domesticated plants is a second principal dimension of disruptive selection in
Cannabis(reflective of a more general disruptive selection for existence in culti-
vation or existence in nature).
The two kinds of disruptive selection described in the preceding paragraphs are
combined in the classification shown in Fig.1.12.
1.15 Conclusions
By the standards of conventional plant classification, only one species ofCannabis
merits recognition,C. sativa. Its variation pattern has been generated by human
domestication, a situation well known to mislead some botanists into recognizing
more species than appropriate.
There are three different traditions of classifying species which include
domesticates: (1) the same way that exclusively wild plants are treated: according to
a formalized Latinized nomenclatural code; (2) according to a formalized
semi-Latinized nomenclatural code designed especially for domesticated plants;
and (3) by non-Latinized, informal systems. Each of these systems has some merits
forC. sativa, but also some theoretical problems. The variation pattern ofC. sativa
is complex, particularly because of world-wide hybridization which has obscured
differences. Moreover, some authors have employed taxonomic names in confused
ways. Accordingly, recognition of and reference to taxonomic groups must take
care to communicate clearly what is and isn’t included under particular taxonomic
names. An appropriate recommendation is the KISS principle: Keep it Simple.
From both an economic and an evolutionary perspective, the most important
source of variation inCannabishas been human disruptive selection of cultivated
(domesticated) biotypes for stemfiber (accompanied by resin with limited THC)
and biotypes with high amounts of THC for use as intoxicants and medicinals.
Fig. 1.12 Classification of
Cannabis sativamodified
from Small and Cronquist
( 1976 ), illustrating conceptual
bases of delimitation
54 E. Small