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Cacti & Succulent Identification



Cacti can be notoriously difficult to ID correctly, perhaps more so than any other plant material in the world. There are probably more Cacti incorrectly labelled than any other form of plant life. From a two dimensional photograph it can be all but impossible. So how can we even attempt to ID a plant?

Well some plants (and it is not always the common ones) are so distinctive that they almost shout their name out loud. In other cases even a scientist would have to resort to spine count; colour of spines; shape of areole and, of course, rib count. Several Mammillarias, Rebutia and Gymnocalycium are so alike that it is only at flowering time that they can be correctly identified.

Looking on the internet or at photographs in books is a poor substitute for handling or seeing the plant in person. I have very little knowledge of large columnar cacti because they do not grow in England, but with a little detective work, one can make an educated guess. If you go on the internet, try to look at as many different photographs as possible of the same species of plant; it is amazing how they can differ.

In particular, columnar cacti can be extremely difficult to name correctly. Many seedlings have no resemblance to their parents until they have reached a considerable height.

Plant hybridisation does occur in nature, but it is primarily conducted by nurserymen. This can also fool us when it comes to ID. There will be many plants around that are of mixed parentage. This is fine if it is done correctly and a new variety or form is produced. The new plant should be better than the original. Either more disease resistant or easier to grow or flower.

In the classification of cacti the Genus (plural genera) is a grouping of similar, closely related and morphologically similar Species. Similarly, genera are grouped into families, families into orders, orders into classes, and classes into phyla or divisions.

The genus name is always written with a capital letter e.g. Gymnocalycium. The species name is always written in lower case e.g. buenkeri (Gymnocalycium buenkeri).

I have included this information because sometimes it is relatively easy to identify the Genus that a plant belongs to, i.e. Gymnocalycium, but virtually impossible to say which species, in this example buenkeri.

Having said all this do we now feel that trying to ID a plant is almost impossible? The answer to that is "no, of course, it is not impossible", but a few rules need to be adhered to. I made a wrong ID the other week. Being convinced that a particular plant that I was trying to ID with a photograph was Euphorbia canariensis. Was it carelessness on my part? Well, in a way, yes it was. I had not got all the facts and made a wrong assumption. The plant was not even a Euphorbia, it was in fact a cactus. Appearances can be deceptive.

Finally when making an ID, a flowering plant is always a bonus. Everyone always has the consolation that at the end of the day we collect and are interested in cacti (not plant labels).

Author: John Chippindale, Leeds, England

Index of Articles
Introductory and Naming
     Wherefore Art Thou Cactaceae?
     How to Write a Scientific Name Correctly
     Cacti & Succulent Identification
     Cereus Peruvianus -The Least and Best Known Cactus
     More About Cereus Peruvianus

Cultivation and How-To
     The Sun Burned Cacti
     Grafting on Pereskiopsis
     Making Your Own Cactus Soil
     Growing NON-Hardy Cacti in Cold Climates
     Tools of the Trade
     Growing Cactus with Artificial Light
     Making a Hypertufa Planter
     Cactus Flowers - Fake or Real?
     How-To-NOT Build a Cactus Terrarium
     Raising Cactus From Seed
     Growing Cacti in Terracotta

Conservation
     Is Cultivation Conservation?
     Interview: Cactus Conservation in Paraguay with Alex Arzberger
     The Fate of the Minnesota Ball Cactus

Variety
     A Cactus Odyssey in Arizona
     Mangrove Cactus
     Have a Cup of Cactus
     Opuntia as an Invasive Species in Australia
     The Creating of "Springtime Succulence"
     Making Botanical Illustrations
     Adapt or Perish
     Chasing the Wild Epis
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