I’m hiding behind an ancient oak tree. It’s all gone very quiet. Then I hear a low grunt and when I peek round, five metres away on the other side of the trunk a red deer stag is carefully lowering himself into the bracken. He sits gasping for breath in the October sun.

A few minutes ago I was walking up through Queen Mother’s Copse in Richmond Park when I heard the stag roaring behind me. He emerged from the copse edge on a track in parallel with mine and I had a horrible feeling he was sizing me up as a rival. As soon as I had the opportunity I ducked behind this tree and hoped he wasn’t very bright.

I wasn’t expecting to play hide and seek with a stag today. I knew it was rutting season and I’d need to be wary of the deer but this is one nature encounter I could do without.

Feeling a bit silly I back away from the tree. I keep it between me and the stag, until I feel safe enough to turn my back and get back on the track.

I came today to try and find as many different rush species I can. Once I’ve put a safe distance between me and the over-testosteroned stags I can concentrate on finding the most promising areas of this, the largest park in London and one I don’t know very well.

Round Pen Ponds I find stretches of Soft Rush which I know well as we have some in the garden, with its smooth glossy stems and clustered fruit. After looking for some time I also spot bluish clumps of Hard Rush, which up close have round cross section leaves like the Soft Rush but are clearly ridged. Through my hand lens the tufts of egg-shaped fruits (pictured) are more loosely arranged than in the Soft Rush. Rich brown with minute but distinctive “noses”, they’re easily as glossy as conkers.

I spend another hour or so looking but just find more of the same. Then on the way back to the Roehampton Gate something catches my eye on the worn path. I’m pretty sure this is a clump of Slender or Path Sedge, with flat rather than round leaves and a flower head or inflorescence less than half the height of the clump.

I’m so busy photographing the clump that I don’t notice that there is a stag with his harem watching me. Who’d have thought rush-tracking could be so exciting.