Scientific books
- Cowling, R.M. (ed) (1992). The Ecology of Fynbos: Nutrients, Fire, and Diversity. Oxford University Press, Cape Town.
- Cowling, R.M., Richardson, D.M. & Pierce, S.M. (eds) (1997). Vegetation of Southern Africa. Cambridge University Press, Cambridge.
- Davis, G.D. & Richardson, D.M. (eds) (1995). Mediterranean-Type Ecosystems: Functions of Biodiversity. Ecological Studies 109. Springer-Verlag, Berlin
- Richardson, D.M. (ed)(1998). Ecology and Biogeography of Pinus. Cambridge University Press, Cambridge.
- Van Wilgen, B.W., Richardson, D.M., Kruger, F.J. & van Hensbergen, H.J. (eds) (1992). Fire in South African mountain fynbos. Ecological Studies 93. Springer-Verlag, Berlin.
Popular books
- Cowling, R.M. & Richardson, D.M. (1995). Fynbos: South Africa's Unique Floral Kingdom Fernwood Press, Cape Town.
Papers in refereed scientific journals
- Chapin, F.S., Sala, O.E., Burke, I.C., Grime, J.P., Hooper, D.U., Lauenroth, W.K., Lombard, A., Mooney, H.A., Mosier, A.R., Naeem, S., Pacala, S.W., Roy, J., Steffen, W.L. and Tilman, D. (1998). Ecosystem consequences of changing biodiversity. Experimental evidence and a research agenda for the future. BioScience 48: 45-52.
- Cowling, R.M., Esler, K.J., Midgley, G.F. & Honig, M.A. (1994). Plant functional diversity, species diversity and climate in arid and semi-arid southern Africa. Journal of Arid Environments 27: 141-58.
- Cowling, R.M. & Holmes, P.M. (1992). Endemism and speciation in a lowland flora from the Cape Floristic Region. Biological Journal of the Linnaean Society 47: 367-383.
- Cowling, R.M., Kirkwood, D., Midgley, J.J. & Pierce, S.M. (1997). Invasion and persistence of bird-dispersed, subtropical thicket and forest species in fire-prone fynbos. Journal of Vegetation Science 8: 475-488.
- Cowling, R.M. & Midgley, J.J. (1996). The influence of regional phenomena on an emerging global ecology. Global Ecology and Biogeography Letters 5: 63-65.
- Cowling, R.M., Mustart, P.J., Laurie, H. & Richards, M.B. (1994). Species diversity; functional diversity and functional redundancy in fynbos communities. South African Journal of Science 90: 333-337.
- Cowling, R.M., Rundel, P.W., Desmet, P.G. and Esler, K.J. (1998). Extraordinarily high regional-scale plant diversity in southern African arid lands: subcontinental and global comparisons. Diversity and Distributions 4: 27-36.
- Cowling, R.M., Rundel, P.W., Lamont, B.B., Arroyo, M.K. & Arianoutsou, M. (1996). Plant diversity in mediterranean-climate region. Trends in Ecology and Evolution 11: 362-368.
- Cowling, R.M. & Witkowski, E.T.F. (1994). Convergence and non-convergence in climatically and edaphically matched sites in mediterranean Australia and South Africa. Australian Journal of Ecology 19: 220-232.
- Cowling, R.M., Witkowski E.T.F., Milewski, A.V. & Newbey, K.R. (1994). Taxonomic, edaphic and biological aspects of narrow plant endemism on matched sites in Mediterranean South Africa and Australia. Journal of Biogeography 21: 651-664.
- Esler, K.J. & Cowling, R.M. (1993). Edaphic factors and competition as determinants of pattern in South African karoo vegetation. South African Journal of Botany 59: 287-295.
- Esler, K.J. & Cowling, R.M. (1995). The comparison of selected life history characteristics of Mesembryanthema species occurring on and off mima-like mounds (heuweltjies) in semi- arid South Africa. Vegetatio, 116: 41-50.
- Esler, K.J., Cowling, R.M. & Ivey, P. (1992). Seed biology of three species of Mesembryanthema in the southern Succulent Karoo. South African Journal of Botany 58: 343-8.
- Esler, K.J. & Phillips, N. (1994). Experimental effects of water stress on semi-arid karoo seedlings: implications for field seedling survivorship. Journal of Arid Environments 26: 325-337.
- Desmet, P.G., Shackleton, C.M. & Robinson, E.R. (1996). The population dynamics and life history attributes of aPterocarpus angolensis population in the Northern Province, South Africa. South African Journal of Botany (in press).
- Dyer, C. and Richardson, D.M. (1992). Population genetics of the invasive Australian shrub Hakea sericea (Proteaceae) in South Africa. South African Journal of Botany 58: 117-24.
- Higgins, S.I. & Richardson, D.M. (1996). A review of models of alien plant spread Ecological Modelling 87: 249-265.
- Higgins, S.I. & Richardson, D.M. (1998). Pine invasions in the southern hemisphere: modelling interactions between organism, environment and disturbance. Plant Ecology 135: 79-93.
- Higgins, S.I., Richardson, D.M. & Cowling, R.M. (1996). The role of plant-environment interactions and model structure on the predicted rate and pattern of invasive plant spread. Ecology 77: 2043-2054.
- Hoffman, M.T., Midgley, G.F. & Cowling, R.M. (1994). Plant richness is negatively related to energy availability in semi-arid southern Africa. Biodiversity Letters 2: 35-38.
- Holmes, P.M. & Cowling, R.M. (1993). Effects of shade on seedling growth, morphology and leaf photosynthesis in six subtropical thicket species from the eastern Cape, South Africa. Forest Ecology and Management 61: 199-220.
- Holmes, P.M. & Cowling, R.M. (1997). Diversity, composition and guild structure relationships between soil-stored seed banks and mature vegetation in alien plant-invaded South African fynbos shrublands. Plant Ecology 133: 107-122.
- Honig, M.A., Cowling, R.M. & Richardson, D.M. (1992). The invasive potential of Australian banksias in South African fynbos: A comparison of the reproductive potential of Banksia ericifolia and Leucadendron laureolum. Australian Journal of Ecology 17: 305-314.
- Kilian, D. & Cowling, R.M. (1992). Comparative seed biology and coexistence of two fynbos shrub species with soil-stored seed banks. Journal of Vegetation Science 3: 637-646.
- Laurie, H. & Cowling, R.M. (1994). Lottery coexistence models extended to plants with disjoint generations. Journal of Vegetation Science 5: 161-168.
- Laurie, H. & Mustart, P.J. (1992). LDNS (Lineal Data, Nested Scales): A self-scaling method for detecting pattern in vegetation. South African Journal of Botany 58: 537-539.
- Le Maitre, D.C., van Wilgen, B.W. & Richardson, D.M. (1993). A computer system for catchment management: Background, concepts and development. Journal of Environmental Management 39: 121-142.
- Lombard, A.T., Cowling, R.M., Pressey, R.L. & Mustart, P.J. (1997). Reserve selection in a species-rich and fragmented landscape on the Agulhas Plain, South Africa.Conservation Biology 11: 1101-1116.
- Manders, P.T. & Richardson, D.M. (1992). Colonization of Cape fynbos communities by forest species. Forest Ecology and Management 48: 277-93.
- McDonald, D.J. & Cowling, R.M. (1994). Towards a profile of an endemic mountain fynbos flora: implications for conservation. Biological Conservation 72: 1-12.
- McDowell, C.R. & Moll, E.J. (1992). The influence of agriculture on the decline of the West Coast Renosterveld, South-Western Cape, South Africa. Journal of Environmental Management 35: 173-92.
- Midgley, J.J., Cowling, R.M., Hendricks, H, Desmet, P.G., Esler, K.J. and Rundel, P. (1997). Population ecology of tree succulents (Aloe and Pachypodium) in the arid northern Cape; decline of a keystone species.Biodiversity and Conservation 6: 869-876.
- Moolman, J. & Cowling, R.M. (1994). The impact of elephant and goat grazing on the endemic flora of South African succulent thicket. Biological Conservation 68: 53-61.
- Mustart, P.J. & Cowling, R.M. (1993). Effects of soil and seed characteristics on seed germination and their possible roles in determining field emergence patterns of four Agulhas Plain (South Africa) Proteaceae. Canadian Journal of Botany 71: 1363 - 1368.
- Mustart, P.J. & Cowling, R.M. (1993). The role of regeneration stages in the distribution of edaphically restricted fynbos Proteaceae. Ecology 74: 1490 - 1499.
- Mustart, P.J. & Cowling, R.M. (1992). The impact of flower and cone harvesting on the seed banks and seed set of serotinous Cape Proteaceae. South African Journal of Botany 58: 337-342.
- Mustart, P.J. & Cowling, R.M. (1992). Seed size: phylogeny and adaptation in two closely related Proteaceae species-pairs. Oecologia 91: 292-5.
- Mustart, P.J., Cowling, R.M. & Dunne, T.T. (1994). Reproductive strategies of two closely related species pairs on adjacent, different soil types in South African fynbos. Vegetatio 111: 161-171.
- Mustart, P.J., Cowling, R.M. & Wright, M.G. (1995). Clustering of fertile seeds in infructescences of serotinous Protea species: an anti-predation mechanism? African Journal of Ecology 33 (in press).
- Mustart, P.J., Juritz, J., Makua, C., Van der Merwe, S. & Wessels, N. (1995). Restoration of the Clanwilliam cedar Widdringtonia cedarbergensis: The importance of monitoring seedlings planted in the Cederberg, South Africa. Biological Conservation 72: 73-76.
- Mustart, P.J., Moll, E.J. & Taylor, H.C. (1993). The efficient use of small plots in a fynbos phytosociological study in the northern Cederberg: a quick way to collect plant-environmental data. Bothalia 23: 265 - 269.
- Ojeda, F. (1998). Biogeography of seeder and resprouterErica species in the Cape Floristic Region - Where are the resprouters? Biological Journal of the Linnean Society 63: 331-347.
- Ojeda, F., Maranon, T. & Arroyo, J. (1996). Patterns of ecological, chorological and taxonomic diversity at both sides of the Strait of Gibraltar. Journal of Vegetation Science (in press).
- Palmer, A.R. & Cowling, R.M. (1994). An investigation of topo-moisture gradients in the eastern karoo, South Africa, and the identification of factors responsible for species turnover. Journal of Arid Environments 26: 135-147.
- Pierce, S. M., Esler, K.J. & Cowling R.M. (1995). Smoke-induced germination of succulents (Mesembryanthemaceae) from fire-prone and fire-free habitats in South Africa.Oecologia 102: 520-522.
- Rejmanek, M. & Richardson, D.M. (1995). What attributes make some plant species more invasive? Ecology 77: 1655-1661.
- Richards, M.B., Stock, W.D. & Cowling, R.M. (1995). Water relations of seedlings and adults of two fynbos Protea species in relation to their distribution patterns. Functional Ecology 9: 575-583.
- Richardson, D.M., Cowling, R.M. & Lamont, B.B. (1996). Non-linearities, synergisms and plant extinctions in South African fynbos and Australian kwongan. Biodiversity and Conservation 5: 1035-1046.
- Richards, M.B., Cowling, R.M. & Stock, W.D. (1995). Fynbos plant communities and vegetation-environment relationships in the Soetanysberg hills, Western Cape.South African Journal of Botany 61: 298-305.
- Richardson, D.M. & Cowling, R.M. (1995). The ecology of invasive alien pines (Pinus spp.) in the Jonkershoek Valley, Stellenbosch, South Africa. Bontebok.
- Richardson, D.M., Cowling, R.M., Lamont, B.B. & van Hensbergen, H.J. (1995). Coexistence of Banksia species (Proteaceae) in south-western Australia: the role of local and regional processes. Journal of Vegetation Science 6: 329-342.
- Richardson, D.M. & Fraser, M.W. (1995). Birds of Swartboskloof, Jonkershoek Valley, Stellenbosch: A Mountain Fynbos Habitat. Southern Birds 18: 1-44.
- Richardson, D.M. & McMahon, J.P. (1992). A bioclimatic analysis of Eucalyptus nitens to identify potential planting regions in southern Africa. South African Journal of Science 86: 380-387.
- Richardson. D.M. & Cowling, R.M. (1993). Biodiversity and ecosystem processes: Opportunities in mediterranean-type ecosystems. Trends in Ecology and Evolution 8: 79-81.
- Richardson, D.M., van Wilgen, B.W., Le Maitre, D.C. Higgins, K.B. & Forsyth, G.G. (1994). A computer-based system for fire management in the mountains of the Cape Province, South Africa. International Journal of Wildland Fire 4: 17-32.
- Richardson, D.M., Williams, P.A. & Hobbs, R.J. (1994). Pine invasions in the Southern Hemisphere: determinants of spread and invadability. Journal of Biogeography 21: 511- 527.
- Rundel, P.W., Cowling, R.M., Esler, K.J., Mustart, P.J., van Jaarsveld, E. & Bezuidenhout, H. (1995). Winter growth phenology and leaf orientation in Pachypodium namaquanum (Apocynaceae) in the succulent karoo of the Richtersveld, South Africa. Oecologia 101: 472-477.
- Tribe, G.D. & Richardson, D.M. (1994). The European wasp, Vespula germanica (Fabricus) (Hymenoptera: Vespidae) in southern Africa, and its potential distribution in southern Africa as predicted by ecoclimatic matching. African Entomology 2: 1-6.
- Tucker, K. & Richardson, D.M. (1995). An Expert System for Screening Potentially Invasive Alien Plants in Fynbos. Journal of Environmental Management 44.
- Van Wilgen, B.W., Richardson, D.M. & Seydack, A.H.W. (1994). Managing fynbos for biodiversity: constraints and options in a fire-prone environment. South African Journal of Science 90: 322-329.
Refereed chapters in books
[no reprints available]
- Barbéro, M., Loisel, R., Quézel, P., Richardson, D.M., Romane, F. (1998). Pines of the Mediterranean Basin. In: Richardson, D.M. (ed.), Ecology and biogeography of Pinus, pp. 153-170. Cambridge University Press, Cambridge.
- Bond, W.J., Cowling, R.M. & Richards, M. (1992). Competition and coexistence. In: Cowling R.M. (ed), The ecology of fynbos: Nutrients, fire and diversity. Oxford University Press, Cape Town, pp. 206-225.
- Cowling, R.M. (1998). Chaparral shrublands. In: Calow, P. (ed.), The Encyclopedia of Ecology and Environmental Management, p. 122. Blackwell Science, Oxford.
- Cowling, R.M. (1998). Mediterranean climate regions - conservation. In: Calow, P. (ed.), The Encyclopedia of Ecology and Environmental Management, pp. 433-434. Blackwell Science, Oxford.
- Cowling, R.M. & Hilton-Taylor, C. (1994). Patterns of plant diversity and endemism in southern Africa: an overview. In: Huntley, B.J. (ed), Botanical Diversity in Southern Africa, pp. 31-52, National Botanical Institute, Pretoria.
- Cowling, R.M. & Hilton-Taylor, C. (1997). Phytogeography, flora and endemism. In: Vegetation of Southern Africa, eds. Cowling, R.M., Richardson, D.M. & Pierce, S.M. Cambridge University Press, Cambridge.
- Cowling, R.M. & Holmes P.M. (1992). Flora and vegetation. In: Cowling R.M. (ed), The ecology of fynbos: Nutrients, fire and diversity. Oxford University Press, Cape Town, pp. 23-61.
- Cowling, R.M., Holmes, P.M. & Rebelo, A.G. (1992). Plant diversity and endemism. In: Cowling R.M. (ed), The ecology of fynbos: Nutrients, fire and diversity. Oxford University Press, Cape Town, pp. 62-110.
- Cowling, R.M. & Olivier, N.J.J. (1992). Indigenous plants. In: Fuggle R.F. and Rabie M.A. (eds), Environmental management in South Africa. Juta, Cape Town, pp. 212-249.
- Cowling, R.M., Pierce, S.M., Stock, W.D. & Cocks, M. (1994). Why are there so many myrmecochorous species in Cape fynbos? In: Arianoutsou, M. & Groves, R.H. (eds),Plant-animal interactions in mediterranean-type ecosystems, pp 159-168, Kluwer, Dordrecht.
- Cowling, R.M., Richardson, D.M. & Mustart, P.J. (1997). Fynbos. In: Vegetation of Southern Africa, eds. Cowling, R.M., Richardson, D.M. & Pierce, S.M. Cambridge University Press, Cambridge.
- Cowling, R.M., Richardson, D.M., Schulze, R.E., Hoffman, M.T., Midgley, J.J. & Hilton-Taylor, C. (1997). Species diversity at the regional scale. In: Vegetation of Southern Africa, eds. Cowling, R.M., Richardson, D.M. & Pierce, S.M. Cambridge University Press, Cambridge.
- Davis, G.D., Richardson, D.M., Keeley, J.E. & Hobbs, R.J. (1996). Mediterranean-type ecosystems: The influence of biodiversity on their functioning. In: Mooney, H.A., Cushman, J.H., Medina, E., Sala, O.E. & Schulze, E-D. (eds), Functional Roles of Biodiversity: Global Perspectives, Wiley, Chichester.
- Hobbs, R.J., Richardson, D.M. & Davis, G.W. (1995). Mediterranean-type ecosystems: Advantages and constraints for studying the function of biodiversity. In: Davis, G.D. & Richardson, D.M. (eds), Mediterranean-Type Ecosystems: Functions of Biodiversity, pp. 1-42, Springer-Verlag, Berlin.
- Linder, H.P., Meadows, M.E. & Cowling, R.M. (1992). History of the Cape flora. In: Cowling, R.M. (ed) The ecology of fynbos: Nutrients fire, and diversity. Oxford University Press, Cape Town, pp. 113-134.
- Manders, P.T., Richardson, D.M. & Masson, P.H. (1992). Is fynbos a stage in succession to forest? Analysis of the perceived ecological distinction between two communities. In: Van Wilgen, B.W., Richardson, D.M., Kruger, F.J. & van Hensbergen, H.J. (eds), Fire in South African mountain fynbos, Springer-Verlag, Berlin, pp. 81-107.
- Midgley, J.J., Cowling, R.M., Seydack, A.H.W. & van Wyk, G.F. (1997). Forest. In: Vegetation of Southern Africa, eds. Cowling, R.M., Richardson, D.M. & Pierce, S.M. Cambridge University Press, Cambridge.
- Perry, J.P., Graham, A. & Richardson, D.M. (1998). The history of pines in Mexico and Central America: In: Richardson, D.M. (ed.), Ecology and biogeography of Pinus, pp. 137-149. Cambridge University Press, Cambridge.
- Richardson, D.M. & Cowling, R.M. (1992). Why is a mountain fynbos invasible and which species invade? In: Van Wilgen, B.W., Richardson, D M., Kruger, F.J. & Van Hensbergen, H.J. (eds), Fire in South African mountain fynbos, Springer-Verlag, Berlin, pp. 161-181.
- Richardson, D.M. (1998). Forestry trees as invasive aliens. Conservation Biology 12: 18-26.
- Richardson, D.M. Cowling, R.M., Bond, W.J., Stock, W.D. & Davis G.W. (1995). Links between biodiversity and ecosystem function in the Cape Floristic Region. In: Davis, G.D. & Richardson, D.M. (eds), Mediterranean-Type Ecosystems: Functions of Biodiversity, pp. 285-333, Springer-Verlag, Berlin.
- Richardson, D.M. & Higgins, S.I. (1998). Pines as invaders in the southern hemisphere. In: Richardson, D.M. (ed.), Ecology and biogeography of Pinus, pp. 450-473. Cambridge University Press, Cambridge.
- Richardson, D.M., Macdonald, I.A.W., Hoffmann, J.H. & Henderson, L. (1997). Alien plant invasions. In: Vegetation of Southern Africa, eds. Cowling, R.M., Richardson, D.M. & Pierce, S.M. Cambridge University Press, Cambridge.
- Richardson, D.M., Macdonald I.A.W., Holmes, P.M. & Cowling, R.M. (1992). Plant and animal invasions. In: Cowling, R.M. (ed), The ecology of fynbos: Nutrients, fire and diversity. Oxford University Press, Cape Town, pp. 271-308.
- Richardson, D.M. & Rundel, P.W. (1998). Ecology and biogeography of Pinus - An introduction. In: Richardson, D.M. (ed.), Ecology and biogeography of Pinus, pp. 3-46. Cambridge University Press, Cambridge.
- Richardson, D.M. & van Wilgen, B.W. (1992). Ecosystem, community and species response to fire in mountain fynbos: Conclusions from Swartboskloof experiment. In: van Wilgen, B.W., Richardson, D.M., Kruger, F.J. and van Hensbergen, H.J. (eds), Fire in South African mountain fynbos, Springer-Verlag, Berlin, pp. 273-284.
- Smith, R.E., van Wilgen, B.W., Forsyth, G.G. & Richardson, D.M. (1992). Co-existence of seeders and sprouters: the role of ecophysiology and soil moisture. In: van Wilgen, B.W., Richardson, D.M., Kruger, F.J. & van Hensbergen, H.J. (eds), Fire in South African mountain fynbos, Springer-Verlag, Berlin, pp. 108-122.
- Versfeld, D.B., Richardson, D.M., van Wilgen, B.W., Chapman, R.A. and Forsyth, G.G. (1992). The climate of Swartboskloof. In: Van Wilgen, B.W., Richardson, D.M., Kruger, F.J., and van Hensbergen, H.J. (eds), Fire in South African mountain fynbos, Springer-Verlag, Berlin, pp. 21-36.
Popular articles
- Azorin, E.J. (1992). Acacias as a woodfuel resource. Informantics, June 1992: 12-15.
- Azorin, E.J. (1995). Invasive acacias in the south western Cape, South Africa: The firewood and charcoal industry plays a major role in conservation by significantly reducing annual wood biomass productivity.Aliens 2 (Newsletter of the Invasive Species Specialist Group of the IUCN Species Survival Commission).
- Cowling, R.M. (1993). What is ecotourism and how does it benefit plant conservation? Veld & Flora 79: 3-5.
- Cowling, R.M. (1994). Fynbos in the Eastern Cape. Part 1. Pelea 13: 98-108.
- Esler, K.J. & Rundel, P.W. (1995). The tip of the iceberg: Mesembryanthemaceae in California. Veld & Flora. March 1995:12.
- Holmes, P.M. (1996). Alien clearing: Pandora's Box or Treasure Chest? Veld & Flora (in press).
- McDowell, C.R. & Oliver, E.G.H. (1992). Extinct erica rediscovered! African Wildlife 46: 133.
- McDowell, C.R. & Oliver, E.G.H. (1992). Will the rediscovered Erica alexandri be exterminated by pines? Veld & Flora 78: 88-89.
- Mustart. P.J. (1993). What is the Cederberg without the cedar? Veld & Flora 79: 114 - 117.
- Mustart, P.J. & Bond, W.J. (1994). The decline of the Clanwilliam cedar - natural or man-made?. Africa-Environment & Wildlife 2(3): 80-81.
- Mustart, P.J. & Cowling, R.M. (1992). Fynbos ecology for wildflower harvesters. Pamphlet distributed to participants of the workshop on the utilization of wildflowers in natural fynbos, March 1992.
- Mustart, P.J. & Cowling, R.M. (1992). Ekologie het die hulp van veldblomplukkers nodig. SAPPEX News 76.
- Mustart, P.J. (1992). How to safeguard your seed from predators: Proteas do it their way. Proteaceae Atlas Newsletter 15 and SAPPEX News 76.
- Mustart, P.J. (1993). The impact of wildflower harvesting on seed stores of Agulhas Plain Proteaceae.SAPPEX News 78.
- Richardson, D.M. (1992). Starlings. Why have they been so successful? African Wildlife 46: 207-210.
- Richardson, D.M. (1992). The eradication of plant invaders. Earthyear 3: 76-77.
- Richardson, D.M. (1994). The hakea saga: The continuing chronicle of an Australian invader at the Cape. Journal of the Mountain Club of South Africa 95.
- Richardson, D.M. (1995). Pine trees on the move down south. Aliens 2 (Newsletter of the Invasive Species Specialist Group of the IUCN Species Survival Commission).
- Richardson, D.M. & Cowling, R.M. (1993). Fynbos - beautiful to behold, critical to conserve. Africa - Environment & Wildlife 1(3): 48-57.
- Richardson, D.M. & van Wilgen, B.W. (1992). Swartboskloof. A study of the effects of fire in mountain fynbos. African Wildlife 46: 160-164.
- Richardson, D.M., van Wilgen, B.W. & Le Maitre, D.C. (1992). Catchment management with GIS. Environmental Planning and Management 3(5): 4-13.
- Richardson, D.M. & Cowling, R.M. (1993). Managing biological invasions: Assessing the risk of new introductions - Spotlight on banksias. Veld & Flora 79: 24-25.
- Rundel, P.W., Cowling, R.M., Esler, K.J., Mustart, P.J., van Jaarsveld, E. & Bezuidenhout, H. (1994). Why the halfmens (Pachypodium namaquanum) leans to the north. Veld & Flora. December 1994: 106-107.