Cannabis afghanica
A subspecies of Cannabis indica that originated in (or near) Afghanistan. Like indica (and unlike sativa), it is a short plant. Unlike indica that can grow to a maximum height of 8-10 feet outdoors, afghanica will only grow to a maximum height of 6 feet. Cannabis afghanica leaves look similar to indica plant leaves, but they are even wider.
The plants have a high cannabinoid content and in Afghanistan they are most often used to produce hashish (rather than marijuana). The hashish from Afghanistan has mainly been produced by hand rubbing (although sieving has a long history in the area).
This may account for the origin of the subspecies. Indica plants being selectively cultivated and mated to produce a subspecies of short plants with a fairly high THC content. Being geographically isolated (over a period of centuries), plants developed certain characteristics that now distinguish Cannabis afghanica from Cannabis indica.
A seed strain that comes from afghanica heritage will usually have afghan, afghani, or something along those lines in its name. For example, afgani haze is a strain that was developed by crossing Cannabis afghanica with haze plants.