ترجمه متون علوم گیاهی

[orkideh4]

تواین تاپیک ترجمه متون مربوط به علوم گیاهی روقرارمیدیم.هرکسی هم که مایل به همکاری باشه میتونه اعلام کنه.

[hajibehzad]

Auxins
There is only one naturally occurring auxin: indole-3-acetic acid (IAA) and this is chemically related to the amino acid tryptophan.
There are many synthetic auxins - aromatic compounds with carboxylic sidechains often affect plant growth in the same way that IAA does. These are used commercially rather than IAA because they are cheaper and more stable. For example naphthalene acetic acid (NAA) is used to control fruit set and sucker growth on trees after pruning. Indole butyric acid is used to promote rooting in cuttings. Far and away the biggest use of auxin-like compounds is as herbicides (2,4-D and MCPA). Applied at high concentration they promote uncoordinated growth and finally death, particularly in broad-leaved weeds. Cytokinins
There are a number of naturally occuring cytokinins all related to the nucleotide adenine. They can occur as the free base or as a riboside. Synthetic cytokinins include benzyladenine and kinetin. Cytokinins are used in tissue culture media, and for growth control in fruit.
Ethylene
Ethylene is the only gaseous hormone in the plant world; it is a simple hydrocarbon gas that is derived from the amino acid, methionine, via an unusual cyclic compound which is also an amino acid, ACC (1-aminocyclopropane-1-carboxylic acid).
The gas is used commercially for ripening fruit, particularly bananas. There are also synthetic compounds, such as ethephon (chloro-ethanephosphonic acid) that can be sprayed onto plants in solution; once inside the tissues ethephon breaks down to liberate ethylene. Ethephon is used to promote ripening on the tree, leaf abscision in ornamentals, growth control in seedlings and flowering in pineapples. Abscisic acid
Abscisic acid (ABA) is one of two related compounds (the other is xanthoxin) that are in the isoprenoid group and related to carotenoids ABA is a very expensive material and so far there are no synthetic analogs or practical uses
Gibberellins
The gibberellins (GAs) are the largest group with over 70 compounds although not all are biologically active. Like ABA they are derived from the isoprenoid pathway. Gibberellins are used commercially to break dormancy of "difficult" seeds, and to promote set of grapes and other fruits.
Many growth retardants used on flowering pot plants, woody plants and turf are "anti- gibberellins". Compounds such as ancymidol and uniconazole block GA synthesis and produce dwarf plants. Genetic dwarfs are often deficient in gibberellin. Hormone action At the cell level hormones attach to a protein receptor which sends a signal down a transduction pathway to switch on particular genes. Through transcription and translation this leads to production of an enzyme protein which actually causes the change in plant growth. A good example from the early stages of plant development is the role of GA in cereal seed germination. As the seed imbibes water the embryo produces GA. This induces synthesis of amylase in the aleurone layer which secretes the enzyme to the endosperm. Amylase breaks down starch to glucose which diffuses to the embryo and is used for the early stages of plant growth.

[orkideh4]

اکسین
ایندول-3-استیک اسید تنها اکسین طبیعی است که ازلحاظ شیمیایی مربوط به امینواسیدتریپتوفان می باشد.
تعداد زیادی از ترکیبات اروماتیک مصنوعی اکسینی با زنجیره جانبی کربوکسیلیک وجود دارد که همانند اکسین عمل کرده و اغلب روی رشدگیاهان تاثیر می گزارند، چراکه که مقرون به صرفه تر و پایدارتر از ان می باشند. برای مثال نفتالین استیک اسیدبرای کنترل میوه ها ورشد پاجوش روی درختان بعدازهرس کردن استفاده می شود. ایندول بوتیریک اسید درجلوانداختن ریشه زنی در قلمه زنی استفاده میشود. از ترکیبات شبه اکسینی نظیر 2-متیل -4-کلرو فنوکسی استیک اسید و 2،4- دی کلرو فنوکسی استیک اسیدبه عنوان علف کش استفاده می شود.کاربرد وسیع انها سبب رشد غیر طبیعی وسرانجام مرگ به ویژه در علفهای هرزمی گردد.

سیتوکینین ها
تعدادی ازسیتوکینین های طبیعی وجودداردکه همه به نوکلئوتید ادنین مربوط می شوند.انها میتوانند بصورت مستقل و یا ریبوزید وجود داشته باشند.سیتوکینین های طبیعی شامل بنزیل ادنین و کیتین می باشد. سیتوکینین ها درکشت بافت وبرای کنترل رشد درمیوه استفاده می شوند.

اتیلن
تنها هورمون گازی گیاهان اتیلن می باشد، که گازهیدروکربن ساده ای است که ازامینواسید متیونین همراه با یک چرخه ی مرکب غیرمعمول از امینو سیکلو پروپان کربوکسیلیک اسید مشتق شده است. گاز تجاری برای رسیدن میوه ها بویژه موزهامی باشد. همچنین ترکیبات مصنوعی ازقبیل اتفون(کلرو-اتان فسفونیک اسید)وجود دارد که میتواند روی گیاهان بصورت محلول پاشیده شود. اتفون در بافتهای درونی به اتیلن ازاد می شکند. اتفون درجلوانداختن رسیدگی درختان میوه، قطع برگهای زینتی، کنترل رشد دربذرافشانی و گلدهی دراناناس استفاده میشود.

ابسیزیک اسید
ابسیزیک اسیدیکی از دو ترکیب ایزوپرنوئیدیه مربوط به کارتنوئید است( ترکیب دیگر گزانتوکسین می باشد). ابسیزیک اسیدیک ماده ی خیلی گرانقیمت با مصارف زیاد بوده و جایگزین مصنوعی ندارد.

ژیبرلین ها
ژیبرلین ها بزرگترین گروه بابیش از 70 ترکیب هستند که همه ی انها فعالیت زیستی ندارند. مثل ابسیزیک اسید انهاازایزوپرنوئید مشتق شده اند. ژیبرلین ها برای شکستن دوره ی خواب دانه ها ودرجلو انداختن رسیدگی انگورها ودیگرمیوه ها استفاده ی تجاری دارند. بسیاری از عوامل ضد رشد روی گلدهی گیاهان گلدانی، گیاهان چوبی و چمن ترکیبات انتی ژیبریلین هستند. ترکیباتی ازقبیل انسیمیدول و یونیکونازول سنتز ژیبریلین رامسدود وگیاهان کوتاه قد را افرایش می دهند. ژنتیک کوتاه قدها اغلب درژیبرلین ناقص است.

عمل هورمون
هورمون های سلولی به یک پروتئین گیرنده وصل شده و یک پیام برش مسیر ترجمه برای اتصال روی ژن های نسخه برداری و ترجمه فرستاده و باعث تغییردررشد گیاهان میشوند. یک مثال خوب ازمراحل سریع از توسعه گیاه نقش ژیبرلین درجوانه زدن دانه ی حبوبات است. جنین اب جذب کرده، ژیبرلین تولید میکند که موجب سنتز امیلاز درلایه ی الئورون که انزیم رابه اندوسپرم ترشح میکند میشود. امیلازنشاسته رابه گلوکزتجزیه میکند که به مصرف جنین و مراحل ابتدایی رشد می رسد.


مترجم: Orkideh4
(باتشکرازاقای حاجی بهزاد)

[hajibehzad]

Plant secondary metabolites is a generic term used for more than 30,000 different substances which are exclusively produced by plants. The plants form secondary metabolites e.g. for protection against pests, as colouring, scent, or attractants and as the plant's own hormones. It used to be believed that secondary metabolites were irrelevant for the human diet. The importance of these substances has only recently been discovered by scientists. Secondary metabolites carry out a number of protective functions in the human body. Plant secondary metabolites can boost the immune system, protect the body from free radicals, kill pathogenic germs and much more.
In contrast to the primary metabolites (carbohydrates, fats, proteins, vitamins and mineral nutrients) secondary metabolites do not have nutrient characteristics for human beings. They are usually found in very small amounts but have an effect on humans.
Secondary metabolites have a scientifically proven effect on health. However many of these effects are unknown. The exact requirement of the individual substances is likewise unknown. A diet which is rich in plant foods contains a variety of secondary metabolites and contributes to protecting the body against cancer and cardiovascular illnesses. Secondary metabolites and their effects are currently being intensively researched

• Carotenoids
  Carotenoids are organic pigments occurring in plants and are mostly found in red, orange and yellow fruits and vegetables. Other vegetables such as broccoli, spinach or curly kale also contain carotenoids. Carotenoids have antioxidative effects and prevent cancer. In addition to this they boost the immune system and reduce the risk of getting heart attacks.
  
• Phytosterols
  
• Phytosterols are found in plant foods such as sunflower seeds, sesame, nuts and Soya beans. Phytosterols protect against colon cancer and lower cholesterol levels. Phytosterols are chemically similar to cholesterol and therefore they compete against each other for absorption in the body.
  
• Saponins
  Saponins are flavour additives, which are found in legumes and spinach. Saponins boost the immune system, lower the cholesterol levels in the blood and reduce the risk of getting intestinal cancer.
  
• Glucosinolates
  
• Glucosinolates are flavour additives, which are found in all types of cabbages, mustard, radish and cress. Glucosinolates prevent infections and inhibit the development of cancer.
  
• Flavonoids
  Flavonoids are organic pigments occurring in plants which give plants a red, violet or blue colour. Flavonoids have a particularly broad spectrum of efficacy. Flavonoids inhibit the growth of bacteria and viruses, protect the cells against the damages of free radicals, protect against cancers and heart attacks, have a repressive effect against inflammations and they influence blood coagulation.
  
• Protease-inhibitors
  
• Protease-inhibitors are found in plants that are rich in protein such as legumes, potatoes and wheat and they inhibit the decomposition of protein. Protease inhibitors protect the body against cancers and regulate the blood sugar levels.
  
• Terpenes
  Terpenes are plant flavours for e.g. the menthol in peppermint oil or the essential oils in herbs and spices. Terpenes decrease the risks of cancer.
  
• Phytoestrogens
  Phytoestrogens are natural plant hormones which are similar to the ***ual hormones. Phytoestrogens are mostly found in wheat, legumes and wheat products. Phytoestrogens protect the body against hormonal dependant cancers such as breast, uterine and prostrate cancer.
  
• Sulphides
  
• Sulphides are compounds containing sulphur which are mostly found in plants that belong to the lily family such as onions, leeks, asparagus and garlic. Sulphides inhibit the growth of bacteria, lower cholesterol levels, protect the body from free radicals and have preventive effects against cancer.
  
• Phytic acid
  Phytic acid is found in wheat, legumes and flaxseeds. Phytic acid was considered undesirable for a long time because it binds trace elements such as iron and zinc and it also affects various digestive enzymes. However new studies have proved that phytic acid has an antioxidant effect in the large intestine

[orkideh4]

متابولیت های ثانویه گیاهی

متابولیتهای ثانویه گیاهی واژه ای کلی برای بیش از 30 هزار محصول منحصرا گیاهی می باشد. اشکال گیاهی متابولیتهای ثانویه به عنوان مثال عاملی برای حفاظت در مقابل افات، رنگ، عطر، جلب و یا به صورت خود هورمون گیاهی هستند.مصرف کنندگان عقیده دارند که متابولیتهای ثانویه در رژیم غذایی انسان تاثیر گذار نیستند. اهمیت این مواد اخیرا توسط دانشمندان کشف شده است. متابولیتهای ثانویه برخی از اعمال حفاظتی در بدن انسان انجام میدهند. متابولیتهای ثانویه گیاهان میتوانند سیستم ایمنی را تقویت کرده، بدن را از رادیکال های ازاد حفظ کرده و عوامل بیماریزا را نابود کنند.
در مقابل متابولیتهای اولیه (کربوهیدرات ها - چربی ها - پروتئینها و ویتامینها و مواد غذایی معدنی) نظیر متابولیتهای ثانویه ویژگی های غذایی برای انسان ها ندارند.انها در مقادیر ناچیز و بسیار کم اثر برای انسان می باشند.
اگرچه تعدادی از اثرات متابولیتهای ثانویه به صورت اختصاصی ناشناخته هستند اما به طور علمی ثابت شده که در سلامتی تاثیر گذار هستند. یک رژیم غذایی گیاهی که سرشار از انواع متابولیتهای ثانویه می باشد به حفاظت بدن در برابر سرطان و بیماریهای قلبی عروقی کمک می کند. در حال حاضر بررسیهای زیادی در مورد این محصولات در حال انجام می باشد.

کاروتنونیدها
رنگدانه های الی گیاهی بوده و عمدتا در میوه ها و سبزیجات قرمز، نارنجی و زرد رنگ یافت می شوند. دیگر سبزیجات از قبیل کلم بروکلی، اسفناج و کلم پیچ نیز حاوی کاوتنوئیدها می باشند. کارونوئیدها اثرات انتی اکسیدانی داشته و از سرطان جلوگیری میکنند.علاوه بر این انها سیستم ایمنی را بالا برده و خطر ابتلا به حمله قلبی را کاهش میدهند.

فیتواسترولها
فیتواسترولها در غذاهای گیاهی از قبیل دانه افتابگردان، کنجد، اجیل و دانه های سویا یافت میشوند. فیتو استرولها بدن را در مقابل کلنی های سرطانی محافظت کرده و سطح کلسترول را کاهش میدهند. از نظر شیمیایی مشابه کلسترول بوده و در بدن در جذب رقابتی قرار دارند.

ساپونین ها
ساپونین ها چاشنی های افزودنی بوده و در حبوبات و اسفناج یافت می شوند. سیستم ایمنی را بالا برده، سطح کلسترول خون را پایین اورده و خطر ابتلا به سرطان روده را کاهش می دهند.

گلوکوسینولاتها
چاشنی های افزودنی اند که در همه انواع کلم ها، خردل، تربچه و شاهی یافت میشوند. از عفونت جلوگیری کرده و سبب مهار پیشرفت سرطان می شوند.

فلاونوئیدها
رنگدانه های الی بوده و به گیاهان رنگ قرمز، بنفش و یا ابی میدهند. فلاونوئید ها طیف اثر گسترده ای دارند. رشد باکتری ها و ویروس ها را مهار کرده و سلولها را در مقابل تخریب رادیکالهای ازاد محافظت میکنند.اثر سرکوب کنندگی علیه التهاب داشته و سبب انعقاد خون می شوند.

انتی پروتئازها
در گیاهانی که غنی از پروتئین اند یافت میشوند، نظیر حبوبات، سیب زمینی و گندم و از تجزیه پروتئین جلوگیری میکنند. از بدن در برابر سرطانها محافظت کرده و سطح قند خون رو تنظیم میکنند.

ترپن ها
چاشنی های گیاهی نظیر منتول در اسانس نعنا یا اسانسهای گیاهی و ادویه جات که خطر ابتلا به سرطان را کاهش میدهند.

فیتواستروژن ها
هورمون های گیاهی طبیعی اند که شبیه هورمون های جنسی عمل می کنند. اکثرا در گندم، حبوبات و محصولات گندمیان یافت میشوند. بدن را علیه سرطان های وابسته به هورمون از قبیل سرطان پستان، رحم و پروستات محافظت میکنند.

سولفید ها
ترکیباتی اند حاوی سولفور که اکثرا در گیاهان متعلق به خانواده زنبق از قبیل پیاز ها؛ تره فرنگی، مارچوبه و سیر یافت میشوند. سولفید ها مانع رشد باکتری ها شده و سطح کلسترول خون را پایین می اورند. از بدن در برابر رادیکالهای ازاد محافظت کرده و بازدارنده پیشروی سرطان می باشند.

فیتیک اسید
در گندم و حبوبات و تخم کتان یافت میشوند. به دلیل ایجاد باندهای اتصالی با عناصر کمیاب از قبیل اهن و روی برای مدتی طولانی نامطلوب در نظر گرفته می شدند و همچنین انزیمهای گوارشی مختلف را تحت تاثیر قرار می دهند. به هر حال مطالعات جدید نشان می دهند که فیتیک اسیدها اثر انتی اکسیدانی در روده بزرگ دارند.


مترجم:asal_mohsenian
باتشکرازاقای حاجی بهزاد

[hajibehzad]

INTRODUCTION TO TAXONOMY




Castilleja miniata
What is Taxonomy and Where Did it Originate?
by
Jamie Fenneman
Taxonomy is the method by which scientists, conservationists, and naturalists classify and organize the vast diversity of living things on this planet in an effort to understand the evolutionary relationships between them. Modern taxonomy originated in the mid-1700s when Swedish-born Carolus Linnaeus (also known as Carl Linnaeus or Carl von Linné) published his multi-volume Systema naturae, outlining his new and revolutionary method for classifying and, especially, naming living organisms. Prior to Linnaeus, all described species were given long, complex names that provided much more information than was needed and were clumsy to use. Linnaeus took a different approach: he reduced every single described species to a two-part, Latinized name known as the “binomial” name. Thus, through the Linnaean system a species such as the dog rose changed from long, unwieldy names such as Rosa sylvestris inodora seu canina and Rosa sylvestra alba cum rubore, folio glabro to the shorter, easier to use Rosa canina. This facilitated the naming of species that, with the massive influx of new specimens from newly explored regions of Africa, Asia, and the Americas, was in need of a more efficient and usable system.
Although trained in the field of medicine, botany and classification were the true passions of Linnaeus and he actively explored northern Europe and described and named hundreds of new plant species during his lifetime. As well, Linnaeus spent a great deal of time describing and naming new plant specimens that were sent to him from around the world by other botanists, including from the newly explored regions of the New World. Linnaeus classified this multitude of new plant species based upon their reproductive structures, a method which is still largely in use today. In fact, the majority of the species described by Linnaeus are still recognized today, indicating how far ahead of his time he truly was. Although somewhat rudimentary by today’s standards, Linnaeus’ methods of describing species in such a way as to represent the relationships between them changed the face of taxonomy and allowed biologists to better understand the complex natural world around us.

Carex aurea
How Do We Classify Plants?
Plants, and indeed all organisms, are classified in a hierarchical system that attempts to illustrate the evolutionary relationships between the various groupings within the hierarchy. This concept of relatedness forms the backbone of modern classification schemes. Scientists who attempt to classify organisms and place them within an evolutionary framework are called Taxonomists, the most famous of which would be Linnaeus himself.At the broadest level, all organisms on the planet are classified into 5 Kingdoms: Animalia (animals), Plantae (plants, some multicellular algae),Fungi (fungi), Monera (prokaryotic bacteria), and Protista (eukaryotic bacteria, most algae, etc.), representing the most ancient branches of the evolutionary “tree of life.” Organisms in any given Kingdom may be separated from organisms in any other Kingdom by many hundreds of millions, if not billions, of years of evolution. Historically, all organisms known were grouped into only two Kingdoms: organisms that had finite growth, moved, and ate were grouped into the Kingdom Animalia, while organisms that had indefinite growth, didn’t move, and didn’t eat were grouped into the Kingdom Plantae. Of course, as science progressed, it became increasingly evident that such a simplistic approach to taxonomy was ineffective and many species were found that did not fit either grouping particularly well. The proposal to move to an eight-Kingdom system suggests that our current classification system, with its five Kingdoms, may yet change again as our understanding of the diversity of organisms around us continues to grow.
Within each Kingdom, the organisms are grouped into several Phyla (sing. Phylum), also known as Divisions, which represent smaller groupings of more recognizable forms. Although the Kingdom Animalia contains a large number of Phyla (such as chordates [including vertebrates], echinoderms, annelids, arthropods, etc.), Kingdom Plantae contains only ten. The Phylum Bryophyta (mosses, liverworts, hornworts), the most primitive of all true plants, differs from other plant Phyla in that it is non-vascular, meaning that it lacks water-conducting tissues which bring water from the roots of the plant up into the crown, and that the gametophyte (vegetative) generation predominates over the sporophyte (reproductive) generation. The Phyla Psilophyta (whisk ferns), Lycopodiophyta (club-mosses, spike-mosses, quillworts), Equisetophyta(horsetails), and Polypodiophyta (true ferns), including all vascular plants that reproduce using spores, also form an ancient, though largely artificial, grouping and are often referred to as Pteridophytes. The Phyla Cycadophyta (cycads),Ginkgophyta (ginkgo), Gnetophyta (vessel-bearing gymnosperms), and Coniferophyta (conifers) form a second primitive grouping of vascular plants, known as Gymnosperms, which are characterized by the presence of ***** seeds (the literal translation of “gymno-sperm”). The final Phylum, Magnoliophyta, contains all of the vascular, flowering plants that are considered to be the most advanced and recently-evolved plants occurring on the planet today.

Brodiaea coronaria
Within each Phylum, the organisms involved are grouped into progressively smaller, more refined groupings of similar individuals. Below Phylum, organisms are grouped into Classes, Orders, and Families, the latter being the largest-order taxonomic grouping that is commonly used by amateur botanists. As an example, the Phylum Magnoliophyta is split into 2 well-known Classes: Magnoliopsida (Dicotyledons) and Liliopsida (Monocotyledons) based on a variety of features from leaf venation and flower structure to growth form, root structure, and seed structure, each class with its subsequent Orders and Families. Each family is further divided into Genera (sing. Genus) representing organisms with similar morphology, structure, reproductive organs, and, perhaps most importantly, evolutionary history. These genera represent groupings that many of us are most familiar with, such as Rhododendron, Rosa, Chrysanthemum, etc. and are designed to illustrate that the individual organisms grouped within the same genus are very closely related to each other. In fact, the genus is the taxonomic grouping that represents the closest relationship between organisms which, at the smallest taxonomic level, are called Species. Each individual species is given a specific name that, when combined with the generic name, produces the two-term “binomial” naming system that Linnaeus pioneered. For example, within the genus Rosa are a variety of species such as acicularis, nutkatensis, and woodsii. Through the binomial naming system, these species becomeRosa acicularis, R. nutkatensis and R.woodsii (the generic name is shortened to the first initial when listing several species in the same genus).

Erythronium oreganum
Of course, as with many scientific theories or strategies, there are problems with this system in the way it is currently applied and as a result it is in a continual state of flux, especially at the lower levels of the hierarchy. Even at the highest level (Kingdom), several groups are still cause for debate among taxonomists as to their placement. For example, how do we classify lichens? Lichens were originally placed within the Kingdom Plantae until further research showed that what we call “lichens” are actually a symbiotic relationship between certain species of fungi and certain species of algae. The two species, which can often survive independent of each other, combine to form a third plant-like “species” of organism called “lichen” that differs greatly from either of its two parent species yet functions as its own reproductive, evolutionary organism (thus meeting the criteria for a “species”). Currently lichens are included within the Kingdom Fungi since the fungal partner is the driving force behind the union (essentially “cultivating” its algal partner in order to produce its own nourishment) but this treatment still does not really fit with traditional taxonomy.Another example of how nature continually confounds attempts to classify it is the vast array of plant-like organisms grouped under the term “algae.” The confusion results from the fact that most algae are unicellular or, if multicellular, composed of a single or very few cell types amassed together to function as a larger individual. So, do we classify multicellular algae based on the characteristics of the single cell (Protista) or as an independent multicellular organism (Plantae)? Most algae are currently placed within the Kingdom Protista despite their often plant-like appearance, with only a few of the multi-cellular forms remaining within the Kingdom Plantae. This treatment is not followed by all authors, however, as some retain all of the algae as a subkingdom within the Kingdom Plantae. Regardless of the treatment, it is obvious that the great diversity within the group “algae,” as well as its unusual morphological and cellular characteristics, is a hindrance to botanists who attempt to classify them within our current taxonomic systems.

Sedum spathulifoliium
What is a “Species”?
At the lowest level of the classification hierarchy is the “species”, a human-derived concept that, to this day, is still not completely understood by scientists. The general consensus in past decades has been that a “species” is a group of similar individuals which can reproduce successfully with each other while at the same time being reproductively isolated from other similar species (known as the “Biological Species Concept”). This interpretation worked reasonably well when it was first proposed, but the more we learn about ecological systems the more apparent it becomes that nature is by no means so simple. The evolutionary process is a continuum whereby a portion of the population of one entity gradually becomes more and more distinctive and discrete, eventually reaching a state in which it is reproductively isolated from its parent “species.” The infinite range of variation between the two ends of this evolutionary process means that many populations are difficult to assign to either a parent species or a new, independent species.A newer species concept, known as the “Phylogenetic Species Concept”, attempts to give specific status to any identifiable populations that have a unique evolutionary history and differ collectively in some characteristics from other populations. This system, which places more weight on the evolutionary process and genetic differences between populations, naturally results in a far greater number of recognizable species than the more conservative Biological Species Concept. In truth, however, neither of these widely accepted concepts appears to fully represent the extraordinary complexities of the natural world, and perhaps the most effective current method of species classification is a combination of both systems.
<Ranunculus californicus and Plectritis congesta
Subspecific Taxonomy
Another method used by taxonomists to deal with the variation within species is the use of “infraspecific” or “subspecific” taxonomy. Many species are not uniform in appearance throughout their distribution, and by assigning subspecies and varietal names to the identifiable populations scientists are able to catalogue and name this variation.
Populations that are approaching species status are typically categorized as subspecies (often written as “ssp.” or “subsp.”), especially when these forms have discrete geographic distributions. For example, in the species Salix reticulata(net-leaved willow) individuals occurring throughout the mountain ranges of the interior of the province with hairy capsules and a strong net-like pattern of venation on the leaves are named S. reticulata ssp.reticulata, while the populations on the Queen Charlotte Islands that have hairless capsules and a weaker net-like venation pattern on the leaves are known as S. reticulata ssp.glabellicarpa. These two subspecies have different geographic ranges and represent evolutionary lines that are fairly well defined, but are similar enough to be classed within the same species.