Tropical fern frond. Light micrograph (LM). Transverse section through the frond of a tropical fern. A central vascular bundle (meristele) with central xylem tissue (red) surrounded by phloem (lblue) is visible. A trophophyll frond is a vegetative leaf analogous to the typical green leaves of seed plants that does not produce spores, instead only producing sugars by photosynthesis. A sporophyll frond is a fertile leaf that produces spores borne in sporangia that are usually clustered to form sori. Magnification: x25 when printed at 10 centimetres wide.