Phycomyces blakesleeanus

Description:

Phycomyces blakesleeanus is a filamentous fungus in the Order Mucorales of the phylum Zygomycota or subphylum Mucormycotina. The spore-bearing sporangiophores of Phycomyces are very sensitive to different environmental signals including light, gravity, wind, chemicals and adjacent objects.Phycomyces also exhibits an avoidance response, in which the growing sporangiophore avoids solid objects in its path, bending away from them without touching them, and then continuing to grow upward again. This is believed to result from an unidentified "avoidance gas" that is emitted by the growing zone of the sporangiophore. This gas would concentrate in the airspace between the Phycomyces and the object. This higher concentration would be detected by the side of the sporangiophore's growing zone, which would grow faster, causing the sporangiophore to bend away.

Notes:

Phycomyces blakesleeanus became the primary organism of research of the Nobel laureate Max Delbrück starting in the 1950s, when Delbrück decided to switch from research on bacteriophage and bacteria to P. blakesleeanus.