Corticolous and saxicolous communities

“The dull necessity of weeding arises, because every healthy plant is a racist and an imperialist; every daisy (even) wishes to establish for itself an Empire on which the sun never sets.”

(Ian Hamilton Finlay, Detached Sentences on Gardening)


It may be that of all the plants at Little Sparta, only the algal cells inside the all-pervasive lichen have no designs on this inland empire. Their fusion with fungal cells into a single organism seems entirely unbigoted, a mutually-beneficial collaboration between two distinct kingdoms of eukaryote life. But the mutualism isn’t clear-cut — it may be that the algae get nothing out of the association, and by some measures they suffer by it, algal cells dying to feed the fungal net which traps them, individual cells pierced by structures which in other fungi are the tools of unarguable parasitism. Unlike the fungal symbiont of a lichen, the algal or cyanobacterial symbiont can live independently, by photosynthesis, and often grows faster on its own than when incorporated into a lichen.

“Lichens are fungi that have discovered agriculture” – Trevor Goward.

And lichen too are imperialists. As ground cover, their secretions are thought to inhibit not only fungal growth but the germination of the seeds of higher plants, encouraging a monoculture of lichen, which nevertheless helps build the soil. They have a taste for polyester resin, so the little boat moored by Lochan Eck is not safe, and the garden’s fibreglass tortoises may one day be reduced to a mesh of inedible silica. They love rock art and sculpture equally. I thought of them as purely destructive, until I saw in Finlay’s library a copy of the minor classic Panzer Warfare: Rules For Mass-Armor Battles of WW II with Small-Scale Miniature Figures by Brian Blume (TSR Rules, 1975; price $4.00). The frontispiece:


shows a group of toy tanks, in the shade of two clumps of fruticose lichen, making shift for trees or netting. Lichen as camouflage: a well-aged garden is less susceptible to air-strikes.


As a child in the 1970s, I was very fond of Observer’s Books, the series of pocket hardbacks published by Frederick Warne & Co. I think the first one I got was the 1975 edition of the Observer’s Book of Unmanned Spaceflight, though a few, including the Observer’s Book of Cacti, have a unicorn bookplate pasted in with my name on, printed in sharp pencil on the Book of Spaceflight, tentatively joined-up and in blue pen on the Book of Cacti. I had thirty or so, almost all about nature or biology or geology — I would never have asked for the Observer’s Book of Modern Art, or of Folk Song or Jazz, though I still wonder what those books could have been like. The only one I ever received unexpectedly was the Observer’s Book of Lichens, brought home by my mother from a jumble sale, priced 30p, at a time when the new books cost £1.50 or so. I don’t think either of us knew what lichen were, but she knew I liked the books, and I remember the weird excitement of its evening arrival. I remember too the slight strangeness of the object, the design a bit different, the dust-jacket not quite uniform with the others on the shelf. I read it, of course, but there weren’t really any lichen to see in Glasgow in the 1970s, when petrol was still leaded. It felt like an exercise in the acquiring of a purely abstract knowledge, the vocabulary of thallus, isidium, soralium, lecanorine not readily transferable, though I’ve used thallus once or twice. I gave the book away many years later, when some friends took up hill-walking and became interested in the lichen they saw. I always kind of regretted this, especially as lichen started appearing closer to home (I even have lichen on my windowsill in Ancroft Street now). When I arrived at Little Sparta, I knew I needed a guide to lichen — of all the volunteer laureates of the garden, the rosebay willowherb and the piggy-back plant, only the lichen are entirely anonymous to me. I bought a copy of The Observer’s Book of Lichens on abebooks. It’s an earlier edition, from the 1960s, not as good as the 1977 one I had (which is described, in The Observer’s Book of Observer’s Books, as “The best beginner’s guide to lichens available, and one of the best nature titles in the series”). I still don’t know one lichen from another.