Samara - A winged fruit that does not split spontaneously. (e.g. maple).

Scale - A small, usually dry leaf that is closely pressed against another organ.

Scape - A leafless flower stalk that grows from the ground.

Sepal - A leaf or division of the calyx.

Serrate - Saw-toothed, with the teeth pointing toward the apex.

Sessile - Having no stalk.

Sheath- an expanded or tubular structure that partially encloses a stem or other organ.

Shoot - A stem or branch and its leaves, especially when young.

Shrub - A woody plant that produces no trunk but branches from the base.

Simple - Not compounded (leaves) or branched (stems, flower clusters).

Smooth - Not rough (compare glabrous).

Solitary - Not growing as part of a cluster or group.

Spadix - A fleshy spike.

Spathe - One or two bracts enclosing a flower cluster. (especially a spadix).

Spatulate - Shaped like a spoon, with a narrow end at the base.

Spike - A flower cluster in which sessile flowers grow along part of the length of the peduncle.

Spikelet - A small spike, particularly one of the few-flowered spikes making up the inflorescence of a grass.

Spore - A one-celled reproductive body produced by relatively primitive plants.

Spur - A slender, hollow projection from a petal or sepal.

Stamen - The male or pollen-bearing organ of a flower.

Strobile - A cone or cone-like structure.

Style - The slender, elongated part of a pistil.

Suture - A natural seam or groove along which a fruit splits.

Taproot - A single main root that grows vertically into the ground.

Terminal - Occurring at or growing from the end opposite the base. (compare lateral).

Ternate - Occurring in threes or divided into three parts.

Trifoliate - Having three leaves.

Trifoliolate - Having three leaflets.

Tripinnate - Descriptive of a pinnate leaf having pinnate leaflets with pinnate pinnules.