The major biotic regions of the southwestern part of North America, which provide the local context of the desert biomes, are show in the map below;  the deserts themselves are shown in greater detail in other maps later on.  A more detailed consideration of Arizona's biotic communities will be found here.

In the northeastern corner we see the southwestern edge of the great plains grasslands as they reach into eastern New Mexico.  At top right are two tongues of the Petran (Rocky Mountain) forest system where they stretch into northern N.M.;  a final outlier of this montane forest is seen in the Sacramento Mtns. of southern N.M. at centre-right (although similar forests are found at higher elevations south into Mexico.)  The lower mountains of Mexico support forests and evergreen woodlands which are structurally rather like the Petran forests, but are floristically distinct - this is the Madrean system dominating eastern Sonora and western Chihuahua.  Small outliers of this mainly Mexican system extend northwards into the U.S.A., in s.e. Arizona:  the Chiricahua, Huachuca and Patagonia ranges are prominent examples.  The high Mogollon plateau runs s.e. - n.w. across central Arizona, and on its top it carries Petran montane forest and woodland, with Madrean woodland and other evergreen systems at lower elevations - the Interior Arizonan.  At lower altitudes this is represented by a chaparral bush-scrub system.  South of the Madrean appears the Sinaloan system - a dry-deciduous thorn-woodland vegetation, closely related to that of the adjacent Sonoran desert.  Forrest Shreve, a pioneer biologist of these regions (see later, below) included part of it within the Sonoran desert.)  Finally, of the non-desert systems, we see the Californian, which here is represented by coastal chaparral scrub, and the Sierran, which is a montane forest, very like the Petran system.
 
 
 
 

Here we see the entire North American desert system.  We shall encounter the Great Basin cold desert mainly while in transit to and from the warm desert systems;  likewise, we spend little or no time in the Chihuahuan desert.  We usually spend a little time in the southern and eastern margins of the Mojave desert. The Sonoran desert is our primary concern, and you can see that most of it is located in Sonora and Baja California.  Later in these notes you will find a table outlining the major characteristics of these four desert systems, followed by a similar, more detailed characterisation of the various sub-sections of the Sonoran desert itself.

Great Basin  Elevation largely >1200m. with mountains up to 3000m.  Basin & Range topography w/ alkali flats or dry lakes in largely closed basins.  Hard frosts >1 week common.  Mean precipitation (2-300mm.) +/- evenly distributed throughout year.  Most winter precip. as snow.

Simple vegetation - +/- pure stands of low bushes - Atriplex in more alkaline, finer, soils near centre of basins, Artemisia  in  coarser marginal soils.  Few annuals.  Cacti , agaves & yuccas unimportant element of flora - few can withstand long, hard frosts.

Mojave  Mainly 600-1200m. Basin & range, but mountains lower & more numerous than in Gt, Basin, few supporting other than desert scrub.  Winter and spring rain.  More arid than Gt. basin, only the margins receiving on average >120mm;  mostly ~100mm. or less.

Predominantly shrubby vegetation - ~70% is Larrea & Ambrosia.  Few cacti.  Few trees, restricted to washes and higher elevations.  Prominent here is the endemic Joshua Tree, Yucca brevifolia.  Rich winter annual flora.  In many ways, a transition between Sonoran & Gt. Basin assemblages.

Sonoran  Mostly <600m;  entirely <950m.  Plains dotted w/ hills & mountains;  few closed basins;  some permanent rivers.  Rains often light and uncertain, bi-seasonal.  Lower elevation mean <200mm.;  higher elevations get 2-300mm.

Flats dominated by shrubs, as in Mojave.  Bajadas, hills & lower slopes have highly diverse life-forms, including many cacti and trees, forming up to 50% of cover, sometimes forming layered vegetation.  Higher slopes show Yucca, Nolina, Agave, Dasylirion.

Chihuahuan  Entirely east of continental divide.  Over 50% >1200m.  Vast plains & high mountain ranges.  5-10°C cooler than Sonoran;  frosts common in northern sections.  60-70% of precipitation (mean 2-300mm.) in summer months, mostly as rain, but some snow in winter.

Mostly shrubby vegetation, but some few trees mostly in rocky or riparian areas.  Cacti  small & insignificant.  Most obvious plants are Yucca, Dasylirion, Nolina & Agave (A. lechugilla  is a marker.)  Fouquieria  also widespread.  Of the very common and widespread spp., only Larrea, Prosopis & Fouquieria  in common w/ Sonoran.

Here is a map showing the geographical distribution of precipitation in the Sonoran Desert, with some climate diagrams showing how its seasonal patterning changes on moving east from the Pacific coast.

Notice the especially dry portions of the desert in the Colorado valley and in the coastal parts of Baja California and Sonora;  the generally smooth increase in precipitation as one moves away from the coasts;  and, in the climate diagrams at the top of the map (see explanation of climate diagrams in the Climate & Deserts document), note the shift from a winter-rain regime in the west (San Diego) through bi-modal patterns in central Arizona (Gila Bend and Tucson - though Tucson has more summer than winter rain) to a largely summer rain system in Hermosillo.  Further east still, say in New Mexico and Chihuahua, there is practically no winter rain atall.  This longitudinal shift in rainfall has important impacts on the vegetation.
 

Since the graphic isn't entirely clear, here's the key to rainfall levels:  A = 0-50mm;  B = 50-100mm;  C = 100-200mm;  D = 200-300mm;  E = 300-400mm;  F = 400-500mm;  G = 500-600mm;  H = 600-700mm.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

The total annual rainfall map above shows only part of the picture that concerns the vegetation.  Also of considerable importance are: regularity & seasonality of precipitation, annual means, seasonal extremes & variability in temperature, as well as features of the local soils, topography and so forth.  In this diagram we emphasise the substantial climatic differentiation among the various subsections (see below for descriptions of the subsections) of the desert;  it plots temperature and rainfall data from the summer and winter three-month periods.  The regional means for the winter and summer periods are connected for ease of comparison of the regions and comprehension of the overall pattern.

Our primary focus is the Sonoran desert, which occupies some 300,000 km², almost 2/3 of which is in Mexico.  It extends from 35°N, just north of Needles, on the Colorado River, south to 27°N in mainland Mexico, and to 24°N in Baja California Sur.  To the east, the Sonoran desert merges into semi-desert grassland and Chihuahuan desert scrub;  to the northeast it merges into chaparral scrub;  to the northwest it merges into the Mojave desert scrub;  to the west, it merges into the chaparral and conifer woodlands of the Californian mountains.

These boundaries towards the east, north and west correspond quite well with the extent of territory within which there is no more than 24 hours  of sub-freezing temperatures (within the desert, though there are some localities entirely without frost, other areas have up to four months with a chance of at least some nightly frost.)

To the south, both in mainland Mexico &  in Baja California, the vegetation gradually increases in density & stature until it turns into drought-deciduous thornscrub, where no frosts occur, and it is more mesic.  The maps and diagrams have adequately shown the characteristic bimodal rainfall pattern, but they fail to convey the very different character of the two sorts of rains.  Winter rain is typically rather gentle, widespread, and of several days duration;  summer rain is local, short-lived and often violently torrential.  Winter rains achieve good penetration;  summer rains mostly finish up in washes, as flash-floods.

Virtually the entire flora of this desert is of subtropical origin, and it has developed in this region surprisingly recently.  As the glaciers were receding from much of Canada ~8-9000 years ago, conifer woodlands, similar to those still found in n. Arizona, Nevada and Utah, was receding from the area now occupied by the northern Sonoran Desert.  The flora is still evidently in flux, with much evolution presumably still going on;  the fauna similarly is recently-arrived, and much of it is still broadly distributed across all of the southern arid belt of N. America.

On the next sections is a synopsis of characteristic features of the several subsections, as originally described by Shreve.  Following that are some charts showing, in a little more detail, the ecological extents of some of the major elements of the flora.  Later still, you will find a chart showing the diversity of morphological body-forms evolved by desert plants, as they were distinguished by Shreve in his studies of the Sonoran desert.  Many of these same body plans, or life-forms, are to be found in desert vegetations elsewhere in the world, even though they have been developed convergently from other phylogenetic groups.  As an example:  true cacti are restricted to the Americas, but cactus-like stem-succulents have been evolved within the Asclepiadaceae & Euphorbiaceae.

The vegetation of the Sonoran desert is extremely diverse, and this is a reflection of its topographic and climatic diversity (see above).  This vegetational diversity was codified over 50 years ago by a pioneer in the study of the North American deserts, Forrest Shreve.  He divided the desert into seven regions, which we continue to use here.  However, other more recent workers, notably Brown and Lowe have made modifications.  Nevertheless, as you can see in the maps below, the essence of Shreve's system is retained.  below the maps you will find a table wherein the vegetation types and floras of the subsections are characterised.

PHYSICAL  CHARACTERISTICS	VEGETATION  CHARACTERISTICS
Lower Colorado-Gila section Elevation sea level to 400m.  Temperature  Hotter and more arid  on average than all other sections.  Precipitation ~100mm.  Terrain  85% plains or gentle bajadas.  Soils mainly fine to very fine, except on the few hills and upper bajadas.	Microphyllous Larrea-Ambrosia  desert. Vegetation typically very simple & open, heavily dominated by small to medium-sized bushes.  Flats dominated by Larrea tridentata  Ambrosia dumosa;  Atriplex canescens  found in alkaline areas.  Typical of washes:   Baccharis sarothroides  Chilopsis linearis  Ambrosia ambrosoides  Justicia californica.  Dalea spinosa  In washes and on slopes:  Prosopis juliflora  P. pubescens  Cercidium floridum  Cercidium microphyllum  Olneya tesota  Condalia lycioides  Lycium andersonii  Encelia frutescens  Castela emoryi  Upper bajadas:  Ambrosia deltoidea  Fouquieria splendens  Krameria grayi  Echinocereus engelmannii   Opuntia echinocarpa
Arizona Upland section Elevations 150-950m.  Precipitation  Most mesic section of the true desert, with overall mean  ~300mm., strongly biseasonal (so only short dry seasons), ~50% in summer months.  Terrain  ~90% of land surface is bajada, draining mostly into the Gila River;  very few closed basins.  Soils highly diverse depending on slope;  fine soils of flats often with hard-pan.	Crassicaulescent Cercidium-Opuntia  desert. Cover mostly 20-60%.  Highly diverse:  open scrub to quite substantial 'woodland.'  In the more dense stands at higher elevations, direct sight-line can drop to <35m.  Succulents and green-stemmed plants abundant;  both summer & winter ephemerals.  Diverse rooting systems, including taproot (Ephedra), taproot + laterals (Larrea, Prosopis, Ambrosia), and subsurface (most cacti.)  Flats w/ fine soils dominated by Larrea tridentata.   Typical associates:  Prosopis juliflora  Acacis constricta  A. greggii  Opuntia arbuscula  O. versicolor  O. spinosior  O.fulgida  Typical of washes:   Baccharis sarothroides  Ambrosia ambrosoides  Justicia californica  Chilopsis linearis.  Also some large trees:  Populus fremontii  Fraxinus velutina  Juglans major  Platanus wrightii  In washes and on slopes:  Prosopis juliflora  Cercidium floridum  Cercidium microphyllum  Olneya tesota  Condalia globosa  Lycium fremontii   Celtis tala  Zyziphus obtusifolia  Opuntia phaeacantha  Cereus gigantea.  Upper bajadas:  Ambrosia deltoidea  Fouquieria splendens  Celtis tala  Krameria grayi  Echinocereus engelmannii   Opuntia echinocarpa  O. fulgida  O. versicolor  O. phaeacantha  O. leptocaulis  Cereus gigantea  Acacia constricta  A. greggii  Simmondsia chinensis  Ephedra trifurca  Ferocactus wislizenii  Encelia farinosa  Calliandra eriophylla  Krameria grayi  Psilostrophe cooperi  Jatropha cardiophylla  Canotia holacantha
Sonoran Plains section Elevation ~750m. in east;  ~100m. in west.  Temperature more moderate than Lower Colorado desert;  frosts infrequent & mild.  Precipitation somewhat lower than Arizona Upland, but more markedly summer regime.  Terrain  ~85% flat plains sloping gently towards the west.	Arbosuffrutescent Olneya-Encelia  desert. Dominated by open stands of low trees,  with shrubs and large cacti.  Larrea  reduced in abundance, especially in south, as trees increase in abundance & stature.  Vines become important.  Dominant trees:  Prosopis juliflora  Cercidium floridum  Cercidium microphyllum  Olneya tesota.   Increasingly frequent in the south are:  Ipomaea arborescens  Acacia willardiana  A. cymbispina  Cercidium sonorae  C. praecox.  Other trees include:  Bursera microphylla.  Bushes and shrubs include:  Celtis pallida  Condalia lycioides  Jatropha cardiophylla  Acacia constricta Caesalpinia pumila  Lycium brevipes  Krameria parvifolia.  In southern reaches, Larrea becomes replaced by  Forchammeria,  Encelia declines, Fouquieria splendens gives way to F. macdougalli,  Cereus giqantea gives way to  Stenocereus thurberi and  Lophocereus schottii.
Sonoran Foothills section (now = Sinaloan Thornscrub)  Elevation from ~1000m. in east to sea level in west. Precipitation 350-500mm., ~75% in summer months.  Terrain mixed:  low hills, mesas, bajadas & mountain slopes.	Arborescent Acacia-Prosopis  desert. Larrea,  Simmondsia virtually absent.  Mostly a drought-deciduous low woodland of  thorny trees and bushes, inceasing in stature & density towards the south (cover - from 50% in n. to 100% in s.)  Cacti of much reduced importance, though Stenocereus and Pachycereus obvious, and Rathbunia alamosensis, Opunia fulgida and Lophocereus are common.  Prominent bushes & trees:  Prosopis juliflora  Acacia cymbispina  A. farnesiana  A. pennatula  Bursera odorata  Caesalpinia pumila  C. sonorae  Ceiba acuminata  Encelia farinosa  Dodonea viscosa  Fouquieria mcdougalli  F. diguetii  Guaiacum coulteri  Eysenhardtia orthocarpa  Jatropha cardiophylla  Ipomaea arborescens  Lantana velutina  Lysiloma divaricata  Mimosa laxia  Olneya tesota  Sapium biloculare
Central Gulf Coast section Elevation sea-level to ~150m.  Temperatures moderated by proximity of the sea.  Precipitation light (~70-150mm.) and uncertain, with no seasonal dominance.  Terrain  Bajadas and mesas, with few and short washes.	Sarcocaulescent Bursera-Jatropha desert. Mainly widely-spaced shrubs (Larrea, Jatropha, Euphorbia, Fouquieria) and small trees (Cercidium, Olneya, Bursera) separated by bare ground (cover ~10-20%).  The more striking elements of the region are the swollen-trunk plants, often with latex or aromatic resins, and the large columnar cacti. Virtually no low shrub element, in contrast to Arizona Upland section (Ambrosia) or to Vizcaino section (Ambrosia, Viguiera.)  In Baja, from north to south, there is a shift from dominance by plants typical of the Colorado desert - Larrea tridentata  Fouquieria splendens  Cercidium microphyllum  - to  the following:  Bursera laxifolia  B. hindsiana  Jatropha cinerea  Fouquieria diguetii.  Cacti are represented by a large number of cholla species (Opuntia bigelovii, O. clavellina, O. cholla, O. ramosissima, and O. tesajo) by cardon (Pachycereus pringlei), and by Ferocactus.  Boojum Tree  (Fouquieria [Idria] columnaris) also present in some localities.  Upland sections, in addition to the taxa mentioned may have Pedilanthus macrocarpus  Krameria parvifolia  Agave sobria  Lycium brevipes.  Steamways are markedly different, and may support Lysiloma candida  Prosopis juliflora  Cercidium floridum.
Vizcaíno section Elevation sea-level to ~1700m.  with ~75% <500m.  Precipitation very light (mean ~100mm.) and uncertain but aridity moderated by cooler temperatures and sea-fogs.  Terrain level plains on Pacific coast, low hills inland, washes, foothills, bajadas and mountains up to the peninsular divide.	Sarcophyllous Agave-Ambrosia  desert. Highly diverse, depending on terrain, from uniform low, sparse, scrub to rich, complex mixes of diverse life-forms.  Abundant most places are fleshy-leaved plants e.g. Mesembryanthemum, Agave, Dudleya;  often prominent are Idria, Pachycereus, Yucca valida, Pachycormus discolor.  Several species of Agave and Ambrosia.  Perennial grasses +/- absent.  In north, ecotone with California chaparral, with Myrtillocactus cochal  Euphorbia misera  Bergerocactus emoryi.  Characteristic northern vegetation: Ambrosia camphorata  A. chenopodifolia  Agave shawii  Viguieria deltoidea  Encelia farinosa  Fouquieria splendens  Simmondsia chinensis  Eriogonum fasciculatum  Ephedra californica and chollas (Opuntia.)  Vegetation more xeric inland, with A. dumosa and Larrea.  Gradually, southern taxa dominate, including  Idria columnaris  Pachycereus pringlei  Lophocereus schotii  Agave shawii  A. cerulata  A. deserti  Ambrosia magdalenae  Viguiera deltoidea  Opuntia molesta  O. clavellina  Yucca valida  Pachycormus discolor  Machaerocereus gummosus  Jatropha cinerea  Pedilanthus macrocarpa  Fouquieria diguetii  Near coast, fog supports dense epiphyte cover  of lichens and bromeliads  (Tillandsia recurvata)
Magdalena section (now part of Vizcaino) Elevation sea-level to  ~1500m., mostly below 500m.  Climate similar to Vizcaino, but frosts infrequent.  Terrain mix like Vizcaino, but also extensive lava flows (malpais) and many closed basins (playas.)	Arbo-crassicaulescent Lysiloma-Machaerocereus  desert. Shreve erected this section to acknowledge the absence of the bizarre Idria, Pachycormus, Yucca valida and Agave shawii of the Vizcaino, the prominence of large trees, and of several large cacti.  Despite the distinct aspect, the two regions are closely related.  In the north, the vegetation is much like of the Gulf Coast, including:  Larrea  Jatropha cuneata  J. cinerea  Bursera microphylla.  The large trees include:  Lysiloma candida  Prosopis torreyana  Prosopis palmeri  Cercidium peninsulare  Bursera laxiflora  Fouquieria diguetii   Notable larger cacti include:  Machaerocereus gummosus  Stenocereus thurberi  Pachycereus pringlei  Opuntia cholla  Lophocereus schotti .  On the sandy plains is found the strange Machaerocereus eruca,  an endemic mobile creeping cactus.  This plains vegetation also includes:  Opuntia cholla  Encelia farinosa  Ambrosia magdalenae  Pachycereus pringlei  Jatropha cinerea  Fouquieria diguetii  Larrea  Euphorbia magdalenae  E. californica.

 

The deserts of the world support some of the most distinctive plant body forms known and the Sonoran Desert provides most of them to the student. One of the foremost early students of the Sonoran Desert was Forrest Shreve, and he provided a categorization-system to bring some order to the diversity of plant morphologies - what he called Life-Forms. The tree-type diagram below illustrates this system. 

It begins by recognising the major distinction between Ephemeral and Perennial plants - those that complete an entire life-cyle, followed by death of the recognisable plant body vs. those wherein the plant body persists several years, perhaps to produce seed several times. 

Following that dichotomy, the life-forms are broken down further according to which parts of the plant provide the perennating structures — those that remain alive from one growing season to the next, and other aspects of plant habit. 

We shall be meeting examples of all these life-forms during the course, and it is one of your tasks to enter a species name into the boxes in this graphic as an example taxon.

With a few exceptions, a given plant taxon is referred to in texts and articles by use of but a single scientific name (genus and species). By contrast, many taxa have several vernacular names. In our case, this is complicated by there being both English ad Spanish common names. Further, the same vernacular name may refer to several distinct taxa!

 This adds up to confusion, and you are encouraged to use taxonomic (Latin/Greek) in preference to vernacular names (after all, some taxa don't even have vernacular names.

 However, many sources make reference to plants only by vernacular names and so to reduce your confusion, here's a correspondence for the major taxa ch you may encounter.
 
 

 Acacia sp.   Acacias   espino, huisache, una de gato
 Agave spp.   Century plants   lechugilla, amole, maguey, mescal
 Allenrolfea   Pickleweed, Iodine bush
 Ambrosia spp.   Bursage, Burrobush, Western ragweed
     (Franseria)
 Anisacanthus   Hummingbird  bush  chuparosa
 Arctostaphylos sp.  Manzanita   Manzanita
 Argemone   Pricklepoppy   chicalote
 Artemisia spp.   Sagebrush
 Asclepias spp.   Milkweed   ajamente
 Astragalus   Locoweed
 Atriplex spp.   Saltbush,shadscale  chamiso
 Baccharis
  sarothroides  Desert broom
  glutinosa  seepwillow   batamote, hierba del pasmo

 Baileya multiradiata   Desert marigold
 Beloperone californica  see Justicia
 Berberis spp.   Barberry   Agritos, algerita
 Bursera spp.   Elephant tree   copal, torote
 Caesalpinia   Bird of Paradise
 Calliandra   Fairyduster, Feather  Huajillo, mesquitilla,
     duster, False mesquite  tabardillo, zapotillo, cabeza de angel
 Canotia holacantha   Crucifixion Thorn

 Carnegiea gigantea   Saguaro
 Cassia     Senna
 Castela emoryi   Crucifiction Thorn
 Ceanothus   Deerbush, buckbrush
 Ceiba    Silk Cotton Tree,  pochote
     Kapok Tree
 Celtis    Hackberry   Palo blanco, tala
 Cercidium
  microphyllum  Foothills Paloverde  palo verde
  floridium  Blue Paloverde
  sonorae      palo estribo
  praecox      palo brea
  peninsulare      palo de pua
 Cercis    Redbud, Judastree
 Cereus
  greggi   Night-blooming cereus  Reina de la noche

  Lemairocereus thurberi   organ-pipe cactus  pitahaya duice
  Stenocereus  

  Lophocereus schotti  senita    senita
  Pachycereus  cardon    cardon

  Chilopsis linearis  Desert Willow,
     Desert Catalpa
 Chrysothamnus  Rabbitbrush   chamisa
 Cleome spp.   Burrofat
 Cocos    Coconut palm   cocotera
 Coleogyne   Blackbrush
 Condalia   Graythorn   Crucillo
 Cordia parviflora       palo de asta
 Cowania   Cliffrose, buckbrush,
     quinine bush
 Dalea
  spinosa  Smoketree
  emoryi   Dye bush
 Dasylirion   Sotol
 Dodonaea   Hopbush
 Dudleya spp.   Liveforever   Siempreviva
 Echinocereus   Hedgehog cactus
 Encelia farinosa  Brittlebush   Incienso
 Ephedra spp.   Mormon Tea   canutillo
 Eriogonum spp.  Buckwheat
 Erythea (Brahea)
  armata       Palma ceniza
  brandegeei  Fan Palm   palma de taco
 Erythrina   Coral bean, Coral tree  chilicote
 Eschscholtzia   Mexican Goldenpoppy  Copa de oro
 Euphorbia spp.  spurge    candelilla
 Eysenhardtia   kidneywood
 Ferocactus sp.   Barrel cactus   biznaga
 Flourensia   Tarbush
 Forchammeria       jito
 Fouquieria
  splendens  ocotillo
  macdougalli  Tree Ocotillo   palo Adan
  diguettii  Tree Ocotillo   palo Adan
 Franseria  see Ambrcsia
 Fraxinus   Ash    fresno
 Gutierrezia   Snakeweed
 Haplopappus   Burroweed, jimmyweed,
     Turpentine bush
 Hilaria spp.   Tobosa grass
 Holacantha emoryi  Crucifixion thorn  amargoso
  (Castela emoryi)
 Hymenoclea   Burrobrush, Cheeseweed
 Idria columnaris   BooJum Tree   Cirio
 Ipomaea arborescens   Morning Glory   Palo santo
 Jacobinia californicae      Chuparosa
 Jatropha
  cardiophylla (cordata)  Limber bush   Sangre de Cristo
  cinerea      lomboy, zapo,
  cuneata      torote prieto, sangre de drago
 Juglans    walnut
 Justicia californica   Beloperone   chuparosa
 Koeberlinia spinosa  Crucifixion thorn junco
 Krameria   Ratany
 Lantana   lantana
 Larrea tridentata  Creosote bush    gobernadora, hediondilla
 Lycium spp.   squawberry    Tomatillo
 Lysiloma       palo blanco, manta
 Machaerocereus
  gummosus      pitahaya agria
  eruca   Caterpillar cactus
 Mammillaria spp.  Pincushion cacti, Fishhook cacti
 Mesembryanthemum  Ice plant    Flor del sol
 Mimosa spp.   Sensitive plant, catclaws
 Muhlenbergia spp.  muhly grass
 Nicotiana   Tree tobacco
 Nolina    Beargrass    Sacahuista
 Olneya tesota   Ironwood    Palo fierro
 Opuntia
  (Cylindropuntia)  Chollas
 Opuntia
  (Platyoeuntia)   Prickly Pears
  Pachycormus discolor  Elephant tree   copalquin, torote blanco
 Parkinsonia    Mexican paloverde, Horse Bean
 Pedilanthus macrocarpus     candelilla
 Phoenix dactylifera  Date palm   datil
 Phoradendron   Desert Mistletoe
 Platanus   Sycamore
 Populus   Cottonwood, poplar, aspen alamo
 Porophyllum gracile  Stinkweed   yerba del venado
 Prosopis spp.   Mesquite, screwbean  algarrobo, tornillo
 Psilostrophe   Paperflower
 Rathbunia   octopus cactus
 Salsola kali   Russian thistle, tumbleweed
 Salvia    Sage, Desert sage
 Sambucus   Elderberry
 Sapium biloculare  Mexican jumping bean
 Sarcobatus   Greasewood
 Simmondsia chinensis   Jojoba
 Sphaeralcea   Globemallow
 Suadea   Seepweed, inkweed,  quelite
     iodine bush
 Tamarix   Saltcedar
 Tillandsia recurvata   Ballmoss   heno pequeno
 Tiquilia   Borage
 Vizcainoa geniculata      guayacan
 Washingtonia   Fan palm   palma
 Yucca
  brevifolia  Joshua tree
  valida       Datilillo
  elata   Soapweed   Datil, palmilla
 Zizyphus   graythorn   crucillo