Annual herb, up to 320 mm high. Stems usually very short. Leaves usually congested in a basal rosette, bipinnate to pinnate. Flower head usually discoid (containing only disc florets), rarely disciform (containing a few filiform florets), peduncles 8-180 mm long; bracts in 2 or 3 series, multi to single-nerved. Receptacle flat to conical. Filiform florets (if present) in the outermost series, never a complete series. Disc florets yellow or white, 4-lobed. Fruits formed from the disc florets with swelling usually present at the base, sometimes extending upwards or covering the entire inner face. Flowering time is midwinter to late spring (July to October).

Cotula barbata can be confused with many other discoid species of Cotula because it can occur in both white and yellow forms. The yellow-flowered form can be confused with C. thunbergii, C. pedicellata and C. tuberculata. It differs from C. thunbergii in that C. barbata has ovate outer bracts whereas C. thunbergii has lanceolate to narrowly ovate outer bracts. C. barbata also lacks a basal skirt (swelling at the end of the disc floret) that is present in C. thunbergii. Cotula barbata differs from C. pedicellata in that C. barbata usually has basal swelling on the disc fruit that sometimes extends upwards or covering in the entire inner face of the disc fruit or it can lack swellings completely whereas in C. pedicellata, the swellings on present at both the apical and basal poles of the disc fruit. Cotula barbata differs from C. tuberculata in that C. barbata the disc fruits are smooth whereas in C. tuberculata, it has protruding tubercules. The yellow-flowered form could also be confused with the discoid species found in the Eastern Cape and Kwa-Zulu Natal, mostly around the Drakensberg region, but these species have apically swollen peduncles which are absent in C. barbata.

Fig. 2. Cotula barbata fruits. A disc fruit where the swelling covers the entire inner face (left) and a disc fruit with a basal swelling (right).

The white-flowered form can be confused with C. loganii and C. nudicaulis. Cotula barbata differs from C. loganii in that C. barbata has ovate outer bracts whereas in C. loganii the outer bracts are obovate. Cotula barbata differs from C. nudicaulis in that spongy outgrowths are absent in C. barbata and are present in C. nudicaulis.

Fig. 3. Cotula barbata floral bracts. Multi-nerved (left) and single-nerved (right). Outer bract on the the left middle bract in the middle and inner bract on the right.