Ads
related to: indusium fern
Search results
Results From The WOW.Com Content Network
In ferns, the sori form a yellowish or brownish mass on the edge or underside of a fertile frond. 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.
The Polypodiidae, commonly called leptosporangiate ferns, formerly Leptosporangiatae, ... and are typically covered with a scale called the indusium, ...
The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers.They differ from mosses by being vascular, i.e., having specialized tissues that conduct water and nutrients, and in having life cycles in which the branched sporophyte is the dominant phase.
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]
Many ferns of this genus have stout, slowly creeping rootstocks that form a crown, with a vase-like ring of evergreen fronds 30 to 200 centimetres (10 to 80 in) long. The sori are round, with a circular indusium, except in South American species which lack an indusium. [5]
Associated with each sorus in many species is a membranous protective structure called an indusium, which is an outgrowth of the blade surface that may partly cover the sporangia. Some fern species feature frond dimorphism, in which fertile and sterile fronds differ in appearance and structure.
The sori are often covered by a flap of tissue called an indusium, a useful characteristic for classifying the Cyatheaceae. Some indusia are cup-shaped (cyatheoid), while others are hood-shaped (hemitelioid), enclose the sorus (sphaeropteroid), or scaly. Like most ferns, members of the Cyatheaceae are homosporous.
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: Adiantum L. – maidenhair ferns [6] [7]