Question: What type of vegetation does Citharexylum and Cuminum have in common?
Context: Citharexylum is a genus of flowering plants in the verbena family, Verbenaceae.  It contains shrub and tree species commonly known as fiddlewoods or zitherwoods.  They are native to the Americas, ranging from southern Florida and Texas in the United States to Argentina.  The highest diversity occurs in Mexico and the Andes.  The generic name is derived from the Greek words κιθάρα ("kithara"), meaning "lyre", and ξύλον ("xylon"), meaning "wood," referring to the use of the wood in the sounding boards of string instruments. Several species, especially "C. caudatum" and "C. spinosum", are cultivated as ornamentals. The Dinaric calcareous silver fir forests are an endemic vegetation type of the littoral Dinaric Alps, located in southeastern Europe.  Pure stands of Dinaric calcareous Silver fir —"Abies alba" forests appear on limestone escarpments in the montane zones of Orjen, Velebit, Biokovo and Prenj.  They comprise one of the most interesting formations of Balkan vegetation types as the forests bear several rare plants and are of striking beauty.  As a highly endemic and rare vegetation type of the Dinarids it needs protection. Lourensford Alluvium Fynbos is a critically endangered vegetation type that is endemic to Cape Town.  Though closest to Fynbos, it has characteristics of both Fynbos and Renosterveld vegetation and is thus actually a unique hybrid vegetation type. 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. Citharexylum berlandieri is a species of flowering plant in the verbena family, Verbenaceae, that is native to the Lower Rio Grande Valley of Texas in the United States and Mexico as far south as Oaxaca.  Common names include Tamaulipan fiddlewood, Berlandier fiddlewood, negrito fiddlewood, negrito, and orcajuela.  It is a shrub or small tree, reaching a height of 6 m .  The type specimen of this species was collected from the hills near Las Canoas, San Luis Potosí by Cyrus Pringle in 1890.  It was described as a new species the following year by Benjamin Lincoln Robinson, who chose the specific epithet to honour French naturalist Jean-Louis Berlandier. Cuminum is a genus of four flowering plants in the family Apiaceae.  The most significant is "Cuminum cyminum", source for the cumin seeds that are a popular spice. 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. 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. 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. 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).
Answer: plants