Trichocereus key

[Torsten]

With all this discussion and confusion about what cactus is what species I am wondering why no keys are being used to positively identify them. After all, a species is an arbitrary unit defined by the type description. I presume that this type description uses the same process for cacti as with other plants. I know the shortcoming is that most keys rely on flower parts and some cacti simply don't flower well, often, or at all in some climates, but other than the VERY vague description i Backeberg I have never seen anything even resembling a decent type description or key.

So my questions are:

1) are all Trich species fully described with a published type description?

2) does anyone have the descriptions?

3) has there ever been a key published?

[Evil Genius]

Hi,

there is a key at the lycaeum. Do you think the key is reliable?

http://leda.lycaeum.org/?ID=16084

I often use "Ritters Kakteen in Südamerika 1-4". It is unfortunately in german but the descriptions should be comprehensible for non-germans too.

[ 23. August 2005, 18:08: Message edited by: Evil Genius ]

[Torsten]

nice key for starters, but not quite comprehenive enough. a good key will give more than one variable in case this variable cannot be distinguished.

They key does not use any flower part characteristics (except colour).

This key seemes to be based on observations of the VERY general morphology. In fact, any key that I can use without reaching for my botanical dictionary is probably not good enough

[Evil Genius]

He He,

i was happy too to finally find a key which suitable for me...i assume that would have been too easy.

Because of the Ritter i have to say that there are a lot of minor differences in the descriptions compared to backeberg. It seems they didn´t liked each other very well...

[ 23. August 2005, 18:25: Message edited by: Evil Genius ]

[Gunter]

The key that exists is weak. Pachanoi, peruvianus, macrogonus, and bridgesii (etc) can all key to each other (then there are types like pallarensis and scopulicolis). I'll think about this some more. It might be fun to make a layman's key that doesn't involve flowers and is only approximate, it would have many of the same flaws but might help cultivators. I would make it an 'oid' key, so out with the species notions, and instead of peruvianus and pachanoi, it would only key out pachanoid, and peruvianoid.

Anybody want to give me a hand with this?

[Torsten]

the point though is that each species was defined by one person and hence this holotype is a fixed entity. It doesn't matter much if others disagree or not.

There are certain finite traits that justify the speciation (at least in the authors opinion) and these are the traits I would like to have access to. I've just searched for an hour and I cannot find a single holotype description of any cactus on the web.

The reason why I fidn this is important because really we are throwing around names of cacti that we ID on the basis of mostly inferior and superficial morphological traits. I would assume that these were rarely the traits used for publishing the definition of the species, so I don't see why we have to use them.

It's like defining a piece of orange coloured fruit as an orange by it's colour, whereas the fruit is actually an apricot, but we didn't bother checking if it was citrus or stonefruit which would be the more relevant characteristic used in the definition of the species.

[Torsten]

archaea - that's a great idea, but exactly opposite of what I was asking for

YOu are approaching this from the sensible and logical relationship aspect, which is probably more significant when searching for active cacti and for cross breeding.

I actually want to go the other way. I want to go to the arbitrary definition of each single species.

Why am I going the less logical way? Because I am sick of hearing people argue EVERYWHERE about something they do not even know what it is. I am happy for people to call things bridgesioids and pachanoids etc, but it bugs me when someone goes and defines a plant on traits that were likely irrelevant to the definition of the species. If we are going to go as specific as a species then we can't just make shit up and have to stick to the original definition. So in essence I hope that by providing proper definitions of holotypes we can move on and start calling all of them hybrids and -oids.

I've been hanging out with orchid people too much

[ 23. August 2005, 18:55: Message edited by: Torsten ]

[Gunter]

We could take a good looks at old type herbarium specimens when and where available. If we assemble a list of them then such a project can start.

[Torsten]

so 3 days are up and not a single holotype has been produced!?! Looks to me that we have the blind leading the blind here

Seriously folks, if we're going to do some serious taxonomy then the type description is where we need to start. Everything else is irrelevant in terms of taxonomy.

[Gunter]

K the type species for the genus , which was proposed as a subspecies, is T macrogonus, described by Otto.

This is the one that was described from the Berlin specimen. Then you have several species like T pachanoi described by B&R.

I forget off the top of my head who first described some of them, it was after Otto and before B&R...

I'll look it up this weekend.

I think we can find some translations for the original descriptions.

However the original descriptions are frustrating when keying things out.

[Torsten]

Finding out the names of who defined them isn't difficult. What is difficult is getting the actual descriptions. I'd love to see some of them please.

Keep in mind that I am fluent in german and can probably translate much (but not all) of the botanical stuff in the descriptions. And while I hate latin, I can probably also decipher a latin description (I'll regret making that statement!). In the old days all botanical descriptions were in latin, so not sure how serious the germans too themselves

[apothecary]

I'd be willing to help out with the latin too, at least as far as I can.

[ramon]

http://entheogen.netfirms.com/articles/art...cereus.html#Ack

[ 28. August 2005, 09:17: Message edited by: Popeye ]

[Benzito]

That's a good key popeye, but the one glaring omission I noticed, was that you didn't describe the colour of the areole. Sorry, not trying to bring you down, just something I noticed.

Most of this thread is too complex for me to keep up with anyway.

[faslimy]

double post

[ 27. August 2005, 11:02: Message edited by: faslimy ]

[faslimy]

the problem is that it's a little more complex than one definition meets all for every plant associated with a species. a key would need to describe each clone and have a universal label as unknown hybridization is rife within the genus

[ 27. August 2005, 11:04: Message edited by: faslimy ]

[Torsten]

Originally posted by faslimy:

the problem is that it's a little more complex than one definition meets all for every plant associated with a species. a key would need to describe each clone and have a universal label as unknown hybridization is rife within the genus

Agreed, and it isn't what I am trying to do. However, if a clone fits the species description 100% then it is quite likely to be that species and this would be a good starting point.

[Gunter]

It would be nice to get some genes to compare, and even to compare to archaeological cactus evidence.

[gusto]

I too, would like to read the original species descriptions out of curiosity. And though I don't know the nomenclature rules, I assume the original description takes precedence and sets the species description 'in stone'.

I don't see how, in the real world, this makes it the gold standard. Particularly if the original species distinction is poorly defined or based on a non-typical plant or plants.

Until some hard data by genetic analysis become available, I'm afraid we're just chasing our tails.

[trucha]

To answer Torsten's original questions:

1. No.

2. Yes on some. Soon on others. Not yet on most. See details farther below

3. Sure. If you want to count them.

Britton & Rose 1920 and again in Backeberg 1959.

To clarify this for anyone out there not familiar with keys: For a taxonomic key to be valid, all clones within that species need to fall within that species position within the key.

Keys aren't descriptions but are just simple lists of those features capable of separating species. They are arranged in a logical organization that is navigable for species identification purposes with only yes or no questions.

Anyone out there who has ever used a real taxonomic key knows the joy of having a good one in your hands. Sometimes they are frustrating but a good one is always useful. For instance, I once used a key to identify a snake I had found. The primary distinguishing characteristics of the "Common ground snake" turned out to be a complete lack of distinguishing characteristics. To learn this I had to count the scales across its body, on sections of its face and elsewhere to be able to answer "no" to every question. It took a bit but led me directly to the right ID. All of these features however were features a person could examine.

Floral features on plants that many growers never get to see flower is not an approach capable of creating of a key that is functional for those people.

People MAY however have to settle for creation of a key that has only a high probability of being right rather than truly a definitive one.

The most important element of this sad story:

No matter what language they are in, the botanical descriptions are largely inadequate and many would be tossed out today if they were attempted for submission.

Britton & Rose's description of peruvianus is almost laughable, the original description of cuzcoensis is hardly better. Neither one provides any information on details that are actually meaningful.

The description of macrogonus is so bad that it should probably be chucked entirely. Salm-Dyck did a barely useful description of material under cultivation in Berlin and lacking in origin data. Otto used the name earlier (we assume this was for the same material?) yet apparently did so without any description. Riccobono's type species for the genus was Otto's Cereus macrogonus which Riccobono apparently thought the same as another plant now called Eriocereus tephracanthus. What does this mean? WTFK?

Backeberg fell in between Ritter and Britton & Rose in terms of his descriptions.

Despite Ritter's conflicts (and seemingly mutal hatred) with Backeberg, Ritter took some pains to try and write descriptions that can be compared with each other.

He did publish some names with inadequate descriptions and this has caused the IOS/Kew/Cactus Consensus Inquiry people to toss them out while they capriciously preserved names by Britton & Rose or Salm-Dyck that have equally inadequate (or worse) descriptions.

The descriptions are sort of OK when talking about a single plant in the middle of what exists.

For instance if I was looking at a typical peruvianus and someone was reading the description to me, I would agree with most of what it says.

When reading a number of them and then trying to actually use the features stated within them as unique descriptors capable of segregating them into species, their uniqueness rapidly falls apart (as anyone attempting this with Backeberg or Britton & Rose's key has already learned).

Worse, when anyone starts looking at the real world, unless they have a way of identifying hybrids, they are going to run into multiple layers of problems (unless perhaps for people who might just enjoy arguing endlessly of course)

Lately, I've again become focused on acquiring copies of all original descriptions of the trichs, typing them up so they can be put into html files, translating them if necessary (ideally this will someday be multidirectional) and plan to post this online to accompany the rather cobwebbed trich name list at the Trout's Notes website.

Basically the entries now there for scopulicola and such will be expanded to include all of the species.

Obviously the creation of this public database is taking me a while.

If anyone else out there wants to contribute some time to the effort, please let me know and I can write your name into the slot so that portion of the work is not duplicated. Any contribution of effort would of course be acknowledged.

Things needed:

Scans or photocopies of pertinent papers (I have a list of what titles are sought and what have already been submitted to paper retrieval services)

Typing copies of the published descriptions in the original language of publication

Translating any nonEnglish descriptions into English (or translating any English descriptions into any other language)

Proof reading typed text

Pertinent resources that are here at the moment:

Backeberg 1977 Lexicon (photocopies of pertinent sections)

Backeberg 1959 Die Cactaceae (photocopies of pertinent sections)

Britton & Rose

Ritter's Kakteen in Sudamerika

Hunt's Cactaceae Checklist Second edition

Anderson's The Cactus Family

The 1974 IOS Bulletin wherein the "reunion" was announced.

Also photocopies of papers by

Madsen on pachanoi

Ostolaza on pachanoi

Salm-Dyck on macrogonus

A lot of interesting information is certain to emerge from this project.

For instance, Echinopsis forbesii mentioned in Britton & Rose and present as a 70 plus year old single column in the Huntington turned out to be Echinopsis validus after a careful RE-reading of Backeberg 1959.

[ 02. September 2005, 02:03: Message edited by: trout ]