Friday, February 1, 2013

Carl Linnaeus: The Botanical Mr. Organized!

Carolus Linnaeaus
courtesy of the Linnaean Society of New York
Why do we have to use crazy binomial latin names (genus and species) when we are talking about trees, shrubs and flowers?  Why can't we just use common names and say Yellow Sneezeweed(Helenium amarum), Purple Lungwort(Pulmonaria longifolia), Monkey Puzzle Tree(Araucaria araucana) or my favorite,  the savory Sausage Tree(Kigelia africana)?  We can, and with these examples there is little confusion with  the exception of maybe knowing the exact species.

However, in many cases using common names can be confusing because they can refer to many different plants that are not related and they can be highly regionalized and not carry recognition  everywhere.  One of the classic common names that extends way beyond its true plant is Cedar.  There is one genus in the Pine family called Cedrus, that refers to a small group of true cedars:  Deodar, Atlantic and Lebanon.  However, cedar is used as a common name in many genus: Thuja, Calocedrus, Cupressus, Cryptomeria, Juniperus, Chamaecyparis, Torreya and some others.

Not only can a common name be used across many different genus, but one genus can have many different common names.  Amelanchier is a commonly used plant in New England and many of its species are native to New England, but it can go by many common names:  Serviceberry, Shadblow, Shadbush, Saskatoon, Juneberry, Sarvis-Tree and many other regionalized geographic names.

Carl Linnaeus, in his two major works in the late 18th century, started the process of classifying plants, animals and minerals.  Now this isn't a task like trying to index files on your computer, or organizing your children's baby clothes.  His novel approach organized plants based upon their sexual parts (i.e. petals, stamens, pistils, etc.)  He looked at flowers to determine similarities and grouped them together.  Discussion of plants sexual parts at this time in history was not readily accepted, and many of his writings were considered pornographic.  But, his system was the first to put some order to the plant, animal and mineral worlds.

The task of classifying plants was massive and continues today with interntional organizations meeting to discuss the reclassifying of plants and families.  Back in Linnaeus's time, the plants were classified by their flowers with such commonalities as number of flower petals, number of stamens, female and male flowers on separate plants(Holly plants, where only female plants berry), female and male flowers on the same plant(pine trees that have male pollen in spring followed by female cones).

In the following century along came Charles Darwin, and he said that evolution should determine what plants are closely related.  These two arguments have come together to form the current classification system.  Today with all of the recent genetic science, botanists have started to shake up lots of plants and families.    If you remember back to high school biology, everything is put into the following botanical ranks:  Kingdom, Division, Class, Order, Family, Genus, Species.  We use Genus and Species in our regular conversations about plants, and we often will refer to Family to help understand common cultural and flowering traits.  This is what is called Linnaean Classification

In the plant world, as well as the animal world, plants are broken down into the aforementioned hierarchical groups, and the lowest levels of this grouping are the genus and species which we use most often.  Amelanchier(Genus) canadensis(species) is a native Serviceberry of Canada that can be inferred from the species name. Quite often the genus and species will refer to its country of origin, name of the person who discovered the plant, color of flowers or any number of other relationships to the plant.  Styrax japonicas is native to Japan, Kigelia africana is native to Africa, Echinacea purpurea has purple flowers, Alchemilla alpina is an alpine or rock garden plant, Fuschia is named after a German botanist named Leonard Fuchs and additional examples are endless.


The Ericaceae family contains many genus: Rhododendron, Azalea, Pieris, Erica(Heather), Kalmia(Mtn. Laurel), Vaccinium(Blueberry), Enkianthus, Leucothoe, Oxydendrum and many lesser known plants.  It helps to know that these plants are in the same family because they all like acid soils, moisture and organic material in their soil.  You might think that they are very different plants, but their flower structure(i.e. sexual parts) are very similar on close inspection.  The Aster family (Asteraceae) is filled with plants that have daisy like flowers, it is one of the largest plant families.  The Pine family (Pinaceae) is filled with needled evergreens, but is only one of many evergreen families.

Most recently, a huge uproar (as big an uproar as there can be in the horticultural world) occurred over the splitting of the Dicentra genus.  Everyone knows Bleeding Heart, those wonderful plants with the heart shaped flowers that hang in a long line.  Well, some geneticist tested several species of Dicentra and found out that Dicentra spectabalis is not closely related to other Dicentra species and therefore gave it a new genus, Lamprocapnos.  Dicentra and Lamprocapnos are both in the Fumariaceae family so they are not that distant, but from a genetic and evolutionary point of view are different enough to merit a different genus.

These changes are not made lightly by a body of scientists that makes our bipartisan government look cooperative.

The USDA has a page where you can learn the pedigree of any plant

So what does this all mean when we go outside to enjoy our gardens...absolutely nothing

I find this interesting, in doses, and I hope you found it interesting too.



To help in remembering some details I referred to the following sites and publications:

How to Identify Plants by H.D. Harrington
Linnaean Society of London - www.linnaean.org
Linnaean Society of New York - www.linnaeannewyork.org
Class materials and notes from my Botany Class  at Strybing Arboretum in S.F., CA




2 comments:

  1. I find it interesting in doses, too, but grow frustrated with new unpronounceable Latin names. Sometimes the reclassification seems irrelevant, but I'm sure a taxonomist would argue other wise. :o) LOVE that sausage tree!! What a cool conversation piece.

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  2. I confess that my nerdy academic self (not to mention my borderline OCD personality) loves this stuff. (I see that you have this classified under "Geek Talk" :-)!) -Jean

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