# List of plant genus names with etymologies (Q–Z)

Since the first printing of Carl Linnaeus's Species Plantarum in 1753, plants have been assigned one epithet or name for their species and one name for their genus, a grouping of related species. Many of these plants are listed in Stearn's Dictionary of Plant Names for Gardeners. William Stearn (1911–2001) was one of the pre-eminent British botanists of the 20th century: a Librarian of the Royal Horticultural Society, a president of the Linnean Society and the original drafter of the International Code of Nomenclature for Cultivated Plants.
The first column below contains seed-bearing genera from Stearn and other sources as listed, excluding names with missing derivations and those names that no longer appear in more modern works, such as Plants of the World by Maarten J. M. Christenhusz (lead author), Michael F. Fay and Mark W. Chase. Plants of the World is also used for the family and order classification for each genus. The second column gives a meaning or derivation of the word, such as a language of origin. The last two columns indicate additional citations.

## Key

    Latin: = derived from Latin (otherwise Greek, except as noted)
    Ba = listed in Ross Bayton's The Gardener's Botanical
    Bu = listed in Lotte Burkhardt's Index of Eponymic Plant Names
    CS = listed in both Allen Coombes's The A to Z of Plant Names and Stearn's Dictionary of Plant Names for Gardeners
    G = listed in David Gledhill's The Names of Plants
    St = listed in Stearn's Dictionary of Plant Names for Gardeners

## Genera

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
Genera :
| Genus | Meaning or derivation | Family | Order | Ref | G |
| Quercus | Latin name | Fagaceae | Fagales | CS | G |
| Quillaja | Chilean name | Quillajaceae | Fabales | St | G |
| Ranunculus | Latin: little frog (some species are aquatic) | Ranunculaceae | Ranunculales | CS | G |
| Raphanus | Greek and Latin name | Brassicaceae | Brassicales | CS | G |
| Raphia | needle (the fruit) | Arecaceae | Arecales | St | G |
| Ravenala | Malagasy name | Strelitziaceae | Zingiberales | St | G |
| Renanthera | kidney anther (the kidney-shaped pollen-masses) | Orchidaceae | Asparagales | St | |
| Reseda | Latin name | Resedaceae | Brassicales | St | G |
| Restio | Latin: rope-maker | Restionaceae | Poales | Ba | G |
| Retama | Arabic name | Fabaceae | Fabales | St | G |
| Rhabdothamnus | rod (twiggy) bush | Gesneriaceae | Lamiales | St | G |
| Rhamnus | Greek and Latin name | Rhamnaceae | Rosales | CS | G |
| Rhaphidophora | needle-bearing (the fruit) | Araceae | Alismatales | St | G |
| Rhaphiolepis | needle scale (the bracteoles). Previously Raphiolepis. | Rosaceae | Rosales | CS | G |
| Rhaphithamnus | needle bush (the spines) | Verbenaceae | Lamiales | St | G |
| Rhapidophyllum | needle leaf (the spines at the base) | Arecaceae | Arecales | St | |
| Rhapis | needle (the leaf segments) | Arecaceae | Arecales | CS | G |
| Rheum | Greek name | Polygonaceae | Caryophyllales | CS | G |
| Rhexia | Latin name | Melastomataceae | Myrtales | St | G |
| Rhinanthus | nose flowers | Orobanchaceae | Lamiales | Ba | G |
| Rhipsalis | wicker | Cactaceae | Caryophyllales | St | G |
| Rhodanthe | rose-red flowers | Asteraceae | Asterales | Ba | G |
| Rhodanthemum | rose-red flowers | Asteraceae | Asterales | Ba | G |
| Rhodiola | little rose | Crassulaceae | Saxifragales | CS | G |
| Rhodochiton | rose-red cloak (the red calyx) | Plantaginaceae | Lamiales | CS | G |
| Rhodocoma | rose-red hair | Restionaceae | Poales | Ba | |
| Rhododendron | rose-red tree. Greek and Latin name. | Ericaceae | Ericales | CS | G |
| Rhodohypoxis | rose-red Hypoxis | Hypoxidaceae | Asparagales | CS | G |
| Rhodomyrtus | rose-red myrtle | Myrtaceae | Myrtales | St | |
| Rhodospatha | rose-red spathe | Araceae | Alismatales | St | |
| Rhodothamnus | rose-red shrub (the flowers) | Ericaceae | Ericales | St | G |
| Rhodotypos | rose-red type (the flowers) | Rosaceae | Rosales | CS | G |
| Rhoicissus | from Latin and Greek names | Vitaceae | Vitales | St | G |
| Rhombophyllum | rhomboid leaves | Aizoaceae | Caryophyllales | St | G |
| Rhopalostylis | club pillar (the spadix) | Arecaceae | Arecales | St | G |
| Rhus | Greek and Latin name | Anacardiaceae | Sapindales | CS | G |
| Rhynchelytrum | beak husk (on the flowers) | Poaceae | Poales | St | G |
| Rhyncholaelia | snout Laelia | Orchidaceae | Asparagales | Ba | |
| Rhynchosia | beak (the lower petals) | Fabaceae | Fabales | St | G |
| Rhynchostylis | beak pillar (the column of the flowers) | Orchidaceae | Asparagales | St | |
| Ribes | Arabic: acidic (the fruit). Arabic name. | Grossulariaceae | Saxifragales | CS | G |
| Ricinus | Latin: tick (the seeds) | Euphorbiaceae | Malpighiales | CS | G |
| Ripogonum | wicker knees (the many joints on the tangled stalks). Previously Rhipogonum. | Ripogonaceae | Liliales | St | G |
| Robinsonia | Daniel Defoe's Robinson Crusoe | Asteraceae | Asterales | Bu | |
| Rockinghamia | Rockingham Bay in Queensland, Australia | Euphorbiaceae | Malpighiales | Bu | |
| Romulea | Romulus of mythology | Iridaceae | Asparagales | St | G |
| Rorippa | German name | Brassicaceae | Brassicales | St | G |
| Rosa | Latin name | Rosaceae | Rosales | CS | G |
| Rosselia | Rossel Island of Papua New Guinea | Burseraceae | Sapindales | Bu | |
| Rosularia | little rosettes | Crassulaceae | Saxifragales | Ba | G |
| Rotala | wheel-like (the whorls of leaves) | Lythraceae | Myrtales | St | |
| Roupala | Guyanese name | Proteaceae | Proteales | St | |
| Rubia | Latin: red (the roots, used in dyeing) | Rubiaceae | Gentianales | St | G |
| Rubus | Latin name | Rosaceae | Rosales | CS | G |
| Rumex | Latin name | Polygonaceae | Caryophyllales | CS | G |
| Ruscus | Latin name | Asparagaceae | Asparagales | CS | G |
| Ruta | Latin name | Rutaceae | Sapindales | CS | G |
| Sabal | South American name | Arecaceae | Arecales | St | G |
| Sabazia | epithet of the god Dionysus | Asteraceae | Asterales | Bu | |
| Saccharum | sugar | Poaceae | Poales | CS | G |
| Saccolabium | baggy lip | Orchidaceae | Asparagales | St | |
| Sagina | Latin: fodder | Caryophyllaceae | Caryophyllales | CS | G |
| Sagittaria | arrow (the leaves) | Alismataceae | Alismatales | CS | G |
| Salacia | Salacia, a goddess | Celastraceae | Celastrales | Bu | |
| Salicornia | Latin: salt (-marsh) horn (the branches) | Amaranthaceae | Caryophyllales | St | G |
| Salix | Latin name | Salicaceae | Malpighiales | CS | G |
| Salpichroa | trumpet + colour (the flowers) | Solanaceae | Solanales | St | G |
| Salpiglossis | trumpet tongue (the style) | Solanaceae | Solanales | St | G |
| Salsola | Latin: salt (the habitat) | Amaranthaceae | Caryophyllales | St | G |
| Salvia | Latin name | Lamiaceae | Lamiales | CS | G |
| Samanea | South American name | Fabaceae | Fabales | St | G |
| Sambucus | Latin name | Adoxaceae | Dipsacales | CS | G |
| Samolus | Latin name | Primulaceae | Ericales | St | G |
| Sanguinaria | Latin: blood (the sap) | Papaveraceae | Ranunculales | CS | G |
| Sanguisorba | Latin: blood-absorbing (the styptic roots) | Rosaceae | Rosales | CS | G |
| Sanicula | Latin: little healer | Apiaceae | Apiales | Ba | G |
| Santalum | Greek and Latin name | Santalaceae | Santalales | St | G |
| Santolina | Latin name | Asteraceae | Asterales | CS | G |
| Sapindus | Latin: soap of India | Sapindaceae | Sapindales | St | G |
| Sapium | Latin name | Euphorbiaceae | Malpighiales | St | G |
| Saponaria | Latin: soap | Caryophyllaceae | Caryophyllales | CS | G |
| Saraca | East Indian name | Fabaceae | Fabales | St | G |
| Sarcocaulon | fleshy stems | Geraniaceae | Geraniales | St | |
| Sarcochilus | fleshy lips | Orchidaceae | Asparagales | St | |
| Sarcococca | fleshy berries | Buxaceae | Buxales | CS | G |
| Sarcostemma | fleshy garland | Apocynaceae | Gentianales | St | G |
| Saruma | anagram of Asarum | Aristolochiaceae | Piperales | Ba | |
| Sasa | Japanese name | Poaceae | Poales | CS | G |
| Sassafras | Spanish name | Lauraceae | Laurales | St | G |
| Satureja | Latin name, from Arabic | Lamiaceae | Lamiales | CS | G |
| Satyria | satyrs, mythological creatures | Ericaceae | Ericales | Bu | |
| Satyrium | Greek name; also from satyrs, mythological creatures | Orchidaceae | Asparagales | Bu | G |
| Sauromatum | lizard | Araceae | Alismatales | St | G |
| Saururus | lizard tail | Saururaceae | Piperales | St | G |
| Saxifraga | Latin: stone-breaking | Saxifragaceae | Saxifragales | CS | G |
| Scabiosa | itching | Caprifoliaceae | Dipsacales | CS | G |
| Scadoxus | umbel glory | Amaryllidaceae | Asparagales | St | G |
| Schima | shade | Theaceae | Ericales | Ba | G |
| Schinus | Greek and Latin name | Anacardiaceae | Sapindales | St | G |
| Schisandra | divided male parts (the anthers) | Schisandraceae | Austrobaileyales | CS | G |
| Schismatoglottis | divided tongue (the spathes) | Araceae | Alismatales | St | |
| Schizachyrium | split chaff | Poaceae | Poales | Ba | G |
| Schizanthus | divided flowers | Solanaceae | Solanales | St | G |
| Schizocodon | divided bell (the corollas) | Diapensiaceae | Ericales | St | |
| Schizolobium | divided lobe (the pods) | Fabaceae | Fabales | St | G |
| Schizopetalon | divided petals | Brassicaceae | Brassicales | St | G |
| Schizophragma | divided wall (the septa in the fruit) | Hydrangeaceae | Cornales | CS | G |
| Sciadopitys | umbel or parasol + pine or fir (the leaves) | Sciadopityaceae | Pinales | CS | G |
| Scilla | Greek and Latin name | Asparagaceae | Asparagales | CS | G |
| Scindapsus | Greek name | Araceae | Alismatales | St | G |
| Scirpus | Latin name | Cyperaceae | Poales | CS | G |
| Scleranthus | hard flowers | Caryophyllaceae | Caryophyllales | St | G |
| Sclerocactus | harsh cactus (the spines) | Cactaceae | Caryophyllales | St | |
| Scoliopus | bent (the flower stalks) | Liliaceae | Liliales | St | G |
| Scolopia | thorn | Salicaceae | Malpighiales | Bu | |
| Scolymus | Greek and Latin name | Asteraceae | Asterales | St | G |
| Scopelogena | high cliffs (the habitat) | Aizoaceae | Caryophyllales | Bu | |
| Scorpiurus | scorpion tail (the pods) | Fabaceae | Fabales | St | G |
| Scorzonera | Old French and Italian derivation | Asteraceae | Asterales | St | G |
| Scrophularia | Latin: scrofula | Scrophulariaceae | Lamiales | CS | G |
| Scutellaria | Latin: saucer (on the fruiting calyx) | Lamiaceae | Lamiales | CS | G |
| Scuticaria | Latin: whip (the leaves) | Orchidaceae | Asparagales | St | |
| Scyphanthus | beaker flowers | Loasaceae | Cornales | St | G |
| Scyphostegia | beaker cover | Salicaceae | Malpighiales | St | |
| Secale | Latin name | Poaceae | Poales | St | G |
| Sechium | from a West Indian name | Cucurbitaceae | Cucurbitales | St | G |
| Securidaca | Latin: axe (on the end of the pods) | Polygalaceae | Fabales | St | G |
| Securigera | Latin: axe-bearing (the pods are axe-shaped) | Fabaceae | Fabales | St | G |
| Sedum | Latin: sitting (on rocks and walls). Latin name. | Crassulaceae | Saxifragales | CS | G |
| Selago | Latin name | Scrophulariaceae | Lamiales | Ba | G |
| Selenia | Selene, a moon goddess | Brassicaceae | Brassicales | Bu | |
| Selenicereus | moon (night-blooming) Cereus | Cactaceae | Caryophyllales | St | G |
| Selenipedium | moon sandal (the lip of the flowers) | Orchidaceae | Asparagales | St | |
| Selinum | Greek name | Apiaceae | Apiales | Ba | G |
| Semele | Semele of mythology | Asparagaceae | Asparagales | St | G |
| Semiaquilegia | Latin: half Aquilegia | Ranunculaceae | Ranunculales | Ba | G |
| Semiarundinaria | Latin: half Arundinaria | Poaceae | Poales | Ba | G |
| Sempervivum | Latin: ever-living. Latin name. | Crassulaceae | Saxifragales | CS | G |
| Senecio | Latin: old man (the whitish hairs on the fruit) | Asteraceae | Asterales | CS | G |
| Senna | Arabic name | Fabaceae | Fabales | Ba | G |
| Serapias | Serapis of mythology | Orchidaceae | Asparagales | St | G |
| Sericocarpus | silky fruit | Asteraceae | Asterales | St | G |
| Serissa | East Indian name | Rubiaceae | Gentianales | St | G |
| Serratula | Latin: little saw (the leaf edges) | Asteraceae | Asterales | CS | G |
| Sesamum | Greek and Latin name, from a Semitic name | Pedaliaceae | Lamiales | St | G |
| Sesbania | from an Arabic name | Fabaceae | Fabales | St | G |
| Seseli | Greek and Latin name | Apiaceae | Apiales | St | G |
| Setaria | bristles (on the spikelet) | Poaceae | Poales | CS | G |
| Sibiraea | Siberia | Rosaceae | Rosales | St | G |
| Sicana | from a Peruvian name | Cucurbitaceae | Cucurbitales | St | |
| Sicyos | Greek and Latin name | Cucurbitaceae | Cucurbitales | St | G |
| Sida | Greek name | Malvaceae | Malvales | St | G |
| Sidalcea | from Sida and Alcea | Malvaceae | Malvales | CS | G |
| Siderasis | rusty fur (the reddish hair) | Commelinaceae | Commelinales | St | |
| Sideritis | Greek and Latin name | Lamiaceae | Lamiales | St | G |
| Sideroxylon | iron wood | Sapotaceae | Ericales | St | G |
| Siegfriedia | Siegfried, a legendary hero | Rhamnaceae | Rosales | Bu | |
| Silene | Greek name | Caryophyllaceae | Caryophyllales | CS | G |
| Silphium | Greek and Latin name | Asteraceae | Asterales | CS | G |
| Silybum | Greek name | Asteraceae | Asterales | CS | G |
| Simethis | Symaethis, one of the Naiads of Greek myth. Also Symethus. | Asphodelaceae | Asparagales | St | G |
| Sinapis | Latin name | Brassicaceae | Brassicales | St | G |
| Sinobambusa | Chinese Bambusa | Poaceae | Poales | Ba | G |
| Sinomenium | Chinese moon (the curved fruit-stone) | Menispermaceae | Ranunculales | St | G |
| Siphocampylus | tubes bending (the corollas) | Campanulaceae | Asterales | St | G |
| Sisymbrium | Greek and Latin name | Brassicaceae | Brassicales | St | G |
| Sisyrinchium | Greek name | Iridaceae | Asparagales | CS | G |
| Sium | Greek name | Apiaceae | Apiales | St | G |
| Skimmia | from a Japanese name | Rutaceae | Sapindales | CS | G |
| Smilax | Greek and Latin name | Smilacaceae | Liliales | CS | G |
| Smyrnium | myrrh-scented | Apiaceae | Apiales | CS | G |
| Solanum | Latin name | Solanaceae | Solanales | CS | G |
| Soldanella | little coin, probably (the leaves) | Primulaceae | Ericales | St | G |
| Solidago | Latin: making whole (for supposed healing properties) | Asteraceae | Asterales | CS | G |
| Sonchus | Greek and Latin name | Asteraceae | Asterales | St | G |
| Sonerila | Malabar name | Melastomataceae | Myrtales | St | |
| Sophora | from an Arabic name | Fabaceae | Fabales | CS | G |
| Sorbaria | Sorbus-like | Rosaceae | Rosales | CS | G |
| Sorbus | Latin name | Rosaceae | Rosales | CS | G |
| Sorghum | from an Italian name | Poaceae | Poales | St | G |
| Sparaxis | torn (spathes) | Iridaceae | Asparagales | St | G |
| Sparganium | ribbon (the leaves). Greek and Latin name. | Typhaceae | Poales | CS | G |
| Spartium | Greek name | Fabaceae | Fabales | CS | G |
| Spathiphyllum | spathe leaves | Araceae | Alismatales | CS | G |
| Spathodea | spathe-like (calyx) | Bignoniaceae | Lamiales | St | G |
| Spathoglottis | spathe tongue (the lip) | Orchidaceae | Asparagales | St | |
| Speirantha | spiral flowers | Asparagaceae | Asparagales | Ba | G |
| Sphaeralcea | globe (the fruit) + Alcea | Malvaceae | Malvales | CS | G |
| Spilanthes | dotted flowers (dotted with pollen) | Asteraceae | Asterales | St | G |
| Spinacia | from an Arabic and Persian name | Amaranthaceae | Caryophyllales | CS | G |
| Spiraea | Greek and Latin name | Rosaceae | Rosales | CS | G |
| Spiranthes | spiral flowers | Orchidaceae | Asparagales | St | G |
| Spondias | Greek name | Anacardiaceae | Sapindales | St | G |
| Spyridium | basket-like (calyx) | Rhamnaceae | Rosales | St | |
| Stachys | Greek and Latin name | Lamiaceae | Lamiales | CS | G |
| Stachytarpheta | spike thicket | Verbenaceae | Lamiales | St | G |
| Stachyurus | spike tail (the inflorescences) | Stachyuraceae | Crossosomatales | CS | G |
| Staphylea | clusters (of flowers) | Staphyleaceae | Crossosomatales | CS | G |
| Stelis | Greek name | Orchidaceae | Asparagales | St | |
| Stellaria | Latin: star (the flowers) | Caryophyllaceae | Caryophyllales | St | G |
| Stenandrium | narrow male parts (the stamens) | Acanthaceae | Lamiales | St | |
| Stenanthium | narrow flower (sepals and petals) | Melanthiaceae | Liliales | St | G |
| Stenocactus | narrow cactus | Cactaceae | Caryophyllales | Ba | |
| Stenocarpus | narrow fruit | Proteaceae | Proteales | St | G |
| Stenocereus | narrow Cereus | Cactaceae | Caryophyllales | Ba | |
| Stenoglottis | narrow (lip) tongue | Orchidaceae | Asparagales | St | G |
| Stenospermation | narrow seedlet | Araceae | Alismatales | St | |
| Stenotaphrum | narrow trench (on the stalks) | Poaceae | Poales | St | G |
| Stephanotis | Greek name | Apocynaceae | Gentianales | St | G |
| Sterculia | Sterquilinus of mythology | Malvaceae | Malvales | St | G |
| Stictocardia | spotted heart (-shaped leaves) | Convolvulaceae | Solanales | St | G |
| Stigmaphyllon | stigma leaves | Malpighiaceae | Malpighiales | St | G |
| Stipa | coarse fiber | Poaceae | Poales | CS | G |
| Stomatium | mouth | Aizoaceae | Caryophyllales | St | G |
| Stratiotes | Greek and Latin name | Hydrocharitaceae | Alismatales | St | G |
| Streptocarpus | twisted fruit | Gesneriaceae | Lamiales | CS | G |
| Streptopus | twisted stalks | Liliaceae | Liliales | St | G |
| Streptosolen | twisted (corolla) tubes | Solanaceae | Solanales | St | G |
| Strobilanthes | cone of flowers | Acanthaceae | Lamiales | CS | G |
| Stromanthe | bed of flowers (the inflorescences) | Marantaceae | Zingiberales | St | G |
| Strombocactus | spinning-top cactus | Cactaceae | Caryophyllales | St | G |
| Strongylodon | rounded (calyx) teeth | Fabaceae | Fabales | St | |
| Strophanthus | cord flowers | Apocynaceae | Gentianales | St | G |
| Strychnos | Greek and Latin name | Loganiaceae | Gentianales | St | G |
| Stylidium | little pillar (the style and stamens form a column) | Stylidiaceae | Asterales | St | G |
| Stylophorum | style-bearing | Papaveraceae | Ranunculales | St | G |
| Styphnolobium | harsh pod | Fabaceae | Fabales | Ba | G |
| Styrax | Greek and Latin name, from an Arabic name | Styracaceae | Ericales | CS | G |
| Succisa | truncated (the rhizome) | Caprifoliaceae | Dipsacales | CS | G |
| Swida | Czech name | Cornaceae | Cornales | St | |
| Syagrus | Latin name | Arecaceae | Arecales | Ba | G |
| Sycopsis | fig-like (the leaves) | Hamamelidaceae | Saxifragales | CS | G |
| Symphoricarpos | clusters bearing fruit | Caprifoliaceae | Dipsacales | CS | G |
| Symphyotrichum | joined hairs | Asteraceae | Asterales | Ba | |
| Symphytum | Greek and Latin name | Boraginaceae | Boraginales | CS | G |
| Symplocarpus | combination fruit (the ovaries grow together) | Araceae | Alismatales | St | G |
| Symplocos | combination (the unified stamens) | Symplocaceae | Ericales | St | G |
| Synechanthus | continuous flowers | Arecaceae | Arecales | St | |
| Syneilesis | rolling up | Asteraceae | Asterales | Ba | G |
| Syngonium | united gonads (the ovaries) | Araceae | Alismatales | St | G |
| Syringa | pipe (the stems) | Oleaceae | Lamiales | CS | G |
| Syzygium | joined | Myrtaceae | Myrtales | St | G |
| Tabebuia | Brazilian name | Bignoniaceae | Lamiales | St | G |
| Tacca | from an Indonesian name | Dioscoreaceae | Dioscoreales | St | G |
| Tagetes | Tages of mythology | Asteraceae | Asterales | CS | G |
| Taiwania | Taiwan | Cupressaceae | Pinales | St | G |
| Talinum | (unclear) | Talinaceae | Caryophyllales | Ba | G |
| Tamarindus | from an Arabic name | Fabaceae | Fabales | St | G |
| Tamarix | Latin name | Tamaricaceae | Caryophyllales | CS | G |
| Tanacetum | from a Medieval Latin name | Asteraceae | Asterales | CS | G |
| Tapeinochilos | short lip | Costaceae | Zingiberales | St | G |
| Taraxacum | from an Arabic and Persian name | Asteraceae | Asterales | St | G |
| Taxodium | Taxus-like | Cupressaceae | Pinales | CS | G |
| Taxus | Latin name | Taxaceae | Pinales | CS | G |
| Tecoma | from a Nahuatl name | Bignoniaceae | Lamiales | CS | G |
| Tectona | from a Tamil name | Lamiaceae | Lamiales | St | G |
| Telephium | Latin name; also from Telephus, a mythological king | Molluginaceae | Caryophyllales | Bu | G |
| Tellima | anagram of Mitella | Saxifragaceae | Saxifragales | CS | G |
| Telopea | distant viewing (the flowers) | Proteaceae | Proteales | CS | G |
| Telosma | distant scent | Apocynaceae | Gentianales | St | G |
| Tephrosia | ashen (the leaves) | Fabaceae | Fabales | St | G |
| Terminalia | Latin: terminal (the leaves are at the end of the shoots) | Combretaceae | Myrtales | St | G |
| Tetracentron | four spurs (on the fruit) | Trochodendraceae | Trochodendrales | St | G |
| Tetraclinis | four + bed (of leaves) | Cupressaceae | Pinales | St | G |
| Tetradium | foursome | Rutaceae | Sapindales | Ba | G |
| Tetragonia | four-angled (fruit) | Aizoaceae | Caryophyllales | CS | G |
| Tetragonolobus | four-angled pods | Fabaceae | Fabales | St | G |
| Tetranema | four threads (the stamens) | Plantaginaceae | Lamiales | St | G |
| Tetrapanax | four (-petalled) Panax | Araliaceae | Apiales | CS | G |
| Tetrastigma | four-part stigma | Vitaceae | Vitales | Ba | G |
| Tetratheca | four boxes (the anthers) | Elaeocarpaceae | Oxalidales | St | G |
| Teucrium | Greek and Latin name | Lamiaceae | Lamiales | CS | G |
| Thalassia | Thalassa, a sea divinity | Hydrocharitaceae | Alismatales | Bu | G |
| Thalassodendron | Thalassa (a sea divinity) + tree | Cymodoceaceae | Alismatales | Bu | G |
| Thalictrum | Greek and Latin name | Ranunculaceae | Ranunculales | CS | G |
| Thamnocalamus | shrubby reed | Poaceae | Poales | Ba | G |
| Thaumasianthes | Thaumas, a god | Loranthaceae | Santalales | Bu | G |
| Thelesperma | nippled seeds | Asteraceae | Asterales | St | G |
| Thelocactus | nippled cactus | Cactaceae | Caryophyllales | St | G |
| Theobroma | god food | Malvaceae | Malvales | St | G |
| Thermopsis | lupin-like | Fabaceae | Fabales | CS | G |
| Thesium | Latin name | Santalaceae | Santalales | Bu | G |
| Thespesia | holy | Malvaceae | Malvales | St | G |
| Thladiantha | eunuch (staminode) flowers | Cucurbitaceae | Cucurbitales | St | G |
| Thlaspi | Greek and Latin name | Brassicaceae | Brassicales | St | G |
| Thrinax | trident | Arecaceae | Arecales | St | G |
| Thuja | Greek name | Cupressaceae | Pinales | CS | G |
| Thujopsis | Thuja-like | Cupressaceae | Pinales | CS | G |
| Thymus | Greek and Latin name | Lamiaceae | Lamiales | CS | G |
| Thysanotus | fringed (flowers) | Asparagaceae | Asparagales | St | G |
| Tiarella | little crown (the fruit) | Saxifragaceae | Saxifragales | CS | G |
| Tibouchina | from a Guianese name | Melastomataceae | Myrtales | St | G |
| Tigridia | Latin: tiger (flowers) | Iridaceae | Asparagales | CS | G |
| Tilia | Latin name | Malvaceae | Malvales | CS | G |
| Tipuana | from a South American name | Fabaceae | Fabales | St | G |
| Titanopsis | Titan (Helios) of mythology | Aizoaceae | Caryophyllales | St | G |
| Tithonia | Tithonus | Asteraceae | Asterales | St | G |
| Tococa | Guyanese name | Melastomataceae | Myrtales | St | G |
| Tolumnia | Tolumnia, a nymph | Orchidaceae | Asparagales | Bu | G |
| Toona | Sanskrit name | Meliaceae | Sapindales | Ba | G |
| Trachelium | neck | Campanulaceae | Asterales | St | G |
| Trachelospermum | neck (-shaped) seeds | Apocynaceae | Gentianales | CS | G |
| Trachycarpus | rough fruit | Arecaceae | Arecales | CS | G |
| Trachymene | rough membrane (on the fruits) | Apiaceae | Apiales | St | G |
| Trachystemon | rough stamens | Boraginaceae | Boraginales | CS | G |
| Tragopogon | goat beard (the silk) | Asteraceae | Asterales | St | G |
| Trapa | Latin: from caltrop (the four-pointed fruit) | Lythraceae | Myrtales | St | G |
| Trichilia | three-part (ovary) | Meliaceae | Sapindales | St | G |
| Trichodiadema | hairy crowns | Aizoaceae | Caryophyllales | St | G |
| Tricholaena | hairy cloak (on the spikelets) | Poaceae | Poales | St | G |
| Trichopilia | hairy cap (on the anthers) | Orchidaceae | Asparagales | St | G |
| Trichosanthes | hairy (fringed) flowers | Cucurbitaceae | Cucurbitales | St | G |
| Trichostema | hair-like stamens | Lamiaceae | Lamiales | St | G |
| Tricyrtis | three swellings (the red nectaries below the petals) | Liliaceae | Liliales | CS | G |
| Tridax | Greek and Latin name | Asteraceae | Asterales | St | G |
| Trifolium | three leaflets. Latin name. | Fabaceae | Fabales | CS | G |
| Trigonella | little three-cornered (flowers) | Fabaceae | Fabales | St | G |
| Trilisa | anagram of Liatris | Asteraceae | Asterales | St | G |
| Trillium | three (-leaved) Lilium | Melanthiaceae | Liliales | CS | G |
| Triosteum | three bones (the hard seeds) | Caprifoliaceae | Dipsacales | St | G |
| Triphasia | triple (the flower parts) | Rutaceae | Sapindales | St | G |
| Triplaris | triple (the flower parts) | Polygonaceae | Caryophyllales | St | G |
| Tripleurospermum | three-ribbed seeds (the achenes) | Asteraceae | Asterales | St | G |
| Tripogandra | three bearded male parts (the longer stamens) | Commelinaceae | Commelinales | St | G |
| Tripterygium | three wings (on the fruit) | Celastraceae | Celastrales | St | G |
| Trisetum | three bristles | Poaceae | Poales | St | G |
| Tristagma | three drops (the nectaries) | Amaryllidaceae | Asparagales | CS | G |
| Triteleia | triple-complete. Previously Tritelaia. | Asparagaceae | Asparagales | Ba | G |
| Trithrinax | three tridents (the leaves) | Arecaceae | Arecales | St | G |
| Triticum | Latin name | Poaceae | Poales | St | G |
| Tritonia | Latin: weather vane (a metaphor for the diverse stamens) | Iridaceae | Asparagales | CS | G |
| Tritoniopsis | Tritonia-like | Iridaceae | Asparagales | Bu | G |
| Trochodendron | wheel (appearance of the stamens) + tree | Trochodendraceae | Trochodendrales | CS | G |
| Trollius | from a Swiss German name | Ranunculaceae | Ranunculales | CS | G |
| Tropaeolum | trophy | Tropaeolaceae | Brassicales | CS | G |
| Tsuga | from a Japanese name | Pinaceae | Pinales | CS | G |
| Tuberaria | tuber-like (the thick roots) | Cistaceae | Malvales | St | G |
| Tulipa | Turkish: turban | Liliaceae | Liliales | CS | G |
| Tussilago | (remedy for) coughing | Asteraceae | Asterales | St | G |
| Typha | Greek and Latin name | Typhaceae | Poales | CS | G |
| Typhonium | Typhon, a mythological monster | Araceae | Alismatales | Bu | G |
| Ugni | Mapuche name | Myrtaceae | Myrtales | Ba | G |
| Ulex | Latin name | Fabaceae | Fabales | CS | G |
| Ullucus | Peruvian name | Basellaceae | Caryophyllales | St | G |
| Ulmus | Latin name | Ulmaceae | Rosales | CS | G |
| Umbellularia | Latin: little umbels | Lauraceae | Laurales | CS | G |
| Umbilicus | Latin: navels (in the leaves) | Crassulaceae | Saxifragales | CS | G |
| Uniola | Latin name | Poaceae | Poales | St | G |
| Unxia | epithet of the goddess Juno | Asteraceae | Asterales | Bu | |
| Urceolina | Latin: little pitcher (the flowers) | Amaryllidaceae | Asparagales | St | G |
| Urera | Latin: stinging | Urticaceae | Rosales | St | G |
| Urtica | Latin name | Urticaceae | Rosales | St | G |
| Utricularia | Latin: little bottles (that trap insects) | Lentibulariaceae | Lamiales | St | G |
| Uvaria | Latin: like a bunch of grapes | Annonaceae | Magnoliales | St | G |
| Uvularia | Latin: uvula (a metaphor for the hanging flowers) | Colchicaceae | Liliales | CS | G |
| Vaccaria | Latin: cow, possibly | Caryophyllaceae | Caryophyllales | St | G |
| Vaccinium | Latin name | Ericaceae | Ericales | CS | G |
| Valeriana | Medieval Latin name | Caprifoliaceae | Dipsacales | CS | G |
| Valerianella | Latin: little Valeriana | Caprifoliaceae | Dipsacales | St | G |
| Vallaris | Latin: fence stakes (which they sometimes grow on) | Apocynaceae | Gentianales | St | G |
| Vanda | from a Sanskrit name | Orchidaceae | Asparagales | St | G |
| Vandopsis | Vanda-like | Orchidaceae | Asparagales | St | G |
| Vanilla | Spanish name, derived from Latin: vagina (sheath), for the pods | Orchidaceae | Asparagales | St | G |
| Veratrum | Latin: true black (the roots) | Melanthiaceae | Liliales | CS | G |
| Verbascum | Latin name | Scrophulariaceae | Lamiales | CS | G |
| Verbena | Latin: ceremonial plant | Verbenaceae | Lamiales | CS | G |
| Verbesina | Latin: like Verbena | Asteraceae | Asterales | CS | G |
| Verticordia | Latin: turner of hearts (an epithet of Venus of mythology) | Myrtaceae | Myrtales | St | G |
| Viburnum | Latin name | Adoxaceae | Dipsacales | CS | G |
| Vicia | Latin: binding (the tendrils). Latin name. | Fabaceae | Fabales | CS | G |
| Vinca | Latin: winding around. Latin name. | Apocynaceae | Gentianales | CS | G |
| Vincetoxicum | Latin: conquering poison | Apocynaceae | Gentianales | St | G |
| Viola | Latin name | Violaceae | Malpighiales | CS | G |
| Viscum | Latin name | Santalaceae | Santalales | St | G |
| Vitex | Latin name | Lamiaceae | Lamiales | CS | G |
| Vitis | Latin name | Vitaceae | Vitales | CS | G |
| Wollemia | Wollemi National Park in Australia | Araucariaceae | Pinales | Ba | G |
| Xantheranthemum | yellow Eranthemum | Acanthaceae | Lamiales | St | G |
| Xanthisma | yellow (flowers) | Asteraceae | Asterales | CS | G |
| Xanthoceras | yellow horn (the glands between the petals) | Sapindaceae | Sapindales | CS | G |
| Xanthocyparis | yellow cypress | Cupressaceae | Pinales | Ba | G |
| Xanthorhiza | yellow root | Ranunculaceae | Ranunculales | CS | G |
| Xanthorrhoea | yellow sap | Asphodelaceae | Asparagales | St | G |
| Xanthosoma | yellow body | Araceae | Alismatales | St | G |
| Xeranthemum | (long-lasting) dry flowers | Asteraceae | Asterales | St | G |
| Xerochrysum | dry gold | Asteraceae | Asterales | Ba | |
| Xerophyllum | dry leaves | Melanthiaceae | Liliales | CS | G |
| Xylobium | wood-life (they are epiphytes) | Orchidaceae | Asparagales | St | G |
| Yucca | Caribbean name | Asparagaceae | Asparagales | CS | G |
| Yushania | Yu Shan | Poaceae | Poales | CS | |
| Zamia | from a Latin name | Zamiaceae | Cycadales | CS | G |
| Zamioculcas | Zamia + Arabic name | Araceae | Alismatales | Ba | G |
| Zanthoxylum | yellow wood | Rutaceae | Sapindales | St | G |
| Zea | Greek and Latin name | Poaceae | Poales | CS | G |
| Zelkova | from a Georgian name | Ulmaceae | Rosales | CS | G |
| Zemisia | Zemi, ancestral spirits of the Taíno | Asteraceae | Asterales | Bu | |
| Zephyra | Zephyrus, a god | Tecophilaeaceae | Asparagales | Bu | G |
| Zephyranthes | western flower | Amaryllidaceae | Asparagales | CS | G |
| Zigadenus | yoked glands (in pairs) | Melanthiaceae | Liliales | St | G |
| Zingiber | Greek and Latin name, from a Sanskrit name | Zingiberaceae | Zingiberales | St | G |
| Zizania | Greek and Latin name | Poaceae | Poales | St | G |
| Ziziphus | Greek and Latin name, from a Persian name | Rhamnaceae | Rosales | St | G |
| Zygopetalum | yoked petals | Orchidaceae | Asparagales | St | G |