These genera and Ephedra also hve advanced tracheids with a structure reminiscent of angiosperm vessels, whereas in other gymnosperms the xylem is composed solely of more primitive tracheids.
These genera and Ephedra also hve advanced tracheids with a structure reminiscent of angiosperm vessels, whereas in other gymnosperms the xylem is composed solely of more primitive tracheids.
这些属以及麻黄属植物和被子植物一样有进化的管胞，而其他的裸子植物的木质部只由很多导管组成。