Question: What type of vegetation does Orbeopsis and Hesperaloe have in common?

<P0-S0> Desert dry wash is a North American desert vegetation type (or biome) occurring in the flat bottoms of canyons and drainages that lack water at or near the surface most of the year, and are subject to periodic severe flooding events. <P0-S1>  Desert dry wash is contrasted with desert riparian vegetation, which occurs in desert canyons and drainages where there is year-round water at or near the surface. <P0-S2>  Plants must either be able to survive the severe flooding conditions or be able to reestablish themselves before the next flooding event. <P0-S3>  Some of these plants have evolved so that in order for their seeds to germinate, the seeds must be scarified or abraded by tumbling sand, gravel, and rocks during the flooding event. <P0-S4>  They must then quickly send down roots deep enough to be able to tap into deep underground water reserves, in order to survive the dry period after the flooding. <P0-S5>  Common dominant species of the desert dry wash include smoke tree ("Psorothamnus spinosus"), desert willow ("Chilopsis linearis"), catclaw ("Senegalia greggii"), cheesebush ("Ambrosia salsola"), and waterweed ("Baccharis sergiloides"). <SEP> <P1-S0> Hesperaloe (false yucca) is a genus of flowering plants in the family Asparagaceae, subfamily Agavoideae. <P1-S1>  It contains perennial yucca-like plants with long, narrow leaves produced in a basal rosette and flowers borne on long panicles or racemes. <P1-S2>  The species are native to the arid parts of Texas in the United States and Mexico and are sometimes cultivated as xerophytic ornamental plants. <SEP> <P2-S0> Orbeopsis is a genus of plants in the Apocynaceae, first described as a genus in 1978. <P2-S1>  They are native to southern Africa. <SEP> <P3-S0> 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. <P3-S1>  It is contrasted with the desert dry wash vegetation type in which water at or near the surface is lacking most of the year. <P3-S2>  The visual character is of large, lush green trees surrounded by dry desert vegetation and soil coloration. <P3-S3>  The area may be in a patch surrounding a spring (oasis), or in a strand following the course of water flow. <P3-S4>  Over 80% of known desert wildlife species use desert riparian areas. <P3-S5>  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"). <P3-S6>  Salt cedar is particularly causing problems for this ecosystem because it is able to extract water more efficiently than cottonwoods and willows. <P3-S7>  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.