JUNGLE
A jungle is a rainforest or a forest whose canopy trees have been logged (cut), causing lush growth on the forest floor (also known as a secondary forest).

JUNIPER
Junier is a conifer and a gymnosperm with blue, woody fruits and overlapping, scale-like leaves. Classification: division Coniferophyta, family Cupressaceae.

JURASSIC PERIOD
Birds evolved and many dinosaurs flourished during the Jurassic period, 208-146 million years ago. Flowering plants appeared about 140 million years ago, during the late Jurassic period.

JUVENILE
A juvenile plant is is in an early phase of plant growth in which it increases in size but has not yet flowered.

The kapok tree, Ceiba pentandra, is a large, deciduous, tropical tree that is native to tropical America, Africa, and the East Indies. This fast-growing tree is generally from 45 to over 100 feet (14-30 m) tall; the kapok is the tallest tree in Africa. It has pink, white, or yellow flowers in clusters. The light-weight silky down from the seed pods (sometimes called Java cotton) is used as pillow stuffing, sleeping bag stuffing, life jacket stuffing, furniture upholstery, insulation, and for other uses. The green leaves are lanceolate (lance shaped) and palmately compound (with 5 to 9 leaflets). The yellow-green oil from the seeds is used in foods and to manufacture soap. Young leaves are also cooked and eaten; the wood is also used. The night-blooming flowers are pollinated and the seeds are spread by fruit bats.

KELP
Kelp is a plant that lives in the oceans. This cold-water seaweed belongs to the family Laminariaceae. Kelp is a large, floating plant that grows in large masses (called kelp forests) and is held to the sea floor by a holdfast. Kelp is usually brown. Kelp is used by people as food, a food additive, fertilizer (when reduced to ash), and as an ingredient in many other products. Kelp evolved during in the Miocene epoch.

KELP FOREST
A kelp forest is a marine ecosystem (a biome) that is dominated by large kelp plants. These oceanic forests grow in cold and temperate waters, especially along the western coasts of the continents.

KINGDOM
In classification, a kingdom is the highest grouping of similar organisms. A kingdom contains one or more phyla (plural of phylum). Life on Earth is divided into five kingdoms: Animalia (animals), Plantae (plants), Fungi, Protista (protozoans and eucaryotic algae), and Monera (blue-green algae).

K-T BOUNDARY
The K-T Boundary was the boundary between the Cretaceous and Tertiary periods, occurring 65 million years ago. This was a time of the huge K-T mass extinction.

K-T EXTINCTION
The K-T extinction was the mass extinction that occurred 65 million years ago, at the boundary of the Cretaceous and Tertiary periods.

KUDZU
Kudzu is a type of legume, a flowering plant that bears its protein-rich seeds in pods and can fix nitrogen from the soil (due to the symbiotic root bacteria rhizobia). Its tubers are edible and the fiber is useful. The plant has a woody stem, wide leaves, and purple flowers. Kudzu is native to Japan and was introduced to the United States around 1876; it soon became a nuisance weed in the southern US. Classification: Kingdom Plantae, class Magnoliopsida, order Rosales, family Leguminosae (pulses), genus Pueraria, specie P. hunbergiana.

LAGERSTATTEN
Lagerstätten (meaning "fossil deposit places" in German) are geological deposits that are rich with varied, well-preserved fossils, representing a wide variety of life from a particular era. These spectacular fossil deposits represent an amazing "snapshot" in time. Some Lagerstätten include the La Brea Tar Pits (California, USA), Ediacara Hills (South Australia), Burgess Shale (B.C., Canada), Solnhofen (Germany), and Mazon Creek (Illinois, USA)

LAMINA
The lamina is the blade of a leaf.

LANCEOLATE
Lanceolate leaves are shaped like a lance; they have a broad base and taper to a point.

LATERAL
Lateral means of, near, or from the side of an organism.

LATEX
Latex is a milky substance that is tapped from rubber trees.

LAURASIA
Laurasia was the northern supercontinent formed after Pangaea broke up during the Jurassic period. Laurasia included what are now North America, Europe, Asia, Greenland, and Iceland.

LAVA
Lava is molten rock. It usually comes out of erupting volcanoes.

LEAF
A leaf is an outgrowth of a plant that grows from a node in the stem. Most leaves are flat and contain chloroplasts; their main function is to make food energy through photosynthesis. The first leaf to grow from a seed is called the cotyledon.

LEAF ABSCISSION
Leaf abscission is the normal separation of a leaf from a plant. Abscisic acid is the plant hormone involved in leaf abscission.

LEAF AXIL
The leaf axil is where the petiole of the leaf attaches to the stem.

LEAF DIMORPHISM
Having two types of leaves on the same plant.

LEAF GAP
A leaf gap is a break or gap in the plant's stele (cylinder of vascular tissue) at the base of a node (where a leaf is). In the absence of a leaf, there would be no gap, i.e., an unbroken cylinder of vascular tissue

LEAFLET
A leaflet is part of a compound leaf. Each leaflet looks like a small leaf.

LEAF SCAR
A leaf scar is mark on a plant's stem that is left where a leaf was once attached.

LEGUME
A legume is a flowering plant that bears its protein-rich seeds in pods and can fix nitrogen from the soil (due to the symbiotic root bacteria rhizobia). Some legumes include lentils, beans, clover, alfalfa, lespedezas, vetches, kudzu, and peas. Classification: Kingdom Plantae, class Magnoliopsida, order Rosales, family Leguminosae.

LEMMA
A lemma is a bract (a reduced, leaf-like structure associated with a flower) in a grass spikelet that is located below the stamens and pistil of the flower.

LENTICEL
A lenticel is a small pore in the bark of a tree through which gas exchange occurs.

LEPIDODENDRON
Lepidodendron (also known as the "scale tree") was a giant club moss (a tree-like plant) whose long trunk had bark with a diamond-shaped pattern (the scars of old, dead branches that fell off). This ancient lycopod was over 130 ft (40 m) tall; the trunk was over 6 ft (1.8 m) in diameter. Lepidodendron lived in swampy areas during the Carboniferous Period (about 360 to 286 million years ago). It has spirally-arranged leaves that ended in cones. By the time the dinosaurs lived, the giant club mosses had died out and were replaced by smaller club mosses.

LEPTOCYCAS
Leptocycas gracilis was a cycad (a primitive seed plant) that lived during the late Triassic period. It was a palm-like tree with a long, woody trunk that lived in warm climates. This tree was about 4.8 ft (1.5 m) tall. Separate male and female plants exist (they are dioecious). This gymnosperm had long, divided leaves and produced large seed cones.

LIANA
Liana is a woody, climbing vine that grows on tree trunks in order to reach sunlight in the rainforest. Rattan, used for making wicker furniture, is made from liana vines.

LIAS EPOCH
The Lias epoch was the early part of the Jurassic period, about 206 to 180 million years ago.

LICHEN
Lichens are organisms that are a symbiosis between algae and fungus. The photosynthetic algae produces food and the fungus provides protection for the algae. Lichens can survive in a variety of conditions and are found worldwide.

LIGNOTUBER
A lignotuber is a root or woody stem base that stores water.

LIGNULE
Lignules (which means tongue) are the two small flaps at the base of a monocot's leaf that wrap around the stem.

LIPID
A lipid is a fat. Membranes in cells are composed of two lipid layers (with proteins dissolved within them).

LINNEAN SYSTEM
The Linnean System is a method of classifying organisms based on a simple hierarchical structure. Organisms are divided into groups using the following system: Kingdom, Phylum, Class, Order, Family, Genus and Species.

LIVERWORT
Liverwort is a green, moss-like plant belonging to the family Hepaticae. This small, simple plant lives in moist, shady areas and has wide, flat leaves that lie close to the ground. Liverworts reproduce with spores.

LIVING FOSSILS
Living fossils are organisms that lived during ancient times and still live today, like the Coelacanth, the horseshoe crab, the gingko tree, cycads, horsetails, club mosses, and many, many other well-adapted organisms.

LOAM
Loam is a type of rich, crumbly soil that contains an almost equal amount of sand and silt, plus a smaller amount of clay (it contains from 28 to 50% silt, less than 52% sand, and 7 to 27% clay).

LOESS
Loess is the term for soil particles that have been moved to another location by the wind.

LONGITUDINAL STRIATE VENATION
Longitudinal Striate venation is a vein pattern found in monocots leaves. A leaf with longitudinal striate venation has its veins arranged almost parallel to one another, running the length of the leaf (also called parallel venation).

LOW SEASONALITY
Low seasonality is when there is a small difference in temperature between the seasons (with mild winters and summers). Compare to stong seasonality, in which the difference in temperatures between the seasons is big (for example, with a hot summer and a cold winter).

LYCOPSIDS
Lycopsids (club mosses) are primitive, vascular plants (pteridophytes) that evolved over 375 million years ago (during the Devonian). Huge club mosses went extinct during the Permian mass extinction; smaller ones lived during the time of the dinosaurs. These plants live near moisture (in order for their spores to germinate). These fast-growing, resilient plants propagate with rhizomes (underground stems).

LYSOSOME
Lysosomes are organelles within plant cells (and other eukaryotic cells) that contain digestive enzymes and is involved with the digestion of food. A lysosome fuses with a vacular membrane that contains food, and the lysosome's enzymes digest the food, breaking the food down into its components.