tracheids bụ elongated mkpụrụ ndụ na lignified nke abụọ thickening nke cell mgbidi, pụrụ iche maka conduction nke mmiri, na mbụ pụtara na osisi n'oge ha mgbanwe ka ala na Silurian oge ihe karịrị 425 nde afọ gara aga (lee Cooksonia). The nwere nke xylem tracheids akọwa vascular osisi ma ọ bụ Tracheophytes. Tracheids na-apụta, elongated xylem mkpụrụ ndụ, ndị kasị mfe nke nwere na-aga n'ihu bụ isi mgbidi na lignified nke abụọ mgbidi thickening n'ụdị nke yiri mgbaaka, hoops, ma ọ bụ reticulate netwọk. More mgbagwoju tracheids na valve-dị ka valves na-akpọ pnosperytes akara ókè-ala na-aga n'ihu. The xylem gymnosperytes na ndị ọzọ na-aga n'ihu na-agba ọsọ na mmiri na-akpalite dị ka mgbidi na-eme ka mmiri na-agba ọsọ.
Ndị tracheids