Pruinescence

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Pruinescence

 

Pruinescence

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Within biology, pruinescence is a form of epicuticular wax—a protective layer covering fruit, leaves, and other parts of a plant's morphology.

 

also known as pruinose and pruina

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Pruinescence is a whitish wax coating or fine white powder covering several kinds of fruit, leaves, and other parts of a plant's morphology. It's that fine powdery coating you find on grapes, plums, and on the leaves of several succulents. It's a plant's way of protecting itself: from loss of moisture, and excessive surface wetting, to bacterial and fungal invasion, as well as deterring overzealous insects—their claws incapable of finding decent traction.

Almost all plants have some form of epicuticular wax to protect them—often translucent in nature—but when it's white in colour, we have the rather poetic option of naming it pruinescence. The wax deters water from penetrating the cuticle, by doing so a self-cleaning action is created. Water can't go in, so instead it falls or rolls away, and takes with it any dirt clinging to the surface. The wax has another function, depending from plant to plant, it holds varying degrees of UV (ultraviolet) reflective qualities. This quality protects it from excess sun damage, but it also adds an extra layer of narrative. You see, much of nature is hidden from us, our senses only allow what they allow and what our conscious mind decides to hold importance to. What might look ordinary to us is extraordinary under the right sense.

To us it appears as varying shades of white, but to those creatures capable of observing UV light another narrative unfolds—one of invitation or warning. It's quite tempting as humans to think our view of the world is the only that matters, that the whole of it was built to serve us, but nothing could be further from the truth. It's humbling to realise just how little we are capable of registering, the wide range of communication we stand outside of. But, it's also fascinating, because our technology, as it grows and specialises, compensates for what we cannot register through our own physical means.

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Outside of Botany

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The term isn't unique to botany, it's used in entomology—the study of insects—as well. Pruinescence is a system of communication: to recognise one's own species, and to warn and deter others. When applied to insects, pruinescence still implies a wax coating, but it's colours can vary from white to pale blue, and a few others.

At least to us, it appears as those colours, to insects, capable of seeing UV light they appear quite different. For us, what might appear as different colours, to them might mean different strengths of UV reflectivity.

Those most associated with pruinescense belong to the Odonata order, which contains dragonflies and damselflies. As with plants, the amount of wax created differs between species, but it can also differ between the female and the male of the species, known as sexual dimorphism. With males showing a greater production of pruinescence (Gorb, 1995).

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Etymology

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to become like frost | to glisten like frost

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pruina

frost | freeze

From Latin

-escence

to become | a state of being | a process

Middle French, derived from the Latin -escentia. A suffix attached to words to denote a process or state of being.

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As a Specific Epithet

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pruinatus | pruinata | pruinatum | pruinosus | pruinosa | pruinosum

As a specific epithet the name is used within botany, mycology, and zoology. It's given to those with a whitish or frosted coating or appearance. It's not always clear, on first glance, which physical characteristic the name refers to.

examples

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Xerocomellus pruinatus | a mushroom belonging to the Boletaceae family, its members are known for their thick stems and caps. Their appearance, as well as their relative safety, make them ideal for novice mushroom hunters. Xerocomellus pruinatus is known under its common name of matte bolete.

Stenocereus pruinosus | a cactus with a green colouring and a light white coating. All cacti belong to the Cactaceae family, which in turn is divided up into a few subfamilies and several tribes.

Physalis pruinosa | a species of physalis, commonly known as strawberry groundcherry—which if you give it too much thought becomes a stranger name which each passing second. They belong to the same family, Solanaceae or nightshade, as tomatoes (Solanum lycopersicum), potatoes (Solanum tuberosum), tobacco (Nicotiana tabacum), and goji berries (Lycium barbarum). It's papery husk has a light beige colour, and the berries a pale yellow.

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As an adjective

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pruinose

Pruinose, to describe something that appears whitish, frosted, or covered with fine white powder.



Notes

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Though, it's a rather nice word, pruinescence doesn't seem to be in great use any longer, at least not within botany. Pruinescence hints at a frost like appearance. But, true white doesn't exist in nature, it can't, colour doesn't exist in a vacuum, it is constantly influenced by all the others that surround it. So what is white or pruinose in nature, might to another be glaucous, a pale greyish-blue or green epicuticular wax.

Colours always influence one another, and wether you'd like to call something pruinose or glaucous, you have to keep in mind that epicuticular wax is never so thick and opaque as to completely cover the colour of the cuticle underneath it. So, if the skin of the fruit is a purple blue, won't the colour of the wax lean more towards glaucous, or might it by its very contrast lean more towards pruinescence? Both words do seem to have a clearer definition within zoology and entomology.


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Perennial

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Perennial

 

Perennial

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Any plant that lives longer than two years.

 

A perennial is recurrent, lasting. Within botany, any plant that lives longer than two years is called a perennial. Known for its ability to though out the seasons the year throws at it. Not all perennials can take the seasons of the world round, so those bred outside of their native region will most often be grown as an annual or biennial. Others, known as herbaceous perennials, will die down for their dormant season—most often winter—giving the illusion of death. But, all they need is for their root structure to remain intact below ground, ready come spring—or any other suitable season—to send up new shoots.

And, that's what many perennials come down to, the ability to keep their root structure intact, and to re-establish plant growth above ground once the weather becomes agreeable. On top of their ability to reproduce by seed or cutting, several perennials have the ability to propagate by expanding their root system. They do so laterally, and this spreading root system will send up shoots near the parent plant. Which can be dug up or cut away and replanted.

Perennial means a plant lives longer than two years, though the actual amount a perennial can cycle through varies wildly from characteristic to characteristic, from genus to genus, and region to region. Perennials can live from a handful of years to several millennia. What eventually causes them to pass is damage and age. Though some plants seem to fall even out of the range of the latter. Senescence—the process of ageing, and therefore breaking down into death—is something a very small amount of organisms are simply not built to do. They can be damaged, physically brought harm to, they can fall prey to negative environmental factors, but ageing or noticeable ageing isn't wired into them. We call this negligible senescence, the absence of measurable signs of ageing. Meaning the organism does not lose in strength, nor increases its chance of dying, or reproductive capacity as it grows older. It simply racks up year after year into a kind of immortality.

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Examples

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When people think of perennials, they'll often think of trees and bushes—plants that form woody growth. But, a great deal of perennials don't fall under either category, so here are a few examples of plants you might not have known to be perennials.

+ The banana family (Musaceae) are herbaceous perennials. Once the top part of the plant is spent, meaning once the fruit has matured, everything above ground will start to die down. It's rhizome (root) structure, however continues on to send new banana suckers up.

Banana plants have a natural tendency towards vegetative propagation (non-sexual reproduction). With each plant capable of sending out suckers, baby banana plants that grow away from the mother plant above ground, though still connected below ground through its root structure.

Within commercial cultivation, these suckers are cut away from the mother, and replanted. This method causes each plant to be a clone of the one before it, and the one before, and the one before, into a long history of human-aided and guided reproduction.

+ Solanum lycopersicum is known as a perennial in its native region of South America. But, ask most people—at least those with a minimum of garden experience—and they'll tell you they're annuals.

Tomato cultivars lean towards two categories: determinate and indeterminate. The first are bred for commercial viability and convenience, but not longevity. They're compact in growth, and predictable in their fruit's maturation process— for fruit that matures during the same period can be picked at the same time.

Whereas, indeterminate tomato plants or vining tomatoes grow rather bushy. It continues to produce new flowers, even as earlier ones have set to fruit and ripen. The changing season and the eventual cold is what kills these kinds of cultivars off. But, under the right circumstances or in their native region, the cold never hits, and they can live as perennials.

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AS A SPECIFIC EPITHET

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Some plants will carry their perennial nature in their nomenclature. As a specific epithet, perennial is expressed as perennis (m,f) and perenne (neuter).



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Epithet

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Epithet

Epithet

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Within botanical taxonomy an epithet refers to the taxa following either the genus or species.

 

A specific epithet refers to the second part of the botanical name of a plant, known as species. It follows the first part of the botanical name, known as genus. An infraspecific epithet refers to any subtaxa below species. An epithet (plural: epithets) adds specific information to what might otherwise be construed as a generic name or information.

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Examples

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Persea americana 'Hass' (Hass Avocado) - Hass, which is the name of the cultivar, is the infraspecific epithet. Hass avocado has thick, knobbly skin which turns a very dark shade of green to almost black when ripe. The flesh is a buttery, pale green.

Theobroma cacao (Cacao) - Theobroma is the genus or generic name, whilst cacao is the species or specific epithet.

 

Outside of Botany

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An epithet is a byname (word or phrase). It can be descriptive, characterising, or a descriptive substitute for the name or title of a living or non-living thing. William The Conqueror is one of the epithets for William I of England. The Scottish Play is an epithet (descriptive substitute) for Shakespeare's play 'Macbeth'. 

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Botanical Terms and Taxa mentioned

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Below are links to The Hungry Child's internal database on the terms and taxa that were used in this article, or might be useful alongside it. If you feel that something is missing or unclear, leave a comment or send me an email.

Genus (genera| cultivar

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Taxonomy

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Taxonomy

Taxonomy

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Taxonomy, within biology, is the science of defining groups of biological organisms based on their shared characteristics, and the subsequent naming of these groups.

 

Taxa (singular: taxon) means arrangement, hence taxonomy is an arrangement method or classification system. It can refer to the generic names the system is divided in, such as: family, genus, species. But, it can also refer to the specific. For example: Zingiberaceae (The Ginger Family). Which includes some of the following genera: Zingiber, Alpinia, Curcuma, and Elettaria. Which in turn contain the following species: Zingiber officinale (Ginger), Alpinia galanga (Galangal), Curcuma longa (Curcuma or Turmeric), Elettaria cardamomum (Green Cardamom).

A specific taxon can be named by a person (author), but it can also be named after a person (eponymy). When a species is named and described—or re-described, and by extension often reassigned to a different genus or family—it will have the author's name (abbreviated) next to it. As such: Genus species Author. Or, Genus species (ex. Author) Author.

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Botanical Terms and Taxa mentioned

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Below are links to The Hungry Child's internal database on the terms and taxa that were used in this article, or might be useful alongside it. If you feel that something is missing or unclear, leave a comment or send me an email.

Genus (genera)

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Morphology

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Morphology

Morphology

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Study of Form

 

Morphology, within Botany, is the study of the outward appearance of a plant. Such as the colour, shape, structure, pattern, and size, known as external morphology. As well as the study of its internal form and structure known as internal morphology or anatomy. It does not deal with function, which is known as Physiology.

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Inflorescence

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Inflorescence

INFLORESCENCE

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An inflorescence is a group or cluster of flowers on a single stem.

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Genus

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Genus

Genus

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a taxonomic category containing one or more species

 

In the 18th century Carl Linnaeus devised a two-word or binomial system to name plants.  The botanical name of a plant belongs to a larger arrangement method or taxonomy, with genus ranking below family, but above species. Genus forms the first part of the botanical name of a plant. It is capitalised and written in italics. As such: Genus species

When you list multiple species within a genus, you can abbreviate the genus. As such: F. carica, F. religiosa, and F. benghalensis. The 'F.', in this case, stands for Ficus (fig). Genus is the singular form, and genera is the plural. A genus is a noun and has a gender—female, male, or neuter. The gender doesn't influence the spelling of the genus, but it does influence the spelling of the species name.

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Examples

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+ Acer - Maple - the presence of the species name transforms the generic into the specific. For example: Acer palmatum (Japanese Maple or Momiji), Acer saccharum (Sugar  Maple), Acer sempervirens (Cretan Maple).

+ Solanum - is a large and diverse genus, it contains several economically valuable food crop species. Such as Solanum lycopersicum (tomato), Solanum tuberosum (potato), and Solanum melongena (aubergine/eggplant).  

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Botanical Terms and Taxa mentioned

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Below are links to The Hungry Child's internal database on the terms and taxa that were used in this article, or might be useful alongside it. If you feel that something is missing or unclear, leave a comment or send me an email.

cultivar | epithet (related to species)

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Last modified on 2016, February 15th

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Gall

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Gall

GALL

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A gall, in terms of insects and plants, is when a plant is tricked in to growing an abnormal outgrowth by an insect, fungi, virus, or bacteria. The growth most often serves as a protection from outside forces and as a food source for the trickster. The plant tissue is completely under its control.  

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Drupe

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Drupe

DRUPE(S)

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A fruit consisting of a fleshy outer part—including the skin, which can be thin, soft, or though—and a hard pit or stone on the inside.

 

The pit consists of two parts, an outer hard part—called an endocarp—and an inner part, where the seed is nestled. The defining character for a fruit to be called a drupe: the stone or pit must be derived from the ovarian wall of the flower. Certain fruits, like the brambles—including blackberry and raspberry—are considered drupes as well. Because of their size and multitude of seeds, they're called drupelets. Some examples include: olives, peaches, mango, almonds, plums, coconut, dates, coffee, etc.

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Deciduous and Evergreen

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Deciduous and Evergreen

DECIDUOUS

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A tree or plant that loses its 'living' leaves during winter

 

The plant no longer sends nutrients to the leaf, effectively cutting it off from the rest of the plant. The leaves then turn brown, rich ochres, or purples. In temperate or polar climates this coincides with autumn. In warmer areas such as tropical, subtropical and arid regions it coincides with the dry season. Even though the leaves turn colour, not all deciduous plants shed their leaves.

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As a specific epithet

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deciduus | decidua | deciduum

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EVERGREEN

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A tree or plant that retains its green leaves throughout the year

 

An evergreen plant loses its leaves gradually throughout the year and never at once. It is in a continuing process of growing new leaves and shedding old ones. Evergreen plants can be found within cold climates, as well as rainforests. When you see the botanical name of a plant and the second part of its name is sempervirens, rest assured that it is an evergreen.

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As a specific epithet

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sempervirens


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modified on 2016, April 25th.

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Cultivar

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Cultivar

CULTIVAR

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a cultivated variety

 

Cultivars come in to existence through careful breeding and selection. A cultivar is not the same as a variety on a species, it's a cultivated variety. The difference, a cultivar is man-made, selected for flavour, strength, resistance to pests, etc. Whilst a variation naturally occurs in nature.

A cultivar is an infraspecific taxa, meaning a subrank below species—it's also the lowest infraspecific taxa. A Group—capital 'G'—is a collection of cultivars with close resembling physical characteristics. Not all cultivars belong to Groups.

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Cultivar Names

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The name of a cultivar is written as such: Genus name specific epithet 'cultivar epithet' or Genus name 'cultivar epithet' (Genus species 'cultivar'). The cultivar name is held between single quotation marks, each word within capitalised (apart from conjunctions) and modern cultivar names (those given after 1959) should not include latin or latinised names. There's no 'connecting term', meaning an abbreviated (generic) infraspecific taxa, and the name is not written in cursive. Examples of connecting terms are: subsp. (subspecies), var. (variety), f. (form).

So, it delineates from the way we write other infraspecific taxa, which we write as such: Genus name specific epithet connecting term infraspecific taxa. For example: Genus species subsp. name of subspeciesGenus species var. name of variety, Genus species f. name of form.

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Examples

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+ Persea americana 'Hass' or Persea 'Hass' - Avocado, Hass cultivar - cultivated by amateur horticulturist Rudolph Hass (around 1926). It has thick, knobbly skin which turns a very dark shade of green to almost black when ripe. The flesh is a buttery, pale green. It's the most grown cultivar of avocado worldwide.

+ Solanum lycopersicum 'Coeur-de-Boeuf' or Solanum 'Coeur-de-boeuf' - Tomato, Coeur-de-Boeuf cultivar (beefsteak type). The name means ox or beef heart in French.

Acer saccharum 'Legacy' or Acer 'Legacy' - Sugar maple, Legacy cultivar. Maple syrup is made from the sap of the sugar maple. The Legacy cultivar is hardy, and resistant to drought and pests.

Prunus avium 'Bing' or Prunus 'Bing' - Sweet Cherry, Bing cultivar. Cultivated at the Lewelling fruit tree nursery in Oregon (around 1875) and named for Seth Lewelling's Chinese foreman, Ah Bing. It's unclear wether Lewelling or Bing developed the cultivar, or if they did so together.

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Botanical Terms and Taxa mentioned

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Below are links to The Hungry Child's internal database on the terms and taxa that were used in this article, or might be useful alongside it. If you feel that something is missing or unclear, leave a comment or send me an email.

genus | epithet

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More on Taxonomy

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Last modified on 2016, February 21st

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Bract

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Bract

BRACT

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A specialised or modified leaf, mostly associated with the reproductive part of the plant, such as the flowers, inflorescence, or cone.

 

They often have an attractive or protective function, and mostly differ from the actual leaves of the plant—in shape, colour, and size. On a pineapple, they're the spiny, rough bits you feel on the rind, just underneath each of the single parts that make up the fruit. On a conifer cone (pine cones, fir cones, giant sequoia cone) a layer of them separates each row of scales from one other, in most cones the bracts are smaller than the scales and you can only see them when you start taking apart the cone. On some cones the bracts extend beyond the scales, and they overhang on each scale. 

 

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