ABSTRACT
This family comprises the most common and well-known ferns. In the flora of Romania, there are 44 species out of approximately 2800 found worldwide. These plants are perennial herbaceous with rhizomes and leaves of the trophosporophyll type (the leaves serve both in assimilation and bearing sporangia). The leaves are initially coiled and circinate at the tip. They are rarely entire, usually simple pinnate or compound pinnate, with both leaves and petioles covered with membranous, brown scales. The sori have a vertical, mechanical ring that opens through an oblique slit and are located on the lower surface of the leaves. They have various forms and group sporangia with spores. The shape and position of the sori, as well as the presence or absence of the indusium, have been the basis for dividing the family into subfamilies, sometimes leading to classifications where species are grouped into multiple botanical families. The sporangia contain isospores, from which monoecious protals develop, which are green, leafy, cordiform, and display antheridia and archegonia on the lower surface. 1 - 2
