| Name | Children | Media (from resource) | Traits |
|---|---|---|---|
| Xiphias | 1 | 0 | 0 |
| Xiphias gladius Linnaeus 1758 (Broadbill Swordfish) | 0 | 0 | 1 |
| Xiphiidae (swordfishes) | 1 | 0 | 0 |
| Xyala Cobb 1920 | 2 | 0 | 0 |
| Xyala imparis Boucher & Helléouët 1977 | 0 | 0 | 1 |
| Xyala striata Cobb 1920 | 0 | 0 | 1 |
| Xyalidae Chitwood 1951 | 1 | 0 | 0 |
| Xylaria | 1 | 0 | 0 |
| Xylaria hypoxylon (L.) Grev. 1824 (Candle-snuff Fungus) | 0 | 0 | 1 |
| Xylariaceae | 1 | 0 | 0 |
| Xylariales | 2 | 0 | 0 |
| Xylophaga W. Turton 1822 | 2 | 0 | 0 |
| Xylophaga dorsalis (W. Turton 1819) (wood piddock) | 0 | 0 | 1 |
| Xylophaga praestans E. A. Smith 1903 | 0 | 0 | 1 |
| Xysticus | 1 | 0 | 0 |
