I haven't made the search function yet, but here's a list of plants that are on the website so far.
Abutilon theophtrasti
Acer negundo
Alhagi maurorum
Amaranthus
Argemone pleiacantha
Artemisia bigelovii
Artemisia filifolia
Asclepias subverticillata
Astragalus lentiginosus
Atriplex canescens
Bassia scoparia
Berberis
Bouteloua gracilis
Bryum argenteum
Capsella bursa-pastoris
Castilleja
Celtis reticulata
Chaetopappa ericoides
Chamaebatiara millefolium
Chamaesaracha coronopus
Chenopodium
Chorispora tenella
Convolvulus arvensis
Cryptantha sensu-lato
Cucurbita
Cylindropuntia whipplei
Cymopterus
Datura
Descurainia pinnata
Descurainia sophia
Dimorphocarpa
Dysphania
Dyssodia papposa
Elaeagnus angustifolia
Ephedra
Ericameria nauseosa
Erigeron canadensis
Erigeron divergens
Erodium cicutarium
Euphorbia
Fallugia paradoxa
Forestiera pubescens
Gaillardia
Glandularia
Grimmia
Gutierrezia
Heterotheca
Hopia obtusa
Houstonia rubra
Hymenothrix
Ipomopsis longiflora
Juglans
Juniperus monosperma
Kallstroemia parviflora
Krascheninnikovia lanata
Lactuca serriola
Lamium amplexicaule
Lycium pallidum
Machaeranthera tanacetifolia
Malva neglecta
Mannia californica
Marrubium vulgare
Medicago lupulina
Melilotus albus
Mentzelia
Mirabilis linearis
Mirabilis multiflora
Morus alba
Myriopteris gracilis
Notholaena standleyi
Oenothera
Oenothera curtiflora
Opuntia
Oxalis
Parthenocissus quinquefolia
Pectis
Pellaea truncata
Physalis longifolia
Plantago lanceolata
Plantago major
Plantago patagonica
Populus fremontii
Portulaca oleracea
Purshia stansburyana
Ribes
Rumex
Salix exigua
Salsola
Sanvitalia abertii
Senecio flaccidus
Sisymbrium irio
Solanum elaeagnifolium
Solanum jamesii
Sphaeralcea ambigua
Sphaeralcea coccinea
Sphaeralcea hastulata
Sphaeralcea leptophylla
Stanleya pinnata
Stellaria
Stephanomeria pauciflora
Syntrichia
Tamarix
Taraxacum
Tortula
Tradescantia occidentalis
Tragopogon dubius
Tribulus terrestris
Trifolium repens
Ulmus pumila
Verbascum thapsus
Verbena
Verbesina encelioides
Vesper
Vitis arizonica
Woodsia cochisensis
Xanthisma spinulosum
Xanthium strumarium
Yucca
Zinnia grandiflora