Some good information here, but I think it's also important to rember that the terms 'sativa' and 'indica' are purely a convention of convenience, and have next to no scientific validity.
OK, as a generalisation one might say that a lowland tropical plant with thin leaves, airy buds and long flowering is a 'sativa', whereas a short, bushy, quick, wide-leaf Afghan is an 'indica'. Others might make the distinction based on whether the weed makes you want to march or flop, but again this is a pretty broad generalisation.
There are some myths in the cuurrent cannabis community (some not totally unfounded) about 'sativas' causing paranoia while 'indicas' cause a euphoric couchlock. In my experience this is quite misleading. The scariest weed I ever smoked was definitely what would be called a full-on indica, and of course, there are loads of easygoing 'sativas'. Growth habit is no guide either. They might not be common in today's established canna scene, but there are several exception to the indica-short / sativa-tall oversimplification.
So perhaps we really should be looking simply at what cannabinoid (/terpenoid) profiles produce what effects, without getting too hidebound in distinctions of pseudo-terms like 'sativa' and 'indica'.
I started a topic on the above subject on another board a while back, but the only thing I managed to establish is that we know next to nothing about it!
(Though we do have tons of entertaining mythology, most of it completely off the wall)
and about indicas being single cola columnar plants, I think that has to do mostly with the little amount of veg time most of these plants get when grown indoor, outdoors they can grow to be very tall and bushy. but it's true that sativas are usually more elongated than indicas and not as leafy.
i said indicas grown outdoors in the equator/tropics, due to the 12/12 photopheriod.
paz
Hi Elevator Man,THCV is the one that interests me most, as it's allegedly the cannabinoid with the highest ceiling, and is almost totally transparent body-wise, but produces a very psychedelic high.