Tip Growth of Fungal Hyphae

The shapes of tips of rapidly growing hyphae approximate more closely to half ellipsoids of revolution than to hemispheres. It is concluded that provided growth is isotropic the specific rate of wall area expansion will be more nearly proportional to the cotangent of the position angle than to its cosine. Certainly better qualitative fits to the observed data are given by cotangent rather than by cosine curves.