Ferns and Fern Allies in the Canberra Region
Pleurosorus rutifolius - Blanket Fern
Pleurosorus rutifolius is a very small fern that lives among rocks on the dry hillsides near Canberra. It is exceptionally drought hardy and survives where only two or three other, equally xeriphytic ferns can.
The fronds are usually no more than 6cm (2.4") in length and are
frequently less than half that size. The pinnae are covered thickly
with hairs. This plant was growing among rocks in grassland under a
sparse tree cover, on a north-facing (sunny) Bush hillside in inner
Canberra. There were several other examples growing in the same area.
It is always found in rock crevices. The fern is reported to be easy
to grow but dislikes too much water and humidity!
A closely related species, Pleurosorus subglandulosus, reported in the Canberra region, but not previously in the Australian Capital Territory, has just turned up in the Molonglo Gorge in the dry north eastern quarter of the Territory. (See a description of a walk up the gorge during which I found the first specimen - on the trips page, soon.). There is debate as to whether it is a distinct species from P. rutifolius. The distinguishing feature is that the tiny hairs covering both sides of the pinnae in both species are tipped with small glands in the case of P. subglandulosus but not with P. rutifolius. In reality, the latter does show some glandular tipped hairs, hence the debate. I collected the specimen because it "looked slightly different" from the other P. rutifolius plants growing nearby (where they are quite common). This doesn't prove anything, of course, as the variation may just be caused by the immediate microclimate. But it does show how a simple hunch can find new species.