Plant of the Month – May 2016

BUCKBUSH or ROLYPOLY

(Salsola australis)

p1   p2(Photo: E. Cousins, Cape Jervis; plant, close-up of a flower on a ridged stem)

This prickly little flowering annual can grow into a ball about knee high, bright green where a lot of the local plants are a duller colour. The hard stems are really ridged, as seen in the second photo. There you can also see the needle-like tips on the small, cylindrical leaves, making the plant feel spiky. Notice also the papery, cream disk there too? That is a fruit. It has a flattened wing all around, with 5 lobes; the fruit is protected by 3 leaves under it. The plant can break off at ground level and blow away like tumbleweed, dispersing the seeds in the fruit. These seeds then germinate from autumn to winter, with new plants flowering in spring-summer. Earlier called Salsola tragus, buckthorn has been renamed Salsola australis after some detective work by SA Herbarium experts. ‘Salsola’ itself is from the Latin word for ‘salty’.