The older types of Gymnosperms are inelastic and dying out.
Companion cells are not found in the Pteridophyta and Gymnosperms. In the latter their place is taken by certain cells of the medullary rays and bast parenchyma.
In many Gymnosperms the male nucleus penetrates the female nucleus before fusing with it (Blackman, Ikeno).
oak, ash, elm, &c.; the articles FIR and Pine treat of two large groups of conifers; general information is provided by the articles Plants and Gymnosperms; tree cultivation will be found under Forests And Forestry and Horticulture; and the various types of tree whose wood is useful for practical purposes under Timber.