| Name | Accession number | Synonym | Species | Habit | Locality |
|---|---|---|---|---|---|
| XX-51 | TR.HS | DEU | |||
| XX-55 | TR.HS | DEU | |||
| XYLOKASTRO | XYLOCKASTRON[126][127]; XILOCASTRO[761][946]; | TR.AE | S | GRC | |
| XZ-4 | TR.AE | W | USA | ||
| Y-10-8 | TR.AE | CHN | |||
| Y10-BINDAWARRA | AUS-25603 | TR.AE | S | AUS:South-Australia | |
| Y-1496-15 | TR.AE | W | CHN:Sichuan | ||
| Y-1781-48 | CI-12794 | TR.AE | I | USA:Maryland | |
| Y-2862 | CI-12669 | TR.AE | S | USA:Maryland | |
| Y-3231 | CI-12559 | TR.AE | W | USA:Maryland | |
| Y-405 | K-58777 | TR.AE | S | IND | |
| Y-88-3-A | PI-564766 | TR.AE | W | USA:Indiana | |
| Y-89-4034 | TR.AE | AUS:WA | |||
| Y-921716 | TR.AE | CHN | |||
| YAANZAO | YAAN-ZAO[1557]; YA-ANZAO[3499]; | TR.AE | W | CHN:Sichuan | |
| YABBA | YABRA[1451]; | TR.AE | S | AUS:Victoria | |
| YABRUDI | K-17102; | TR.DR | S | SYR | |
| YABRUDI-BAYARDI | K-17120 | JABRUDI-BAJARDI[1920]; | TR.DR | S | SYR |
| YA-CHIAO-HUNG | K-59364 | TR.AE | W | CHN | |
| YACHT | AFRC-9464 | VDH-1734-89[1478][1541][4325]; | TR.AE | W | NLD |