Non-vascular plant

Non-vascular plants are plants without a vascular system consisting of xylem and phloem. Although non-vascular plants lack these particular tissues, many possess simpler tissues that are specialized for internal transport of water.

Non-vascular plants include two distantly related groups:

  • Bryophytes, an informal group that is now treated as three separate land plant Divisions, namely Bryophyta (mosses), Marchantiophyta (liverworts), and Anthocerotophyta (hornworts). In all bryophytes, the primary plants are the haploid gametophytes, with the only diploid portion being the attached sporophyte, consisting of a stalk and sporangium. Because these plants lack lignified water-conducting tissues, they can't become as tall as most vascular plants.
  • Algae - especially the green algae. Recent studies have demonstrated that the algae consist of several unrelated groups. It turns out that the common features of living in water and photosynthesis were misleading as indicators of close relationship. Only those groups of algae included in the Viridiplantae are still considered relatives of land plants.[1]:6[2]

These groups are sometimes referred to as "lower plants", referring to their status as the earliest plant groups to evolve, but the usage is imprecise, since both groups are polyphyletic and may be used to include vascular cryptogams, such as the ferns and fern allies that reproduce using spores. Non-vascular plants are often among the first species to move into new and inhospitable territories, along with prokaryotes and protists, and thus function as pioneer species.

Non-vascular plants do not have a wide variety of specialized tissue types. Mosses and leafy liverworts have structures called phyllids that look like leaves, but are not true leaves because they are single sheets of cells with no internal air spaces, no cuticle or stomata and no xylem or phloem. Consequently, phyllids are unable to control the rate of water loss from their tissues and are said to be poikilohydric. Some liverworts, such as Marchantia have a cuticle and the sporophytes of mosses have both cuticles and stomata, which were important in the evolution of land plants.[3]

All land plants have a life cycle with an alternation of generations between a diploid sporophyte and a haploid gametophyte, but in all non-vascular land plants the gametophyte generation is dominant. In these plants, the sporophytes grow from and are dependent on gametophytes for taking in water and mineral nutrients and for provision of photosynthate, the products of photosynthesis.

Algae are a type of non-vascular plant.


  1. ^ Copeland, H.F. (1956). The classification of lower organisms. Palo Alto: Pacific Books.
  2. ^ Adl, S.M.; et al. (2005). "The new higher level classification of eukaryotes with emphasis on the taxonomy of protists". Journal of Eukaryotic Microbiology. 52 (5): 399–451. doi:10.1111/j.1550-7408.2005.00053.x. PMID 16248873.
  3. ^ Glime (April 19, 2015). "WATER RELATIONS: PLANT STRATEGIES" (PDF). Bryophyte Ecology. Archived (PDF) from the original on March 28, 2016. Retrieved December 8, 2016.
Acid maceration

Acid maceration is a technique to extract organic microfossils from a surrounding rock matrix using acid.

Hydrochloric acid or acetic acid may be used to extract phosphatic fossils, such as the small shelly fossils, from a carbonate matrix.

Hydrofluoric acid is also used in acid macerations to extract organic fossils from silicate rocks. Fossiliferous rock may be immersed directly into the acid, or a cellulose nitrate film may be applied (dissolved in amyl acetate), which adheres to the organic component and allows the rock to be dissolved around it.


Aglaophyton major (or more correctly Aglaophyton majus) was the sporophyte generation of a diplohaplontic, pre-vascular, axial, free-sporing land plant of the Lower Devonian (Pragian stage, around 410 million years ago). It had anatomical features intermediate between those of the bryophytes and vascular plants or tracheophytes.

A. major was first described by Kidston and Lang in 1920 as the new species Rhynia major. The species is known only from the Rhynie chert in Aberdeenshire, Scotland, where it grew in the vicinity of a silica-rich hot spring, together with a number of associated vascular plants such as a smaller species Rhynia gwynne-vaughanii which may be interpreted as a representative of the ancestors of modern vascular plants and Asteroxylon mackei, which was an ancestor of modern clubmosses (Lycopsida).

Carbon-to-nitrogen ratio

A carbon-to-nitrogen ratio (C/N ratio or C:N ratio) is a ratio of the mass of carbon to the mass of nitrogen in a substance. It can, amongst other things, be used in analysing sediments and compost. A useful application for C/N ratios is as a proxy for paleoclimate research, having different uses whether the sediment cores are terrestrial-based or marine-based. Carbon-to-nitrogen ratios are an indicator for nitrogen limitation of plants and other organisms and can identify whether molecules found in the sediment under study come from land-based or algal plants. Further, they can distinguish between different land-based plants, depending on the type of photosynthesis they undergo. Therefore, the C/N ratio serves as a tool for understanding the sources of sedimentary organic matter, which can lead to information about the ecology, climate, and ocean circulation at different times in Earth’s history.C/N ratios in the range 4-10:1 are usually from marine sources, whereas higher ratios are likely to come from a terrestrial source. Vascular plants from terrestrial sources tend to have C/N ratios greater than 20. The lack of cellulose, which has a chemical formula of (C6H10O5)n, and greater amount of proteins in algae versus vascular plants causes this significant difference in the C/N ratio.When composting, microbial activity utilizes a C/N ratio of 30-35:1 and a higher ratio will result in slower composting rates. However, this assumes that carbon is completely consumed, which is often not the case. Thus, for practical agricultural purposes, a compost should have an initial C/N ratio of 20-30:1.Example of devices that can be used to measure this ratio are the CHN analyzer and the continuous-flow isotope ratio mass spectrometer (CF-IRMS). However, for more practical applications, desired C/N ratios can be achieved by blending common used substrates of known C/N content, which are readily available and easy to use.

Climate change in Washington

Climate change in the US state of Washington is a subject of study and projection today.

Hydrofluoric acid

Hydrofluoric acid is a solution of hydrogen fluoride (HF) in water. It is a precursor to almost all fluorine compounds, including pharmaceuticals such as fluoxetine (Prozac), diverse materials such as PTFE (Teflon), and elemental fluorine itself. It is a colourless solution that is highly corrosive, capable of dissolving many materials, especially oxides. Its ability to dissolve glass has been known since the seventeenth century, even before Carl Wilhelm Scheele prepared it in large quantities in 1771. Because of its high reactivity toward glass and moderate reactivity toward many metals, hydrofluoric acid is usually stored in plastic containers (although PTFE is slightly permeable to it).Hydrogen fluoride gas is an acute poison that may immediately and permanently damage lungs and the corneas of the eyes. Aqueous hydrofluoric acid is a contact-poison with the potential for deep, initially painless burns and ensuing tissue death. By interfering with body calcium metabolism, the concentrated acid may also cause systemic toxicity and eventual cardiac arrest and fatality.

List of model organisms

This is a list of model organisms used in scientific research.


Nematothallus is a form genus comprising cuticle-like fossils. Some of its constituents likely represent red algae, whereas others resemble lichens.


Orestovia is a lower-middle Devonian thallophyte known from fossilised cuticle, cutinite. Described as an enigmatic taxa, Orestovia has variously been categorised as a brown algae, an algae of unknown affinities, a thalloid non-vascular plant, and an early vascular plant, or even the result of the alternation of generations of some other group.Orestovia are typically found as paper coals. Individual remains are naked, unbranched, cutinised axes up to 20 cm in length and 2 cm wide, tapering distally. Most specimens are preserved as hollow, cuticular sheaths that often exhibit an epidermis-like cellular pattern. The cuticles bear structures which have been described as representing stomata.Spores are sometimes preserved between its layers of cuticle. A reconstruction looks similar to the extant fern Pilularia globulifera (Marsileaceae) in the water with a creeping rhizome and naked, upright axes.Orestovia remains have been documented from the following locations, In Russia: Pavlovsk, Voronezh Oblast, Graham Bell Island, Arctic Ocean and the Kuznetsk Basin, Siberia. In China: Luquan, Yunnan.


Puckapunyal (more formally the Puckapunyal Military Area, but also known as the Puckapunyal Camp or Puckapunyal Army Base, and colloquially as "Pucka") is an Australian Army training facility and base 10 km west of Seymour, in central Victoria, south-eastern Australia.

Southwest National Park

Southwest National Park is an Australian national park located in the south-west of Tasmania, bounded by the Franklin-Gordon Wild Rivers National Park to the north and the Hartz Mountains National Park to the east. It is a part of a chain of national parks and state reserves that make up the Tasmanian Wilderness World Heritage Area. Covering an area of 6,183 km2 (2,387 sq mi), it is Tasmania's largest national park.The park is well known for its pristine wilderness, remoteness and unpredictable severe weather. The area is largely unaffected by humans. Although evidence shows Tasmanian Aborigines have visited the area for at least 25,000 years, and European settlers have made occasional forays into the park area since the 19th century, there has been very little permanent habitation and only minimal impact on the natural environment. Within the area there is only one road, to the hydroelectricity township of Strathgordon. The southern and western reaches of the park are far removed from any vehicular access. The only access is by foot, boat, or light aircraft.

The tiny locality of Melaleuca in the extreme south-west provides an airstrip and some very basic facilities, mainly to service the National Park Service.

Starved Rock State Park

Starved Rock State Park is a state park in the U.S. state of Illinois, characterized by the many canyons within its 2,630 acres (1,064 ha). Located just southeast of the village of Utica, in Deer Park Township, LaSalle County, Illinois, along the south bank of the Illinois River, the park hosts over two million visitors annually, the most for any Illinois state park.Before European contact, the area was home to Native Americans, particularly the Kaskaskia who lived in the Grand Village of the Illinois across the river. Louis Jolliet and Jacques Marquette were the first Europeans recorded as exploring the region, and by 1683, the French had established Fort St. Louis on a large sandstone butte overlooking the river, they called Le Rocher (the Rock). Later after the French had moved on, according to a local legend, a group of Native Americans of the Illinois Confederation (also called Illiniwek or Illini) pursued by the Ottawa and Potawatomi fled to the butte in the late 18th century. In the legend, around 1769 the Ottawa and Potawatomi besieged the butte until all of the Illiniwek had starved, and the butte became known as "Starved Rock". The area around The Rock was designated a National Historic Landmark in 1960. The park region has been the subject of several archeological studies concerning both native and European settlements, and various other archeological sites associated with the park were added to the National Register of Historic Places in 1998.

In the late 19th century, parkland was developed as a vacation resort. The resort was acquired by the State of Illinois in 1911 for a state park, which it remains today. Facilities in the park were built by the Civilian Conservation Corps in the 1930s, which have also gained historic designation.

A flood from a melting glacier, approximately 14,000-17,000 years ago led to the topography of the site and its exposed rock canyons. Diverse forest plant life exists in the park and the area supports several wild animal species. Of particular interest has been sport fishing species.


Steganotheca is a genus of bushy, probably vascular plants with branched axes, known from upper Silurian strata. It has terminal sporangia and reached 5 cm in height.


Thallophytes (Thallophyta or Thallobionta) are a polyphyletic group of non-mobile organisms traditionally described as "thalloid plants", "relatively simple plants" or "lower plants". They formed a now abandoned division of kingdom Plantae that included fungi, lichens and algae and occasionally bryophytes, bacteria and slime moulds. Thallophytes have a hidden reproductive system and hence they are also incorporated into the similarly abandoned Cryptogamae (together with ferns), as opposed to Phanerogamae. Thallophytes are defined by having undifferentiated bodies (thalli), as opposed to cormophytes (Cormophyta) with roots and stems. Various groups of thallophytes are major contributors to marine ecosystems.

Vascular plant

Vascular plants (from Latin vasculum: duct), also known as tracheophytes (from the equivalent Greek term trachea), form a large group of plants (c. 308,312 accepted known species) that are defined as those land plants that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They also have a specialized non-lignified tissue (the phloem) to conduct products of photosynthesis. Vascular plants include the clubmosses, horsetails, ferns, gymnosperms (including conifers) and angiosperms (flowering plants). Scientific names for the group include Tracheophyta, Tracheobionta and Equisetopsida sensu lato.

Plant groups
Plant morphology
Plant growth and habit
Plant taxonomy
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