Fig 2. Description of a non-septate reproductive hypha as a series of well-mixed tanks.

Phenomena are denoted by capital letters: (i) Nutrient is provided by the vegetative hypha (tank 0) at the base of the reproductive hypha (tanks 1 to n) and moves towards the tip (tank n) by diffusion between the tanks and convective flow of the cytoplasm. This convective flow is due to evaporation at the hyphal tip; (ii) In the vesicle-producing zone (tanks i+1 to n-1), nutrient is used to produce vesicles containing cell wall precursors; (iii) The vesicles move towards the tip with a fixed velocity (i.e. there is no diffusive contribution to their transport) that can be different from that of the cytoplasm; (iv) The tip (tank n) extends due to the absorption of vesicles.