Glossary of Biological Terms – Volker’s Plant Galls

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Paraphyses

Paraphyses are sterile, hair-like cells in the hymenium of ascomycetes, located between the asci. Their shape and colour can sometimes be used for identification.

Parasite

A parasite is an organism that obtains food at the expense of another organism (the host), thereby harming it and potentially causing the host’s death.

Parasite (mycology)

A parasitic fungus attacks living organisms, whether healthy or weakened, damages them and may eventually cause their death.

Parasitoid

A parasitoid is an animal that lives parasitically during its development and subsequently kills its host.

Parthenogenesis

In parthenogenesis, also called agamy, offspring develop from unfertilised eggs. It is a form of asexual reproduction.

Peridermium

Aecia with walls that are initially closed like a dome (peridermia producing peridermiospores).

Peridioles are components of the gleba of gasterothecia. They are lens- to disc-shaped, about 1–2 mm in diameter, each containing a glebal chamber and enclosed by a secondary peridium. They function as diaspores. Initially, each peridiole is connected to the peridium by a strand of trama. These strands become mucilaginous and serve as attachment threads when the peridioles are ejected by water droplets from the funnel-shaped, mature fruiting bodies.

Peridium

A multilayered, persistent outer wall of the fruiting bodies of gasteroid fungi that does not become transformed into spore mass.

Perithecium

Perithecia are pear-, spherical- or flask-shaped fruiting bodies of ascomycetes or lichens. Unlike an apothecium, a perithecium does not have an exposed fertile disc.

Petrophilous

Preferring or inhabiting rocky or stony habitats.

Phytocecidia

Phytocecidia are plant galls caused by plant parasites such as ascomycetes and rust fungi.

Phytoparasitism

Phytoparasitism is the parasitic acquisition of resources from plants. Phytoparasites obtain essential resources from a host plant, which often provides them with nutrients.

Phytoptocecidia

Phytoptocecidia are plant galls caused by mites.

Pith gall

A type of gall in which growth originates in the inner layers of the plant; such galls are particularly characteristic of gall wasps.

Plectenchyma

Plectenchyma (interwoven tissue, pseudotissue) is a term from plant morphology. It is found particularly in red algae and fungal fruiting bodies. At first glance it may resemble true tissue, but it actually consists of adhering, fused or interwoven cell filaments. Unlike true tissue, cellular connections such as pits occur only within the individual filaments.

Pleometrosis

In pleometrosis, several ant queens or queens of other social hymenopterans (and, very rarely, termites) establish a colony together. They lay eggs jointly and also care for the brood together. Although pleometrotic foundation is known in a number of species, it is relatively uncommon in nature. Pleometrosis is often, but not always, associated with several fertile, egg-laying reproductive individuals in a colony (polygyny). The opposite condition, in which a queen establishes a new colony alone and independently of other queens, is called haplometrosis (or haplometrosis).

Pleomorphism

In biology, pleomorphism refers to the occurrence of multiple forms in certain microorganisms or cells of multicellular organisms.

Polygyny

In biology, polygyny generally refers to a mating system in which a male mates with several females during a reproductive period; it is a form of polygamy.

Polylecty

The collection of pollen from many different flowering plants by polylectic bees. Such species can also be described as pollen generalists. Many nevertheless show preferences for particular plants while avoiding others.

Prosoplasmatic

A specialised tissue produced through gall formation. Prosoplasmatic galls are those whose shape and size characteristics are highly characteristic of the particular gall type. They are produced mainly by dipterans and hymenopterans, as well as by many mites and hemipterans.

Psychrophilic

A preference for lower temperatures.