chapter 22 crossword

2. the central part of an ovule, containing the embryo sac
5. a division of plants, grouped within the gymnosperms, that consists of some 70 species across the three relict genera: Gnetum, Welwitschia, and Ephedra.
8. each of the microscopic particles, typically single cells, of which pollen is composed
10. seed plants with a long fossil history that were formerly more abundant and more diverse than they are today.
11. a "solid or highly viscous substance" of plant or synthetic origin that is typically convertible into polymers
12. a flowering plant's unit of reproduction, capable of developing into another such plant
13. a division of vascular land plants containing a single class, Pinopsida

1. the protective outer coat of a seed
3. a tough outer protective layer, especially that of an animal or plant.
4. having the male and female reproductive organs in separate individuals
6. a leaf that bears sporangia
7. a monotypic genus of highly unusual non-flowering plants.
9. a group of seed-producing plants that includes conifers, cycads, Ginkgo, and gnetophytes.