Gomphocarpus cancellatus buds in two developmental stages

The inflorescence of Gomphocarpus cancellatus is striking, a quite unusual structure among plants of its distribution area. The globose inflorescence seen here consists of several flat-topped flower clusters. The flowers in each cluster are joined on stalks that emerge from leaf axils near the stem-tip, the uppermost one from the tip.

Five such clusters are visible in the picture, some clusters at different developmental stages. The lower three visible clusters are already open, the other two still budding. The youngest buds right at the top are still small, their narrow green sepals still clasping the dark blue buds. The second cluster has buds that have swollen notably and changed colour to some dull red-purple, their green sepals receded some distance. On their outside surfaces the petals are dark bluish purple on central spots, the red-purple margins still cohering.

There are distinctly discrete stages of floral development per cluster, not one gradual range of all possible developmental stages found among the individual flowers. A faint indumentum of downy white hairs covers sepals and closed petals of the buds. The open flowers have their petals turned right back and down, away from the central flower parts.

Five tubular white structures are visible in the flower centre. They have elliptic openings at the top. These structures inside the corolla are the coronas. Here they appear as hollow tubes, surrounding the flower style (www.plantzafrica.com; Manning, 2007).