Cannabis sativa L. - Botany and Biotechnology

(Jacob Rumans) #1

in ways that are distinctive from the conventional way of classifying wild plants
(for examples, see Styles ( 1986 ); Styles [for reviews, see Hetterscheid et al. ( 1996 )
and Hammer and Morimoto ( 2012 )]. A comprehensive non-formal classification
system forCannabishas not yet been proposed.


1.12 How Many Species of Cannabis Merit Recognition?


As evidenced by the preceding discussion, the contention that there are several
species ofCannabisis simply a semantic preference, not dictated just by scientific
considerations but by personal idiosyncrasies. Botanical taxonomists are familiar
with competing taxonomic interpretations regarding species status, but most have
limited tolerance for eccentric recognition of species that are inconsistent with
conventional norms. In particular, most taxonomists are suspicious of alleged spe-
cies that are 100% interfertile, as are the putative species ofCannabis. More criti-
cally, when no one has provided a reliable means of morphologically distinguishing
the proposed species, few plant taxonomists would accept their recognition. There is
no supreme organization or authority that judges the comparative merit of given
taxonomic treatments. However, competing taxonomies are judged by users, the
most knowledgeable of which are those who prepare guides to theflora of regions.
Today, virtually all authoritativefloras recognize only one species ofCannabis,
C. sativa[see for example Qaiser ( 1973 ), Tutin and Edmonson ( 1993 ), Small ( 1997 )
and Wu et al. ( 2003 )] indicating that the designation of more than one species is
inappropriate by contemporary standards. Moreover, as stated by de Meijer ( 2014 ):
“A monospecific concept...has implicitly been adopted in virtually all, nontaxo-
nomic, publications onCannabis...The current pattern ofCannabisdiversity is
primarily due to intentional actions of humans and reflects a long, intense, and
divergent process of domestication which has blurred any natural evolutionary
pattern of diversity. It is even questionable if truly wildCannabisstill exists.”
As discussed above, the recognition of more than one species ofCannabisis
typical of the overclassification of domesticated crops. Harlan and de Wet ( 1971 )
wrote about this problem:“Man has been very active in manipulating the gene pools
through repeated introductions or migrations, followed by natural or artificial
hybridization. The germ plasm of domesticated plants has been repeatedly and
periodically stirred. The environment provided has been artificial, unstable and often
very extensive geographically. Selection pressures have been very strong, but bio-
logically capricious and often in diverse directions. The end result is an enormous
amount of conspicuous variation among very closely related forms. Faced with this
situation, the traditional taxonomist tends to overclasssify. Hefinds conspicuous
either-or characters, often without intermediates, and frequently bases“species”on
them. The characters may be controlled by one or a few genes and have little
biological significance. Too many species and too many genera are named.”
Based on multivariate statistical similarities of allozyme frequency, Hillig
(2005a, b) separated European fiber plants from the three more easterly


50 E. Small

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