Holyn Thigpen via Atlas Obscura:

‘“Oldest” is not one definitive measurement but several, depending on what type of living thing you’re looking at. Some record-holders, like Utah’s Pando, are clonal colonies, while others, such as a spruce trunk, are individual, continuously growing organisms whose age is counted directly through rings, layers, or growth bands. Still others, like deep-sea sponges, grow so slowly that their age can only be estimated. Understanding which kind of “old” you’re looking at helps explain why the ages on this list vary so widely.

• Pando Clonal quaking aspen colony 1+ million years Utah, USA
• Honey Mushrooms Fungal network 2,400 years Oregon, USA
• Old Tjikko Norway spruce 9,550 years Sweden
• King Clone Creosote colony 11,700 years California, USA
• Methuselah Tree Bristlecone pine ~4,800 years California, USA
• Prometheus Bristlecone pine ~5,000 years Nevada, USA
• Li Jiawan Grand Ginkgo King Ginkgo ~4,000 years China
• Fortingall Yew Yew 2,000–5,000 years Scotland
• Llangernyw Yew Yew 4,000–5,000 years Wales
• Volcano Sponge Sponge ~15,000 years Antarctica
• Black coral Coral colony 4,000+ years New Zealand…’