Cordaianthus

…Depending on the shape of the leaves, they are sometimes called Eu - Cordaites if they are blunt-headed, Dory - Cordaites if they are sharp-headed, and Poa - Cordaites if they are narrow. The trunk has a true central column like conifers, but the pith is large and produces separate male and female cones that can reach a diameter of 1.5 cm, and is called Cordaianthus . From the Cordaites species, the leaves became extremely small, the pith also became small, and the cones were simplified, and it is thought that they evolved into modern conifers via the Lebachiaceae, which were found in the Permian period. …

*Some of the terminology that mentions "Cordaianthus" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…葉の形によって，鈍頭のものをユーコルダイテスEu‐Cordaites，鋭頭のものをドリコルダイテスDory‐Cordaites，幅の狭いものをポアコルダイテスPoa‐Cordaitesと区別して呼ぶことがある。樹幹は針葉樹と同じく真正中心柱をもつが髄は大きく直径1.5cmにも達する雌雄別々の球果をつくり，コルダイアンサスCordaianthusと呼ばれる。コルダイテス類から葉は極端に小型となり，髄も小型化し，球果も単純化し，二畳紀に産するレバキア科Lebachiaceaeを経て現生の針葉樹類に進化したと考えられている。…

※「Cordaianthus」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報