Paper presented at the IFEAT Int. Conference in Cape Town

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The Cape Floral Kingdom, often also referred to as ‘Fynbos’ due to the fine shrubby nature of most ofits ca. 8,700 species, ranges over a narrow band (~60km wide) along the South Western Cape coastlinefrom ~200km north of Cape Town to Port Elizabeth, ~700km to the east of Cape Town. In general‘Fynbos’ vegetation is characterised by many low bushy shrub-like plants and few trees [2] .Natural occurrenceTypical Fynbos scene The natural ranges for A. betulina and A.crenulata are, however, much smaller than thetotal Cape Floral Kingdom range and also aregeographically separated:• Natural A. betulina occurs in mountainousregions from Gouda northwards to Piketberg,Aurora in the west to the Cederbergmountains northeast of Piketberg [3] .• A. crenulata is found naturally in an evensmaller area, ranging from the HottentotsHolland mountains around Somerset-West inthe south to the mountains around Tulbagh,~100km to the north.• The natural occurrence of the third “species”,A. betulina x crenulata (or hybrid buchu), isrelatively unclear.Two phenotypically indistinguishable chemotypes of A. betulina have been described [3] :• an isomenthone chemotype that is mainly found in the wild in the Piketberg region, and• a diosphenol chemotype that occurs naturally only in the eastern portion of A. betulina’srange, in the Cederberg mountains.The hybridThere is a school of thought that ascribes the emergence of the hybrid, A. betulina x crenulata, to theplanting of cultivated A. betulina and A. crenulata plants in the same fields by early buchu farmers.Another school of thought describes it not as a true hybrid species, but rather as a unique population orchemotype of A. crenulata (since phenotypically, adult A. betulina x crenulata plants usually havemuch more in common with A. crenulata than A. betulina, and the chemistry of its essential oil is99
much closer related to that of A. crenulata, although it does contain elements of A. betulina oil aswell). A third school of thought doubts its existence altogether, ascribing the chemistry of a buchu oilcontaining characteristics of both species to the distillation of both A. betulina and A. crenulata plantsin one batch. Since the identification of all the components found in buchu oil in 1975 [4] and thedevelopment of accurate analytical GC analyses of buchu oils obtained from single plants withinSouth Africa in the early 1990s, it has been shown that A. betulina x crenulata certainly does exist.Whether it is a true hybrid, or a population / chemotype of A. crenulata still remains unclear.It has to be stressed that, due to cultivation of buchu, and the small area in which it successfully grows,the natural ranges of each of the species described here do not reflect the cultivated ranges well. Theold habit of obtaining buchu seeds or plant material only from a certain area as an assurance of itsgenetic identity is therefore a very risky venture indeed.Morphological characteristicsThe three species of buchu that are currently cultivated for essentialoil production are perennial shrubs with woody branches and smalldotted leaves and they are sometimes difficult to distinguish fromeach other within the first year of growth.At the mature stage:• A. betulina displays a round leaf and is commonly knownas ‘round leaf buchu’; while• A. crenulata has an oval leaf and is called as such.Botanical drawings of buchu leafshapes for commercial species A. betulinaA. crenulata100
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Paper presented at the IFEAT Int. Conference in Cape Town

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