Plant Science Terms - L

Labellum - spongy tip on sponging mouth parts found in houseflies, flesh flies, and blow flies, used to suck up liquids or readily soluble food

Lanceolate - lance-shaped; broadest below the middle and tapering toward the apex

Landscape design - profession concerned with the planning and planting of outdoor space to secure the most desirable relationship between land forms, architecture, and plans to best meet human needs for function and beauty

Larva (larvae is plural) - immature form of an insect that undergoes complete metamorphosis. Different from the adult in form, a caterpillar for example. The newly hatched, wingless, often wormlike form of many insects before metamorphosis

Latent bud - buds that do not grow for long periods of time and can become embedded in the enlarging stem tissue. These buds grow only when conditions necessary for their growth occur, such as drastic pruning. Not all plants have latent buds

Lateral - branch attached to and subordinate to another branch or trunk

Lateral bud - undeveloped shoot or flower that is found at the node. Also described as a bud in a leaf axil, on the side of the stem. Commonly known as an axillary bud

Lateral meristem - cylinders of actively dividing cells that start just below the apical meristem and are located up and down the plant. Includes the vascular cambium and the cork cambium.

Lawn Substitute - plants that can take light foot traffic and may be used as substitutes for "normal" lawn grasses.  While these plants cannot tolerate heavy foot traffic they will work in some areas

Layering - vegetative method of propagation that produces new individuals by stimulating adventitious roots to form on a stem. There are two primary methods of layering. In ground layering, a low-growing branch is bent to the ground and covered by soil. The second is air layering where moist rooting medium is wrapped around a node on an above-ground stem

Leachate - liquid that has passed through unprocessed organic material. May contain pathogens, phytotoxins, and anaerobic microorganisms that could be harmful to plants

Leaching - downward movement of water and soluble nutrients or salts through the soil profile. Responsible for nutrient losses but can also be beneficial in ridding a soil of excess salts

Leader - developing stem or trunk that is longer and more vigorous than the laterals. (See also Central leader)

Leaf - principal organ of photosynthesis, contains a bud at its base

Leaf arrangement - arrangement of leaves on the stem

 

Leaf-axil - area between the leaf or petiole and the stem

Leaf-bud cuttings - cuttings consisting of a leaf blade, leaf stalk, and a short piece of the stem. Leaf cuttings. Entire leaves with or without the leaf stalks

Leaf curl - rolling and curling of leaves

Leaf galls - swellings on leafy tissue

Leaf scar - visible, thickened crescent or line on a stem where a leaf was attached 

Leaf scorch - damage to a leaf, due to adverse environmental conditions such as high temperatures, that causes rapid water loss resulting in dead tissue

Leaflets - individual parts of a compound leaf

Leaves - vegetative plant parts that are lateral outgrowths of stems that have developed special structures for photosynthesis

Legume - simple, dry, dehiscent (see definition of dehiscent) fruit with one locale that splits along two seams

Lenticel - small opening on the in the cork of a woody stem, fruits, and roots that allows exchange of gases between internal tissues and the atmosphere  

Lepidoptera - major order of insects that have two pairs of wings and sucking or siphoning mouthparts as adults and chewing mouthparts as larvae (moths, butterflies)

Lesion - localized area of discolored or dead tissue

Life cycle - successive stages of growth and development of an organism

Light Feeders - plants that do not need a lot of fertilizer for optimal performance.  Over feeding Light Feeders can cause toxicity

Lignin - complex organic substance in cell walls that makes them firm and rigid

Ligule - thin projection from the top of the leaf sheath in grasses; it may be a fringe of hairs, membranous, or absent

Lime - rock powder (ground limestone) consisting primarily of calcium carbonate that is used to raise soil pH (decrease acidity) 

Linear - narrow, five or more times longer than wide; approximately the same width throughout

Living mulches - plant that is used to cover an area of soil and add nutrients, enhance soil porosity, decrease weeds, and prevent soil erosion

Loam - soil with roughly equal proportions of sand, silt, and clay particles

Lobed - Incisions extend less than halfway to the midrib

Locales - cavities of the ovary of the pistil of a flower

Lodge - fall over, usually due to rain or wind. Corn and tall grasses are examples of plants susceptible to lodging

Long-day (short-night) plant - plant requiring more than 12 hours of continuous daylight to stimulate a change in growth, e.g., a shift from the vegetative to reproductive phase. (See also Short-day plant, Day-neutral plant)

 

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