cybium

[Gr. kybion =a species of tunny.] 1. Ichthy.: A genus of fishes, natives of the seas about the East Indies. to a genus of fo il fishes from the London clay of 2. Palæont.: Aga iz gives the name of Cybium Sheppey. , aş; expect, Xenophon, exist. ph = shus. -ble, -dle, . = bel IMG:content-1679.png:[blocks in formation] 1. Bot .: An order of Gymnosperms, first separated by Richard, who considered them as plants inter. mediate between ferns and palms. In 1827 Robert Brown established their affinity with the Coniferse. The order contains nearly 100 species, grouped in nine genera. The genus Cycas is confined to trop- ical Asia and Austral asia, and to the Mascarine sule globose, one-celled, opening with five teeth. Islands. It is distinguished by the seeds being borne on the margins of altered open leaves. The stems are simple, cylindrical, and covered with the permanent bases of the leaves. In all the other genera the seeds are borne in pairs on scales which form a cone. The staminal flowers are arranged in cones in the whole order. Besides the species of Cycas found in Australia, there are two endemic genera, Macrozamia with imbricating scales to the fertile cone, and the anomalous genus Bowenia with peltate scales and bipinnatisectleaves. Africa has also two endemic genera, Encephalartos with cylindrical stems covered with the permanent bases of the leaves, and Stangeria with a short somewhat spherical naked stem, and leaves with forked veins. The American Cycadacese have been referred to four genera; the greater number of the species belong to Zamia, with peltate scales arranged in vertical series, and usually short repeatedly-branched stems. One species in Cuba with a slender cylindrical stem and velvety cones, is separated from Zamia and named Micro cycas, while species taller stems, found in tropical America, are at once dis tinguished by their two horned cone scales, from which the generic name Ceratozamia has been given to them. Dion is an anomalous Mexican genus containing two species. The large seed-bearing cone is composed of woolly, thin, ovate-acute scales, with slender pedicels. 2. Paleo - botany : The Cycadaceae form an important element in the Floras of Secondary age, wherever these have been investigated. Some fo ils from the palæozoic rocks have been erroneously referred to this order. Besides species referable to the modern types, the Secondary rocks contain two extinct forms. One of these, Williams on i a, is an obscure plant from the Oolites of Yorkshire, England, and of India, with uncertain affinities; and the other, Bennett i tes, has a compound fleshy fruit borne in the axils of the leaves, which has the same relation to the cone-bearing Cycads that the fruit of the Yew has to the cone-bearing Conifere. The species of this tribe constitute the "crow's nests" of the Portland quarries, and are found in the oõlitic and cretaceous rocks of the South of England and the North of Scotland. The tertiary strata have hitherto yielded only some doubtful fragments. adj. suff. -ous.]