The forecast had promised warm spring sunshine – ideal weather for a forest bathing class. Instead, a squally shower arrived without warning, and we ended up hugging tree trunks more out of necessity than mindfulness. In full leaf, the mature beech grove canopy would have kept us dry, but this early in the season, the leaves had only just unfurled, letting the rain through to saturate my jumper. For a while, we listened in silence as the foliage changed its voice, a dry whisper deepening into a steady, percussive patter.

Thankfully, the downpour passed as quickly as it had arrived. Light filtered through the leaves, and we drifted back along the path until the trees opened into a small clearing. The instructor suggested that we sit on a semi-circle of fallen trunks, urging us to feel the texture of the rough-stalked feather moss (Brachythecium rutabulum) cushioning our makeshift benches. Flasks were passed around, the nettle and chamomile tea offering a welcome warmth.

The woman beside me lifted her hat from her lap and paused, peering into its shallow crown. There was a cucumber spider inside. Its abdomen was just 5mm long but an eye-catching yellowish-green, with a conspicuous red mark just below the spinnerets.

Five species occur in Britain, but only two are common: Araniella cucurbitina, first described in 1757 by the Swedish arachnologist Carl Alexander Clerck as Araneus cucurbitinus, before being reassigned to its current classification in 1942; and Araniella opisthographa, originally described as Araneus cucurbitinus opisthographa by the Polish arachnologist Władysław Kulczyński in 1905, then later recognised as a distinct species. They often share the same habitat, can typically only be distinguished by microscopic examination of their genitalia, and are believed to hybridise on occasion.

I offered my finger. The spider stepped from woven straw to skin. After a moment’s orientation on my knuckle, it began moving upward, tracing the contours of my hand. Clambering on to my sleeve, its colouration became startlingly vivid against the black fleece, its cryptic camouflage compromised. I coaxed it back on to my finger and gently guided it on to a low branch. In the diffuse beech light, the green was perfectly leaf-matched, the spider disappearing seamlessly into the surrounding foliage.