KNOTTY-BUTT PASPALIDUM

(Setaria constricta)

(Photo: E. Cousins, Cape Jervis; habit, stem)

This summer grass was pointed out to us by Corey Jackson (Yankalilla Council/NRM) on our site at Cape Jervis. Why knotty-butt? Well, the rootstock of the grass apparently looks knotted! Why ‘constricta’? Read on! Classified as ‘near threatened’, this grass seems to be doing well this year with the extra rain and cooler temperatures. It grows as a tussock pretty low to the ground at about 20-30cm in height, with a width roughly the same. The grass blades are just 2-3mm wide. The stem bearing the seeds (the ‘inflorescence’) is only about as high as the plant, but much branched. The seeds themselves have no bristles, are about 2-3mm long and with a constriction about ¼ of the way up from the base… so take your magnifier along if you go looking for this one! Possibly a good plant for finches, wrens, and other grass-seed eating birds. Let us know if you see any birds eating the seeds!

WITCHGRASS

(Panicum capillare var. brevifolium)

(Photos: E. Cousins; growth habit, emerging flower head or inflorescence)

The mild, damp summer was kind to weeds as well our ‘good’ plants on site this year. This weedy grass was producing lots of seed when we came across it at our February working bee. It is a hairy, tufted grass…check those hairs out in the second photo! Notice also the slight purple in the plant, and the dominant midrib on the leaf. You might be able to spot all the ribbing on the stems as well. The flower head is very open and wide, at up to 40cm, with many branches. Single spikelets, each containing two flowers (one of which is fertile, the other sterile), adorn these branches. Unlike the leaves and stem, these spikelets aren’t hairy, but rough! Later, the mature flower head, full of seed, breaks off as a single structure, blowing away to spread the seed.