Sporophore development and proliferation in Hydnum auriscalpium Fr.

Abstract

The development and proliferation of sporophores of Hydnum auriscalpium on pine cones maintained in damp chambers are described. Investigations indicate that humidity is the most important environmental factor, a R.H. of 95% + being essential for development and proliferation. Extremes of light treatment proved inhibitory to the completion of stipe elongation. During development there is a change from negative geotropism during stipe development, through the diageotropic reaction of pileus formation to the positive geotropism of the spines. The three responses ensure the vertical alignment which is essential for efficient spore dispersal. The sporophore is dimitic, the skeletal hyphae of the superficial layer enclosing a central core largely composed of thin-walled generative hyphae. Septate hairs bearing clamp connexions develop from the superficial layer. Proliferation involves the re-organization by the central core of growing apices which then penetrate the superficial layer. A comparison of the dimensions of the sporophores produced in the field and of those produced in the laboratory suggests that environmental conditions, particularly water supply and humidity, may limit sporophore development in the field.