Tubular Bells

Merciera leptoloba is a member of the bellflower family, Campanulaceae. As the common family name suggests, most members of this family have bell-shaped flowers, i.e. with a broad tube. (Indeed, the scientific name is also based on the Latin for bell: campana.) But as in many families, there is a black sheep that does not fit in with what is expected. The genus Merciera is one of those black sheep and the bell is a tubular one, with flared ends.

The genus Merciera is restricted to the Western Cape of South Africa. There are only 6 species and all have the long tubular flowers with spreading lobes at the end. This shape is known in botanical terms as “salverform” or the even more technical and unpronouncable “hypocrateriform”. Both terms basically mean that the corolla, i.e. a tubular flower, has the lobes at the end spreading at right angles to form a flat plate or tray (imagine a waiter holding a tray or salver on top of his arm). In Merciera, the lobes are very narrow and so the end of the flower appears star-shaped with 4 or 5 points to the star. The genus also differs from other members of the Campanulaceae in South Africa in forming only a single seed for each flower; other genera produce capsules with many seeds (such as the one illustrated for Prismatocarpus brevilobus)

The species we get most commonly here in the Overberg is Merciera leptoloba. This is easily recognised as it has spikes of pure white star-shaped flowers with 5 long lobes ("leptoloba" means narrow lobes). The plants are low growing. The stems trail for a short distance before becoming erect to produce the flowering spikes rarely more than 10cm high. It is found from the Kogelberg, east along the Klein River Mountains and as far south as Bredasdorp. It is restricted to fynbos on sandy well-drained soils of the lower mountain slopes. Its main flowering time is November to December but the odd flower continues into March. Merciera azurea with its blue flowers also occurs in the area but we have not found it as yet at Phillipskop. We should also keep our eyes out for the very local endemic Merciera brevifolia, which occurs on the neighbouring mountains of Babylonstoring and Shaws Mountain. It has white flowers like Merciera leptoloba but is more slender with longer stems and shorter leaves.

Merciera leptoloba is not known in general cultivation, but it is striking when in flower and would make a very beautiful plant for the edge of a border or in a rock garden.