Analysis of the intracellular membranes of Iris germanica rhizomes ind
icated high amounts of iridals when compared to sterols and lower ster
ol amounts than in other plant microsomes. Microsomal preparations fro
m other plants and animals were also shown to incorporate high amounts
of iridals, with a special affinity for free iridals. The localizatio
n of free iridals within the cellular membranous fraction and their st
erol-like structural role are discussed.