Hemiptera plant. Phloem sap, which has a higher concentration of sugars and nitrogen, is under positive pressure unlike the more dilute xylem sap. Most of the Sternorrhyncha and a number of Auchenorrhynchan groups feed on phloem. Phloem feeding is common in the Fulgoromorpha, most Cicadellidae and in the Heteroptera. The Typhlocybine Cicadellids specialize in feeding on non-vascular mesophyll tissue of leaves, which is more nutritious than the leaf epidermis. Most Heteroptera also feed on mesophyll tissue where they are more likely to encounter defensive secondary plant metabolites which often leads to the evolution of host specificity. Obligate xylem feeding is a
Phoenix (plant) thin layer of fruit pulp. The central soft part of the stem of "P. rupicola, P. acaulis," and "P. humilis" is a rich source of starch. Palms are felled to extract this central ‘pith’ which is dried, powdered, stored and used for preparation of bread by Indian natives. The "P. canariensis" sap is cooked to a sweet, thick syrup. "P. sylvestris" Roxb. is widely used in India as a source of sugar. The sugary sap from some African palms yields country liquor on fermentation (palm wine). While "P. dactylifera" is grown for its edible dates, the Canary Island date palm