Plateau and other deserts are also less favourable for plant growth due to exposure to wind and other evaporating factors. Vegetation in such areas are restricted to notches and crevices. An array of hillocks and notably the arch-shaped Tuwaya Mountain range (c. 1000m) that stretches about 800 km along the central region is the main landmark of this Province. Vegetation is virtually nil on these hillocks except for a few grass species and some perennial plants. However the west facing slopes hold significant number of annuals and perennials. Wadis on the other hand, which receive additional supply of runoff water along with fine soil from the elevated places, are the real seat of the main vegetation. Acacias are the dominant group in such wadis. In depressions where the soil is composed of loam and silt, the vegetation is dominated by annuals. There are several raudhas in the region, most of which are located near sand dunes and are influenced by the vegetations of both sand-dunes and rocky habitats. Tree species are rare in the central region. Out of 70 tree species present in Saudi Arabia, the central region contains only Acacia gerrardii and A. raddiana in the wadis and a few stands of Ziziphus spina-christi, Maerua crassifolia, Moringa peregrine, Capparis decidua and Ficus spp., either in open plains or in the gullies of hillocks.
Common plants of some of the major habitats of the central region are as follows:
Valley (Wadi)
Acacia gerrardii
Acacia ehrenbergiana
Acacia tottilis
Lycium shawii
Aizoon canariense
Blepharis ciliaris
Amaranthus viridis
Arnebia hispidissima
Alkanna orientalis
Atriplex leucoclada
Conyza bonariensis
Xanthium strumarium
Tripleurospermum auriculatum
Convolvulus glomeratus
Convolvulus oxyphyllus ssp. oxycladus
Brassica tournefortii
Zilla spinosa
Cucumis prophetarum
Stipa capensis
Trigonella hamosa
Cistanche phelypaea
Rumex vesicarius
Haplophyllum tuberculatum
Scrophularia deserti
Teucrium oliverianum
Fagonia indica
Tribulus terrestris
Peganum harmala
Calotropis procera
Raudhats (Meadow)
Amaranthus graecizans
Asphodelus tenuifolius
Arnebia hispidissima
Lappula spinocarpos
Heliotropium arbainense
Bassia eriophora
Chenopodium murale
Anthemis deserti
Achillea fragrantissima
Calendula arvensis
Centaurea pseudosinaica
Filago desertorum
Ifloga spicata
Scorzonera intricata
Zoegea purpurea
Aaronsohnia factorovskyi
Urospermum picroides
Sonchus oleraceus
Reichardia tingitana
Convolvulus arvensis
Sisymbrium irio
Notoceras bicorne
Cenchrus ciliaris
Lolium rigidum
Hordeum murinum
Phalaris minor
Schismus barbatus
Trigonella anguina
Trigonella hamosa
Spergula fallax
Astragalus corrugatus
Medicago laciniata
Malva parviflora
Tripleurospermum auriculatum
Open Plains (Plateau)
Heliotropium bacciferum
Trichodesma africanum
Agriophyllum minus
Bassia muricata
Halothamnus bottae
Cornulaca monocantha
Helianthemum lippii
Salsola imbricata
Asteriscus heirochunticus
Pulicaria jaubertii
Scorzonera musillii
Convolvulus pilosellifolius
Convolvulus oxyphyllus ssp. oxycladus
Ochradenus baccatus
Farsetia aegyptiaca
Moricandia sinaica
Morettia parviflora
Diplotaxis harra
Erucaria hispanica
Capsella bursa-pastoris
Citrullus colocynthis
Chrozophora oblongifolia
Cenchrus ciliaris
Pennisetum divisum
Panicum turgidum
Senna italica (Cassia italica)
Rumex dentatus
Fagonia bruguieri
Sabkhah (Salt Pans)
Anabasis setifera
Halopeplis perfoliata
Traganum nudatum
Suaeda aegyptiaca
Aeluropus lagopoides
Tamarix nilotica
Zygophyllum simplex
Zygophyllum coccineum
Juncus rigidus
Cressa cretica
Capparis spinosa
Arthrocnemum macrostachyum
Salicornia europaea
Cyperus laevigatus
Citrullus colocynthis
Cleome amblyocarpa
Fagonia bruguieri
Peganum harmala
Phragmites australis
Imperata cylindrica
Leptochloa fusca
Sand Dunes
Moltkiopsis ciliata
Centropodia forsskalii
Cakile arabica
Savignya parviflora
Calligonum comosum
Artemisia monosperma
Cyperus conglomerates
Stipagrostis drarii
Plantago boissieri
Plantago psammophila
Scrophularia hypercifolia
Silene villosa
Savignya parviflora
Plantago ciliata
Stipagrostis plumosa
Haloxylon persicum
Anthemis deserti
Astragalus schimperi
Dipterygium glaucum
Eremobium aegyptium
Sporobolus spicatus
Mountains
Periploca aphylla
Capparis cartilaginea
Echinops spinosissimus
Erodium deserti
Lasiurus scindicus
Erodium glaucophyllum
Schimpera arabica
Avena fatua
Isatis lusitanica
Brachypodium distachyum
Hordeum murinum
Hyparrhenia hirta
Tetrapogon villosus
Lavandula pubescens
Salvia aegyptiaca
Teucrium polium
Plantago amplexicaulis
Emex spinosa
Caylusea hexagyna
Ochradenus baccatus
Themeda triandra
Mimosaceae
Mimosaceae
Mimosaceae
Solanaceae
Aizoaceae
Acanthaceae
Amaranthaceae
Boraginaceae
Boraginaceae
Chenopodiaceae
Compositae
Compositae
Compositae
Convolvulaceae
Convolvulaceae
Cruciferae
Cruciferae
Cucurbitaceae
Gramineae
Leguminosae
Orobanchaceae
Polygonaceae
Rutaceae
Scrophulariaceae
Labiatae
Zygophyllaceae
Zygophyllaceae
Zygophyllaceae
Asclepiadaceae
Amaranthaceae
Asphodelaceae
Boraginaceae
Boraginaceae
Boraginaceae
Chenopodiaceae
Chenopodiaceae
Compositae
Compositae
Compositae
Compositae
Compositae
Compositae
Compositae
Compositae
Compositae
Compositae
Compositae
Compositae
Convolvulaceae
Cruciferae
Cruciferae
Gramineae
Gramineae
Gramineae
Gramineae
Cruciferae
Papilionaceae
Papilionaceae
Papilionaceae
Papilionaceae
Papilionaceae
Malvaceae
Asteraceae
Boraginaceae
Boraginaceae
Chenopodiaceae
Chenopodiaceae
Chenopodiaceae
Chenopodiaceae
Cistaceae
Chenopodiaceae
Asteraceae
Asteraceae
Asteraceae
Convolvulaceae
Convolvulaceae
Resedaceae
Brassicaceae
Brassicaceae
Brassicaceae
Brassicaceae
Brassicaceae
Brassicaceae
Cucurbitaceae
Euphorbiaceae
Poaceae
Poaceae
Poaceae
Caesalpiniaceae
PolygonaceaeZygophyllaceae
Chenopodiaceae
Chenopodiaceae
Chenopodiaceae
Chenopodiaceae
Gramineae
Tamaricaceae
Zygophyllaceae
Zygophyllaceae
Juncaceae
Convolvulaceae
Capparaceae
Chenopodiaceae
Chenopodiaceae
Cyperaceae
Cucurbitaceae
Capparaceae
Zygophyllaceae
Zygophyllaceae
Gramineae
Gramineae
Gramineae
Boraginaceae
Poaceae
Brassicaceae
Brassicaceae
Polygonaceae
Asteraceae
Cyperaceae
Poaceae
Plantaginaceae
Plantaginaceae
Scrophulariaceae
Caryophyllaceae
Brassicaceae
Plantaginaceae
Poaceae
Chenopodiaceae
Asteraceae
Papilionaceae
Capparaceae
Brassicaceae
Poaceae
Asclepiadaceae
Capparaceae
Asteraceae
Geraniaceae
Poaceae
Geraniaceae
Brassicaceae
Poaceae
Brassicaceae
Poaceae
Poaceae
Poaceae
Poaceae
Lamiaceae
Lamiaceae
Lamiaceae
Plantaginaceae
Polygonaceae
Resedaceae
Resedaceae
Poaceae
Acacia ehrenbergiana
Rhanterium epapposum
Lycium shawii
Cenchrus ciliaris