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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 ]
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.
Hymenophyllaceae: displaying the thinnest fronds of any fern species, [7] hymen is derived from the Greek word for 'membrane', and phyllon meaning 'leaf'. [5] Another defining feature is the sorus structure, a two-flapped indusium which houses the sporangia in a protective receptacle, often clustered around a central axis. [ 5 ]
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 ]
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.
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.
Adiantum L. – maidenhair ferns [6] [7] Cheilanthoid ferns; primarily epipetric in semiarid habitats; leaves mostly with well-developed scales or trichomes , often bipinnate or otherwise highly compound; sporangia mostly born in marginal sori with false indusia that are +/- continuous around the leaf margins; several genera, including:
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.