Erythema nodosum, a painful disorder of the subcutaneous fat, is the most common type of panniculitis. Generally, it is idiopathic, although the most common identifiable cause is streptococcal pharyngitis.Erythema nodosum may be the first sign of a systemic disease such as tuberculosis, bacterial or deep fungal infection, sarcoidosis, inflammatory bowel disease, or cancer.rythema nodosum nodules vary from 0.4 to 4 inches (1 to 10 cm) in diameter and are poorly demarcated, reflecting their subcutaneous anatomic location (Table 11â4; Figure 1) . Pretibial involvement is most common, although the extensor surfaces of the forearm, the thighs, and the trunk also may be affected.
xeric - being deficient in moisture; deserts provide xeric environments. 1  hydric - having or characterized by excessive moisture; a hydric habitat. 2  mesic - having or characterized by moderate or a well-balanced supply of moisture; mesic habitats.
xylem. n. 1. (Botany) a plant tissue that conducts water and mineral salts from the roots to all other parts, provides mechanical support, and forms the wood of trees and shrubs. It is of two types (protoxylem and metaxylem), both of which are made up mainly of vessels and tracheids.zÄ«â²lÉm). xylem. Xylem cells in the stem carry water from a plant's roots to its leaves. The phloem distributes food that is made in the plant's leaves to other parts of the plant. The cambium cells divide into either xylem or phloem cells.