Basic structure of dicotyledonous stem-Sunflower stem. Inner structure of dicotyledonous stem reveals epidermis, cortex and stele. Epidermis. Epidermis is protective in function and creates the outermost layer of the stem. Epidermis is a single layer of parenchymatous rectangular cells.
Culture. Plumbago is propagated from cuttings in the summer, but you can also grow it from seed. Plant plumbago in light, sandy, well-drained soils, spacing each shrub 36 to 60 inches apart to allow room to grow. If spaced properly, blue plumbago will naturally cascade in a fountain shape.
Black walnut trees are easy to start from seed. In a favorable site, they often reach 80 to 100 feet in height and their crowns may spread an equal distance.Black walnuts secrete juglone, a chemical that is toxic to many plants. Locate your planting at least 60 feet from any sensitive plants or garden areas.lack walnut trees are easy to start from seed. In a favorable site, they often reach 80 to 100 feet in height and their crowns may spread an equal distance.