Sap activity, which transforms excess ingested sugar into long-chain oligosaccharides." A much larger set of animals do however consume phloem sap by proxy, either "through feeding on the honeydew of phloem-feeding hemipterans. Honeydew is physiologically less extreme than phloem sap, with a higher essential:non-essential amino acid ratio and lower osmotic pressure," or by feeding on the biomass of insects that have grown on more direct ingestion of phloem sap. Maple syrup is made from reduced sugar maple xylem sap. The sap often is harvested from the Sugar Maple, "Acer saccharum". In some countries (e.g., Lithuania, Latvia, Estonia, Finland, Belarus, Russia) harvesting
Tissue (biology) layer of cells) or stratified (multiple layers of cells). However, other cellular features, such as cilia may also be described in the classification system. Some common kinds of epithelium are listed below: In plant anatomy, tissues are categorized broadly into three tissue systems: the epidermis, the ground tissue, and the vascular tissue. Plant tissues can also be divided differently into two types: Meristematic tissue consists of actively dividing cells, and leads to increase in length and thickness of the plant. The primary growth of a plant occurs only in certain, specific regions, such as in the tips of stems or