science

Taxonomy of the Cactaceae

Taxonomy of the Cactaceae is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Taxonomy of the Cactaceae rather than just read about it. In short: In 1984, the International Organization for Succulent Plant Study set up a working party, now called the International Cactaceae Systematics Group, to produce a consensus classification of the cactus family, down to the level of genus. Their classification has been used as the basis for systems published since the mid-1990s.

Key takeaways

Taxonomy of the Cactaceae belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Taxonomy of the Cactaceae to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Taxonomy of the Cactaceae from memory before moving on to harder problems.

Reference excerpt

In 1984, the International Organization for Succulent Plant Study set up a working party, now called the International Cactaceae Systematics Group, to produce a consensus classification of the cactus family, down to the level of genus. Their classification has been used as the basis for systems published since the mid-1990s. Treatments in the 21st century have generally divided the family into around 125–130 genera and 1,400–1,500 species, which are then arranged in a number of tribes and subfamilies. However, subsequent molecular phylogenetic studies have shown that a very high proportion of the higher taxa (genera, tribes and subfamilies) are not monophyletic, i.e. they do not contain all of the descendants of a common ancestor. As of August 2023, the internal classification of the family Cactaceae remained uncertain and subject to change. A classification incorporating many of the insights from the molecular studies was produced by Nyffeler and Eggli in 2010.

Overview The classification of the family Cactaceae remains uncertain as of August 2023. Since the mid-1990s, the system produced by the International Cactaceae Systematics Group (ICSG) of the International Organization for Succulent Plant Study has been used as the basis of many published classifications. Detailed treatments produced in the 21st century have divided the family into around 125–130 genera and 1,400–1,500 species, which are then arranged into a number of tribes and subfamilies. The ICSG classification of the family recognizes four subfamilies: Pereskioideae (consisting only of the genus Pereskia), Opuntioideae, Maihuenioideae (consisting only of the genus Maihuenia) and Cactoideae. Molecular phylogenetic studies suggest that Pereskia is not monophyletic (i.e. its species are not the complete set of descendants of a common ancestor), so that Pereskioideae is not monophyletic although the three other subfamilies are. The Bayesian consensus cladogram from a 2005 study is shown below:

Five tribes have been recognized within the subfamily Opuntioideae: Tephrocacteae, Pterocacteae, Austrocylindropuntieae, Cylindropuntieae and Opuntieae. All but the first, Tephrocacteae, were shown to be "essentially monophyletic" in molecular phylogenetic study in 2009. A summary of the consensus Bayesian tree is shown below (tribes are bold; the number of species in the study is shown in parentheses).

Many of the genera within the Opuntioideae are not monophyletic. Maihueniopsis is highly polyphyletic, appearing in four separate lineages. The two largest genera within the subfamily, Opuntia and Cylindropuntia are also not monophyletic. The classification of the Opuntioideae is thus uncertain as of March 2012; Griffith and Porter say that changes in classification will require "broad information (of multiple data types) regarding all species of opuntioid cacti". The ICSG classification divides the subfamily Cactoideae into nine tribes. However, phylogenetic research has not supported most of these tribes, nor even the genera of which they are composed. A 2011 study found that "an extraordinarily high proportion of genera" were not monophyletic, including 22 (61%) of the 36 genera in the subfamily Cactoideae sampled in the research. Of the nine tribes recognized within Cactoideae, one, Calymmantheae, comprises a single genus, Calymmanthium. Of the remaining eight, only two (Cacteae and Rhipsalideae) have been shown to be monophyletic. A summary of the cladograms for the Cactoideae presented in a 2011 paper is shown below (ICSG tribes in bold).

The classification of the Cactaceae thus remains subject to change, from the genus level upwards. In 2016, David Hunt wrote that "the advent of molecular systematic studies in the past two decades will hopefully have a stabilizing effect on classification in due course, but has so far had the opposite effect".

Nyffler and Eggli (2010) classification In 2010, Nyffler and Eggli produced a classification based on an explicit phylogeny. The broad outlines of their cladogram agree with that of Hern et al. (2011), shown above, although some details are different. Their classification corresponds to the cladogram shown below.

The table below shows how the genera recognized by Nyffler and Eggli are placed into their subfamilies and tribes (they also use some subtribes, not shown here). The column headed "Older tribe (if different)" shows the ICSG classification of the subfamily Cactoideae (as presented by Anderson in 2001) with a 2002 classification of the subfamily Opuntioideae. There are differences in the genera recognized in the systems; where the older system does not recognize the genus, "–" is shown.

Earlier classification Unless otherwise indicated, the subfamily placement of the genera listed here is based on Anderson's 2001 presentation of the ICSG classification, as is the tribal placement of the genera of the subfamily Cactoideae. The division of the subfamily Opuntioideae into tribes is additional to the ICSG system.

Subfamily Pereskioideae

Pereskia Mill. synonyms: Peirescia Zucc. (orth. var.), Peireskia Steud. (orth. var.), Perescia Lem. (orth. var.), Rhodocactus (A.Berger) F.M.Knuth

Subfamily Opuntioideae

Tribe Austrocylindropuntieae Austrocylindropuntia Backeb. Cumulopuntia F.Ritter

Tribe Cylindropuntieae Cylindropuntia (Engelm.) F.M.Knuth – chollas Grusonia F.Rchb. ex Britton & Rose including Corynopuntia F.M.Knuth, Micropuntia Daston Pereskiopsis Britton & Rose synonyms: Peireskiopsis Vaupel (orth. var.) Quiabentia Britton & Rose

Tribe Opuntieae

Brasiliopuntia (K.Schum.) A.Berger Consolea Lem. Miqueliopuntia Fric ex F.Ritter Opuntia Mill. – prickly pears synonyms: Airampoa Fric, Cactodendron Bigelow, nom. inval., Cactus Lem., Chaffeyopuntia Fric & Schelle, Clavarioidia Kreuz. (nom. inval.), Ficindica St.-Lag., Nopalea Salm-Dyck, Parviopuntia Soulaire & Marn.-Lap. (nom. inval.), Phyllarthus Neck. ex M.Gómez (nom. inval.), Salmiopuntia Fric (nom. inval.), Subulatopuntia Fric & Schelle, Tunas Lunell, Weberiopuntia Fric including Nopalea Salm-Dyck Salmonopuntia P.V.Heath Tacinga Britton & Rose Tunilla D.R.Hunt & Iliff

Tribe Pterocacteae Pterocactus K.Schum.

Tribe Tephrocacteae Maihueniopsis Speg. including Puna R.Kiesling Tephrocactus Lem. synonyms: Pseudotephrocactus Fric

Subfamily Maihuenioideae

Maihuenia (Phil. ex F.A.C.Weber) K.Schum.

Subfamily Cactoideae

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Taxonomy of the Cactaceae

Start with the simplest possible case. Write down what Taxonomy of the Cactaceae claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Taxonomy of the Cactaceae before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Taxonomy of the Cactaceae ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Taxonomy of the Cactaceae

In research: Taxonomy of the Cactaceae appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Taxonomy of the Cactaceae in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Taxonomy of the Cactaceae is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cacti, Plant taxonomies, so understanding it makes those chapters shorter.
In everyday life: Look for Taxonomy of the Cactaceae outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Taxonomy of the Cactaceae” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Taxonomy of the Cactaceae in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Taxonomy of the Cactaceae means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Taxonomy of the Cactaceae out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Taxonomy of the Cactaceae in simple terms?

Why does Taxonomy of the Cactaceae matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Taxonomy of the Cactaceae?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Taxonomy of the Cactaceae.