Clubmoss (Lycopodium clavatum) strobilus. Light micrograph of a section through a strobilus from a stag's-horn clubmoss plant, showing the leafy sporophylls (red). Sporophylls are leaves that bear sporangia, where spores (green) are produced. Strobili are structures that consist of sporangia-bearing structures densely collected along a stem (vertical, centre). Magnification: x4 when printed 10 centimetres wide.