Weed of the month: January 2017

COMMON STORKS BILL

(Erodium cicutarium)

(Photos: E. Cousins, plant, close-up of flower; Cape Jervis. http://www.cabi.org/isc/datasheet/21843 ripe fruit )

Shin high, with deeply divided leaves, this weed loves disturbed or arid sites. There it will outcompete native plants. The annual weed has a rosette of deep green leaves at the base, which might produce a bit of stem as it grows older.  From the basal leaf rosette, slender stalks grow, supporting a small cluster of flowers. The flowers are 5-petalled and pink, each petal roughly elliptic in shape, 4-6mm long.

It is the long seed pods though that give the plant its common name. These grow as a ‘beak’ 3-4 cm long. As they ripen and dry, they twist to produce the corkscrew seen in the photo on the right. At this stage the feathery seeds are released into the air. Another Erodium, with the common name of Long Storks Bill, produces a beak up to 10cm long!

Plant of the month: January 2017

AUSTRALIAN BROOMRAPE

(Orobanche cernua var. australiana)

(Photos: E. Cousins, a single stem, close-up of a flower head; Cape Jervis)

When we saw these at Cape Jervis in early December, the plants were just starting to set seed, in what looked like little parcels of fine brown grit. Looking at the stem in the first photo, you can imagine what the plant looks like before the flowers appear: an asparagus stalk! Unlike asparagus though, these stems are covered in tubular purple flowers, each with leaves at their base (those brown flaps). Notice there is no green at all in the plant (stem, flowers OR leaves)! This isn’t because it is an old plant or anything, but because the plant is parasitic, relying on nearby plants for food. Although rare in SA, the patches we found were healthy and fairly extensive. Maybe this is because the adjacent Senecio host plants were also abundant and flourishing this year, after all those early rains!!