finalfullthesisdjpotter

Chapter 1 Introduction
period of several weeks. This period is extended if pollen is not received. An example
of a well-developed inflorescence is shown at the front of this thesis (Page ii). Just as
leaf shape varies according to provenance, the shape of the inflorescence does also.
The inflorescences of the female can become very sticky due to a covering of resinous
glandular trichomes. These are the main source of the cannabinoids, a group of
terpenoid compounds unique to Cannabis. Consequently, the female inflorescence is
the most importance plant part to those exploiting it for its recreational or medicinal
properties. Part of a fertile female inflorescence is shown in Figure 1.2b, and the fertile
white stigmas are clearly visible against the bracts of this purple variety.
As a result of pollination the female develops copious numbers of seeds, or more
correctly achenes. These have been collected by man more several millennia for their
great nutritional value, the oil produced from crushed seeds also being used for
culinary purposes and to light lamps. The stems of some varieties are a rich source of
fibre which has also been used by man for several millennia for the production of paper,
rope, textiles and more latterly building materials and automotive parts (Wills, 1998).
During the reign of Henry VIII and Elizabeth I, farmers in this country were legally
required to grow hemp to ensure that the navy had sufficient rope and sail cloth
(Hansard (Australia), 1996). So common was Cannabis sativa L in the English
countryside that in his herbal of 1653 Nicholas Culpeper wrote, “This is so well known
in this country that I shall not need to write any description of it”.
5mm
(a) (b) (c)
Figure 1.2. (a) Male (left) and female cannabis (right) in later stage of flowering. (b) Female
cannabis inflorescence. (c) A cluster of male flowers with sepals split open and reflexed to
expose the anthers.
As a consequence of its various uses, growing of Cannabis sativa L spread to all
continents, apart perhaps from Antarctica. The original source of the species is heavily
debated but is commonly thought to have evolved in central Asia in a region
approximately 30° - 35°N with the Himalayas to the south, Turkestan to the west,
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