collegium musicum. a group of usually amateur musicians, often connected with a university, who meet to study and perform chiefly old or little-known music.
Spores and Sporangium. Ferns differ from flowering plants and trees because they do not produce seeds. Instead, ferns reproduce using spores. The sporangium is the structure responsible for producing and releasing spores. Sporangium form in many different ways, sometimes appearing as brown fruitdots on the undersides of leaves. Others grow as slender stalks up from the plant. When the sporangia burst, the wind carries spores to new ground, where they form reproductive structures that, if fertilized, will grow into a new fern.
Mitochondrion structure. Mitochondria are the energy factories of the cells. The energy currency for the work that animals must do is the energy-rich molecule adenosine triphosphate (ATP). The ATP is produced in the mitochondria using energy stored in food. Just as the chloroplasts in plants act as sugar factories for the supply of ordered molecules to the plant, the mitochondria in animals and plants act to produce the ordered ATP molecules as the energy supply for the processes of life.