Longest leaf lifespan

The longest-lived leaves of all plants belong to the welwitschia (Welwitschia mirabilis), named after Austrian botanist Dr Friedrich Welwitsch who discovered the plant (looking like a "stranded octopus") in 1859 in its native Namib Desert of Namibia and Angola. Small specimens of the welwitschia have been carbon-dated to 500–600 years old, with larger examples estimated to be as much as 2,000–3,000 years old, though that requires further scientific analysis. Each plant produces only two leaves, with a mean average total leaf area of 1 m2 (10.7 sq ft), and never sheds them. Ancient individuals can sprawl out over 10 m (33 ft) in circumference.

For a long time, it was believed that welwitschia survived exclusively by absorbing moisture from fog via the stomata on its leaves, however more recent studies have suggested that tap roots (up to 3 m; 10 ft deep) and shallow hair roots on the underside of the leaves are equally integral to water collection.

Growth rate fluctuates across seasons, with an average rate of 0.2–0.5 mm per day.