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Napiform - turnip shaped (root).
Nastic - of a movement made by a part of a fixed plant in response to a non-directional or diffuse stimulus. The direction of movement is always related to the nature of the plant part and not to the stimulus.
Natural selection - the driving force behind evolution, whereby organisms best adapted to their environment and most able to withstand environmental pressures are most likely to survive and reproduce, ensuring propagation and survival of their genes through the gene pool.
Necrosis - sudden discoloration (yellow progressing to brown) of plant tissue, followed by die back of the epidermis, caused by many factors.
Nectar - a sugary secretion produced by flowers and other vegetative parts. Nectar attracts pollinators to flowers.
Nectary - a multicellular glandular structure secreting nectar. Found in flowers and on vegetative parts in some species.
Nematode - an unsegmented roundworm with elongated rounded body, pointed at both ends. Most Nematodes are free-living in soil, fresh and salty water, but some are important parasites of animals and humans. Nematoda with over 20,000 species described, is the most common phyla of animals.
Neotype - a specimen selected to serve as the taxonomic species type when the original type material is missing.
Neri - of a species with a large number of a particular differentiated structure from the Greek nêrithmos = countless. e.g. countless spines = nerispina, nerispinus.
Neutral - i. applied to flowers with neither stamens nor pistils.
ii. applied to soils, liquids etc. which are neither acidic nor basic.
New World - coloquial- the north, central and southern Americas.
Niche - the position that an organism occupies within its environment.
Nitrogen fixing - of plants, often legumes, which are able to extract and fix nitrogen from the air by means of a symbiotic relationship with bacteria (e.g. Rhizobium species,) often in root nodules.
Nocturnal - belonging to the night, as of flowers that open at night.
Node - the place on a stem where leaves or branches originate.
Nomenclature - the study of the systematic naming of taxa, using Latin names so that they will be intelligible and uniform in all countries.
Nomen conservandum - nom. cons. - conserved name - the name of a taxon, usually one in which the name is in common usage, which is internationally agreed to be exempt from the usual rules of priority of publication.
Nomen illegitimum - nom. illeg. - a validly published name that is not in accordance with one or more rules, principally those on superfluity and homonymy.
Nomen invalidum - nom. inval. - a name not validly published according to the rules of publication.
Nomen nudum - naked name - a name published without an accompanying description or diagnosis or reference to same.
Nomen rejiciendum - nom. rej. - a name rejected in favour of a conserved name conserved or otherwise ruled as rejected.
Nucellus - The central part of the ovule enclosing the female gametophyte.
Nucleolus - a small round densely-staining region within the cell nucleus which contains ribosomal rRNA subunits and nuclear organisers (multiple copies of genes encoding rRNA).
Nucleus - a large organelle, usually located near the center of the cell and containing the DNA.
Nuda - naked, without spines, wool etc.
Nudiflorus - naked flowers without scales, spines, or wool on the ovary and flower tube.
Nurse plant - a plant, often a shrub, which provides shelter and shade to developing seedlings of other plants.
Nut - a hard-walled fruit containing a single seed that does not split spontaneously.
Nutrient - a chemical substance that an organism ingests to enable it to survive e.g. essential minerals.
Nyctinasty - of a movement in response to changing day and night conditions.
See also: Nastic.