Under Ground stems are modified plant structures that derive from stem tissue but exist under the soil surface. Plants have two axis of growth, which can be best seen from seed germination and growth. Seedlings develop two structures or axis of growth, one that develops up word out of the soil, called stems, and structures that develop downward which are called roots. The roots are modified to have root hairs and branch indiscriminently with cells that take in water and nutrients, while the stems are modified to move water and nutrients to and from the leaves and flowers. Stems have nodes with buds were leaves and flowers arise at specific locations, while roots do not.
In common parlance, a stem is any elongated, usually narrow, extension or supporting structure of an object. ... Loess field in Germany Soil horizons are formed by combined biological, chemical and physical alterations. ... A ripe red jalapeno cut open to show the seeds For other uses, see Seed (disambiguation). ... Roots is: The plural of Root Roots (album) Roots (TV miniseries), a mini-series based on a novel by Alex Haley Roots: The Saga of an American Family, a novel by Alex Haley Roots Canada Ltd. ... The Toronto Maple Leafs are a professional ice hockey team based in Toronto, Ontario, Canada. ...

Different forms of underground stems include:

Bulb - Short, upright organ used by plants for food storage or reproduction, with specialized leaves modified into thick flesh scales. Tulips and Lilies.
Corm - Short, upright, hard or fleshy stems covered with thin, dry papery leaves.
Rhizome - With reduced scale like leaves. The top can generate leafy stems while the bottom can produce roots. Iris.
Stolon - Horizontal stems that run at or just below the soil surface with nodes that root. Also called runners.
Tuber - An enlarged fleshy end of a stem, generally from Rhizomes but often also referring to thickened roots too. Irish Potato. Shallot bulbs A bulb is an underground vertical shoot that has modified leaves (or thickened leaf bases) that are used as food storage organs by a dormant plant. ... A corm is a short, vertical, swollen underground stem of a plant (usually one of the monocots) that serves as a storage organ to enable the plant to survive winter or other adverse conditions such as summer drought and heat (estivation). ... Ginger rhizome A rhizome is, in botany, a usually underground, horizontal stem of a plant that often sends out roots and shoots from its nodes. ... A stolon is an aerial shoot from a plant with the ability to produce adventitious roots and new offshoots of the same plant. ... The large and growing jargon of poker includes many terms. ... Oca tubers For the fungal genus, see Truffle. ...