kale is iirc high in iron. another great greenery that is high in iron is spinach. leafy greens are particularly good sustenance due to the production of good stuff by the efficiency of chloroplasts.
otherwise, plants are largely water and potentially fiber. root plants tend to be high in starch, as they are storehouses for growth of plants in high soil sustenance and low solar energy areas. in these situations, plants need more of a stockpile then plants that are consistently getting solid access to sunlight and water.
notice similarly that fiber tends to come mostly from the superstructures of chlorophilic plants. photosynthesis requires high surface area to absorb light. hence, chloroplastic freestanding plants must have large insoluble skeletons. root plants which have high insolubles usually do so to contain and compartmentalize their root systems and sugar storehouses. great examples are sweet potatoes, taro, lotus root, etc.
