Either woody or nonwoody Generally, adapted to support leaves; also transport materials and provide storage -stolons – grow along soil surface and produce new plants (strawberry) -tubers – enlarged, short, underground stems used for storing starch (potato) -succulent – fleshy, water-storing stems (cactus)

Stems grow in length at tips (apical meristem) and in diameter (lateral meristem) Each leaf is attached to the stem at a node. The spaces between nodes are internodes. Bud – apical meristem capable of developing into a new shoot system, enclosed by specialized leaves (bud scales) - lateral – located at nodes - terminal – located at tips of stems

Dermal tissue – represented by epidermis (protect plant and reduce water loss while allowing gas exchange) Ground tissue – pith and cortex in dicots and gymnosperms, cortex only in monocots Vascular tissue – each bundle contains xylem (towards inside) and phloem (towards outside) -monocots – scattered throughout stems (monkey faces) -dicots and gymnosperms – single ring, with secondary tissues replacing primary tissues

Stems increase in width (thickness) due to division of cells in the vascular cambium (lateral meristem) More secondary xylem is produced than secondary phloem -heartwood – darker wood in the center that no longer transport water -sapwood – functional, lighter-colored wood nearer the outside of the stem

Bark – protective outside covering of woody plants (cork, cork cambium, phloem) -cork cells are dead, and so rupture as the stem continues to expand (textured bark) Springwood – wide, thin-walled xylem produced when water is plentiful Summerwood – smaller, thicker-walled xylem produced when water is limited Annual ring – abrupt change between springwood and summerwood; used to estimate age of plant

Transport nutrients and water -cohesion-tension theory – cohesion and adhesion allow the continuous column of water to move up plant - transpiration (water loss through stomata) occurs while plant exchanges gases Storing water and nutrients -occurs in parenchyma cells in cortex

Support of leaves Translocation – movement of carbohydrates through the plant, from source (where the carbs are made) to sink (where the carbs are used); water follows the movement of carbs, causing pressure which keeps the carbs moving