A chemotaxonomic analysis of cannabinoid variation in Cannabis (Cannabaceae)
Karl W. Hillig and Paul G. Mahlberg
http://www.amjbot.org/cgi/content/full/91/6/966

Thank you for that!

Is there an idiots guide? Way over my head, that lot.

This study confirms that the THC/CBD ratio of individual Cannabis plants can be assigned to one of three discrete chemotypes. The limits between chemotypes coincide with those reported by Vollner et al. (1986) . As expected, plants with high levels of THC were common within the two drug biotypes of C. indica. However, plants with relatively high levels of THC were also common within the hemp and feral biotypes of this species. In contrast, most plants assigned to C. sativa had relatively low levels of THC. Because chemotype I, II, and III plants were found in both species, the chemotype of an individual plant is of limited use for chemotaxonomic determination of species membership.


Fig. 4. Plot of {Delta}9-tetrahydrocannabinol (THC) % vs. cannabidiol (CBD) % for 253 Cannabis plants. Chemotype I, II, and III plants are marked with an X, Y, and square, respectively. Linear regression lines (forced through the origin) are drawn for each chemotype



***

I am useless at biology, but they do not list the individual strains, rather compare examples of strain and then group them into a chemotype based on the proportions of thc/cbd

I will try to remember that paper title in case I ever have dealings with the old bill.



I reckon I might add a geographical dimension and call it chemo-topo-taxonomic.

Roger, I haven't a clue what you're on about.
Try dropping the science-speak? And then lose the pretty picture (means nowt to me, its just gobble-di-gook to my eyes)

I'm saying it does not give a nice table with the strain and ratio next to it, so it might just be telling you what you already know.

Sorry to confuse issues further but I'm pretty sure their defenition of sativa and indica are very different from ours. C. sativa is the likes of fibre and wild hemp, C. indica is anything used for drugs wether wide or narrow leafed. I'll need to look it up got stuff to do just now.

This "feral biotypes" bit is interesting, could there be something fantastic, as yet undiscovered?

most likely I would have thought. In a field with precious little proper research there are plenty of places that havent been closely studied. Syria,Burma,Iran spring to mind, let alone the african continent!

i think it just means wild hemp or the types that are grown for producing bio fuel?

the CBD /CBN / THC figure ratios are out there for various strains, its just down to someone to graph em all side by side

The Sativa Myth

my understanding of the implications of this, right or not:

Cannabis indica = cannabis which gets you stoned = Indian cannabis, South Asian
Cannabis sativa = cannabis which is useful for other stuff = Useful (sativa) cannabis, Eurasian

there are three generalised types of Cannabis indica: Wide 'leaved', Narrow 'leaved', and Chinese... these can be found in cultivated and escaped forms


Cannabis indica WLD (Wide Leaflet Dominant) - most extreme example would be what we think of as typical Afghani strains with fat leaves - including both cultivated and feral types - plants will show various ratios of THC and CBD... generally used for production of hashish or charas... generally more northern in distribution, Cannabis indica WLD is prob. in part an adaptation to desert areas and areas of low rainfall... of our strains: Mazar-i-Sharif is definitiely an example; prob. also Malana

Cannabis indica NLD (Narrow Leaflet Dominant) - generally tropical strains used for ganja production e.g. Thai, Kerala... tend to show only THC... our Highland Lao and Highland Thai would be this type

of our strains the Pahari (Kumaoni) falls between these two types --- Kumaon was once part of Nepal - Nepalese strains are said to not show CBD, just THC... Kumaon and Nepal are close to tropics - subtropical and tropical in many areas

Chinese hemp/seed varieties are also classified as Cannabis indica - usually contain CBD, can sometimes show high THC levels... our Golden Triangle Akka is from this type of genepool but was being grown for seedless ganja

Escaped (feral) populations of Cannabis indica can also show high THC (usually also CBD) --- e.g. wild (jungli) sativas in the Himalaya, Southern China etc. ... the Kullu Junlgi thread shows an example of this type

basically if you follow Hillig, any of the strains we have for sale are C. indica "Indian Cannabis"


Cannabis sativa --- a genepool centred closer to Europe (Eurasian), what we would think of as Hemp - "Useful Cannabis" i.e. for ropes - ships etc. etc.

Well, I dunno. Why change it all around, after all these years? For me, its always bee easy to grasp: Indica = Hash type plants, broad leaflet, squat and skunky to the smell, stoney body buzz. Sativa = equatorial plants, thin leaf blades, lanky and tall, racey and cerebral head rush, sometimes very psychadelic. I just cant see why we should change all this aroud. For years we've known what we mean by Indica and Sativa. We none of us grow for rope, so what is going on here?

Sorry namkha, don't mean to derail the thread. It just puzzles the heck out of me why we should all now change our understanding of things. I just can't call some finest Nigerian or Congo "Indica", because to me, quite simply, it is not. It is "Sativa".

ya know ,they told columbus ,the earth is flat too...
hmm

Your point being what, precisely?
Are you suggesting that Hillig is on the same level as Pythagoras? If so, do tell us why.

NO I am suggesting that you keep an open mind...
and arnold please try not to be so defensive

Not being defensive, I have nothing to defend.
But you seem to have! What exactly is with the:

No ... what??? NO ... point??

Look, I'm interested, that's all. Why do you think Hillig is correct, if you do? Its a huge revision of current understanding, with enormous ramifications.

I do not know if he is correct or not,
but I do know that he had the ability,funding,license, to do the research ,and wrote and published his findings...
so why would this be so hard to believe...?

and NO means just that
No,no...
No was in reference to your first question,
thats why I quoted it...
Are you suggesting that Hillig is on the same level as Pythagoras?
No, I am suggesting that you keep an open mind
ok?

Who said it was (hard to believe)?
I neither believe nor disbelieve. I do see ramifications, though.

A question: Skunk No.1: Indica, Sativa, or Hybrid? The original breeders selected equatorials (Columbian Gold, Mexican) and non-equatorials (Afghanistan) to produce a hybrid with specific traits they wished to see. They worked on producing a 75% Sativa/Indica hybrid.
If Hillig is followed, our current understanding of this goes out the window. Skunk becomes just "Indica". Yes? Or have I got that wrong?
From a growers' point of view, it becomes that much harder to see the reasoning behind the selections that have gone on in breeding a particular strain, if we follow Hillig. I happen to prefer growing Sativa heavy hybrids. But in a world of Hillig's PoV, it would become all but impossible to find such strains. Vaugue descritions of the psychoactve potential are really not the same, nor as useful as declaring a strain "x% Sat/Indica".

Hillig may be right, he may be wrong. There may not even be a right and wrong. But if he is followed, the implications are rather large.

Take a plant like "Afghani". It produces a squat plant, with huge resin production and wide leaf blades. Then take, say, a "Malawi". Hugely tall, lanky and very different in appearance. The high from both is profoundly different. Yet Hillig (and I am only going by what has been said here, as I mentioned ealier, his own words are incomprehensible to me, not being a trained Botanist) suggests that both are "Indica", because they are both "Drug" plants.
Is this not confusing?

Skunk1 is a Hybrid of course you know that...
it will always be a hybrid, no matter what its phenotypical expression shows, now you know that too. {phenotype}
its genectics will never change unless another strain is introduced...{genotype}
Afghani plants produce both Wide leaf wld and narrow leaf varieties nld...
I know this for a fact,dont need hillig to tell me that.
I have both.

Arnold ,I honestly feel that you are baseing your opinions on dutch hybrid cannabis,which is not what it once was...
I have smoked Pure Thai,in Thailand, it will knock you out cold...like a valium
I have smoked Indian Ganja on the Island of Sri Lanka...it too would make the body buzz and the head melt.
neither of these are thin leaved..both medium wide...
are they Sativa or Indica?
Thai ,South Indian...?
I always thought them sativa too... but really how the hell would I know for sure?
Im no freaking scientist,I just grow dope for 30 years...

hang on am i getting this bit right....up to a FULL 9% cbd????i thought it only measured in 0.9? with the decimal point????
wow heavy stuff!
is that true as well theres 1 in there that has 14%?!!!
wow what is it!! iwant some!

In that, my friend, we are alike. Non-scientific, wrinkly, old growers the pair of us!
I am only asking questions, making some observations. Like you, over 3 decades and I still get confused. I just want to understand what gain there is from changing to a Hilligian PoV? Is it really needed?
Oh, yes: Thanks! You've just reminded me how old I am. My first grow was 37 years ago now. Eeek.
And I love the look of your SSH on your "homepage". I must ask you more about that, in another thread maybe sometime huh?

it would be my honor to discuss tips and tricks with you arnold...

I'm not sure how much a phenotype matters when it comes to chemotype.. but a lot of people call what looks like an afghanica ( what most would call an indica ) a sativa because there's a head high. the high doesn't matter in my opinion.

from where I am coming from i.e. about 1 year of indoor growing and 12 years of traveling - mostly in Asia - but also SAmerica, Africa and Caribbean --- the Hillig thing works quite well - it fits with what I am seeing on the ground, unlike the Western/Dutch indoor sativa/indica thing which does not fit at all

if you follow the Western/Dutch "sativas give you an up heady trippy high" thing, then take Thailand as an example

in the North nr. Burma you get plants with pretty big dense buds and medium-thin leaflets which have a very heady dizzy up and trippy high... the buds are not particularly loose in the Northern strains, quite dense

so far that nearly fits

but then in the Northeast nr. to Lao you get the brown "chocolate" strains with a heavy stupefying stone --- not lowland though - Isaan is on a plateau... buds are looser though, presumably as we are further south nearer the tropics

but I have had Lao strains from n.r the Mekong which had massive calyxes and a knock you down stupour stone, more than any other landrace I have smoked except some sieved blonde from Khyber Agency (sat or ind I don't know)

anyway, all of the Thais and Laos are "sativas" according to the standard classification used by westerners - yet the effects vary greatly from the Dutch stereotype, as do the phenos --- most of the Lao and Issan strains are short - about 2m at most

personally it makes more sense to me to call any SEAsian drug strains ganja indicas --- (well, except the WLD ones in Yunnan which they use for handrubbed charas...)

oh yeah, and according to some Thai growers, most Thai strains that are prized by Thais are fairly short strains (ganja lek) ---- the larger drug strains (ganja yai) are generally seen as "take it or leave it".... no doubt there are exceptions to this

...and then how about short wide leaved Burmese strains - sativa or indica? ---- if you ask me they are ganja indicas --- Burmese are often short plants, but then again some will go to 3m

how about the short Nepalese strains I have found (pics to come, location secret)? Narrow leaved but with very tight internodes and a low profile. Sativa or indica? They are used for charas, so I would say they are charas indicas....

are the strains from Malana and Kashmir with medium width leaflets which are used for charas (handrubbed or sieved depending on the village or valley) sativas or indicas....? if you ask me, it is most accurate to call them all charas indicas

as for Afghanistan and Pakistan --- in the Hillig sense you find both WLD and NLD indicas there
according to the Dutch Western definition a real Afghan is one which knocks you on the head and leaves you heavy and fuzzy - it should be short, with short internodes

and yet look at any old school book on Afghanistan and you will see that the most prized Afghan hash was one which has a heady euphoric effect, mellow but not too heavy.... I will back that up with quotes in a following post... it fits with my experience of smoking the best Mazar-i-Sharif I could find

and some Mazar strains can reach up to 3m or more --- NWFP strains can be creeper sativa plants with narrow leaflets and a low profile

I coould give many more examples of how what you find on the ground fails to fit with the Western/Dutch sativa/indica thing

so basically the main reason I chose to follow Hillig's definition is that it fits what I have found traveling between Central and SEAsia across the Himalaya

basically I would chose to modify Hillig with a pragmatic slant - except... "I haven't the Latin"

e.g.

Thai - Cannabis indica NLD var. ganja
Malana - Cannabis indica MLD var. handrubbed charas
Mazar-i-Sharif - Cannabis indica WLD var. sieved charas

someone with more concentration and Classics could make that a little less clunky I'm sure, but I think you see what I'm getting at

oh yeah - I would like to copy out Clarke's paras on the probable way that the Afghan strains of the 70s emerged - if I remember right it is something like this"

the short squat wide-leaved classic Afghan as we think of it is a desert landrace - evolved with short internodes and wide leaves in order to slow down water transpiration and direct night condensation to the centre of the plant
tall drug "sativa" NLD cultivars as recorded by earlier Russian botanists were already in cultivation around the Oxus/Amu Darya in the late 19th cent
migrating Turks from Kasghar etc. hybridised wild WLD indicas with existing NLD indicas....
feral WLD indicas would already have been semi-cultivated by kuchi nomads etc. anyway who used them for medicine

I'll find some modern links to threads showing the kind of plants you find wild in places like Swat and Khyber --- they are WLD indicas... as also in a famous pic of Evans Schultes crouched over a wild plant near Kandahar

if I have got Hillig right, the reason Cannabis sativa - in the sense of Hemp - should be seen as a separate species from drug cannabis is to do with it's DNA --- centuries and breeding have given it a different genetic code - it lacks the code (the BtBt allele or BtBd allele) which is needed to produce the stuff which gets you high - THC

med users should certainly want some
but if you want it to get high it won't be much use - CBD doesn't really get you high, but it has the most useful medical effects cf. Raphael Mechoulam

Hey Arnold,

I think the Western-Dutch sativa/indica thing works fine when confined to what is available from most seedbanks - but it is IME it is useless when you start looking at traditional strains in their homelands ---- which make up the overwhelming % of the cannabis in the world, and the overwhelming % of cannabis biodiversity

Hillig's classification, for me at least, is much more accurate when applied to historic varieties

Just to address your two examples:

The Malawi you are talking about sounds like the lowland Malawi Gold from Nkhotakhota.
How about the Malawis from the northern highlands, and across the border in the same highland ranges as they reach into Southern Tanzania - these are very short plants, with long narrow leaves, and are very fast flowering...


Or the tall narrow leaved Afghan "sativas" which are another strain grown around Mazar and used for charas? (Or the short wide-leaved strains grown and found wild in Swat Valley?) Or the tall narrow leaved strains with dense buds cultivated in Upper Chitral? Or the creeper growth sativas grown in Khyber Agency?
Almost all the latter are northern narrow leaved strains used for charas. Are they sativas? ... I would call them charas indicas, wide or narrow leaved...

I'd call the Malawis "ganja indicas"

as an aside, IMHO most African strains made their way to East Africa from the Malabar Coast (Southern India) with Arab, Indian and Roman traders... some Ethiopian traders may have brought Bengali ganja strains to Ethiopia too

The Nigerian and Congolese "sativas" you mention would almost certainly have made their way to Africa from India, one way or another... their is some material in Schultes on the evidence of cannabis smoking in Africa - earliest material is found in East Africa... the practice spread fast through the continent

Oh, I don't disagree at all namkha - I can see exactly what you're saying and it certainly does make absolute sense, as do Scorpion's observations.
I think what I am saying is that its going to confuse some, when the read the strain descriptions on seed packs.

You have clearly travelled much more than I have you lucky so and so! Envious? No, just a gentle shade of green

hey - if it's any consolation, I live and look like a tramp - I'm told I smell alright though

I reckon for people who can't face reading the whole paper, it's worth reading the conclusion

Small and Cronquist (1976) assumed that the sativa and indica taxa diverged primarily as a result of human selection for fiber and/or seed production on the one hand and for high THC production on the other. However, the present investigation does not support this hypothesis. The high frequency of BT in the feral biotype of C. indica suggests that this allele may have been present at high frequency in the C. indica gene pool prior to domestication. Human selection of plants carrying two copies of the BT allele appears only to be of appreciable significance in the domestication of the NLD biotype. Human selection may have resulted in an increase in the quantitative levels of cannabinoids produced by the WLD biotype, but the average amount of CBD + THC produced by the NLD biotype did not significantly differ from the hemp and feral biotypes of C. indica. In fact, the average amount of THC + CBD produced by the NLD accessions was not significantly greater than the average amount of these two cannabinoids produced by the hemp accessions of C. sativa. Small and Beckstead (1973b) also reported comparable levels of total cannabinoids in their "psychotomimetic" and "non-psychotomimetic" strains. Plants with enhanced levels of THCV were uncommon in most drug accessions, except those from southern Africa and an accession from Afghanistan. This suggests that humans may have selected against this trait in cultivated drug strains.

In contrast with the NLD biotype, the WLD biotype did not have a significantly higher frequency of BT than the hemp and feral biotypes of C. indica. This may be explained by the different products obtained from the two drug biotypes of C. indica. NLD strains are usually cultivated for the production of marijuana (pistillate inflorescences), and it is the product of a single plant that is utilized. WLD strains are traditionally cultivated for the production of hashish (detached glandular trichomes), which is the combined product of many plants. A marijuana plant with two CD alleles (chemotype III) would be ineffectual for its intended use, whereas hashish made from a population of chemotype I, II, and III individuals typically contains more THC than CBD and depending on the proportions of the different chemotypes is more or less psychoactive (Ek et al., 1972 ; Clarke, 1998 ). Thus, human selection is expected to favor chemotype I plants as seed sources for marijuana cultivation, whereas the chemotypes of individual plants cultivated for hashish production are usually unknown to the cultivator (Clarke and Watson, 2002 ).

The presence of allele BT in the C. sativa gene pool suggests that introgression from C. indica might have played a role in the evolution of C. sativa. Wind-blown pollen may have contributed to allele migration between the two gene pools (Cabezudo et al., 1997 ). Relatively high BT frequencies (range 0.38–0.55) were detected in seven hemp accessions from Turkey, Spain, Italy, former Yugoslavia, and southern Russia, which are assignable to the southern eco-geographical group of C. sativa (Davidyan, 1972 ). Additional allozyme markers and morphological traits typical of C. indica were also observed in the southern group of C. sativa (Hillig, 2004 , in press). Cannabis indica may have been introduced into Asia Minor for the purpose of hashish production and hybridized with C. sativa. Davidian (1972) cited evidence that Cannabis was introduced into Europe by both a northern and a southern route. Introgressed stock may have spread into new areas through trade or human migration (Heiser, 1973 ).

The patterns of cannabinoid variation provide evidence of progenitor-derivative relationships. The low frequency of BT and the low levels of propyl cannabinoids in accessions assigned to C. ruderalis suggest that this putative taxon could be the progenitor of C. sativa, but not of C. indica. The feral biotype of C. sativa may be comprised of "escaped" populations of cultivated C. sativa that have merged with naturalized populations of C. ruderalis (Vavilov, 1926 ). The wide range of cannabinoid variation within feral accessions of C. indica suggests that this biotype could be the progenitor of the cultivated biotypes of C. indica. The high incidence of plants in this taxon with enhanced levels of propyl cannabinoids suggests that it is not the progenitor of C. sativa, in which plants with enhanced levels of propyl cannabinoids are much less common. It is unlikely that the feral biotype of C. indica represents an escape of NLD strains from cultivation because the NLD biotype is lacking in cannabinoid variation. The high frequency of BT in the hemp biotype of C. indica suggests the possibility that one or both drug biotypes could have been secondarily derived from this taxon's gene pool. More feral and cultivated populations of C. indica and C. sativa will have to be studied to further resolve these issues.

This study of cannabinoid variation supports a two-species concept for Cannabis. A taxonomic revision that applies valid scientific names to the biotypes of C. indica recognized herein is supported by the chemotaxonomic data.

heh, can someone summerize that into stupid for me?

Blimey namkha - what is that all about? What is BT? What is "psychotomimetic"? And "Allele"??
I think I get a little of what he's saying, though. Its all fascinans, even tremens, yet remaining a mysterium. A holy plant, indeed, borne upon the Ruach Adonai from one continent to another, a sounding of the Logos in the psyche of men, every hit a regeneration of the soul, a baptism in the Divine Pneuma.
Oooh, I love dirty talk!

I think my aftershave balm maybe pychoactive

And I'm sure you smell just lovely M8!

Maybe we can get Booj in to translate? Or at least explain what an allele is for stoners.

Here's an example of an allele - "An example is the gene for blossom colour in many species of flower — a single gene controls the colour of the petals, but there may be several different versions (or alleles) of the gene. One version might result in red petals, while another might result in white petals. The resulting colour of an individual flower will depend on which two alleles it possesses for the gene and how the two interact."

The alleles we're interested in are Bt which is for producing THC and Bd which is for CBD. These come in pairs either Bt Bt (THC strain) Bd Bd CBD strain) or Bt Bd mix of both.

Logos = word of God? Ruach Adonai = ?

The first paragraph says that man didn't have the affect on cannabinoids he thinks he did, wild and feral strains have just as much variation in the alleles. I think, it says more than that but that's what I remember. Will have another look at the rest later.

Cheers for the posts Namkha.

Breath/Spirit of God.
It was just my way of trying to exemplify the dangers of in-house techno-sppeak when addressing those whose discipline is different. I find Scientists are often like theologians, very clever but struggling to make sense to the common man.
Technical vocabulary is essential for those in the know, but a real obstacle to comprehension for those who are not.

So an Allele is a gene? As in, here is a gene that controls say smell. One version yields a fruit smell, another a hashy smell. These variations = "Alleles" of the smell gene?

Still puzzled by "psychotomimetic", though. Going to have to look that one up!

Edit2Add:
Got it! "psychotomimetic" means something that mimics psychosis. That is: something that gets you high.
I think


Yup, great info namkha. Ta muchly for it.

You got psychomimetic yeah. An allele is one of a pair of alleles that make up a gene (other organisms can have more). The different combinations of alleles accounts for the differences we see. I think, pretty sure that's right.

This aint right - I'm learning Science!!

haha funny stuff

yeah, I'm not claiming I've entirely got my head round that Hillig paper - someone somewhere has a list of the 200 or so vars. he tested, which would make things a lot clearer

if I'm following it right, I would also like to know exactly what he is suggesting the original C. indica could have been, and whereabouts the genepool might have been centred - what the closest thing is to it growing now... feral/jungli stands around Tajikistan somewhere or what?

also, the psychoactive southern Eurasian C. sativa thing also makes stuff a bit confusing

anyway Arnold I wouldn't be so sure I smell that great --- prob. a bit better than the Ruach Adoni, but then could anyone say for certain when was the last time Yahwe brushed his teeth?

Hairy Om and all that,

Namkha

Real Seed Co varieties likely to produce plants with significant CBD content

Mazar-i-Sharif
Sheberghan
Parvati
Malana

all the above are from northern hashish/charas producing regions

also:

Golden Triangle Akka
a ganja strain from Lao with Yunnanese origins - part of the Chinese indica genepool, likely to contain CBD

@Namkha
Have you detemined the Cannabinoid profile of the strains above with TLC for identification, if not how sure are you that the strains above do contain CBD in medicinal quantity (>2%).

Peace

El Manito

hey El Manito --- no, none of these have been analyzed --- hence why I'm trying to be careful with the language I'm using i.e. "likely to" --- going on the basis of the Hillig paper that is quite a strong "likely to" --- but no, I can repeat again for emphasis, none of our strains have been analyzed scientifically for cannabinoid profile --- it's something that we intend to do asap, but have not yet

@Namkha

If you need help with that.Just let me know!

Peace

El Manito

i read a book from the 80's and they said the same thing about sativas for hemp and indicas for drugs. i agree that us growers and them scientists might use different descriptions but i just don't think of thin leaf, long flowering plants as indicas.....just sounds like a generalisation to me!

I have hit 3 of my kullu girls with bd/bd pollen to isolate possible bd chemotypes. Will pollinate a fourth one as well as one mazar later. So far 3 have tested positive for thc, but they may be cbd producers too. My method of testing is smoking the leaves which imo is quite accurate. when I bump into a bd/bd plant I'll know because it won't get me high at all. I also have a bd/bt cross I can use but it's easier to go with the cbd only strain.

DR. P, for me the smoke test is the only test and i think that goes for most ppl.

its good that u guys with real tech skills are investigating the THC, CBD content of various strains.
as a Med grower I keep a close watch on this thread
and Namkha it would be sooooo great if u can give an approximate guide to the THC, CBD content of your seeds.
but i think, in some cases, that may prove v difficult with the phenotype variations from your seed suppliers.

what i would really like to know is, what strain or strains were used as the basis for creating Sativex. but thats not going to happen.

The strains which the company GW Pharmaceuticals is using are developed by the company Hortapharm stationed in the Netherlands.I think for the THC-strain they used a Thai strain and for the CBD strain hemp of a some kind.

Namaste

If you really want to get your head around that paper, then Hillig's article on "Genetic evidence for speciation in Cannabis" is a must-read. It includes a list of the strains he included in his research, and is the foundation on which his other studies are built. I picked up a copy of his dissertation on-line , and it cost less than an eighth of sticky bud. It's a heavy slog, but as they say, "no pain, no gain."

Welcome to UK420 Uncle Bugpoop and thank you so very much for that link!

does any one have a complete list of Hillig's papers?

A chemotaxnomoic analysis of cannabinoid variation in cannabis (Cannabaceae)
Karl W. Hillig2 and Paul G. Mahlberg
Department of Biology, Indiana University, Bloomington, Indiana 47405 USA
http://www.amjbot.org/cgi/content/full/91/6/966
2004 - 2004

Genetic evidence for speciation in Cannabis (Cannabaceae)
Karl Hillig
2005

A systematic investigation of cannabis
Karl Hillig
2005

if you can incluude links for where they can be read or downloaded that would be ideal

many thanks