Welcome to Ariadne's Forest Glossary
Glossary: A is for ... acorn, angiosperm, and autotroph.
by Ariadne Unst
Glossary of A...
Forest and Tree Home,
- abiotic factor (n.)
- A non-living component (such as chemical elements, light, water, and wind).
- acaulescent (adj.)
- achene (n.)
- A small, dry, one-seeded fruit that does not split open; from an ovary with a single chamber.
- acid rain (n.)
- Sulphur and nitrogen oxides (released into the atmosphere by heavy
industry and auto emissions) transform into acids, which fall to earth in rain
- active layer (n.)
- Upper zone of soil that (in higher latitudes) experiences daily and seasonal freeze and thaw.
- acorn (n.)
- The fruit of an oak; A one-seed nut fixed in a woody cup.
- acyclic (adj.)
- Having floral parts that are arranged spirally (instead of in whorls).
- adiabatic (adj.)
- A process where no heat enters or leaves the system.
In the atmospherie, when air rises, it expands because of a
reduction in pressure. In the absence of non-adiabatic processes
(condensation, evaporation, radiation), expansion causes
the air to cool at about 1 degree per 300 feet.
- aerobic (adj.)
- Able to live only in the presence of free oxygen.
- A horizon (n.)
- The soil horizon below
the O horizon
the B horizon . In this layer,
humus and other organic materials
are mixed with mineral particles, while
finer particles and soluble substances are washed out.
- akene (n.)
- A small, hard,
one-seeded fruit from a 1-chambered ovary.
Often it appears as a naked seed, such as a sunflower seed.
- alate (adj.)
- Having wings or wing-like structures.
- alien species (n.)
that is not native to (i.e., not found in, unless imposed by humans) a region.
"It is estimated that alien species now make up as much as 18 percent
of the plant populations of the northeastern states"
- alkaline (adj.)
- Soils that are basic rather than acidic with a PH value greater than 7.0.
They contain large amounts of salts of sodium and
potassium, and other soluble minerals.
- allele (n.)
- One of the possible variants of a polymorphic gene.
- allelopathic (adj.)
- Producing chemical compounds that inhibit the growth of other plants close by.
- alternate (adj.)
- A leaf arrangement in which the leaves along the axis
are not opposite to each other and not whorled.
- alpine zone (n.)
- The region above timber line. Grassy slopes (moss and lichens at higher
elevations) and tundra vegetation.
- amino acids (n.)
- Synthesized by plants from nitrogen, carbon, oxygen, and hydrogen.
Used to construct proteins.
- anaerobic (adj.)
- Able to live in the absence of, or not requiring, molecular oxygen.
- androecium (n.)
- The male home of the
consisting of several stamens. Usually a stamen has a thin stalk-like filament
(stamen) with an enlarged end anther) where pollen is
produced ("the male house").
- Inside the carolla (of sepals)
and the calyx (of petals).
- Within is the gynoecium.
- androgynous (adj.)
- Having flowers with stamens and flowers with pistils in the same inflorescence.
- angiosperm (n.)
- A flowering plant whose seeds are enclosed in an ovary that ripens into a
fruit. Angiosperms are divided into: monocotyledons
Compare angiosperm with gymnosperm.
- animal (n.)
- Multicellular organism that includes: eukaryotic cell type,
and a complex nervous system.
- angiosperm (n.)
- A plant whose seeds are enclosed completely in an ovary.
Also (less scientifically), a flowering plant.
- annual (n.)
- A plant that completes its life cycle (from germination
from a seed to the production of new seeds) in one year;
then it dies.
- anterior (adj.)
- On the front side of the plant, away from the axis.
- anther (n.)
- The part of the stamen that develops and bears pollen.
- aquifer (n.)
- Sand, gravel, or porous rock through with groundwater flows.
- arborescent (adj.)
- Similar to the size and habit of a tree.
- arctic climate (n.)
- No month above 10ºC. Usually tundra. Also see
- arctic (or nirval) zone (n.)
- Near and above the permanent snow line. Lichens on bare rock. A few hardy
- arithmetic growth (n.)
- Growth where the change in size or quantity (per unit of time)
is constant; specifically it is independent of population size.
- atmosphere (n.)
- The gases surrounding the earth. From the sea level to 8 miles up is the
troposphere, in which the temperature decreases with height. Above that is the
stratosphere, in which the temperature is constant.
- austral (adj.)
- Southern. Opposite of
- autoecology (n.)
of individual organisms or species. More simple than synecology.
- autogenic succession (n.)
Succession driven by the
modification to the enviroment that the plant community itself causes.
- autotroph (n.)
- A "self-nourishing" organism. Any organism that obtains its energy from
simple chemical reactions. Green plants, which make their own food through photosynthesis,
- axil (n.)
- The upper angle (or cavity) at the junction between a leaf and stem,
or two other structures or organs.
Forest and Tree Home,