Scurf- Deposit of minute scales or particles on foliage that gives foliage a dusty, or mealy, appearance.

Seedling- A young plant soon after seed germination, still with a single, on- branched stem.

Semi-double- Refers to a flower with more than a single layer of petals, but with fewer than are found in a fully double flower.

Sepal- In a flower a separate segment of a divided calyx . Compare petal.

Sessile- Without a stalk; referring to leaves or flowers arising directly from a plant stem.

Sheath- Any tubular structure protectively surrounding another plant organ for example, the sheath that forms the basal part of a grass leaf.

Shrub- A plant that remains fairly small and, instead of having a single stem, produces permanent woody stems that normally branch from the base or trunk.

Simple- Refers to leaves that are not divided into separate segments. The opposite of compound.

Single- Refers to a flower with only one layer of petals or corolla lobes. Compare double and semi-double.

Sinuate- With wavy or scalloped margins in one plane (as differentiated from undulate). The term usually describes leaf margins but can also apply to petals and even sepals.

Spadix- A special kind of flower spike, found chiefly in the family Araceae, in which the usually tiny flowers are embedded in the surface of a fleshy central axis. See also spathe.

Spathe- The large, sometimes brightly colored bract or modified leaf that usually surrounds or encloses the spadix in plants of the family Araceae.

Spore- The tiny, single-celled reproductive body in such plants as ferns and mosses. The dustlike spores of ferns are usually carried in raised brown patches (spore cases or son) on the undersides of fronds.

Spur- In flowers, a spur is a hollow, usually conical or tubular projection from some part of the corolla, and it contains nectar to attract pollinating insects. The term is also used for a short side-branch that carries flower buds, as in hoyas.

Stamen- The male, pollen-bearing organ of a flower, usually consisting of two anthers on a slender filament.

Stigma- The tip section of the pistil (female organ of the flower), which is receptive to pollen and generally becomes very sticky when the flower is ready for pollination.

Stipule- A leaflike or scalelike growth found at the base of the leafstalk in certain plants.

Stolon- A shoot that creeps along the ground and roots and produces a new plantlet wherever it comes into close contact with the surface of the potting mixture or soil. Stolons differ from runners in that runners can root only at their nodes.

Stomata- (singular: stoma) The microscopic breathing pores of plants, most of which are on the undersides of leaves.

Stopping- See pinching out.

Style- The stalk that links the stigma with the ovary in the pistil of a flower. The style is variable in length and width and is entirely lacking in some flowers.

Subshrub- A perennial plant that is woody at the base but that produces soft, herbaceous growth on this framework. See also shrub.

Succulent- Any plant, usually from relatively dry regions, that has fleshy stems and/or leaves that can function as water storage organs.

Sucker- A shoot that arises from the root or rootstock of a plant and develops leaves and roots of its own.

Sympodial- Refers to stems or rhizomes in which successive growing points (pseudobulbs, for example) produce annual inflorescences, and further growth is carried on through branching. Most often used to describe orchids. Compare monopodial.

Taproot- Any strong root growing more or less vertically downward, especially if it is the only or main root of the plant.

Tender- Refers to plants that are subject to injury from cold, especially in winter, at a given latitude. Most houseplants are tender within the Temperate Zone. The opposite of hardy.

Tendril- A threadlike organ of a climbing plant usually arising from a leaf axil, which twines around a support or attaches itself to a surface by means of ter- minal suckers. In some plants, leafstalks act as tendrils.

Terminal- Refers to the uppermost (usually central) bud, growth, or flower on a plant or on a given stem of a plant.

Tessellated- Checkered. Describes variegated petals and leaves that have a Checkered or netted pattern in contrasting colors.

Throat- Refers to the inner portion of The mouth of the corolla of a bell-, trumpet-, or tube-shaped flower when the inner portion is easily visible. See also mouth.

Topdress- To apply a layer of fresh potting mixture to a potted plant, normally after removing an equal amount of old mixture. Topdressing is a generally ac- ceptable alternative to repotting for a plant that has grown too large for moving on to a bigger pot or container.

Tuber- A word used for fleshy storage Organs of different kinds. The few tu- Berous house plants are stem tubers; in other words, a swollen stem stores food for the plant so that it can survive cold and/or drought. Stem tubers can grow above or below the surface of potting mixture and are sometimes found even on aerial stems. New shoots are produced from growth buds (eyes) on the tubers.

Tubercle- A rounded, wartlike projection or swelling on a plant organ. Tubercles are especially abundant on the stems of many cacti; they are a characteristic feature of such plants.

Tunic- The loose, membranous or fibrous outer skin of many types of bulbs and corms.

Undulate- With wavy up-and-down Margins. The term is usually applied to Leaves, but can also apply to petals and sepals. Compare sinuate.

Variegated- Refers to leaves (and sometimes flowers) that are either striped, spotted, or otherwise patterned in a color different from the normal green.

Variety- A plant from that differs from The natural type species. The term variety As used by modern botanists refers only to Variations that have originated in the wild, but the word is also frequently applies to variations arising in cultivation, which should technically be known as cultivars. Names of true varieties are usually in Latin and are not enclosed in quotation marks. See also cultivar.

Vein- A strand of conducting tissue, primarily in a leaf. Large veins are called ribs, and the central vein (which is normally an extension of the leafstalk) is call the midrib or, in compound leaves, the rachis.

Viviparous- Producing young plants (plantlets) asexually on the leaves or stems of the parent plant, sometimes from bulbils.

Whorl- Three or more leaves or flowers that are produced in radiating pattern- like the spokes of a wheel-at at single stem node.

Woody- Refers to plant tissue that becomes lignified and hard, persisting throughout the plants rest periods even if leaves die. Thus, woody stems are more or less permanent. Compare herbaceous.