microscopy has revealed details about their ultrastructure—their microscopic architecture and arrangement. For example, the hyphae of the hapteron form a dense tangled network, while the hyphae of the funicular cord are arranged in a twisted form like a rope. Further, the funicular cord, known to be highly elastic and with a high tensile strength, is made of thicker hyphae than the rest of the funiculus. Also, the ecto- and endoperidium are made of thick-walled, unbranched hyphae, known as skeletal hyphae. It has been proposed that these skeletal hyphae form a structural network that helps the fruiting body maintain the elasticity vital for proper functioning of the spore dispersal mechanism. Life cycle The life cycle of Cyathus stercoreus, which contains both haploid and diploid stages, is typical of taxa in the basidiomycetes that can reproduce both asexually (via vegetative spores), or sexually (with meiosis). Basidiospores produced in the peridioles each contain a single haploid nucleus. After dispersal, the spores germinate and grow into homokaryotic hyphae, with a single nucleus in each compartment. When two homokaryotic hyphae of different mating compatibility groups fuse with one another, they form a dikaryotic (containing two nuclei) mycelia in a process called plasmogamy. After a period of time (approximately 40 days when grown from pure culture in the laboratory) and under the appropriate environmental conditions, fruiting bodies may be formed from the dikaryotic mycelia. These fruiting bodies produce peridioles containing the basidia upon which new basidiospores are made. Young basidia contain a pair of haploid sexually compatible nuclei which fuse, and the resulting diploid fusion nucleus undergoes meiosis to produce haploid basidiospores. Development Extreme variability in fruiting body form and color has been noted for C. stercoreus. Brodie reported discovering a slender-stemmed "twinned" form, with two fruiting bodies originating from the same stalk. As has been shown in laboratory-grown specimens, the development and form of the fruiting bodies is at least partially dependent on the intensity of light it receives during development. For example, exposure of the heterokaryotic mycelium to light is required for fruiting to occur, and furthermore, this light needs to be at a wavelength of less than 530 nm. Lu suggests that certain growing conditions – such as a shortage in available nutrients – shifts the fungus' metabolism to produce a hypothetical "photoreceptive precursor" that enables the growth of the fruiting bodies to be stimulated and affected by light. The fungi is also