Bloomer's Ricegrass: Eriocoma bloomeri (Synonyms: Achnatherum xbloomeri, Achnatherum hymenoides x occidentale, Oryzopsis bloomeri, Stipa bloomeri, Stiporyzopsis xbloomeri)
Henderson's Needlegrass, Henderson's Ricegrass: Eriocoma hendersonii (Synonyms: Achnatherum hendersonii, Oryzopsis hendersonii, Stipa hendersonii)
Indian Ricegrass: Eriocoma hymenoides (Synonyms: Achnatherum hymenoides, Oryzopsis cuspidata, Oryzopsis hymenoides, Stipa hymenoides)
Lemmon's Needlegrass: Eriocoma lemmonii ssp. lemmonii (Synonyms: Achnatherum lemmonii ssp. lemmonii, Achnatherum lemmoni var. lemmonii, Stipa coumbiana, Stipa columbiana var. columbiana, Stipa lemmonii var. jonesii, Stipa lemmonii var. lemmonii)
Letterman's Needlegrass: Achnatherum lettermanii (Synonyms: Stipa lettermanii, Stipa minor, Stipa occidentalis var. minor) ?
Dore's Needlegras: Eriocoma nelsonii ssp. dorei (Synonyms: Achnatherum nelsonii ssp. dorei, Stipa nelsonii var. dorei, Stipa nelsonii ssp. dorei)
Columbia Needlegrass, Nelson's Needlegrass: Eriocoma nelsonii ssp. nelsonii (Synonyms: Achnatherum nelsonii ssp. nelsonii, Stipa columbiana var. nelsonii, Stipa nelsonii ssp. nelsonii, Stipa nelsonii var. nelsonii, Stipa occidentalis, Stipa occidentalis var. nelsonii, Stipa williamsii)
Nevada Needlegrass: Eriocoma nevadensis (Synonyms: Achnatherum nevadense, Stipa nevadensis)
California Needlegrass: Eriocoma occidentalis sp. californica (Synonyms: Achnatherum occidentale ssp. californicum, Stipa californica, Stipa occidentalis var. occidentalis)
Common Western Needlegrass, Pubescent Western Needlegrass: Eriocoma occidentalis ssp. pubescens (Synonyms: Achnatherum occidentale ssp. pubescens, Stipa elmeri, Stipa occidentalis var. pubescens)
Pine Needlegrass: Eriocoma pinetorum (Synonyms: Achnatherum pinetorum, Stipa pinetorum)
Richardson's Needlegrass: Eriocoma richardsonii (Synonyms: Achnatherum richardsonii, Stipa richardsonii)
Thurber's Needlegrass: Eriocoma thurberiana (Synonyms: Achnatherum thurberianum, Stipa thurberiana)
Wallowa Ricegrass: Eriocoma wallowaensis (Synonym: Achnatherum wallowaense)
Webber's Needlegrass: Eriocoma webberi (Synonyms: Achnatherum webberi, Oryzopsis webberi, Stipa webberi)
Giant Feather Grass: Celtica gigantea (Synonym: Stipa gigantea) - Non-native. I'm not sure if this is invasive or not, but it may occasionally be found at old homesites.
Needle-and-thread, Needle and Thread: Hesperostipa comata (Synonyms: Stipa comata, Stipa comata var. comata, Stipa comata var. intosa)
Desert Needlegrass: Pappostipa speciosa (Synonyms: Achnatherum speciosum, Stipa speciosa)