Noun:

Cycad,

cycads தமிழ் அர்த்தத்தின் உதாரணம்:

இது Cycadales என்ற பேரினத்தைச் சேர்ந்தது.

Escarpment Cycad (2006 இலிருந்து).

cycads's Usage Examples:

The plants of the Lower Gondwanas consist chiefly of acrogens(Equisetaceae and ferns)and gymnogens (cycads and conifers), the former being the more abundant.

In rare cases the pinnae of cycads are lobed or branched: in Dioon spinulosum (Central America) the margin of the segments bears numerous spinous processes; in some species of Encephalartos, e.

) with yucca-like leaves, was related to the cycads and conifers; the catkin-like inflorescence, which bore yew-like berries, is called Cardiocarpus.

In the genus Cycas the female flower is peculiar among cycads in consisting of a terminal crown of separate leaf-like carpels several inches in length; the apical portion of each carpellary leaf may be broadly triangular in form, and deeply dissected on the margins into narrow woolly appendages like rudimentary pinnae.

A point of anatomical interest is the occurrence in the vascular bundles of the cotyledons, scale-leaves, and elsewhere of a few centripetally developed tracheids, which give to the xylem-strands a mesarch structure such as characterizes the foliar bundles of cycads.

The mesarch structure of the leaf-bundles is met with in a less pronounced form in the flower peduncles of some cycads.

The same classes of plants occur in the Upper Gondwanas; but there the proportions are reversed, the conifers, and still more the cycads, being more numerous than the ferns, whilst the Equisetaceae are but sparingly found.

The structure of the seed, the presence of two neck-cells in the archegonia, the late development of the embryo, the partially-fused cotyledons and certain anatomical characters, are features common to Ginkgo and the cycads.

Among other trees and shrubs may be mentioned the sumach, the date-palm, the plantain, various bamboos, cycads and the dwarf-palm, the last of which grows in some parts of Sicily more profusely than anywhere else, and in the desolate region in the south-west yields almost the only vegetable product of importance.

This connexion is further established by the absence from both areas of oaks, conifers and cycads, which, as regards the first two families, is a remarkable feature of the flora of the peninsula and Ceylon, as the mountains rise to elevations in which both of them are abundant to the north and east.

Surrounding the pitted wall of the ovum there is a definite layer of large cells, no doubt representing a tapetum, which, as in cycads and conifers, plays an important part in nourishing the growing egg-cell.

Robert Brown was the first to give a clear description of the morphology of the Abietineous cone in which carpels bear naked ovules; he recognized gymnospermy as an important distinguishing feature in conifers as well as in cycads.

Synonyms:

Macrozamia spiralis, burrawong, ceratozamia, Macrozamia communis, Encephalartos caffer, zamia, gymnosperm, dioon, kaffir bread, encephalartos, macrozamia, Cycas revoluta, sago palm,

Antonyms:

None