Macrostylis villosa
(Thunb.) Sond. subsp. villosa

Family : Rutaceae (Citrus family)
Common names : Buchu (Eng.); kousieboegoe (Afr.)

Macrostylis villosa

Macrostylis villosa is a neat compact aromatic shrub producing clusters of white flowers over a long flowering period. Planted together with other fynbos species, it is a lovely addition to a fynbos garden.

Description
Macrosrylis villosa is a small compact shrub, with a rounded shape growing to 30 cm. The hairy, aromatic leaves are needle-like, lance-shaped, dotted with glands and arise directly from the stems.

Leaves

Clusters of white flowers with long exserted styles appear at the branch tips over a long summer flowering period from December to July. Seeds are produced in a 3-segmented capsule from which they are forcibly expelled on ripening.

Conservation status
Unfortunately this species is listed as Endangered (EN) in the Red List of South African Plants. This assessment is based on a population reduction of at least 50 % in the last 140 years. This decline is due to loss of habitat, urbanization, agriculture and alien plant invasion. There are only a few small, very fragmented subpopulations remaining and they continue to be threatened. In an attempt to increase these declining populations, Macrostylis villosa is being replanted into areas on the Cape Peninsula that are being restored.

Distribution and habitat
Macrostylis villosa is a South African endemic confined to the Western Cape. Its natural distribution is from the Cape Peninsula to Mamre. It is a terrestrial species that occurs within the Fynbos biome, preferring sandy flats and lower mountain slopes.

Derivation of name and historical aspects
Macrostylis villosa is a member of the Rutaceae family, which occurs in all temperate and tropical regions of the world but especially in South Africa and Australia. It is one of the distinctive families in the Cape Fynbos flora in which it is represented by 14 genera and 281 species. The genus Macrostylis includes 10 species, all found in the Western Cape. The generic name Macrostylis was proposed by Bartling and Wendland when revising the tribe Diosmeae, to which Macrostylis belongs, in 1824. It is derived from the Greek word makros, meaning long, large or pillar-like, and refers to the long, exserted style. The specific name originates from the Latin word villosus, meaning soft-haired.

Ecology
Buchus are pollinated by bees and butterflies and produce their seeds over a long period with the main seed fall taking place during November and December. Seeds are dispersed from the capsules via a trigger or ballistic dispersal method and germinate in the autumn months, usually after fire and when the rains begin. The aromatic leaves characteristic of buchus are due to glands on the undersides of the leaves and on the fruits. These produce volatile oils that act as an antifeedant discouraging insect attack.

Uses and cultural aspects
Although not much is known of the uses of Macrostylis villosa itself, the Citrus or Buchu family is economically important. Aside from providing citrus fruit such as oranges and lemons, the presence of volatile oils in the leaves is characteristic of the family, and many species are used in industries for producing perfumes, cosmetic soap, food and colorants. They are also used medicinally for the treatment of renal disorders and chest complaints.

Macrostylis villosa

Growing Macrostylis villosa

Macrostylis villosa has a neat compact appearance and is a lovely addition to a fynbos garden. They do best planted in full sun in soil that is slightly acid, well drained and enriched with compost and a well balanced fertilizer. They can be planted fairly densely together with other fynbos species such as restios, phylicas, pelargoniums and helichrysums. Mulch annually with well rotted compost to reduce moisture loss, taking care not to disturb the soil around the root area. Buchus require a moderate supply of water but are susceptible to Phytophthera cinnamomi, a soil- and water-borne fungus. Fungal attacks may be prevented by ensuring that foliage does not remain wet after night fall and by keeping the soil cool during the day with mulch.

Buchus can be propagated by seed and cuttings. Seeds are sown in autumn usually. Use a light and well drained sowing medium, such as a mix of 1 part sand, 1 part loam and 1 part compost. Along with other fynbos species, buchus respond to smoke treatment; 20 % of Rutaceae species tested gave a significant response to smoke. Apply an aqueous smoke extract to the trays after the seeds are sown. Incubate the seed trays in a covered area with good light and air circulation or place in full sun. Keep the trays damp but avoid overwatering. The seeds take 12 months to germinate and the percentage is often quite low. When the seedlings have 4 true leaves, plant them into small pots or bags in a well drained and slightly acid soil. Take care when pricking out not to damage the delicate root system. Keep seedlings in a shaded area for 3 weeks, after which they can be moved into the sun. The growing tips can be pinched out to encourage a bushy growth. Apply a balanced fertilizer to the growing plants regularly. They require about 9 months to become ready for planting, and flowers are produced after 2 years.

Collect cutting material from August to early October from new, semihard shoots that have grown after the plant has flowered. Make a clean cut just below a node and remove the lower third of the foliage. Dip the cutting ends into a rooting hormone such as Seradix 3 and insert the cuttings into a cutting medium of 1 part bark and 1 part polystyrene. Place cuttings in a well aerated propagation unit with intermittent misting and bottom heat of 24 ° C. Rooting takes about 9 to 11 weeks and well rooted cuttings can then be planted into pots or bags. They should be ready to plant in the ground after 78 months.

References and further reading

  • Brown, N.A.C. & Botha, P.A. 2004. Smoke seed germination studies and a guide to seed propagation of plants from the major families of the Cape Floristic Region, South Africa. South African Journal of Botany 70(4): 559581.
  • Brown, N.A.C & Duncan, G.D. 2006. Grow Fynbos plants: A practical guide to the propagation and cultivation of plants from some of the major families of the Cape Floristic Region of South Africa. South African National Biodiversity Institute, Kirstenbosch, South Africa.
  • Goldblatt, P. & Manning, J. 2000. Cape plants. A conspectus of the Cape Flora of South Africa . Strelitzia 9. National Botanical Institute, Pretoria & Missouri Botanical Garden, Missouri.
  • Kesting, D. 2005. Botanical names, what they mean. Wild flowers of the Cape Peninsula. Flora Documentation Programme. Friends of Silvermine Nature Area (FOSNA). Muizenberg, South Africa.
  • Leistner, O.A. (ed.). 2000. Seed plants of southern Africa: families and genera.
  • Strelitzia 10 . National Botanical Institute, Pretoria.
  • Trinder-Smith, T.H. 2003. The Levyns guide to the plant genera of the Southwestern Cape . Bolus Herbarium, University of Cape Town.
  • Van Wyk, B.-E. & Gericke, N. 2000. People's plants: a guide to useful plants of southern Africa . Briza Publications, Pretoria.

 

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