Forty lignocellulosic fine powders were produced by different itineraries to introduce variability in their rheological behaviour and their particle characteristics. The powders’ rheological properties (basic flowability energy, permeability, aeration, cohesion, compressibility) were determined using a Freeman Technology’s powder rheometer, their particle size distributions were measured by laser granulometry and their shapes by optical granulo-morphometry. The starting materials for powders production were maritime pine bark, a layered corky material, and wheat straw, a fibrous tenacious stem material. Different mills were used to produce a set of 20 µm-average particle size powders: a batch vibrating ball-mill, a batch rotary ball-mill, a batch stirred bead-mill, a continuous impact mill, a continuous air jet-mill. Another sample set consisted of bark and straw powders of different mean particle sizes ranging from 10 to 50 µm produced by the vibrating mill. Finally, a last set was composed of blends (different ratios from 50/50 to 90/10) of 20 µm-centred straw powders-to-bark powders of different mean particle sizes (10 µm, 20 µm, 35 µm, 50 µm).