| 翻訳と辞書 |
| archaeopteris ： ウィキペディア英語版 |
archaeopteris
''Archaeopteris'' is an extinct genus of tree-like plants with fern-like leaves. A useful index fossil, this tree is found in strata dating from the Upper Devonian to Lower Carboniferous (), and has a global distribution. The name derives from the ancient Greek (''archaīos'') meaning "ancient", and (''ptéris''), meaning "fern".
Until the 2007 discovery of ''Wattieza'', many scientists considered ''Archaeopteris'' to be the earliest known tree. Bearing buds, reinforced branch joints, and branched trunks similar to today's timber, it is more reminiscent of modern seed-bearing trees than other spore bearing taxa; It combines characteristics of woody trees and herbaceous ferns, and belongs to a group of extinct plants sometimes called the progymnosperms, plants with gymnosperm-like wood but that produce spores rather than seeds.
== Anatomy ==
The trees of this genus typically grew to 10 m in height with leafy foliage reminiscent of some conifers. The large fronds were thickly set with fan-shaped leaflets on stems that inclined sharply upward. The trunks of some species exceeded 1.5 m in diameter. The veining branches diverged dichotomously. There was also intermediate feathering at each frond node or axes.
Leafy shoots occurred in opposite arrangement in a single plane. The leaflets, or pinnules, overlapped one another and were subcircular to wedge-shaped. On fertile branches, some of the leaves were replaced by spore capsules.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「archaeopteris」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|