फर्न्स: एक बड़ा परिवार जो कुछ वर्गीकरण प्रणालियों में कई परिवारों में विभाजित किया गया है (एस्प्लेनियासी और ब्लेचनेसेए और डेवलियाए और डेनस्टाएटियाएएई और ड्रायोपेटाइसीए और ओलियनडेसी और पटरिदासेई सहित

polypodiaceae's Usage Examples:

It is a striking fact that among the numerous Mesozoic Ferns there are comparatively few that can with good reason be referred to the Polypodiaceae, a family which plays so dominant a role at the present day.

It is by no means easy in dealing with fossil ferns to distinguish between certain Polypodiaceae - such as species of Davallia - and members of the Cyatheaceae.

the change in the character of the vegetation was con which have generally been regarded as the fronds of ferns characterized by a central midrib giving off lateral veins which repeatedly anastomose and form a network, like that in the leaves of Antrophyum, an existing member of the Polypodiaceae.

The first includes the Marattiaceae, Osmundaceae, Schizaeaceae, Gleicheniaceae and Matoniaceae; the second the Loxsomaceae, Hymenophyllaceae, Cyatheaceae and the Dennstaedtineae (a group including species placed in the Synopsis Filicum in Dicksonia and Davallia); while the remaining Polypodiaceae constitute the Mixtae.

When the survey is extended to the extinct Ferns of which the fructification is known, many of those from the more ancient rocks are found to group themselves with the existing sub-orders with large sporangia, such as the Marattiaceae, Gleicheniaceae and Schizaeaceae; the Polypodiaceae, on the other hand, do not appear until much later.

A consideration of the Filicaceae as arranged above will show that the several sub-orders may in general terms be said to form a series between those in which the sorus consists of a single circle of bulky sporangia and those Polypodiaceae in which the numerous small sporangia appear to be grouped without order in the sorus.

The dehiscence of the sporangium is almost transverse, as in the Polypodiaceae, but the annulus is slightly oblique.

The prothalli, while resembling those of the Polypodiaceae, have points of similarity with those of the preceding groups.

The prothallus and sexual organs may resemble those of the Polypodiaceae; in Aneimia and Mohria the prothallus, though flattened, is not bilaterally symmetrical, the growing point being on one side; a filamentous type of prothallus is known in Schizaea.

Polypodiaceae.

polypodiaceae's Meaning':

ferns: a large family that in some classification systems has been subdivided into several families (including Aspleniaceae and Blechnaceae and Davalliaceae and Dennstaedtiaceae and Dryopteridaceae and Oleandraceae and Pteridaceae