Fibers that are extracted from the stem of a plant are called “Bast” fibers. Flax, hemp, ramie and nettle are “soft” bast fibers that were plausibly used in clothing worn in the SCA period(600-1600 CE).
The fibers of linen are made from the plant, flax (linum usitatissimum). This plant goes through a complex process that creates soft strong fibers that are then spun into thread. There is some indication that wet-spinning didn’t start until after 1800.
Linen is a very strong cloth that becomes softer the more you wash it. It feels cool to the touch and creases easily. It is prone to wrinkling (wrinkles are period). Flax fibers will rotate clockwise when wetted. It wicks moisture away from the body so it will feel cool in the summer (cooler than the equivalent garment made in cotton).
Hemp fibers are made from the plant, cannabis (Cannabis sativa L.). Hemp is another member of the nettle family. Hemp fibers will rotate counterclockwise when wetted.
Ramie is a fiber extracted from a plant closely related to stinging nettles(with out the stinging part). This fiber was widely used in China. There are some references to it’s presence in “Eighth- and ninth-century grave finds from the northwestern tip of the Caucasus mountains” (“A Medieval Handweaver’s Bibliography”).
Wool comes from the fur of sheep. Wool fibers have small hooks in them that cause one fiber to cling to another. These hooks also cause wool fabric to shrink.
Wool can absorb up to 30% of it’s weight of water before it starts to feel wet.
Fulled wool, worsted wool, wool gaberdine, wool flannel.
Silk is the fiber that is made by silkworms to form the cocoon that the worm used to metamorphosize from worm to moth. In most cases the worm is killed in the process of extracting the fiber.
Raw silk is silk that is woven of silk fibers that still have seracin on them. This is -very- hard to find modernly. The fabric that is modernly refered to as “raw” silk is usually either china silk or silk noil.
Tussah silk is a silk fiber that is gathered after the moths emerge from their cocoons. This is “crewlty-free” silk.