This discolouration is very serious because it is not completely scourable. This applies to wool only. This can apply to both white and coloured fleeces, though mainly coloured. It describes where the tips have been bleached by the sun, making them tender, or on slightly overgrown fleeces where harsh conditions have caused tender tips. These fibres are harsh-handling and lack strength and elasticity.
Meddulated fibres are spongy, air filled cells.
In appearance they are long with a hollow look. Both kemp and medulla are difficult to control in spinning and dyeing. This applies to wool, alpaca and mohair.