A tiny seed – or ‘spore’, in the case of ferns – is picked up by a gust of wind and blown across campus. Its chances of surviving the journey in the concrete landscape are very slim. But this one lands in just the right place: the shady crevice of a roof above one of the entrances to the car park. Rainwater flows down the slanted roof into the crevices, allowing the spore to grow into a hart’s-tongue fern.
In and around the ‘tropical rainforest’ of the campus pond, the common blue damselfly is looking for a suitable partner
The campus pond is ‘clean’ and is full of tiny creatures. As such, it is the perfect…
The species is really quite rare, says ecologist Garry Bakker from the Rotterdam Urban Ecology Unit (Bureau Stadsnatuur). The fern is a picky plant: it needs a moist, shady and calcium-rich environment. Ordinarily, you would find them on the sides of quays and poorly maintained walls. But this slanted, paved roof beneath a shady tree offers the same conditions. Bakker explains: “Think of it as a quay wall, but on its side.”
The hart’s-tongue fern is not alone: a ‘male fern’ is growing close by, and their resemblance might give the impression that they are both ordinary ferns. But close examination reveals a clear difference: the male fern has ‘pinnate’ or serrated leaves, while the hart’s-tongue fern has strap-like leaves without indentations. Male ferns are also much easier to find: they grow on almost every Dutch forest floor.
Plants that grow in the crevices between bricks and stones often face a painful fate: the weeding sickle. But Bakker hopes that a better future awaits the hart’s tongue. “It’s natural vegetation”, he says. “Weeds is a verdict.”