|
Passerina filiformis subsp. filiformis is a shrub
growing up to 2 m. It is currently quite scarce in the Cape Peninsula,
but a healthy community of these plants occurs on Signal Hill where
it is often subjected to mist creeping over the mountain.
Description
P. filiformis subsp. filiformis is distinguished by
the linear, almost needle-shaped leaves that are finely grooved
along the upper surface. The very common P. corymbosa (=
P. vulgaris), is distinguished from this subspecies by narrowly
lanceolate leaves and a diamond-shaped bract.
The leaves are dark green to grayish green, heart-shaped in cross
section, and the length x width is 5.5-8 x 0.6-1 mm, slightly widening
towards the base. The flowering spikes are not covered by a glue-like
substance. A very important characteristic of the plant is the widely
obovate bract at the base of each flower, narrowing abruptly into
a thin point. The bracts are normally much larger than the leaves,
the length x width is ± 7.3 x 2 mm. The salmon-pink flowers
are ± 6.0 mm long when pollination takes place, but they
become red with age.
The conservation status of the species is regarded as 'Least Concern
(LC)' according to the standards set by the IUCN Species Survival
Commission in 2000.
Distribution
Passerina
filiformis subsp. filiformis is endemic to the Northwestern,
Southeastern and Langeberg Centres within the Cape Floristic Region.
It is found in the Cape Peninsula, and is distributed from Piquetberg,
across the Hex River Mountains, to Attaquaskloof in the southwestern
Cape. It grows in rocky areas, mostly on south-facing mountain slopes,
as well as on sandy plains, like the Rietvallei and Stellenbosch
Flats.
Derivation of name and historical aspects
The Latin specific epithet filiformis (= thread-like)
obviously refers to the narrow leaves of this species.
According to Van Wyk & Gericke (2000) the name
bakkerbos commemorates an era in the Cape when the officially
licensed bakers used this plant to heat their ovens. The plants
used at that time were clearly Passerina filiformis subsp.
filiformis. The vernacular name 'sparrow-wort' was suggested
by Miller (1768) for all Passerina species, indicating P.
filiformis as 'sparrow-wort with linear convex leaves'. Wendland
(1798) used the German equivalent fadenförmige Vogelkopf.
Marloth (1925) mentioned the names kannabas and kaalgaar.
The following Afrikaans names appear in Smith (1966) and some of
them also in Palmer & Pitman (1972) and Coates Palgrave (1977):
bakbossie, bakkersbossie, bruingonna, fyntaaibos, gannabas, gonnabas,
kaalgaarbos, kaalgaring, kabelgaring, kannabas, koordehaar, taaibos,
windmakersbessie, windmakersbossie.
Ecology
Passerina filiformis subsp. filiformis is wind-pollinated,
flowering in spring and early summer, the most windy seasons in
the Western Cape. The filiform (thin, wire-like) leaves, that are
heart-shaped in cross section are adapted to the dry summers of
the Mediterranean climate. These leaves have a thick, waxy outer
layer, and contain ample amounts of tannin and mucilage for protection
against ultra-violet radiation and dessication. The fruits are dry
and when they are ripe they passively drop to the ground, where
they germinate or are dispersed by ants, mice or birds.
Uses and cultural aspects
When ignited, plants of subsp. filiformis disappear in a
blaze of hot flame owing to a waxy secretion on the leaves (Smith
1966). The plants were formerly used for heating up the ovens used
to bake bread. Today it is quite scarce around Cape Town, probably
because of the impact of the collecting of this once abundant resource.
At maturity these plants are quite ornamental and they have been
cultivated in Britain and Europe since the time of Linnaeus. Plants
of subsp. filiformis are vigorous resprouters, they are well
adapted to the Cape climate and would be suitable for reclamation
plantings in areas where invasive alien vegetation has been cleared.
The bark is very tough and has been used by indigenous peoples as
twine (Marloth 1925). According to Laidler (1928) a decoction of
this plant has been used by the Khoekhoe for the treatment of shooting
pains.
Growing Passerina filiformis subsp. filiformis
As these plants are small trees, they could make unusual indigenous
Christmas trees when cultivated. Attempts may be made to cultivate
from juveniles that sprout from adventitious roots or suckers. Growing
plants from seed may be easier (Anthony Hitchcock, Kirstenbosch
pers.comm.) Plant in well-drained sandy soil. In the Western Cape,
under normal climatic conditions, they could be tried as an indigenous
substitute for cypress in the garden.
References and further reading
- Coates Palgrave, K. 1977. Trees of southern Africa. Struik,
Johannesburg.
- Laidler, P.W. 1928. The magic medicine of the Hottentots.
South African Journal of Science 25: 433-447.
- Marloth, R. 1925. The flora of South Africa, vol. 2,2.
Darter, Cape Town.
- Miller, P. 1768. The gardener's dictionary, edn 8. London.
- Palmer, E. & Pitman, N. 1972. Trees of southern Africa,
vol. 3. Balkema, Cape Town.
- Smith, C.A. 1966. Common names of South African plants. Memoirs
of the Botanical Survey of South Africa No. 35: 589. Botanical
Research Institute, Pretoria.
- Van Wyk, B-E. & Gericke, N. 2000. People's plants.
Briza Publications, Pretoria.
- Wendland, J.C. 1798. Botanische Beobachtungen. Gebrüdern
Hahn, Hannover.
|
|
Author
Christien Bredenkamp
National Herbarium Pretoria
October 2004
|
|