Mohave says..."Why are plants renamed and reclassified? I get the feeling that the current trend is to try to classify plants according to how they evolved, but still try to make it fit into the division, class, family system. Sort of like trying to pound a round peg into a square hole, but the square hole with the best fit. Or am I way off-base? "

No believe you are correct as it's the best we can do at this time.
Good explanation on the entire picture Mohave.
But my question then is how genetics work is changing our conceptions. Already some plants (again grasses come to mind) have been reclassified based on molecular level investigations giving a different picture of evolution and relationships in the plant world. Will we develop a new system-genetics based-or continue to fit our (new) information to the old system and let this system develop into? something on it's own so to speak??

I know name changing is for the better,
but why change Cassia and Senna plants/shrubs/trees?
Are they really that different from each other?

Is there a web site with all the new corrected name changes?......cheryl

as my taxonomy prof said to me 'froggy, there are spitters and groupers. and until genetics proves em all wrong, that is what we are stuck with...'

being more of a field botanist...i tend to be a grouper. :)

froggy

he he :)) spitters? lol lol

Mohave_Kid, you said:
The three areas of plant taxonamy are Classification .. Nomenclature and Identification ...

Not to split hairs :-) but every every definition of taxonomy that I've seen just refers to classification and not nomenclature. I didn't think that nomenclature was part of classification. If so, it would help a little to explain the standards for botanical names and the multitude of classification systems in use.

Shelley

Hello Shelley ...

"Mohave_Kid, you said:
The three areas of plant taxonamy are Classification .. Nomenclature and Identification ... "

Yep ... I said that ... and George H. M. Lawrence the author of "Taxonamy Of Vascular Plants" says ........... " Taxonamy is a science that includes identification .. nomenclature .. and classification "

Thats the way he defines it and the way I was trained and think of taxonamy. Ofcourse we are here to explore other views .. Right ??

"If so, it would help a little to explain the standards for botanical names and the multitude of classification systems in use. " ... Shelley said.

Now what do you mean by multitudes of classification systems out there ?? I have heard this before and am not sure what you mean by "multitudes" ?? Any examples ?

and hang on Shelley !! ... this forum is new ... I already lost an hour of sleep last night ... eek .. stayed up on the computer too long ... so the wife says LOL ..

Good Day ...

Rosa ...

Yes .. genetics is one of those more or less recent things that cause changes in the way we classify plants ... and some people don't like it !! ... although I myself do not feel it will be the final word all by itself ... it must still be considered only as part of the picture ...

I'm thinking of Opuntia in the Cactus family ... I just speculate ( that means guess ) it has been oversplit do to genetic data ... No doubt though genetic information has and will continue to change our understanding of evolution.

It seems to me one loses the plant some how when only genetic comparisions are made ... nothing seems to be evident anymore you can't see the way one would that works in the field with plants ...

Genetic data reminds me of when computers first arrived ... some dreaded the idea of computer technology but new it was not going away ... anytime soon... but in the end it was for the better.

Complicated question.

Good Day ....

As far as I can tell "Senna" is a common name for the genus / taxa Cassia so this is not splitting as it is meant here ... Now the genus Cassia may have been split at some time .. I don't know ?? ... have not looked into the taxonamy of that genus closely.

I checked Hortus Third ... maybe someone else can add to this ??

Hope that helps.

Good Day ...

Mohave_Kid, we really appreciate your input to this forum, but please don't lose sleep over it. You're doing a great job and it's off to a wonderful start. It will be just fine even if you don't personally reply to every single post within hours.

On the definition of taxonomy, the classification answer is what I find when I look it up in a dictionary. I'll just assume that the word could have varying meanings depending on how it's used.

For the multitude of classification systems, here's a link to a web site I found recently. I don't even begin to claim that I understand this, but for some strange reason I find it interesting.

Shelley

Here is a link that might be useful: Phylogenetic Classification - Evolutionary Systems

Looks like there have been quite a few reassignments from the genus Cassia into both Senna and Chamaecrista. Not sure when this happened...
Senna is also widely used as common name for these.
See link to Plants Database for synonyms.

Here is a link that might be useful: Plants database

Cheryl
if you have not used the above database before, use the pulldown menu on the top and change it from common name to scientific name. Type in Cassia or Senna and it will bring up all names. Green links are accepted names with synonyms underneath in black.

Hello Shelley ...

Looks like your link jumped into the middle of a class on evolution ... botany is indeed a work in progress but still today there are only a few major systems of classification for plants which are indeed constantly being revised and adjusted ... what you dropped in on were the methods of researching such matters ...

I too find it very interesting ... and am no "expert" ... myself I enjoy being able to trace the history of how various groups of plants have been classified and reclassified and renamed through time ... finding old botany books can be a lot of fun ... I also find it insightful to think that every plant I encounter with all of it's features is a part of an entangled puzzle ....

It makes collecting plants a lot more interesting then simply memorizing a bunch of names ...

Glad to here your concerned about my sleep LOL ... I'll be fine if our 3 month old keeps sleeping do well !!!

Good Day ..

First let me say that this is going to be my last post on this subject lest you all get so bored with me that you throw me off the forum ;-) I did not intend to get so deep into the classification of plants. It all started with someone in my plant study group asking how plants are organized into families. I didn't like the answer she was given, so I decided to do a little research. I expected to find THE currectly accepted classification system. I quickly learned there was none.

I've learned that plant classification has been continuously changing since it's beginning. However, scientists have been trying to group plants (and animals) based on evolution since the time of Darwin. But now there's technology that is accelerating the rate at which new data is discovered. Most of information that I've found was on university websites in resources for introductory taxonomy classes. I predict that what seems like advanced research today will be commonly accepted in the next 10 years.

So, why does any of this matter? Well, we're trying to learn the characteristics of plant families so we can identify plants more easily. And the families keep changing. However, if I'd known the answers would be so complex (and not really helpful on a practical level), I never would have started looking into plant taxonomy.

So, I'm moving on to more practical things. Today I colored 2 pages in my Botany Coloring Book and I ordered a hand lens.

Have a great weekend everyone!

Shelley

"So, I'm moving on to more practical things. Today I colored 2 pages in my Botany Coloring Book and I ordered a hand lens. "

LOL ... yes classification can get a bit silly sometimes ... but identification is a good place to start ... families are not changing that fast so make sure you learn them as you start to explore with your lens ...

Good Day ...

Below is a link to a site that linguist find interesting. It says, among many other things "...rules above are for zoological nomenclature. The rules for botanical nomenclature are similar...." so it is not exactly on topic. I am just tossing it in as a FWIW.

Here is a link that might be useful: nomenclature site

Albert, that was a great link. As so often happens, your link led me to another which gives the history of the wrangling which has gone on since Linnaeus with regard to plant names. josh

Here is a link that might be useful: Tutorial on Botanical Nomenclature

I've been doing research on this topic for a paper I'm working on for my LD class. The International Association of Plant Taxonomy meets every six years for the International Botanical Congress (in 2005 it was in Vienna, Austria, 1999 in St. Louis, MO, and 1993 in Japan) for a fun-filled week of seminars, workshops, field trips, speakers, etc. The week before the congress, botanists meet for the Nomenclature section, where they hash out the rules of naming, and vote on any needed changes or clarifications to the rules of naming plants.

From what I've been able to determine, work goes on at every level, with scientists doing their research and sharing information through lower level plant associations that exist at the state level and national level (American Society of Plant Taxonomists) as well as in other countries, and usually through the publication of a paper. The RHS in Great Britain is very active, and was instrumental in developing, with the botanical community, the International Code of Nomenclature for Cultivated Plants. The RHS is voluntarily responsible for maintaining registers for nine plant groups, including conifers, delphiniums, lilies, dianthus, daffodils, dahlias, rhododendrons, clematis and orchids. Organizations in other countries are responsible for others. New plant names are checked against the register before being accepted.

The one thing I haven't been able to determine for certain, is where and when, and by whom, actual changes to the classification of plants is accomplished. My research continues, at least for another week when my paper is due.

If anyone knows the answer to this question, I'd appreciate an email.
Jo

Jo, you have mail, and thanks for reviving this thread.

I've only recently found the Botany Forum and hope to be more active on it from now on. I know no botanists locally to share these kinds of conversations and I find them fascinating.

When I was in grad school, many of my friends were taxonomists and actively looking at the classification of different genera and species. Some were splitters, and others were lumpers and most used cladistics, a classification system based on the rule that all members of a group must have shared a common ancestor more recently than they have with any species outside the group. Plants distantly related but which evolved in response to very similar environmental stimuli often developed very similar phenotypes. While older methods used phenotype only, in the last 20 years or so advances in DNA technology have made it possible to also use genotype in plant classification. Graduate students have to study something and the result of their graduate study is often reclassification of species. Most of us not actively studying taxonomy find it difficult to keep up at best, but for the most part, like it or not, classification is actually becoming more accurate.

Regarding genetic information in classification--it's both a boon & a curse. On the one hand, huge new sets of data are becoming available. On the other hand, there are a lot of taxonomists who want to operate on a very simplistic principle: sequence a gene for all members of some group of species; build a phylogeny; name clades on the phylogeny as species, genera, etc. There are a lot of problems involved. Some genes may be misleading. Some methods of building phylogenies may be misleading. Many clades probably aren't very informative or helpful as taxa. And when new data is flowing in very quickly, naming taxa based on data that'll be superseded in a couple of years just confuses the issue. Luckily, people are learning to be more cautious in jumping to premature conclusions from genetic data, but we still have a whole big pile of taxa that have been named recently based on questionable data or without much consideration for the usability and explanatory content of names.

Patrick Alexander

"The one thing I haven't been able to determine for certain, is where and when, and by whom, actual changes to the classification of plants is accomplished. My research continues, at least for another week when my paper is due."

It's no surprise but as long as the nomenclatural rules are followed as outlined by the International botanical congress publications then anyone can attempt to make a name change providing they can find a recognized journal tp publish their results and taxonamist decide to use the name change and accept it as valid.

There is however a "Cactus Congress" a group of taxonamist that study Cactii that vote as a group to make nomenclatural changes to Cactii taxa. This has been looked down on by some since it could in theory exclude some points of view from being considered. A who you know kind of dilema. There is politics in science too.

Keep in mind "scientist" .. who ever they are can make or change all the names they want but that does not mean everyone will adopt those names.

Those that write and publish books ect. on plants will ultimately decide what classification and nomenclature will be used in print. It's really a complicated matter to follow the history of name origins and changes that have occurred in history.

In Cactii there are many disputes between scientist / taxonamist from universities or of university training ( like those that sit on the Cactus Congress )and serious hobbyist / cactus growers / collectors as to cactus nomenclature and this is the main culprit in why their are many different names for a single cactus taxa many in use at the same time in several publications.

Check out "The Cactus Family" by Anderson in your library to get a glimpse into what is involved.

Good Day ...

I sent Jo contact info for Dr. Billie Turner at UT Austin. If anyone can answer her question he can. If and when he responds, I hope Jo will post here. I have immense respect for the man - while doing wildflower photography, I took several shots of a pretty yellow composite, but all my attempts to key it out were futile. So, I took samples to the herbarium and talked to Billie. It turned out the plant wasn't in Manual of the Vascular Plants of Texas because Crepis setosa had never been identified in Texas. Thanks to him, I got my only taxonomic publication.

I have a funny story on one of Billie's attempts to name a new species. Whether or not this is true I can't say, but the story goes he had discovered a comp with an especially beautiful flower but the name he gave it, Genus? polyorgasmica was rejected by the powers that be. I heard it almost slipped by, but some astute reviewer didn't think it was so funny and the plant got another more prudish species name. LOL

"In Cactii there are many disputes between scientist / taxonamist from universities or of university training ( like those that sit on the Cactus Congress )and serious hobbyist / cactus growers / collectors as to cactus nomenclature and this is the main culprit in why their are many different names for a single cactus taxa many in use at the same time in several publications."

The short version of all those disagreements being that whenever you have high hobbyist interest in a taxonomic group, some of the hobbyists want to recognize all variation at the species level, which leads to large numbers of spurious species. Orchids are the other main group where this has happened.

Also worth mentioning that in plants generally the two main journals where taxonomic changes are being published are Novon and Sida. There are many others, too, but those seem to be the two most significant ones at the moment. Novon in particular is dedicated almost entirely to the publication of new names.

Hello Paalexan ...

"The short version of all those disagreements being that whenever you have high hobbyist interest in a taxonomic group, some of the hobbyists want to recognize all variation at the species level, which leads to large numbers of spurious species."

I agree but at the same time taxa are being divided by new data which in a morphological or better yet a "visual sense" are very simalar .. example : the breakup of the genus Opuntia. This makes new taxa a bit "spurious" to the serious hobbyist.

Also .. I think ... the motivation to accept new nomenclature differs between taxonamist and hobbyist. To the taxonamist new names often demonstrate scientific progress of some kind .. to the hobbyist confusion as to who is called what now ?? To the hobbyist the cost of accepting new names are not justified by the benafits. In this sense the taxonamist is the "splitter" and creator of too many "needless" taxa.

In addition groups like Cactii and Orchids are also fairly complex in morphology and have been researched considerably more then other taxa and to no ones fault one would expect a long nomenclatural history. All this is complicated by variabilty introduced by cultivation.

Lastly .. Who really is the taxonamist ? Does anyone or a single group really have the final word ? A hobbyist could very well bethe "expert". I would guess that in many groups of plants it is much easier for a single expert or small group of experts to agree and set nomenclature. In other popular groups of plants their is a very large audience that needs to agree on who is called what and why. More chance for disagreements and even intentional "revolts" against name changes.

Just some more thoughts ... good chatting with you .. thanks for the Journal references ... very helpful !!

Good Day ...