Flax consisdered a tree due to Joshua 2:6. Wool and linen subject to different laws than other fabrics. Tzaraas (biblical leprosy) of clothing leads to examination by a priest and possible quarantine or burning. Shatnetz (prohibited mixture of wool and linen) as applied to tzitzis (ritual fringes). Lentil-bulk is thr minimum measure of sharetz (creeping thing) that imparts tumah (ritual impurity).