Cannabis Taxonomy: The "sativa" vs. "indica" debate

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arijuana and hemp
(Cannabis) and the
closely related hop genus
(Humulus) are the only widely
known genera included in the
small, but economically valu-
able, Cannabaceae family. Swed-
ish botanist Carl Linnaeus, the
“father of modern taxonomy,”
first published the scientific name
Cannabis sativa in his seminal
Species Plantarum of 1753. The
Latin name Cannabis derives
from Greek (kannabis) and may
have been originally derived from
Scythian. The term sativa simply
means “cultivated” and describes
the common hemp plant that was
widely grown across Europe in
Linnaeus’ time. We, the authors,
consider C. sativa to be native
to western Eurasia and especially
Europe, where, for millennia, the
plant has been grown for its strong
fibers and nutritious seeds, and
from where it was introduced to
the New World multiple times
during early European coloniza-
tion. Cannabis sativa plants also
produce very small amounts of
the compound delta-9-tetrahydro-
cannabinol (THC), the medically
valuable and primary psychoac-
tive cannabinoid found only in
Cannabis. Since C. sativa evolved
within the geographical limits of
western Eurasia, it represents only
a small portion of the genetic
diversity seen in the genus Canna-
bis worldwide.1
In 1785, European natu-
ralist Jean-Baptiste Lamarck
described and named a second
species, Cannabis indica, mean-
ing “Cannabis from India,” after
the origin of the first samples of
this highly psychoactive plant that
By Robert C. Clarke and
Mark D. Merlin, PhD
CANNABIS TAXONOMY:
The ‘Sativa’ Vs.
‘Indica’ Debate
44 • ISSUE 110 • 2016 • www.herbalgram.org
Ripe female marijuana flowers
are covered with glandular
trichomes or resin glands.1
Photo ©2016 Todd McCormick

www.herbalgram.org • 2016 • ISSUE 110 • 45
reached Europe. Cannabis indica has the genetic potential
to produce relatively large amounts of THC. The species is
used for marijuana and hashish production, but in many
regions of eastern Asia it also has a long history of cultiva-
tion for fiber and seed. Humans make cloth out of C. indica
fibers and eat the seeds, but this native eastern Eurasian
species is more commonly used today as a drug plant with
widespread social and medicinal importance reaching well
beyond its original geographical range.1
While Karl Hillig, PhD, was a doctoral student at
Indiana University, he used morphological and chemical
characteristics to investigate the diversity of the Cannabis
genus and proposed taxonomic groupings (subspecies) that
support the original two-species concept.2 -5 Hillig recog-
nized European cultivated Cannabis as a separate species
(C. sativa). Because this species typically has narrow leaflets
and is primarily used for hemp fiber and seed production,
we refer to it as narrow leaflet hemp (NLH). European C.
sativa NLH populations are much less genetically diverse
than those found in many other regions.
Hillig assigned the remainder of the world’s cultivated
varieties to C. indica and divided them into three subspe-
cies. One of these subspecies, C. indica subsp. indica,
includes varieties that span the Indian subcontinent from
Southeast Asia to western India and into Africa. These
traditional drug varieties produce abundant amounts of
THC with little if any cannabidiol (CBD). CBD is the
second most common cannabinoid, and is non-psychoac-
tive, but it has been shown to be medicinally effective for
a variety of indications. By the 19th century, high-THC
C. indica subsp. indica reached the Caribbean region and
steadily spread throughout Central and South America.
Since the 1960s, most of the drug Cannabis that reached
North America and Europe was C. indica subsp. indica.
Marijuana users commonly call domestically grown plants
of these varieties “sativas” because their leaflets are relatively
narrow, and therefore exhibit a superficial resemblance to
those of European NLH plants. However, in our construct,
this is a misnomer as C. sativa plants produce little if any
THC. Based on Hillig’s research, we now refer to members
of C. indica subsp. indica as narrow leaf let drug (NLD)
varieties. Although they have relatively narrow leaf lets like
NLH (C. sativa) plants, the NLD plants can produce an
abundance of THC and are most commonly used for their
psychoactive effects. Based on taxonomic tradition, these
plants are properly called “indicas” rather than “sativas.”
A second C. indica subspecies originated in Afghanistan
where crops were traditionally grown to manufacture sieved
hashish, a mechanically concentrated Cannabis drug. From
1974 , when descriptions and photos of Afghan Cannabis
were published by Harvard professor Richard E. Schultes,
PhD, it became readily apparent that it represented a type
of drug Cannabis previously unknown outside of Eurasia,
belonging neither to Linnaeus’ C. sativa nor Lamarck’s C.
indica.6 Its shorter, more robust stature, and broad, dark
green leaves easily distinguish it from the taller, lighter
green, and more laxly branched NLD varieties. Because
of its limited geographic range and restricted usage, the
Afghan genome is less diverse than the NLD genome. By
the late 1970s, seeds of Afghan hashish varieties reached
Europe and North America and were rapidly disseminated
among marijuana growers. At this time, all Cannabis vari-
Cannabis sativa
Photo ©2016 Steven Foster

46 • ISSUE 110 • 2016 • www.herbalgram.org
eties were commonly considered to be members of a single
species, C. sativa, and the familiar NLD marijuana varieties
were called “sativas” to differentiate them from the newly
introduced and quite different looking Afghan varieties
commonly called “indicas.” Hillig named them C. indica
subsp. afghanica, which we now refer to as broad leaf-
let drug (BLD) varieties to differentiate them from NLD
varieties. On average, populations of BLD plants contain
approximately equal amounts of THC and CBD. Although
BLD varieties are also considered by us to be members of C.
indica, it is more correct to distinguish them from subspe-
cies indica from India by calling them subspecies afghanica,
or simply “Afghans.”
Hillig’s third grouping within C. indica is subspecies
chinensis, which comprises the traditional East Asian fiber
and seed varieties and associated feral populations. We
refer to this group as broad leaf let hemp (BLH). Like other
subspecies of C. indica, varieties of C. indica subsp. chinensis
possess the genetic potential to produce psychoactive THC,
but East Asian cultural traditions, such as Confucian-
ism, have long encouraged the selection of these varieties
for their economically valuable fiber and seed, rather than
their psychoactive potential. As a result, total cannabinoid
production is lower than in subspecies indica and afghanica.
Evolutionary theory predicts that, at some point in time,
there must have been a putative ancestor of the two modern
species, C. sativa and C. indica. This ancient ancestor is
often referred to as C. ruderalis, which may have origi-
nated somewhere in Central Asia. However, by now it is
probably extinct, and seemingly ancestral populations are
more likely descendants of feral plants that escaped from
cultivation long ago. Evolutionary hypotheses based on
plant distribution studies, paleoclimate modeling, archaeo-
logical evidence, and the historical record propose that C.
sativa NLH most likely originated in a temperate region of
western Eurasia, possibly in the foothills of the Caucasus
Mountains, from a putative hemp ancestor with diminished
biosynthetic potential to produce THC. Cannabis indica
likely originated in the Hengduan Mountains, in present-
day southwestern China, from a putative drug ancestor that
had evolved an enhanced ability to produce THC. Early C.
indica populations diversified as they were introduced by
humans to different geographical regions where they may
have further evolved into the three subspecies, all of which
produce THC.1
Cultivated plant varieties are called cultivars, and when
cultivars are grown and maintained by local farmers over
generations, we refer to them as landrace cultivars, or land-
races. Landraces evolve in a balance between natural selec-
tive pressures exerted by the local environment favoring
survival, and human selections favor-
ing a cultivar’s ability to both thrive
under cultivation and produce particu-
lar culturally preferred products. Early
humans spread Cannabis into many new
regions as they moved, and at each new
camp or settlement they selected seed
from superior plants that were suited
to their own uses and processing meth-
ods. By sowing seeds from the most
favorable individuals, traditional farm-
ers developed and maintained the land-
races upon which present-day hybrid
hemp and drug cultivars were founded.
Hemp cultivars were derived from
crosses between different European
NLH landraces and East Asian BLH
Table 1. Twenty-first century Canna-
bis taxonomy
Cannabis is presently subdivided into
two species, C. sativa and C. indica.
Cannabis indica is further divided into
three subspecies, C. indica subsp. chinen-
sis, C. indica subsp. indica, and C. indica
subsp. afghanica. Cannabis sativa and
C. indica subsp. chinensis are hemp
cultivars most commonly grown for fiber
and seed. Cultivars of C. indica subsp.
indica and C. indica subsp. afghanica are
most commonly grown for their drug
content, and most modern sinsemilla
drug Cannabis cultivars are hybrids of C.
indica subsp. indica and C. indica subsp.
afghanica landraces.

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Cannabis sativa
Photo ©2016 Steven Foster

48 • ISSUE 110 • 2016 • www.herbalgram.org
landraces. Traditional Asian,
African, and New World drug
landraces were, until relatively
recently, all pure NLD types.
Before the introduction of BLD
landraces from Afghanistan in
the late 1970s, hybrids between
imported NLD landraces formed
the core genome of domestically
produced drug Cannabis in both
North America and Europe. It is
through crossing NLD and BLD
landraces from such geographi-
cally isolated populations that
modern hybrid sinsemilla (Span-
ish for “seedless”) cultivars were
created.1
Unfortunately, we cannot
return today to a region previ-
ously known for its fine Canna-
bis and expect to find the same
landraces that were growing there
decades before. Cannabis is open-
pollinated, with male and female flowers borne on sepa-
rate plants, and, therefore, two plants are usually required
to produce a seed. Random combinations of alleles (forms
of a gene) and accompanying variation are to be expected.
Cannabis landrace varieties are best maintained by repeated
natural and human selection in situ — nature selecting
for survival and humans selecting for beneficial traits.
Without persistent human
selection and maintenance,
these landrace varieties will
tend to drift back to their
atavistic, naturally selected
survival mode.
The Western world began
using imported marijuana
and hashish in the 1960s,
and all of the remarkable
imported varieties avail-
able then were tradition-
ally maintained landra-
ces. Within a decade, the
demand for quality drug
Cannabis exceeded tradi-
tional supplies, and mass
production in the absence
of selection became the
rule. Rather than plant-
ing only select seeds, farm-
ers began to sow all their
seeds in an effort to supply
market demand, and the quality of commercially avail-
able drug Cannabis began to decline. In addition, travel-
ers returned to the supplying nations and introduced seeds
of “improved” Western sinsemilla varieties that interbred
with the local landraces and thus contaminated the local
genomes. Landraces can no longer be replaced; they can
only be preserved. The few remaining pure landrace variet-
Cannabis resin glands secrete an aromatic essential oil
that contains medicinally important cannabinoids and
terpenoids.1 Photo ©2016 Marcus Richardson
Figure 1. Present-day distribution of Cannabis subspecies
Humans spread Cannabis worldwide for a variety of uses. The putative ancestor (PA) of all Cannabis originated some-
where in Central Asia. Our evolutionary hypothesis proposes that as Cannabis spread into new geographical regions and
cultural contexts, it evolved into four major gene pools and taxonomic groups: C. sativa narrow leaflet hemp (NLH), C. indica
subsp. chinensis broad leaflet hemp (BLH), C. indica subsp. indica narrow leaflet drug (NLD), and C. indica subsp. afghanica
broad leaflet drug (BLD) landraces. These four groups also include feral escapes from cultivation and “wild” populations.1

www.herbalgram.org • 2016 • ISSUE 110 • 49
ies in existence now, some kept alive for decades as seeds and
cuttings, are the keys to future developments in drug Canna-
bis breeding and evolution. It will be a continuing shame to
lose the best results of hundreds of years of selection by local
farmers. After all, our role should be as caretakers preserving
the legacy of traditional farmers for the future benefit of all.
Cannabis research is a work in progress, and not all
researchers agree on a single taxonomy.7 DNA sequencing
is currently being used to characterize the diversity of many
plant and animal groups, including Cannabis. While our
knowledge grows and the evolutionary history of Cannabis is
revealed, changes in taxonomic nomenclature will continue
to reflect our deepening understanding of this medically
valuable, yet controversial, plant. More broadly, whether
we discover that Cannabis plants belong to one or more
species, we can be sure that humans have long known, used,
dispersed, cultivated, and artificially selected these plants to
perpetuate a truly wide range of diversity.
Robert C. Clarke is the author of several Cannabis science
books and has traveled extensively throughout Eurasia docu-
menting traditional Cannabis production and use. His breed-
ing interests include selection and preservation of landrace
varieties, and developing narrow leaflet drug varieties and
hashish cultivars. Clarke is the co-founder and director of
BioAgronomics Group, an international cannabis industry
consultancy, serves as projects manager for the International
Hemp Association, and holds a seat on the Phylos Bioscience
Cannabis Evolution Project scientific advisory board. He may
be contacted at rob@bioagronomics.com.
Mark D. Merlin, PhD, is a professor in the
botany department of the University of Hawai`i
at Mānoa and an elected member of the Linnean
Society of London. A large part of his long-term
biological and historical research has involved drug
plants and their past and present uses by people.
He has authored or co-authored a number of books
on this general subject, including Man and Mari-
juana: Some Aspects of their Ancient Relationships
(Fairleigh Dickinson University Press, 1972), On
the Trail of the Ancient Opium Poppy (Associated
University Presses, 1984), Kava: The Pacific Drug
(co-authored with Vincent Lebot and Lamont
Lindstrom; Yale University Press, 1992), and, most
recently, Cannabis: Evolution and Ethnobotany
(co-authored with Robert C. Clarke; University
of California Press, 2013). He may be contacted at
merlin@hawaii.edu.
Modern sinsemilla crops are vegetatively
reproduced in glass houses to ensure uniformity
and quality.1
Photo ©2016 Todd McCormick
References
1. Clarke RC, Merlin MD. Cannabis: Evolution and
Ethnobotany. Berkeley, CA: University of California
Press; 2013.
2. Hillig KW. A chemotaxonomic analysis of terpe-
noid variation in Cannabis. Biochem Syst Ecol.
2004;32(10):875-891.
3. Hillig KW. A multivariate analysis of allozyme
variation in 93 Cannabis accessions from the
VIR Germplasm Collection. J Indust Hemp.
2004;9(2):5-22.
4. Hillig KW. Genetic evidence for speciation in
Cannabis (Cannabaceae). Genet Resour Crop Ev.
2005;52(2):161-180.
5. Hillig KW, Mahlberg PG. A chemotaxonomic
analysis of cannabinoid variation in Cannabis
(Cannabaceae). Am J Bot. 2004;91(6):966-975.
6. Schultes RE, Klein WM, Plowman T, Lockwood
TE. Cannabis: An example of taxonomic neglect.
Bot Mus Leafl Harv Univ. 1974;23(9):337-364.
7. Small E. Evolution and classification of Cannabis
sativa (marijuana, hemp) in relation to human
utilization. Bot Rev. 2015;81(3):189-294.