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Pteridophytes (ferns and lycophytes) are free-sporing vascular plants that have a life cycle with alternating, free-living gametophyte and sporophyte phases that are independent at maturity. The body of the sporophyte is well differentiated into roots, stem and leaves. The root system is always adventitious. The stem is either underground or ...
An annulus in botany is for ferns an arc or a ring of specialized cells on the sporangium. These cells are arranged in a single row, and are associated with the release or dispersal of spores. In mosses it is a ring of cells around the tip of the sporangium. In flowers it is a ring of hairs within the flower tube.
Fern spores are borne in sporangia which are usually clustered to form sori. The sporangia may be covered with a protective coating called an indusium. The arrangement of the sporangia is important in classification. [6] In monomorphic ferns, the fertile and sterile leaves look morphologically the same, and both are able to photosynthesize.
As one of the oldest plant groups on Earth, these hardy greens can survive just about anything—as long as their environment doesn't get too dry. They can even help keep soil intact during ...
Leaves are evergreen, which appear opposite, and are arranged spirally with four evenly spaced leaves; when viewed from the side it appears as four columns. The branch leaves are green and shiny, the base extends down to the stem (decurrent) and the free portion at the tip is pointed and scale-like.
The fern has spores on the bottom of the fronds, contained in sori. Sori can be found aligned in rows on the underside of fertile fronds. They start as yellow, but as they mature, they turn brown and split. [13] The fern sporulates in summer and early fall. Rhizome sections are also viable offspring and can root themselves in new medium.
Sporangia (clustered in sori) on a fern leaf Equisetum arvense strobilus cut open to reveal sporangia. Sporangia can be terminal (on the tips) or lateral (placed along the side) of stems or associated with leaves. In ferns, sporangia are typically found on the abaxial surface (underside) of the leaf and are densely aggregated into clusters ...
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.