Smith system

Key takeaways

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

Reference excerpt

A system of taxonomy of the cryptogams, the Smith system was published in:

Smith, G.M. (1938). Cryptogamic Botany, vol. 1. Algae and fungi. McGraw-Hill, New York. Smith, G.M. (1955). Cryptogamic Botany, vol. 2. Bryophytes and pteridophytes. 2nd ed. McGraw-Hill, New York.

Division Chlorophyta

Class 1. Chlorophyceae Order 1. Volvocales Family 1. Chlamydomonadaceae Family 2. Volvocaceae Order 2. Tetrasporales Order 3. Ulotrichales Family 1. Ulotrichaceae Family 2. Microsporaceae Family 3. Cylindrocapsaceae Family 4. Chaetophoraceae Family 5. Protococcaceae Family 6. Coleochaetaceae Family 7. Trentepohliaceae Order 4. Ulvales Family 1. Ulvaceae Family 2 Schizomeridaceae Order 5. Schizogoniales Family Schizogoniaceae Order 6. Cladophorales Family 1. Cladophoraceae Family 2. Sphaeropleaceae Order 7. Oedogoniales Family Oedogoniaceae Order 8. Zygnematales Family 1. Zygnemataceae Family 2. Mesotaeniaceae Family 3. Desmidiaceae Order 9. Chlorococcales Family 1. Chlorococcaceae Family 2. Endosphaeraceae Family 3. Characiaceae Family 4. Protosiphonaceae Family 5. Hydrodictyaceae Family 6. Oöcystaceae Family 7. Scenedesmaceae Order 10. Siphonales Family 1. Bryopsidaceae Family 2. Caulerpaceae Family 3. Halicystaceae Family 4. Codiaceae Family 5. Derbesiaceae Family 6. Vaucheriaceae Family 7. Phyllosiphonaceae Order 11. Siphonocladiales Family 1. Valoniaceae Family 2. Dasycladaceae Class 2. Charophyceae Order Charales Family Characeae

Division Euglenophyta

Order 1. Euglenales Order 2. Colaciales (Euglenocapsales)

Division Pyrrophyta

Class 1. Cryptophyceae Class 2. Desmokontae Class 3. Dinophyceae Order 1. Gymnodiniales Order 2. Peridiniales Order 3. Dinophysidales Order 4. Rhyzodiniales Order 5. Dinocapsales Order 6. Dinotrichales Order 7. Dinococcales

Division Chrysophyta

Class 1. Xanthophyceae (Heterokontae) Order 1. Heterochloridales Order 2. Rhizochloridales Order 3. Heterocapsales Order 4. Heterotrichales Order 5. Heterococcales Order 6. Heterosiphonales Class 2. Chrysophyceae Order 1. Chrysomonadales Suborder 1. Cromulinae Suborder 2. Isochrysidineae Suborder 3. Ochromonadineae Order 2. Rhizochrysidales Order 3. Chrysocapsales Order 4. Chrysotrichales Order 5. Chrysosphaerales Class 3. Bacillariophyceae Order 1. Centrales Order 2. Pennales

Division Phaeophyta

Class 1. Isogeneratae Order 1. Ectocarpales Order 2. Sphacelariales Order 3. Tilopteridales Order 4. Cutleriales Order 5. Dictyotales Class 2. Heterogeneratae Subclass 1. Haplostichineae Order 1. Chordariales Order 2. Sporochnales Order 3. Desmarestiales Subclass 2. Polystichineae Order 1. Punctariales Order 2. Dictyosiphonales Order 3. Laminariales Class 3. Cyclosporeae Order Fucales

Division Cyanophyta

Class Myxophyceae (Cyanophyceae) Order 1. Chroococcales Order 2. Chamaesiphonales Order 3. Hormogonales

Division Rhodophyta

Class Rhodophyceae Subclass 1. Bangioideae Order Bangiales Subclass 2. Florideae Order 1. Nemalionales Order 2. Gelidiales Order 3. Cryptonemiales Order 4. Gigartinales Order 5. Rhodymeniales Order 6. Ceramiales

Division Myxothallophyta Class 1. Myxomycetae Subclass 1. Endosporeae Subclass 2. Exosporeae Class 2. Phytomyxinae Class 3. Acrasieae

Division Eumycetae Class 1. Phycomycetae Order 1. Chytridiales Family 1. Rhizidiaceae Family 2. Olpidiaceae Family 3. Synchytriaceae Family 4. Cladochytriaceae Family 5. Woroninaceae Order 2. Blastocladiales Order 3. Monoblepharidales Order 4. Ancylistales Order 5. Saprolegniales Family 1. Saprolegniaceae Family 2. Leptomitaceae Family 3. Pythiaceae Order 6. Peronosporales Order 7. Mucorales Order 8. Entomophthorales Class 2. Ascomycetae Subclass 1. Protoascomycetae Subclass 2. Euascomycetae Order 1. Aspergillales Order 2. Erysiphales Order 3. Hysteriales Order 4. Phacidiales Order 5. Pezizales Order 6. Tuberales Order 7. Helvellales Order 8. Exoascales Order 9. Hypocreales Order 10. Sphaeriales Order 11. Dothidiales Order 12. Laboulbeniales Class 3. Basidiomycetae Subclass 1. Eubasidii Order 1. Agaricales (Hymenomyceatae) Order 2. Lycoperdales (Gasteromycetae) Order 3. Dacryomycetales Order 4. Tremellales Order 5. Auriculariales Subclass 2. Hemibasidii Order 1. Urediniales Order 2. Ustilaginales Family 1. Ustilaginaceae Family 2. Tilletiaceae Class 4. Fungi imperfecti Lichens Subclass 1. Ascholichenes Subclass 2. Basidiolichenes

Division Bryophyta

Class 1. Hepaticae (liverworts) Order 1. Sphaerocarpales Family 1. Sphaerocarpaceae Family 2. Riellaceae Order 2. Marchantiales Family 1. Ricciaceae Family 2. Corsiniaceae Family 3. Targioniaceae Family 4. Monocleaceae Family 5. Marchantiaceae Order 3. Jungermanniales Suborder 1. Metzgerineae Suborder 2. Jungermannineae Order 4. Calobryales Class 2. Anthocerotae (hornworts) Order 1. Anthocerotales Class 3. Musci (mosses) Subclass 1. Sphagnobrya Subclass 2. Andreaeobrya Subclass 3. Eubrya

Division Psilophyta

Class 1. Psilophytinae (psilophytes) Order 1. Psilophytales Family 1. Rhyniaceae Family 2. Psilophytaceae Family 3. Pseudosporochnaceae Family 4. Zosterophyllaceae Family 5. Asteroxylaceae Order 2. Psilotales

Division Lepidophyta Class 1. Lycopodinae (lycopods) Order 1. Lycopodiales Family 1. Protolepidodendraceae Family 2. Lycopodiaceae Order 2. Selaginellales Family 1. Selaginellaceae Family 2. Miadesmiaceae Order 3. Lepidodendrales Family 1. Lepidodendraceae Family 2. Lepidocarpaceae Family 3. Bothrodendraceae Family 4. Sigillariaceae Order 4. Isoetales Family 1. Pleuromeiaceae Family 2. Isoetaceae

Division Calamophyta

Class 1. Equisetinae (horsetails) Order 1. Hyeniales Order 2. Sphenophyllales Order 3. Equisetales Family 1. Calamitaceae Family 2. Equisetaceae

Division Pterophyta

Class 1. Filicinae (ferns) Subclass 1. Primofilices (or Inversicatenales, Coenopterideae, Palaeopteridales) Order 1. Protopteridales Family 1. Protopteridaceae Family 2. Cladoxylaceae Order 2. Coenopteridales Family 1. Zygopteridaceae Family 2. Botryopteridaceae Family 3. Anachoropteridaceae Order 3. Archaeopteridales Subclass 2. Eusporangitae Order 1. Ophioglossales Order 2. Marattiales Subclass 3. Leptosporangiatae Order 1. Filicales Family 1. Osmundaceae Family 2. Schizaeaceae Family 3. Gleicheniaceae Family 4. Matoniaceae Family 5. Dipteridaceae Family 6. Hymenophyllaceae Family 7. Cyatheaceae Family 8. Dicksoniaceae Family 9. Polypodiaceae Family 10. Parkeriaceae Order 2. Marsileales Order 3. Salviniales

Worked examples

Example 1 — a first encounter with Smith system

Start with the simplest possible case. Write down what Smith system 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 Smith system 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 Smith system 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 Smith system

In research: Smith system 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 Smith system 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: Smith system is common in secondary-school and first-year university syllabi. It links to neighbouring topics Systems of algal taxonomy, Systems of fungus taxonomy, Systems of plant taxonomy, so understanding it makes those chapters shorter.
In everyday life: Look for Smith system 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.

How to study Smith system in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Smith system 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 Smith system out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Smith system in simple terms?

A system of taxonomy of the cryptogams, the Smith system was published in: Smith, G.M. (1938).

Why does Smith system 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 Smith system?

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 Smith system.