A-B-C-D-E-F-G-H-I-J-K-L-M-N-O-P-Q-R-S-T-U-V-W-X-Y-Z

A   back to the beginning

Adventitious plant

plantlets that develop asexually from a parent plant: a rooted plantlet forming on a part of the mother plant

Alkaline earths

earth metals, calcium, magnesium, barrium, strontium, and their mineral salts

Alternate

single leaves placed alternately on either side of the stalk

Amphibious

able to exist either on land or in the water

Anaerobic

occurring in an environment that lacks oxygen

Angiosperm

a group of plants whose seeds are borne within a matured ovary

Aquatic

growing in water

Asexual reproduction

any form of reproduction that does not require the union of male and female reproductive material

Axil

the junction of the leaf or petiole and the stem

Axillary

arising from the above junction 

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Biogenic decalcification

When there is a carbon dioxide deficiencey in the water, plants can derive CO2 from the hardening constituents of the carbonate hardness. First they split the hydrogen carbonates into CO2 and carbonates. This causes the pH to rise about one step and the largely insoluable carbonates precipitate and form rough deposits on the leaves and substrate. Some plants such as Vallisneria can even destroy the carbonates and obtain CO2 from them. This raises the pH again by another step. Biogenic decalcification thus causes the water to be 10 to 100 times more alkaline than it was previous. In the dark, the process reverses and the pH drops considerably. Thus these continous large pH swings can pose a significant risk to the well being of fish and animals. The solution is to add enough CO2 to the water and have a significant carbonate level to act as a buffer.

Bipinnate

leaf formed of several leaflets set on either side of the petiole

Bract

specialized scale-like leaf found at the base of a flower

Bullate

blistered, bubbled or puckered in appearance

Bulb

tightly packed fleshy leaves used as a storage organ. Onions and tulips both have bulbs 

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Cation Exchange Capacity (CEC)

Quantifies the ability of media to provide a nutrient reserve for plant uptake. It is the sum of exchangeable cations, or positively charged ions, media can adsorb per unit weight or volume. It is usually measured in milligram equivalents per 100 g or 100 cm3 (meq/100 g or meq/100 cm3, respectively). A high CEC value characterizes media with a high nutrient-holding capacity that can retain nutrients for plant uptake between applications of fertilizer. Media characterized by a high CEC retains nutrients from leaching. In addition, a high CEC provides a buffer from abrupt fluctuations in media salinity and pH. Important cations in the cation exchange complex in order of adsorption strength include calcium (Ca2+) > magnesium (Mg2+) > potassium (K+) > ammonium (NH4+), and sodium (Na+). Micronutrients which also are adsorbed to media particles include iron (Fe2+ and Fe3+), manganese (Mn2+), zinc (Zn2+), and copper (Cu2+). The cations bind loosely to negatively charged sites on media particles until they are released into the liquid phase of the media. Once they are released into the media solution, cations are absorbed by plant roots or exchanged for other cations held on the media particles. Anion exchange capacity Some media retains small quantities of anions, negatively charged ions, in addition to cations. However, anion exchange capacities are usually negligible, allowing anions such as nitrate (NO3-), chloride (Cl-), sulphate (SO4-), and phosphate (H2PO4-) to leach from the media.

Chelators

synthetic organic acids that bind with various trace elements to keep them available in a form that is usable by the plants

Chlorophyll

the pigment that makes plants green. One of the pigments necessary for photosynthesis

Chlorosis

loss of chlorophyll, often a sign of insufficient amounts of iron

Compound leaf

a leaf that is divided into several distinct leaflets

Cordate

heart shaped

Cosmopolitan

found worldwide

Crenate

edged with rounded teeth

Crispate

with wave margins

Cultivar

a man-made (cultivated) variety

Cuticle

the thin skin of the plant. This is thicker and waxy to maintain moisture in emersed growth

Cutting

a fragment of plant material that is capable of growing to become another complete, individual plant 

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Decussate

opposite pairs of shoots set at right angles to the pairs above and below

Denticulate

serrated, edged with small teeth

Distichous

leaves arranged in two rows on either side of the stem

Division

a method of propagation in which the rhizome or vegetative cone is cut into pieces, each of which is capable of becoming a complete new plant 

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Emersed

grown so that the roots and bottom portion of the plant are underwater, rest of the plant grows above the water

Epiphytic

a plant that grows on another plant but is not parasitic

Endemic

a species found only in one specific location

Eutrophic

rich in dissolved nutrients, often caused by pollution 

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Filiform

thread like

Frond

the "leaf" of a fern 

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Hastate

with two out-turned lobes at the base

Herbivore

plant eater

Hybrid

the offspring of two parents of different species or varieties 

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Inflorence

flower cluster

Internode

the area between two nodes on a plant stem 

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Laminae

broad part of the leaf usually attached to the stalk by the petiole. Also called the blade

Lanceolate

spear shaped

Laterite

an iron-bearing red soil found in tropical areas. Formed by centuries of heat and rain.

Leaflet

one part of a compound leaf

Linear

long, narrow, grass-like or strap-like leaf 

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Macronutrients

Nutrients used by plants in relatively large amounts. They are nitrogen (N), phosphorus (P), sulfur (S), calcium (Ca), magnesium (Mg) and potassium (K).

Micronutrients

Nutrients used by plants in small amounts. They are iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), molybdenum (Mo), cobalt (Co), and boron (B).

Monoculture

a large group of a single species of plant

Multipinnate

leaf divided into several sub-groups of leaflets 

N    back to the beginning

Neotropical

from the tropical areas of the new world (South or Central America)

Node

the point on a plant stem from which the leaves and/or roots appear 

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Offset

young plant growing along a stolon from the parent plant

Oligotrophic

deficient in nutrients needed for plant growth

Ovate

egg shaped 

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Paludal

from a marshy or swampy environment

Pectinate

comb like

Pedicel

the stem of an individual flower

Petiole

the "stalk" attaching the leaf to the stem

Photosynthesis

the conversion of light energy into chemical energy:carbohydrates, (sugar and starch), are produced from carbon dioxide and water through the action of light on the chlorophyll of green plants. Oxgen is released in the process

Pinnate

divided

Plumiform

feather shaped

Polymorphous

having multiple shapes 

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R   back to the beginning

Raceme

a group of flowers similar to a spike, but with each individual flower on its own stem

Reniform

kidney shaped

Rhizome

creeping stalk from which stalks and roots grow

Rosette

a plant that rises from a distinct crown 

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Sessile

a leaf that is directly attached to the plant stem with no petiole

Shaft

flower-bearing stalk

Spathe

modified leaf surrounding the flower

Spike

a group of flowers arranged closely at the end of a shaft, and attached directly to the shaft

Sporangium

the reproductive organ of primitive plants like ferns and mosses

Spore

the reproductive unit of primitive plants

Stolon

creeping offshoot or "runner" from which young plants arise

Submersed

growing completly underwater 

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Terrestrial

growing on land

Tuber

a swelling of root or underground stalk that functions as a storage organ as in a potato

Tissue culture

the production of new plants from small amounts of plant tissue under carefully controlled laboratory conditions 

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Vegetative cone

growing tip of the plant. On a stem plant, it is the tip of the stem. On a rosette plant, it arises from the very center of the rosette

Vegetative reproduction

reproduction via means other than sexual. Unless a mutation occurs, each generation of new plants is identical to the parent plant genetically 

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Whorl

a number of leaves evenly spaced around the stem 

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