Question: What type of vegetation does Cerastium and Pavonia have in common?
Context: Vegetation classification is the process of classifying and mapping the vegetation over an area of the earth's surface.  Vegetation classification is often performed by state based agencies as part of land use, resource and environmental management.  Many different methods of vegetation classification have been used.  In general, there has been a shift from structural classification used by forestry for the mapping of timber resources, to floristic community mapping for biodiversity management.  Whereas older forestry-based schemes considered factors such as height, species and density of the woody canopy, floristic community mapping shifts the emphasis onto ecological factors such as climate, soil type and floristic associations.  Classification mapping is usually now done using Geographic Information Systems (GIS) software. Vegetation and slope stability are interrelated by the ability of the plant life growing on slopes to both promote and hinder the stability of the slope.  The relationship is a complex combination of the type of soil, the rainfall regime, the plant species present, the slope aspect, and the steepness of the slope.  Knowledge of the underlying slope stability as a function of the soil type, its age, horizon development, compaction, and other impacts is a major underlying aspect of understanding how vegetation can alter the stability of the slope.  There are four major ways in which vegetation influences slope stability: wind throwing, the removal of water, mass of vegetation (surcharge), and mechanical reinforcement of roots. Pavonia is a genus of flowering plants in the mallow family, Malvaceae.  The generic name honours Spanish botanist José Antonio Pavón Jiménez (1754–1844).  Several species are known as swampmallows. Desert riparian is a North American desert vegetation type (or biome) occurring in the bottoms of canyons and drainages that have water at or near the surface most of the year.  It is contrasted with the desert dry wash vegetation type in which water at or near the surface is lacking most of the year.  The visual character is of large, lush green trees surrounded by dry desert vegetation and soil coloration.  The area may be in a patch surrounding a spring (oasis), or in a strand following the course of water flow.  Over 80% of known desert wildlife species use desert riparian areas.  Common dominant species include Fremont cottonwood ("Populus fremontii"), Arizona ash ("Fraxinus velutina"), arroyo willow ("Salix lasiolepis"), Goodding's willow ("Salix gooddingii"), red willow ("Salix laevigata"), California fan palm ("Washingtonia filifera"), and invasive species such as salt cedar ("Tamarix ramosissima"), giant reed ("Arundo donax"), and Russian olive ("Elaeagnus angustifolia").  Salt cedar is particularly causing problems for this ecosystem because it is able to extract water more efficiently than cottonwoods and willows.  Many noninvasive non-native species may also be found because springs and surface water areas in the desert often were old homesites where such species were intentionally planted, such as elm, black locust, and assorted fruit trees. Cerastium is a genus of annual, winter annual, or perennial plants belonging to the family Caryophyllaceae.  They are commonly called mouse-ear chickweed.  Species are found nearly worldwide but the greatest concentration is in the northern temperate regions.  There are about 200 species.  A number are common weeds in fields and on disturbed ground. Tigridia , the peacock flowers, tiger-flowers or shell flowers, is a genus of bulbous or cormous plants, belonging to the family Iridaceae.  They have large showy flowers and one species, "Tigridia pavonia", is often cultivated for this.  The approximately thirty five species in this family grow in the Western Hemisphere, from Mexico to Chile.  The tigridia flower is short lived, each often blooming for only one day, but often several flowers will bloom from the same stalk.  Usually they are dormant during the winter dry-season.  Its roots are edible and were eaten by the Aztecs of Mexico who called it "cacomitl" and its flower "ocēlōxōchitl" "Jaguar flower".  The genus name means "tiger-like" and alludes to the coloration and spotting of the flowers of the type species "Tigridia pavonia". Pavonia lasiopetala is a species of flowering plant in the mallow family known by the common names that include Texas swamp-mallow, Wright pavonia, and rock rose.  It is native to Texas in the United States and Coahuila and Nuevo León in Mexico. British NVC community OV6 ("Cerastium glomeratum" - "Fumaria muralis" ssp.  "boraei" community) is one of the open habitat communities in the British National Vegetation Classification system.  It is one of six arable weed and track-side communities of light, less-fertile acid soils. Caatinga (] ) is a type of desert vegetation, which can also be called Jola Jolilo (Jou-lah-Jouh-Liloy).  It is the indian name for the Caatinga, and an ecoregion characterized by this vegetation in interior northeastern Brazil.  The name "Caatinga" is a Tupi word meaning "white forest" or "white vegetation" ("caa" = forest, vegetation, "tinga" = white). A wildfire or wildland fire is a fire in an area of combustible vegetation that occurs in the countryside or rural area.  Depending on the type of vegetation where it occurs, a wildfire can also be classified more specifically as a brush fire, bush fire, desert fire, forest fire, grass fire, hill fire, peat fire, vegetation fire, or veld fire.  Fossil charcoal indicates that wildfires began soon after the appearance of terrestrial plants 420 million years ago.  Wildfire’s occurrence throughout the history of terrestrial life invites conjecture that fire must have had pronounced evolutionary effects on most ecosystems' flora and fauna.  Earth is an intrinsically flammable planet owing to its cover of carbon-rich vegetation, seasonally dry climates, atmospheric oxygen, and widespread lightning and volcano ignitions.
Answer: plants