• A flap of the sporangium
  Sporangium
  A sporangium is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. All plants, fungi, and many other lineages form sporangia at some point in their life cycle...
  
   of a moss
  Moss
  Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
  
  , covering the peristome
  Peristome
  The word peristome is derived from the Greek peri, meaning 'around' or 'about', and stoma, 'mouth'. It is a term used to describe various anatomical features that surround an opening to an organ or structure. The term is used in plants and invertebrate animals, such as in describing the shells of...
  
   (appendages surrounding the mouth of a moss capsule).
• The cap of the ascus
  Ascus
  An ascus is the sexual spore-bearing cell produced in ascomycete fungi. On average, asci normally contain eight ascospores, produced by a meiotic cell division followed, in most species, by a mitotic cell division. However, asci in some genera or species can number one , two, four, or multiples...
  
   in certain ascomycetous
  Ascomycota
  The Ascomycota are a Division/Phylum of the kingdom Fungi, and subkingdom Dikarya. Its members are commonly known as the Sac fungi. They are the largest phylum of Fungi, with over 64,000 species...
  
   fungi.
• A lid covering the aperture of pollen
  Pollen
  Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...
  
   grains.
• The bud cap covering the flowers of Eucalyptus
  Eucalyptus
  Eucalyptus is a diverse genus of flowering trees in the myrtle family, Myrtaceae. Members of the genus dominate the tree flora of Australia...
  
  and Corymbia
  Corymbia
  Corymbia is a genus of about 113 species of tree that were classified as Eucalyptus species until the mid-1990s. It includes the bloodwoods, ghost gums and spotted gums. The bloodwoods had been recognised as a distinct group within the large and diverse Eucalyptus genus since 1867...
  
  trees which falls off as they open.
• The covering of a pyxidium (capsule whose upper part falls off when the seeds are released) of a plant, such as the plantain
  Plantain
  Plantain is the common name for herbaceous plants of the genus Musa. The fruit they produce is generally used for cooking, in contrast to the soft, sweet banana...
  
  .
• The flared leaflet
  Leaflet
  A leaflet in botany is a part of a compound leaf. A leaflet may resemble an entire leaf, but it is not borne on a stem as a leaf is, but rather on a vein of the whole leaf. Compound leaves are common in many plant families...
  
   that prevents a pitcher plant
  Pitcher plant
  Pitcher plants are carnivorous plants whose prey-trapping mechanism features a deep cavity filled with liquid known as a pitfall trap. It has been widely assumed that the various sorts of pitfall trap evolved from rolled leaves, with selection pressure favouring more deeply cupped leaves over...
  
   from accumulating rainwater.

See also

• Operculum (disambiguation)