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Window-leaf succulents are always very popular as the shape of
the leaves is unique and when in flower the magenta petals with
lighter centres cover the plant completely. Although this is a miniature
and could never become a spectacular garden plant as it would get
lost among other larger plants, it is collected by discerning succulentophiles.
Description
These minute plants are perennial succulents and are just visible
above the soil surface in their natural habitat. Plants comprise
a cluster of succulent leaves windowed at the tips, with a short,
thickened rootstock underground. Stems are much reduced and during
periods of drought the plants shrink in size as a result of moisture
loss. They sometimes even disappear below the grit under adverse
conditions, making them very difficult to find. The shrinkage is
achieved by means of leaf cells arranged in columnar rows. When
moisture is lost and the contents shrink, the tangential cell walls
contract, drawing the plants deeper into the soil avoiding desiccation
during the dry winter months or in times of drought.
The single flowers are bright magenta with a white or light yellow
centre and are 25 - 35 mm in diameter and are borne on very short
stalks or are stalkless. The five sepals are unequal and closely
resemble the cylindrical leaves. Petals number between 30 and 45
and usually have blunt, rounded tips.
Fruits are quite robust, spongy capsules resembling a barrel and
open when wetted and close when dry (hygrochastic capsules), releasing
the seed.
Capsule closed |
Capsule open
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Distribution
Frithia pulchra grows exclusively in the summer-rainfall
region of South Africa has a restricted distribution. Populations
of these miniature window plants occur in the Magaliesberg from
Hartbeeshoek to the Rustenburg Nature Reserve (North-West Province
and in Gauteng), where higher altitudes are favoured.
Map showing distribution
This species grows in very shallow soils derived from coarse sediments.
Very rough quartzites of the Magaliesberg Formation of the Pretoria
Group of the Transvaal Sequence are involved here and upon weathering,
form a very coarse gravel.
The Red List status of this plant is Vulnerable (D2) as only two
subpopulations have been found, together covering no more than 13.25
hectares (Burgoyne et al. 2000). Plants in the populations are sparsely
scattered and are not in dense groups. It would appear that either
pollinators are not very successful, seeds are not very fertile
or germination and growth are hampered in some way as these plants
are not as numerous as the only other member of the genus.
Name and History
Previously thought to be a monotypic genus and a Gauteng endemic,
the genus Frithia was established by N.E. Brown (1925), a
taxonomist based at Kew Herbarium. At that stage no species were
assigned to this genus and only later was a full description of
Frithia pulchra given (Brown 1926). It was named after Frank
Frith (1872 - 1954), a railway services gardener stationed at Park
Station, Johannesburg, who took the specimens to Brown at Kew
while on a visit to London. Brown named Frithia in honour
of the man who brought him the specimens. The specific epithet pulchra
is derived from the Latin "pulcher" meaning beautiful.
Ecology
Frithia pulchra grows mostly on exposed rock plates, the
roots anchored in cracks between the coarse quartzites. This substrate
reaches very high temperatures in summer and may experience frosts
during severe winters.
Other succulent species sometimes associated with Frithia
are Anacampseros subnuda subsp. subnuda, Crassula lanceolata
subsp. transvaalensis, Crassula setulosa var. setulosa
and Mossia intervallaris.
A hiking trail has been named after this plant and anyone visiting
the Magaliesberg without seeing this plant in habitat has missed
something truly unique.
Economic and Cultural Value
Frithia pulchra with its magenta flowers is an attractive
potplant and is popular with succulent collectors. Forms with flowers
of different colours are available.
Growing Frithia pulchra
Gritty, well drained soil containing a small amount of organic
material will keep this species happy. They can be sown from seed
sown in a gritty sandstone (acid) medium or propagated vegetatively.
They can be grown in pots or out of doors in a rockery. Frithia
is not shy of water and recent observations during periods of heavy
rainfall indicated that they enjoy inundation for short periods,
but the porosity of the substrate should be such that the water
drains away swiftly. Under-watering can lead to disastrous results,
so be generous with water in summer and refrain from any water in
winter except as a light misting.
As Frithia pulchra is listed as vulnerable in the wild,
please make sure that you acquire Frithia plants from reputable
sources where they have been propagated in nurseries and not collected
illegally from the wild. It is illegal to collect plants from the
veld without a permit in South Africa.
References
- BROWN, N.E. 1925. Mesembryanthemum. Gardeners' Chronicle
Ser. III 78: 433.
- BROWN, N.E. 1926. Ficoidaceae. In J. Burtt Davy, A manual
of the flowering plants and ferns of the Transvaal with Swaziland,
South Africa 1,41: 162. Longmans, Green and Co. Ltd., London.
- BURGOYNE P.M. KRYNAUW, S. & SMITH, G.F. 2000. Frithia -
up close and personal. Aloe 37: 38-42.
- E BOER, H.W. 1968. Frithia pulchra var. minor de Boer, var.
nov. Succulenta 47: 147-148.
- GERMISHUIZEN, G. 1975. 'n Aantal bedreigde vetplantsoorte in
Transvaal. Fauna & Flora 26: 5-8.
- HAMMER, S. 1998. Frithia's fairest friends. Mesemb Study
Group Bulletin 13,3: 64.
- HARDY, D. & FABIAN, A. 1992. Succulents of the Tranvaal.
Southern Book Publishers, Halfway House.
- HARTMANN, H.E.K. 1998. Groupings in Ruschioideae (Aizoaceae).
Mesemb Study Group Bulletin 2: 35-36.
- IUCN SPECIES SURVIVAL COMMISION. 1994. IUCN Red List Categories.
IUCN, Gland.
- KROON, N. 1997. Tribute to two amateurs: William Nelson F.R.H.S.,
L.M.C.A., F.L.Sc. (1852-1922) and Frank Frith (1872-1954). PlantLife
16: 15-17.
- PUNT, W., BLACKMORE, S., NILSSON, S. & LE THOMAS, A. 1994.
Glossary of pollen and spore terminology. L.P.P. Contributions
Series No. 1, Utrecht, The Netherlands.
- SMITH, G.F., CHESSELET, P., VAN JAARSVELD, E.J., HARTMANN, H.,
HAMMER, S., VAN WYK, B-E., BURGOYNE, P., KLAK, C. & KURZWEIL,
H. 1998. Mesembs of the world. Illustrated guide to a remarkable
succulent group. Briza Publications, Pretoria.
- VENTER, F. 1983. Frithia pulchra. Fauna & Flora 40:
19-20.
- ZIMMERMANN, N.F.A. 1996. Frithia pulchra N.E.Br. - Eine Reise
zu zwei Populationen im Transvaal mit Besprechung der succulenten
Begleitvegetation. Kakteen und Andere Sukkulenten 47,7:
146-152.
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Author
Patricia Burgoyne
National Herbarium
January 2004
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