In their chapter on man-made habitats Ron Porley and Nick Hodgetts note ageing motor vehicles as “perhaps the most bizarre bryophyte habitat”, and that a few species may well accumulate in the small spaces where water gathers. They particularly note an old Morris Traveller which had a famed bryoflora; our Honda Civic may not have quite as diverse a selection of species, but since our car is twenty years old next year it is worth recording the small community of mosses that have come to call it home.
There are two small cushions that sit neatly where the rain gathers at the base of the front windscreen. Both are common mosses that are obviously good at colonising places that little else can get a toe-hold. The first is very distinctive. It is Bryum argenteum, which has almost cylindrical shoots less than a centimetre tall, and with silvery-white leaf tips. It can also be found on railways, paths, walls and roads since it is quite tolerant of pollution; indeed, a particularly fine (and enormous) colony of it is on the wall of Kings Cross station in York Way.
Its cousin on the Honda is in the same genus, Bryum capillare. It too grows in a wide variety of places so it isn’t surprising to see it catching a lift on a car. It is also quite a small plant, less than a centimetre tall, with tongue-shaped leaves which have a short recurrent point. When dry, the whole plant twists so it looks somewhat different.
Porley and Hodgetts also note that Bryum dichotomum (aka Bryum bicolor) and Ceratodon purpureus are also common inhabitants of cars. It would be interesting to see how long it takes for different species to start to colonise. So, if you see me in a car park peering closely at the vehicles, chances are I’ll be looking to see what they’re growing.
 Porley, Ron and Nick Hodgetts. Mosses and Liverworts. London: Collins, 2005. 126. The New Naturalist Library.