Tall trees, often in dry habitats.
Leaves reduced, simple, a whorled sheath around photosynthetic branchlets that resemble horsetails (Equisetum). Stipules absent.
Monoecious. Perianth very reduced, male flowers with 2 lobes, female flowers without perianth. Stamens 1 per flower, flowers grouped around peduncle with a sheathing bract. Ovary superior, reduced. Male inflorescences in spikes at the top of the tree, female inflorescences in spherical bracteate heads or cones on side branches.
- Vascular plants