants contrast in shape of the sporophyte generation.The hornworts generate spores inside of a greenish, horn-like stalk, instead. The color breaks down and is lucid, to the thallus of the plant.[http://www.discoverlife.org/20/q?search=Bryophyta] With only one thallus many sporophytes can and may be produced. In a hornwort the sporophytes are erect and needle-like. The length of a hornwort sporophyte on average is 10 cm in length. In the genus ''Notothylas'' the sporophytes can be as small as 5 mm long, which are initially short and stout. They are banana-shaped. This structure is a spore capsule nonetheless. Most [sporophytes] apart from the [genus] Notothylas grows consistently clearly above the base. As the sporophytes grow, they are pushed outward. The sporophyte growth the youngest cells are near the base, and the oldest more upward to the top of more mature cells are the cells on the lower part of the sporophyte. Upon these mature cells The sporophyte relies upon the gametophyte greatly for carbohydrates; without the gametophyte or injury to the gamteophyte the sporophyte could suffer. A sporophytes growth splits within its length; beginning at top working its way to the bottom. This happens so that the distribution of the sporophytes can amplify its period. The two halves remain together and joined at the top. The sporophyte even symetrically splits along only one side of the structure to expand the slit on just one side of the capsule. An example of this is shown in the genus' ''Dendroceros'' and ''Megaceros'' sporophytes. In the genus ''Notothylas'', the capsule doesn't split into two. The genus Notothylas, sporophytes can split this way; during this process, however they can decay.[http://www.anbg.gov.au/bryophyte/what-is-hornwort.html] |
== Ecology == | == Ecology == | ||
Revision as of 18:06, 5 May 2009
Please do not edit the article until this banner is removed.
- This page is about the nonvascular plant. For the aquatic plants known as hornwort: see Ceratophyllum
| Hornwort |
|---|
|
| Scientific Classification |
|
| Genera |
|
Family Anthocerotaceae
Family Dendrocerotaceae Family Notothyladaceae |
| bryophyte (plant) |
Contents |
Introduction
Hornworts have a close distinction to another bryophyte plant called a Liverwort. There are 100 known species of hornworts and liverworts.Hornworts are similar to mosses, which people are much more fond of as opposed to liverwort or hornworts.[1] The hornwort is a non-vascular plant. In this order there are three different familes and four different species, that catagorize these plants. Asexual, Hornwort reproduction occurs by self engenderation.
Anatomy
The Thallus is one of the main destinctions between liverworts and mosses. Therefore the thallus' rhizoids are described as plain and simple, which discludes ventral scales. The rhizoids attach this plant to the ground. The sporophyte is seen as long and narrow, and has a central columella. The central columella is made up of sterile tissue as well as basal meristem. In some anthoceros, the hornwort presents pores in the capsule walls or lacks them. In dendroceros, the thallus is strap shaped, the midbrid is strongly noticeable and quite defined. In megaceros, there are usually more than one chloroplast in just one epidermal cell. It grows to about 1-3 cm wide, as a dark-green hue. This plant is perennial, and tends to grow in clusters; this is considered a social-plantae. Archegonia are found and embedded in the surface of the dorsal, behind the apices. The compact ground tissue is measured as 5-8 layers deep. Close to the thallus, is the pores that arise, are similarly distiguished to the stomata. Behind this, the aperature sometimes becomes more round. Hornwort sporophytes tend to be about 3-7cm tall and range from 0.7-9cm. The pseudoelaters, is often unbranched or has somewhat branched filaments.[2]In the hornwort the thalloid holds one cell each with a single chloroplast. Therefore, the bottom and basal growth of the sporophyte is needle-like. The capsule and stomata are columnar.[3]
Reproduction
Sexually
Hornworts can reproduce in two ways, either asexually or sexually. The hornwort plant, is very distinctive and similar to many other bryophyte plants in the way they reproduce. In a few types of species, the male and female, may either grow on just one single plant, however, the female and male organs may be seperated onto two different plants. The archegonia which is the female organ, and antheridia which is the male organ, are encapsulated. They are located at the center region on the upper portion of the thallus. During the growth of the antheridia; the archegonia tends to break down from a result of water. Many multiple sperms become chemically attracted to the female eggs, these eggs are located at the bottom. The female eggs are chemically attracted to the the base of the archegonia. These then make their way through to become fertalized eggs through water. A fertilized egg is also called a [gamete]. And so, the zygotes are spread through out the plant, they can than grow into the next generation. Sporophytes are horn-shaped and grow from the bottom of sheath under the surface of the gametophyte [thallus]. These hornworts [germinate] exactly from the spores.[4]
Asexually
Hornwort reproduction that is asexual, is engendered, by itself, by broken down thallus.[5]
Gametophyte
During the reproduction of a Hornwort, there is a flat greensheet called, the[gametophyte] or [thallus]. The gametophyte in a hornwort is seen as wrinkled and green, as well as spiral-like. The color varies from dark green, light green, and even green-yellow. A hornwort[gametophyte] is usually portrayed as lobed or even sometimes wrinkled, this has a greenish colored sheet this is the [thallus]. The gametophye, depending upon the type of genus, can grow spiral-like. The thallus' color is dark green, light green, even yellowish in Notothylas. The thallus can be many cells thick. In the genus Dendroceros the thallus is strap-like. Each tend to have a thick and central [midrib] with delicate lateral wings. The lateral wings are wavy and ruffle-like. Also, the thallus is connected to hook structures, the smooth rhizoids. Which bloom at the underside of the thallus.[6]
Sporophyte
Hornwort plants contrast in shape of the sporophyte generation.The hornworts generate spores inside of a greenish, horn-like stalk, instead. The color breaks down and is lucid, to the thallus of the plant.[7] With only one thallus many sporophytes can and may be produced. In a hornwort the sporophytes are erect and needle-like. The length of a hornwort sporophyte on average is 10 cm in length. In the genus Notothylas the sporophytes can be as small as 5 mm long, which are initially short and stout. They are banana-shaped. This structure is a spore capsule nonetheless. Most [sporophytes] apart from the [genus] Notothylas grows consistently clearly above the base. As the sporophytes grow, they are pushed outward. The sporophyte growth the youngest cells are near the base, and the oldest more upward to the top of more mature cells are the cells on the lower part of the sporophyte. Upon these mature cells The sporophyte relies upon the gametophyte greatly for carbohydrates; without the gametophyte or injury to the gamteophyte the sporophyte could suffer. A sporophytes growth splits within its length; beginning at top working its way to the bottom. This happens so that the distribution of the sporophytes can amplify its period. The two halves remain together and joined at the top. The sporophyte even symetrically splits along only one side of the structure to expand the slit on just one side of the capsule. An example of this is shown in the genus' Dendroceros and Megaceros sporophytes. In the genus Notothylas, the capsule doesn't split into two. The genus Notothylas, sporophytes can split this way; during this process, however they can decay.[8]
Ecology
Typical Hornworts are found in many tropical areas, and mostly in these tropical areas the plant is diverse. To contrast, in places such as Europe, there are few of these species. They appear in Switzerland, hornworts tend to be annual in Northern Switzerland including other Central European areas as a result of climate changes.[9] In the US hornworts are located in a number of states, all including: (AK, AL, AR, CA, CO, CT, DC, DE, FL, GA, HI, IA, ID, IL, IN, KY, LA, MA, MD, ME, MI, MN, MO, MS, NC, NH, NJ, NM, NY, OH, OK, OR, PA, RI, SC, TN, TX, VA, VT, WA, WI, WV), CAN (AB, BC, LB, MB, NB, NF, NS, NT, NU, ON, PE, QC, YT), DEN (GL), FRA (SPM)
Gallery
 Common-name |
 hornwort |
References
- Anthocerotales by the U.S. Department of Agriculture
- Survey of hornwort populations in selected arable fields in the Swiss Plateau Irene Bisang, Luc Lienhard und Ariel Bergamini, unknown publisher, July 2008.
- Reproduction & Dispersal Heino Lepp, Australian National Herbarium, 15 April 2008.
- Sporophytes Heino Lepp, Australian National Herbarium, 15 April 2008.
- Bryophyta Susan Kornfeld, Ari Kornfeld, Date published unknown.
- Hornwort Reproduction Author unknown, ICRA, date unknown.
- What are liverworts and what are hornworts? What are they used for? David Hershey, MadSci Network, April 15.
- Notes on Some Anthocerotae of New Zealand Ella O. Campbell, Tuatara : Journal of the Biological Society, July 1 1981.
See Also
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