Gymnosperms are seed plants that reproduce via naked seeds not enclosed in an ovary. There are five phyla of extant seed plants, four of which are gymnosperms. Coniferophyta, or conifers, is one of the gymnosperm phyla and includes trees like pines, hemlocks and redwoods. Conifers bear their naked seeds on modified leaves called sporophylls and have adapted traits like wood to support their large size, with some being among the largest and oldest living organisms.

1. Gymnosperms Chapter 18

18. Longleaf pines

19. Foliar unit

20. Open seed cone

21. Pine seedling

23. Swamp bald cypress

24. Common bald cypress

25. Larch meadow

27. Fir

29. Juniper

30. Sequoiadendron

31. Broken branch

34. Dawn redwood

36. Ovulating pine cones

41. Pollen cone

46. Another Pine life cycle figure

61. Ginkophyta

62. Cycadophyta