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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 ]
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 ]
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.
Sori may be covered by a structure called an indusium. Some ferns have their sporangia scattered along reduced leaf segments or along (or just in from) the margin of the leaf. Lycophytes, in contrast, bear their sporangia on the adaxial surface (the upper side) of leaves or laterally on stems. Leaves that bear sporangia are called sporophylls ...
Nephrolepis is a genus of about 30 species of ferns.It is the only genus in the family Nephrolepidaceae, placed in the suborder Aspleniineae (eupolypods I) of the order Polypodiales in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). [1]
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 sori or groups of spore-cases are borne on the back of the frond; they are globose and naked, not covered with a membrane (indusium). Polypodies have some use in herbalism , but are today most important in horticulture where several species, hybrids, and their cultivars like Polypodium 'Green Wave' are commonly used as ornamental plants for ...