As a botanist working for a field museum, you spend many hours in the field looking for new species of plant. On a recent trip, you came across a group of plants that may represent a new species. Each plant has seeds but they are not encased in fruit. Additionally, you notice that male and female cone structures are found on different plants. The cones are very large, and you determine average weight to be 30 kg. In which of the following groups would this plant most likely be classified?