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In some species, they are protected during development by a scale or film of tissue called the indusium (pl.: indusia), which forms an umbrella-like cover. Life cycle significance [ edit ]
Prothallus of the tree fern Dicksonia antarctica (note new moss plants for scale) Spore-bearing plants , like all plants, go through a life-cycle of alternation of generations . The fully grown sporophyte , what is commonly referred to as the fern , produces genetically unique spores in the sori by meiosis .
The indusium is linear and persistent, and the sporangia are brownish. Some common species include Diplazium hymenodes , the peacock fern; Diplazium esculentum , the vegetable fern; Diplazium molokaiense , the Molokai twinsorus fern; and Diplazium lonchophyllum , the lance-leaved glade fern.
Aspidotis densa is a species of fern in the Cheilanthoid subfamily, known by the common name Indian's dream or Serpentine fern or dense lace fern.It is native to the west coast of North America from British Columbia to California and east to the Rocky Mountains in Idaho, Montana, and Wyoming; there is a disjunct population on serpentine soils in Quebec.
Adiantoid ferns (tribe Adianteae Gaudich. 1829 [5]); epipetric, terrestrial or epiphytic in moist habitats, rachis often dichotomously branching; sori relatively small and discrete with sporangia born on the false indusium rather than the leaf blade proper; only one genus:
Athyrium (lady-fern) is a genus of about 180 species of terrestrial ferns, with a cosmopolitan distribution. It is placed in the family Athyriaceae , in the order Polypodiales . [ 1 ] [ 2 ] Its genus name is from Greek a- ('without') and Latinized Greek thyreos ('shield'), describing its inconspicuous indusium (sorus' covering). [ 3 ]
Members of Aspidotis are small ferns, with shiny, tufted fronds generally less than 35 centimeters long (although A. schimperi may be larger [2]).Fertile leaves have false indusia formed by the leaves' inrolled margins, which partially conceal the spore-bearing sori.
The mature sporangia have a wall that is just a single cell thick, [8] and are typically covered with a scale called the indusium, which can cover the whole sorus, forming a ring or cup around the sorus, or can also be strongly reduced to completely absent.