The Empire Mountains are located between the Santa Rita and Rincon mountain ranges, and are bordered on the west by the upper reaches of Davidson Canyon, a major seasonally-dry stream.  Although they are a small range at relatively low elevation, the Empires hold a surprising diversity of native plants, and are especially rich in ferns and flowering shrubs.  Geologically, the Empires can be confusing, with a variety of rock types criss-crossed by many faults.  Rounded granite tors, rugged volcanic cliffs, folded siltstone canyon walls, and long marble and limestone ridges create ideal living conditions for several rare and unusual plants, including Echinomastus erectocentrus var. erectocentrus (Needlespine Cactus) and Graptopetalum bartramii (Bartram's stonecrop).  They are a botanical crossroads located in the transition between Sonoran desert upland and desert grassland, Chihuahuan desert scrub, and Madrean evergreen woodland.  The meandering rocky washes offer a variety of microclimates in close juxtaposition, so species that normally inhabit very different plant communities are found side by side.  For example, Jatropha cardiophylla of the Sonoran Desert grows in a wash among granite tors in close proximity to Madrean Evergreen Woodland plants such as Bouvardia ternifolia.  Petrophytum caespitosum, a Rocky Mountain plant, grows here beside prickly pear cacti and the borderland milkweed, Asclepias macrotis.  Several plants reach the edges of their ranges here: Carnegia gigantea, Vauquelinia californica, and Jatropha cardiophylla - all Sonoran Desert icons - reach their eastern limit, and the Chihuahuan trees Rhus microphylla and Quercus pungens are near their western limit.

Cymopterus multinervatus (Apiaceae):  flowers (February-March), seeds (April).

* NON-NATIVE

Pteridaceae (True Ferns)  PHOTOS:  Desert Ferns Guide
Argyrochosma limitanea ssp. limitanea
Astrolepis cochisensis ssp. arizonica
Astrolepis cochisensis ssp. cochisensis
Astrolepis integerrima
Astrolepis sinuata
Astrolepis windhamii
Bommeria hispida
Cheilanthes eatonii
Cheilanthes feei
Cheilanthes lindheimeri
Cheilanthes tomentosa
Cheilanthes wootonii
Cheilanthes wrightii
Notholaena grayi
Pellaea intermedia
Pellaea ternifolia
Pellaea truncata

GYMNOSPERMS
Cupressaceae (Cypress Family)
Juniperus coahuilensis [= J. erythrocarpa] (redberry juniper)

Ephedraceae (Jointfir Family)
Ephedra trifurca (longleaf ephedra)

Limestone & Marble Hills have a distinctive shrub community dominated by Vauquelinia californica, Mortonia scabrella, Quercus pungens, Rhus choriophylla, Parthenium incanum, and Dalea formosa growing with sotol, ocotillo, Agave palmeri, A. schottii, and all four species of Astrolepis ferns.

ANGIOSPERMS
Acanthaceae (Acanthus Family)
Anisacanthus thurberi (desert honeysuckle)
Carlowrightia arizonica
Dicliptera resupinata (foldwing)
Elytraria imbricata (purple scalystem)
Tetramerium nervosum
 

Anisacanthus thurberi	Tetramerium nervosum	Elytraria imbricata	Dicliptera resupinata

Agavaceae (Agave Family)  PHOTOS:  Agaves
Agave chrysantha (golden-flowered century plant)
Agave palmeri (Palmer agave, large typical form with monochromatic leaves and no offsets)
Agave palmeri (small low-elevation form with banded leaves and multiple offsets)
Agave schottii (lechugilla)
Dasylirion wheeleri (sotol)
Nolina microcarpa (beargrass)
Nolina texana (beargrass, sacahuista) [a single plant on limestone in a sandy wash]
Yucca baccata (banana yucca)
Yucca elata (soaptree yucca)
Yucca schottii (mountain yucca)

Amaranthaceae (Amaranth Family)
Amaranthus palmeri (carelessweed)
Froelichia floridiana (snake cotton)
Gomphrena nitida (ball clover)
Tidestromia lanuginosa (honeymat)

Amaryllidaceae (Amaryllis Family)
Milla biflora (Mexican star)
Dichelostema capitatum (desert hyacinth)

Anacardiaceae (Cashew Family)
Rhus choriophylla (desert sumac)
Rhus microphylla (littleleaf sumac)
Rhus trilobata (skunkbush)
Toxicodendron radicans (poison ivy)

Apiaceae (Parsley Family)
Bowlesia incana
Cymopterus multinervatus (springparsley)
Daucus arizonica (wild carrot)

Apocynaceae (Dogbane & Milkweed Family)
Asclepias asperula (antelope horns; inmortal)
Asclepias macrotis (longhood milkweed)
Asclepias nummularia (dwarf milkweed)
Macrosiphonia macrosiphon (Huachuca rock trumpet)
Sarcostemma (Funastrum) cynanchoides (climbing milkweed)
 

Asclepias asperula	Asclepias macrotis	Sarcostemma cynanchoides

Aristolochiaceae (Pipevine Family)
Aristolochia watsonii (desert pipevine)

Asteraceae (Composite Family; Sunflower Family)
Acourtia nana (desert holly)
Acourtia wrightii (desert peony)
Ambrosia ambrosioides (canyon ragweed)
Ambrosia confertiflora (desert ragweed)
Anaphalis margaritacea (pearly everlasting)
Baccharis salicifolia (seepwillow)
Baccharis sarothroides (desert broom)
Bahia absinthifolia (hairyseed bahia)
Baileya multiradiata (desert marigold)
Bebbia juncea (sweetbush)
Brickellia coulteri (brickelbush)
*Cirsium vulgare (bull thistle)
Encelia farinosa (brittlebush, incienso)
Eupatorium greggii (mistflower)
Ericameria laricifolia (turpentine bush)
Guttierezia sarothrae (escoba de vibora)
Helianthus annuus (sunflower)
Isocoma tenuisecta (burroweed)
Machaeranthera tanacetifolia (spiny aster)
Parthenium incanum (mariola)
Pectis angustifolia
Pilostrophe cooperi (paperflower)
Porophyllum gracile (odora)
Pyrrhopappus pauciflorus (desert chicory)
Rafinesquia neomexicana
*Sonchus oleracea (sow thistle)
Stephanomeria pauciflora (wirelettuce, skeletonweed)
Thelesperma megapotamicum (Hopi tea greenthread)
Xanthium strumarium (cocklebur)
Zinnia acerosa (desert zinnia)

Betulaceae (Birch Family)
Alnus oblongifolia (Arizona alder)

Bignoniaceae (Catalpa Family)
Chilopsis linearis (desert willow)
Tecoma stans (tronadora)

Bixaceae (Lipstick Tree Family)
Amoreuxia palmatifida (Mexican yellowshow)

Amoreuxia palmatifida

Boraginaceae (Forget-me-not Family)
Amsinckia intermedia
Cryptantha pterocarya
Cryptantha
Pectocarya heterocarpa (chuckwalla combseed)

Brassicaceae (Mustard Family)
Draba
Descourainia pinnata (laceleaf mustard)
Lepidium
Lesquerella purpurea (white bladderpod)
Lesquerella gordonii (yellow bladderpod)
Streptanthus carinatus (jewelflower)
Thysanocarpus curvipes (lacepod)

Amorpha fruticosa	Vauquelinia californica	Mortonia scabrella	Crossosoma bigelovii

Capparidaceae (Caper Family)
Polanisia dodecandra (redwhisker clammyweed)

Caprifoliaceae (Honeysuckle Family)
Sambucus cerulea (Mexican elder)

Caryophyllaceae (Pink Family)
Silene antirrhina (sleepy catchfly)

Celastraceae (Bittersweet Family)
Mortonia scabrella (sandpaper bush)

Chenopodiaceae (Goosefoot Family)
Atriplex canescens (fourwing saltbush)
*Salsola tragus (Russian thistle, tumbleweed)

Commelinaceae
Commelina dianthifolia
Commelina erecta (dayflower)

Convolvulaceae (Morning Glory Family)
Convolvulus equitans (Hoary Bindweed)
Evolvulus alsinoides (slender dwarf morning glory)
Evolvulus arizonicus (wild dwarf morning glory)
Ipomoea coccinea (red morning glory)
Ipomoea costellata (small birdfoot)
Ipomoea leptotoma (large birdfoot)

Crassulaceae (Stonecrop Family)
PHOTOS:  Stonecrop
Graptopetalum bartramii (Bartram’s stonecrop)

Crossosomataceae (Rockflower Family)
Crossosoma bigelovii (ragged rockflower)

Cucurbitaceae (Cucumber Family)
Apodanthera undulata (coyote melon)
Marah gilensis (bur cucumber)
Cucurbita digitata (coyote gourd, fingerleaf gourd)
Cucurbita foetidissima (buffalo gourd)

Euphorbiaceae (Spurge Family)
Chamaesyce albomarginata
Chamaesyce arizonica
Chamaesyce fendleri
Chamaesyce florida
Chamaesyce hyssopifolia
Chamaesyce micromera
Chamaesyce polycarpa (sandmat)
Chamaesyce setiloba (Yuma sandmat)
Jatropha cardiophylla (sangre de drago, limberbush) [shrub]
Jatropha macrorhiza (sangre de drago) [perennial herb]

Fabaceae (Legume Family)
Acacia angustissima (whiteball acacia)
Acacia berlandieri (guajillo)
Acacia constricta (whitethorn acacia)
Acacia greggii (catclaw)
Acacia neovernicosa
Amorpha fruticosa (false indigo, leadplant)
Astragalus
Calliandra eriophylla (fairyduster)
Cercidium floridum (blue palo verde)
Dalea formosa (feather dalea)
Dalea mollis (velvet prairie clover)
Dalea wrightii
Erythrina flabelliformis (coralbean)
Lotus greenei (deervetch)
Lupinus arizonicus (Arizona lupine)
Lupinus concinnus (bajada lupine)
Lupinus sparsiflorus (desert lupine)
*Medicago polymorpha (bur clover)
Mimosa aculeaticarpa (wait-a-minute bush)
Mimosa dysocarpa (velvet-pod mimosa)
Prosopis velutina (velvet mesquite)
Senna covesii (desert senna)

Fagaceae (Beech Family)
Quercus arizonica (Arizona white oak)
Quercus pungens (sandpaper oak)
Quercus turbinella (shrub live oak)
Quercus oblongifolia (Mexican blue oak)
Quercus emoryi (Arizona black oak)

Quercus pungens	Quercus oblongifolia	Morus microphylla

Fouquieriaceae (Ocotillo Family)
Fouquieria splendens (ocotillo)

Fumariaceae (Fumitory Family)
Corydalis aurea (yellow corydalis)

Garryaceae (Silk Tassel Family)
Garrya wrightii (silk tassel)

Gentianaceae (Gentian Family)
Centaurium arizonicum (Arizona centaury)

Geraniaceae (Geranium Family)
*Erodium cicutarium (filaree)
Erodium texanum

Hydrophyllaceae (Waterleaf Family)
Eucrypta micrantha (desert hideseed)
Phacelia arizonica (scorpionweed)
Phacelia crenulata

Juglandaceae (Walnut Family)
Juglans major (Arizona walnut)

Krameriaceae (Ratany Family)
Krameria grayi (white ratany)
Krameria erecta (littleleaf ratany)

Lamiaceae (Mint Family)
Modarda citriodora (coyote mint)
*Salvia columbariae (chia)
Trichostema arizonicum (bluecurls)

Liliaceae (Lily Family)
Allium macropetalum (desert onion)
Calochortus ambiguus (false sego lily)
Calochortus kennedyi (mariposa lily)
Zephranthes longifolia (rain lily)

Linaceae (Flax Family)
Linum lewisii (perennial blue flax)
Linum puberulum (yellow flax)

Malpighiaceae
Janusia gracilis (slender janusia)

Malvaceae (Mallow/Hibiscus Family)
Abutilon palmeri (Indian mallow)
Gossypium thurberi (wild cotton)
Herissantia crispa
Hibiscus coulteri (desert rosemallow)
Hibiscus denudatus (rock hibiscus)
Sida abutifolia  (fanpetals)
Sphaeralcea ambigua (desert globemallow)

Martyniaceae (Martynia Family)
Proboscidea althaeifolia (perennial devilsclaw)
Proboscidea parviflora (annual devilsclaw)
 

Proboscidea altheifolia	Proboscidea parviflora

Mentzeliaceae (Mentzelia Family)
Mentzelia multiflora

Moraceae (Mulberry Family)
Morus microphylla (Arizona  mulberry)

Nyctaginaceae (Four O'Clock Family)
Allionia incarnata (trailing four o'clock)
Boerhavia coccinea (scarlet spiderling)
Boerhavia scandens (climbing wartclub)
Boerhavia spicata (creeping spiderling)
Mirabilis bigelovii (desert wishbone bush)
Mirabilis linearis (narrow-leaf four o’clock)

Oleaceae (Olive Family)
Fraxinus velutina (velvet ash)
Menodora scabra (rough menodora)

Onagraceae (Evening Primrose Family)
Epilobium canum (hummingbird trumpet)
Oenothera elata (tall evening primrose)
Oenothera primiveris (desert evening primrose)

Orobanchaceae (Broomrape Family)
Castilleja tenuiflora (Santa Catalina Indian paintbrush)
Orobanche cooperi (desert broomrape)

Orobanche cooperi

Oxalidaceae (Wood Sorrel Family)
Oxalis drummondii (drummond woodsorrel)
*Oxalis stricta (wood sorrel)

Papaveraceae (Poppy Family)
Argemone pleiacantha (prickly poppy)
Eschscholzia californica (Mexican goldpoppy)

Phytolaccaceae (Pokeweed Family)
Rivina humilis (pigeonberry)

Plantaginaceae (Plantain Family)
Plantago patagonica (woolly plantain)

Polemoniaceae (Phlox Family)
Gilia flavocincta
Ipomopsis longiflora (angel trumpet)

Polygalaceae (Milkwort Family)
Polygala alba (white milkwort)
Polygala barbeyana (blue milkwort)
Polygala macradenia (desert milkwort)

Polygonaceae (Knotweed Family)
*Rumex crispus (curly dock)

Portulacaceae (Purslane Family)
Portulaca suffrutescens

Ranunculaceae (Buttercup Family)
Anemone tuberosa (desert anemone)
Clematis drummondii (traveller's joy)
Delphinium parishii (pale larkspur)
Delphinium scaposum (desert larkspur)

Rhamnaceae (Buckthorn Family)
Condalia warnockii (snakewood, bitter condalia)
Sageretia wrightii (mock buckthorn)
Zizyphus obtusifolia (graythorn)

Sageretia wrightii

Rosaceae (Rose Family)
PHOTOS:  Rockmat
Cercocarpus breviflora (mountain mahogany)
Cowania mexicana (cliffrose)
Petrophytum caespitosum (rockmat)
Vauquelinia californica (Arizona rosewood)
*Pyracantha sp. (Firethorn) [single plant in ash grove in granite wash]

Rubiaceae (Madder Family)
Bouvardia ternifolia (trumpetilla)
Houstonia rubra (bluets)

Rutaceae (Rue Family)
Thamnosma texana (desert rue)

Thamnosma texana

Salicaceae (Willow Family)
Populus fremontii (Fremont cottonwood)
Salix exigua (coyote willow)

Sapindaceae (Soapberry Family)
Dodonaea viscosa (hopbush)
Sapindus saponaria var. drummondii (soapberry)

Saxifragaceae (Saxifrage Family)
Heuchera sanguinea (coral bells)

Scrophulariaceae (Snapdragon Family)
Maurandella antirrhiniflora (climbing snapdragon)
Mimulus guttatus (yellow monkeyflower)
Nuttallanthus texanus (toadflax)
Penstemon parryi (Parry penstemon)

Solanaceae (Nightshade Family)
Chamaesaracha sordida (velvet five-eyes)
Chamaesaracha coronopus (greenleaf five-eyes)
Datura discolor
Datura wrightii (sacred datura)
Lycium andersonii (Anderson wolfberry)
Lycium pallidum (pale wolfberry)
Nicotiana obtusifolia (desert tobacco)
*Nicotiana glauca (tree tobacco)
*Physalis philadelphica (tomatillo)
Solanum elaeagnifolium (silverleaf nightshade)

Sterculiaceae (Cacao Family)
Ayenia compacta
Ayenia filiformis

Tamaricaceae (Tamarisk Family)
*Tamarix chinensis (tamarisk, saltcedar) [cow tank]

Ulmaceae (Elm Family)
Celtis laevigata (canyon hackberry)
Celtis pallida (desert hackberry)

Verbenaceae (Verbena Family)
Aloysia wrightii (Wright's beebrush)
Verbena goodingii (Gooding's verbena)
Verbena neomexicana (New Mexico vervain)

Viscaceae (Mistletoe Family)
Phoradendron californicum (mistletoe)
Phoradendron flavescens (oak mistletoe)
Phoradendron juniperinum (juniper mistletoe)

Vitaceae (Grape Family)
Vitis arizonica (canyon grape)

Zygophyllaceae (Caltrop Family)
Kallistroemia grandiflora (caltrop poppy)
Larrea tridentata (creosote bush, greasewood)
Tribulus terrestris (puncture vine)

GRASSES, SEDGES, & RUSHES
Poaceae (Grass Family)
Aristida divaricata (poverty threeawn)
Aristida purpurea (purple threeawn)
*Avena fatua (wild oats)
Bothriochloa barbinodis (cane beardgrass)
Bouteloua aristidoides (needle grama)
Bouteloua curtipendula (sideoats grama)
Bouteloua eriopoda (black grama)
Bouteloua filiformis (slender grama)
Bouteloua chondrosioides (sprucetop grama)
Bouteloua hirsuta (hairy grama)
Bouteloua rothrockii (chuchillo)
Cenchrus spinifex (= C. incertus) (coastal sandbur)
Chloris virgata (feather fingergrass)
*Cynodon dactylon (Bermuda grass)
Digitaria californica (cottontop)
Dasyochloa pulchella (fluffgrass)
*Eragrostis cilianensis (stinkgrass)
*Eragrostis lehmanniana (Lehmann lovegrass)
Heteropogon contortus (tanglehead)
Hordeum arizonica (foxtail barley)
Muhlenbergia repens (aparejo grass)
Panicum arizonicum (Arizona panic grass)
Pleuraphis mutica (tobosa)
Setaria macrostachya (plains bristlegrass)
Sporobolus wrightii (big sacaton)