Unbranched trichomes or filaments (trichomes with a visible sheath) can be either tapered or untapered (even width along the entire length), and either solitary or 'colonial' (several to many trichomes embedded in a mucilage sheath).

Also they may lack cell differentiation (Oscillatoriales) or contain akinetes and heterocysts as well as undifferentiated 'vegetative cells' (Nostocales).