This is a cosmopolitan family with showy flowers, mainly from the
northern hemisphere, but in the southern hemisphere South Africa
is particularly rich in members of this family.
In South Africa the family contains mostly herbs (annual, or perennial)
or rarely small shrubs. The leaves are alternate, rarely opposite,
simple, and without stipules. The flowers are regular, bell-shaped,
funnel-form or salver-form (corolla with a narrow tube and small
spreading lobes) and bisexual. They are borne singly or more often
in inflorescences. The large, showy flowers are predominantly blue
in colour. Petals, sepals and stamens are normally in fives. The
petals are partially or completely fused and are inserted on an
inferior or half inferior or seldomly a superior ovary. There are
as many stamens as corolla lobes. The style is simple with as many
stigmas as carpels. The fruit is a capsule.
The Campanulaceae has a cosmopolitan distribution, although more
abundant in temperate and subtropical regions and consists of about
55 genera and more than 900 species. In South Africa there are 10
genera of which eight are endemic and about 250 species. Some of
the genera are discussed below.
The largest and most widespread genus is Wahlenbergia, which
comprises 170 species. W. capensis is a common blue-flowered
spring annual that is often found along roadsides and on open fields
around Cape Town. Most of the annual species occur on the West Coast
and in the Northern Cape in sandy soil in open vegetation. Recently
all 46 species of the shrubby genus Lightfootia have been
placed in Wahlenbergia.
is a genus of small shrubs found mainly in the southwestern Cape.
Only one of the twenty-four species extends into the Eastern Cape
and KwaZulu-Natal. Plants grow mainly on stony mountain slopes.
Its large blue flowers are borne on the tips of branches in groups
or singly. The best known species in this genus is R. ciliata.
is one of two genera consisting of only a single species. The other
one is Treichelia. Rhigiophyllum squarrosum is a small shrub,
which occurs only in the Napier-Bredasdorp area, whereas Treichelia
longebracteata is an annual known from a few localities in the
Cape Peninsula and one in Hermanus.
Name and History
The regular and irregular flower shapes of members of the Campanulaceae
has always been the subject of dispute and uncertainty. Some taxonomists
prefer to consider the Campanulaceae as one complex, variable family
with several subfamilies. New evidence from morphology and DNA sequence
data has contributed to the current recognition of five subfamilies
within the Campanulaceae: Campanuloideae, Lobelioideae, Cyphiodeae,
Cyphocarpoideae and Nemacladiodeae. Only the Campanuloideae, Lobelioideae
and Cyphiodeae are represented in South Africa, the other two subfamilies
occurring in Chile, southwestern United States and northwestern
Mexico. For the purpose of this article, I consider the Campanulaceae
in the strict sense, that is, not recognizing subfamilies, instead
recognizing the families Campanulaceae, Lobeliaceae and Cyphiaceae.
of shrubby members of the family occurring in the fire-prone fynbos
vegetation of the southwestern Cape, resprout after fire. Plants
in the genus Merciera grow and flower most profusely in recently
burnt veld. After six years, the plants start to die and start disappearing
when the veld remains unburnt for very long periods. Plants in the
dry parts of the country have adapted to long periods of drought
by developing an annual life cycle.
An interesting mechanism has been developed in the family to facilitate
cross-pollination and hinder self-pollination. The flowers are distinctly
protandrous (male reproductive organs mature first), and pollen
is shed upon the style (with the stigma lobes closed up against
one another) in the bud. The style is either sticky or hairy, to
hold the pollen. This is the male stage in the development of the
flower and stamens wilt quickly as the corolla opens. After a time
when the bulk of the pollen has been carried away by insects, the
stigma lobes unfold and the female stage sets in. The stigma is
now ready to receive pollen from another plant.
Economic and cultural value
Species of the genera such as Wahlenbergia, Campanula, Symphyandra,
Jasione and Phyteuma are popular garden ornamentals. Only Wahlenbergia
occurs in South Africa. Occasionally Roella ciliata is planted
as a garden ornamental.
I know no cultural usage of members of the family.
In the Garden
undulata and W. rivularis are popular garden plants.
References and further reading
Cupido, C.N. &
Conrad, F. 1999. Bellflowers. Veld & Flora 85: 180-181
Kovanda, M. 1978. Campanulaceae. In V.H. Heywood, Flowering plants
of the world: 254-256. Oxford University Press, Oxford.
Leistner, O.A. (ed.). 2000. Seed plants of southern Africa: families
and genera. Strelitzia 10. National Botanical Institute,
Van der Walt, L.
2001-01. Wahlenbergia undulata (L.f.) A.DC. (Campanulaceae)
Compton Herbarium, Kirstenbosch