On the Higher Taxa of Embryobionta
Author(s): Arthur Cronquist, Armen Takhtajan and Walter Zimmermann
Source: Taxon, Vol. 15, No. 4 (Apr., 1966), pp. 129-134
Published by: International Association for Plant Taxonomy (IAPT)
Stable URL: http://www.jstor.org/stable/1217531 .
Accessed: 05/04/2014 08:26
Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .
http://www.jstor.org/page/info/about/policies/terms.jsp.
JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact support@jstor.org.

.

International Association for Plant Taxonomy (IAPT) is collaborating with JSTOR to digitize, preserve andextend access to Taxon.

http://www.jstor.org

This content downloaded from 212.238.120.34 on Sat, 5 Apr 2014 08:26:21 AM
All use subject to JSTOR Terms and Conditions

APRIL 1966
VOL. XV No. 4

f

TAXON

News Bulletin of the International Association for Plant Taxonomy. - Published by theInternationalBureau for Plant Taxonomyand Nomenclature, 106 Lange Nieuwstraat, Utrecht,
Netherlands

ON TIHE HIGHER TAXA OF EMBRYOBIONTA
Arthur Cronquist (New York), Armen Takhtajan (Leningrad)and Walter Zimmermann (Tiibingen)

The general system of plants and the nomenclature of higher taxa at the level ofdivisions and classes are now unstable and in a state of confusion. The well known
schemes of classification by which all plants are grouped into only 4 or 5 divisions
have been largely abandoned because they do not adequatelyreflect the great diversity
within the plant kingdom. Phycologists have found it necessary to recognize several
divisions of algae, and students of higher plants have also felt the need for a greaternumberof divisions. Harold C. Bold (1957) has gone so far as to recognize 24 divisionsof plants.
There is now a bewildering plethora of systems and partial systems, each of which
may lay some claim to being the best representationof the similarities, differences, andevolutionary relationships within all or some part of the plant kingdom. The samegroups appear over and over again in many of these systems of classification, but atdifferent taxonomic ranks and in different arrangementswith respect to each other.
It is forcibly brought to our attention that even when the evolutionary relationships
are not in dispute, it is often pcssible to produce more than one system of classification
which is in accord with these relationships.
Each of the authors of the present paper has published works dealing with thegeneral system of higher plants (Zimmermann, 1959; Cronquist, 1960; Takhtajan,
1964 . We have been in correspondencefor several years, but our ideas have been to alarge extent developed independently of each other. In August of 1965 two of theauthors (Cronquistand Takhtajan) had an opportunityfor extended personal consultation in Leningrad. These talks and subsequent correspondence with the third author(Zimmermann) have resulted in the productionof this paper.
No person, and no group, has the authority to decide what system of classification
should be adopted by all, or what parts should be taken from which system to produce
a universally accepted classification. Nonetheless, it seems obvious that it would be
useful if the majority of botanists were agreed on a single overall scheme. It is perhaps
not difficult for professional taxonomists to remember several classifications withdiffering names and ranks for the generally recognized groups, but it is difficult for a
student to find his way through such a jungle. We think that it might therefore be ofsome interest to see what sort of general system of higher plants might be mutuallyacceptable to three botanists from three different countries, such as ourselves. If otherbotanists also find this scheme acceptable, we shall be happy; if not, we have still had
a profitable discussion and a pleasant pipe-dream.
Our purpose here is taxonomic rather than phylogenetic. We believe that any proper
129

This content downloaded from 212.238.120.34 on Sat, 5 Apr 2014 08:26:21 AM
All use subject to JSTOR Terms and Conditions

taxonomic classification must be consistent with phylogeny, but perhaps the classification here presentedmay also satisfy those who reject phylogenetic considerations.
Many of the names we use here are only slightly modified from well known existing
names. In order to avoid possible questions about valid publication we are listingthese as nomina nova and citing previously published descriptions. Some other names
which representwell known groups are here listed as new taxa in order to avoid questions as to typification. The synonymy is intended merely to validate the names used
and to clarify our meaning. Many synonyms, both well-knownand obscure ones, aredeliberatelyomitted as being irrelevantto our purpose.
Zimmermann dissents from the treatment here presented on only one point: Herecognizes the problems associated with the names Cormobionta and Telomobionta,
but he thinks that objections may also be raised to Embryobionta.He therefore thinks
it might have been wiser to adopt the name Cormobionta,based on the well known
name CormophytaEndl. 1836.
Some parts of this scheme are sufficiently well known to be self-explanatory,or atleast the explanations can be found in the separate works of the three authors, (Takhtajan, 1953; Zimmermann,1959; Cronquist, 1960) as well as in many other places.
Other items may require some comment.
We have chosen the name Embryobiontafor the subkingdom,in preference to Cormobionta or Telomobionta.The name Telomobionta,proposed by one of us (Takhtajan,1964), implies the acceptance of a morphological concept which is not accepted by all
botanists and whose acceptanceis not necessary for recognition of the group. The nameCormobionta hardly fits the Rhyniophytes and Bryophytes, which are integral partsof the group. The most characteristic feature of the whole subkingdom is that the
sporophyte begins its development as a parasite on the gametophyte (or on the adultsporophyte , and the name Embryobionta properly reflects this feature.
We have thought it advisable to extend the type concept in nomenclature to the levelof division, following the suggestion of Rickett and Camp (1950). Names of divisions
and lesser groups which are based on morphological characters have therefore beenabandoned in favor of names based on genera. We believe that the logic which has
been applied to extend the type concept in the Rules of Nomenclature from families
up to orders applies equally well to classes and divisions. Now, when both the generalsystem and the nomenclature are still fluid, is the time to introduce the necessarychange.
We have not extended the type concept to the level of the subkingdom, mainly
because we found it impossible to select appropriate genera to provide the names forthe two subkingdoms (Thallobionta and Embryobionta) which we recognize. The
Thallobionta in particular are so diverse that no genus seems to provide an appropriatebase for a name.
We have adopted the standard ending -atae for classes, in accordance with the arguments presented by Nora Zabinkova (1964). Unfortunately Zabinkova's article waspublished too late for its nomenclatural proposals to be properly considered at the X
International Botanical Congress in Edinburgh in 1964. We plan to present the same
proposals for consideratin at the XI International Botanical Congress in Seattle in1969. Reasons for not accepting the class ending -opsida, as now recommended (butnot required) by the rules, may be found in Cronquist, 1960, Zabinkova, 1964 andTakhtajan, 1964.
In certain classes (Isoetatae, Polypodiatae, Pinatae) we have thought it useful toextend our consideration to the level of the subclass. In so doing, we do not intend toforeclose the possibility that subclasses may also be recognized in other classes.
We have chosen the name Rhyniophyta instead of Psilophyta for several reasons.
The name Psilophyta (Zimmermann, 1930) was clearly indicated to 'be a descriptive
130This content downloaded from 212.238.120.34 on Sat, 5 Apr 2014 08:26:21 AM
All use subject to JSTOR Terms and Conditions

name, derived from the Greek psilos, naked, and phyton, plant. Psilophyton was
definitely included in the group: Psilotum on the other hand was attached only as an
Anhang, so it clearly could not provide the type for the name. Had the name been
based on Psilophyton, it should have been Psilophytophyta, an infelicitous compound.
Recent work (Hueber, 1964) suggests that Dawson's reconstruction of Psilophyton
may have included at least two quite different plants, and there is even some questionthat Psilophyton properly belongs with the other fossils that have generally beenreferred to as "Psilophytes". Rhynia, on the other hand, is very well known and may
appropriatelybe selected to typify the "Psilophyte" fossils.
The Bryophytes are here listed after the Rhyniophytes in the belief that the monotelomic sporophyteis reduced from that of a more rhynioid (i.e. polytelomic) ancestor.
The presence of apparently functional stomata in the Anthoceratae. the occasional
occurrence of forked sporophytes in various Bryophytes, and the generally admitted
tendency toward reductionof the sporophytewithin the Bryophyte division all combine
to show that within the Embryobionta the Bryophytes are reduced and derivative
rather than primitive.
Psilotum and Tmesipteris are here regarded as together constituting a distinct
division, the Psilotophyta. We do not doubt that these two genera are fairly closely
related to the fossil Rhyniophytes. The absence of roots in particular testifies to theirprimitiviness. On the other hand we think the differences are sufficiently formidable
to warrant divisional status. The synangial, axillary or foliar sporangia and the apparently telomic leaves of Psilotum and especially Tmesipteris are wholly out of
harmony with Rhyniophyte structure.
The name Equisetophytais substitutedfor the names Calomophytaand Sphenophyta
in the belief that it is preferable to draw group names from living members insteadof fossils when it can reasonablebe done.
We have retained the traditional gymnosperms as a single division (Pinophyta),even though one of us (Cronquist, 1960) has previously recognized two divisions forthis group. Recent studies, especially bv Beck (1962), tend to support the concept thatboth the Pinicae (Coniferophyta) and Cycadicae (Cycadophyta) had a common origin
in the primitive seed ferns, or at least originated from a closely knit group of pregymnosperms. Simpson (1945) has set forth the principle that the characters which marka naturaltaxonomic group may evolve in parallel fashion from a set of ancestors which
do not themselves belong to that group, and Cronquist (1963, 1965), has noted that
this sort of parallelismfrom similar ancestors is a common phenomenon.Zimmermann(1959) independently applied this same concept in maintaining the gymnosperms as
a proper taxonomic group in spite of the possibility that the most recent common
ancestor of the Pinicae and the Cycadicae did not itself have seeds. Lepidocarpon,in the Lycopodiophyta,does or does not have seeds, according to whether one takes as
the essential criterion the parasitism and the enclosure of the female gametophyte, or
the presence of an apparently syntelomic integument. According to Andrews (1961),
the "integument" of Lepidocarpon is an almost closed sporophyll, not homologous
with the integumentof seed plants. Zimmermann(1959) had earlier expressed a similar
opinion. Thus, the "seeds" of Lepidocarponand related organ genera are not homologous with the seeds of the Pinophyta and Magnoliophyta.
We deliberately retain the Gneticae as a subdivision co-ordinate with the Cycadicaeand Pinicae. The relationshipsof the Gneticaewithin the division are still controversial.
Takhtajan favors a relationship to the Cycadicae, and Cronquist to the Pinicae; for
Zimmermannthe question of relationship is open. In any case the Gneticae are so
distinctive that they can well stand as a group coordinate with the conifers and cycads.
The taxonomic treatmenthere proposed is compatible with either of the two conceptsof evolutionary relationship.
131

This content downloaded from 212.238.120.34 on Sat, 5 Apr 2014 08:26:21 AM
All use subject to JSTOR Terms and Conditions

Our decision to treat the angiosperms as a distinct division, rather than subordinating them to a larger group embracing both gymnosperms and angiosperms, ispurely subjective and depends on personal weighting of the characters. It would beequally in accord with probable phyletic affinities to include all seed plants (definedso as to exclude Lepidocarpaceae and Miadesmiaceae) in a single division, or evento treat all vascular plants as a single division. The question is which of these threeequally phylogenetic treatments best reflects the totality of similarities and differences,
so that the mind can effectively grasp and retain the system.
We adopt Magnolia as the type genus of the dicotyledons and of the angiosperms asa whole, and Lilium as the type genus of the monocotyledons, following the reasonablesuggestions of Rickett and Camp (1950).
Referencesin
Studies
1961
H.
N.
ANDREWS
Palaeobotany.New York and London. John Wiley and Sons.
BECKC. B. 1962 - Reconstructionof Archaeopteris, and further consideration of its phylogenetic position. Amer. Journ. Bot. 49: 373-382.
BoLDH. C. 1957 - Morphologyof plants. Harper and Bros. New YorkA. 1960 - The divisions and classes of plants. Bot. Rev. 26(4): 425-482.
- The taxonomic significance of evolutionary parallelism. Sida 1: 109-116.
CRONQUIST A. 1962
The status of the general system of classification of flowering plants. Ann.
CRONQUISTA. 1965
Mo. Bot. Gard. 52: 281-303.
HUEBERF. M. 1964 - New data on the morphology of Devonian Psilopsida and Lycopsida.
A paper presented orally at the Xth International Botanical Congress in Edinburgh.
RICKETTH. W. and CAMP W. H., 1950 - The application and use of botanical names. Bull.
Torrey Bot. Club 77(4): 245-261.
ROTHMALERW. 1948 - Uber das natiirliche System der Organismen. Biol. Z. 67(5/6): 242-250.
SIMPSON G. G. 1945 - The principles of classification and a classification of mammals. Am.
Mus. Nat. Hist. Bull. 85.
TAKHTAJANA. 1953 - Phylogenetic principles of the system of higher plants. Bot. Rev. 19(1):1-45.
TAKHTAJANA. 1964 - The taxa of the higher plants above the rank of order. Taxon 13(5):160-164.
ZABINKOVANORA1964 - Names of taxa above the rank of order. Taxon 13(5): 157-160.
ZIMMERlMANNW. 1930 - Die Phylogenie der Pflanzen. Gustav Fischer Verlag. Jena.
ZJIMMERMANN WV. 1959 - Die Phylogenie der Pflanzen. ed. 2. Gustav Fischer Verlag. Stuttgart.

CRONQUIST

Conspectus systematis Embryobiontorum
Subrcgnum EIMBRYOBIONTAnom. nov. (regio Cormophyta Endl. 1836, Gen. pi.: 42)
1. Divisio RIIYNIOPHYTAdiv. nov. (classis Psilophytinae Fitting et al. 1928, in Strasb. Iehrb.
d. Bot. ed. 17. 403; divisio Psilophyta VW.Zimm. 1930, Die Phylog. d. Pflanzen: 103, max. pars).
Typus: Rhynia Kidston et Lang 1917.
classis nov. (classis Psilophytinac Fitting et al. 1928, in Strasb. Lehrb.
C 1 a s s i s RHYNIATAE
d. Bot. ed. 17: 403).
Typus Rlynia Kidston et Lang 1917.
2.

Divisio BnYOPI)iTAA. Br. 1864.
Typus: Bryum Hedw. 1801.
C 1 a s s i s ATHIOCEIATAE stat. nov. (tribus Anthoceroteae Necs 1838, Lelberm. 4: 319).
Typus: Anthoceros L. 1753.
C 1 a s s i s MAICIIANTIATAE classis nov. (ordo Hepaticae Juss. 1789, Gen. 1p. 7, p.p; classis

132

This content downloaded from 212.238.120.34 on Sat, 5 Apr 2014 08:26:21 AM
All use subject to JSTOR Terms and Conditions

Hepaticopsida Rothm. 1951, in Feddes Repert. 54: 261).
Typus: MarchantiaL. 1753.
C 1a s s i s BRYATAEclassis nov. (Musci Hedw. 1782, Fund. Hist. Nat. Muse. Frond.; Ordo
Musci Juss. 1789, Gen. pl. 10, p.p.; classis Musci Endl. 1836, Gen. pl. 46).
Typus: Bryum Hedw. 1801.
3.

Divisio PSILOTOPHYTAstat. nov. (ordo Psilotales Wettst. 1903, Handb. d. Syst. Bot. 2: 91).

Typus: Psilotum Swartz 1806.
C 1a s s i s PSILOTATAE
stat. nov. (ordo Psilotales Wettst. 1903, Handb. d. Syst. Bot. 2: 91).
Typus: Psilotum Swartz 1806.

4. Divisio LYCOPODIOPHYTA
nom. nov. (Lycopsida Jeffrey 1899, in Trans. Canad. Inst. 6: 632,
p.p.; phylum Lycopsida Jeffrey 1908, in Bot. Gaz. 46: 257 p.p.; divisio Lycophyta Boivin 1956,

in Bull. Soc. Bot. France 103: 492).
Typus: Lycopodium L. 1753.

C l a s s is LYCOPODIATAE
nom. nov. (classis Lycopodinae Prantl 1874, Lehrb. d. Bot.: 123).
Typus: Lycopodium L. 1753.
C 1 a s s i s ISOETATAE
classis nov. (classis Selagines Endl. 1836, Gen. pl. 68; classis Isoetopsida
Rothm. 1951, in Feddes Repert. 54: 262, nomen subnudum).
Typus: Isoetes L. 1753.
5. Divisio EQUISETOPHYTA
nom. nov. (phylum Calamophyta Bessey 1907, in Univ. Nebr. Stud.
7: 45; divisio Equisophyta Boivin 1956, in Bull. Soc. Bot. France 103: 493).

Typus: Equisetum L. 1753.

C l a s s i s HYENIATAE
stat. nov. (subclassis Hyeniidae Pichi-Sermolli 1958, in Uppsala Univ.

Arsskr.6: 76).
Typus: Hyenia Nathorst 1915.

C l a s s i s SPHENOPHYLLATAE
nom. nov. (classis Sphenophyllales Engl. 1892, Syllabus 58).
Typus: Sphenophyllum Koenig 1825.
C 1 a s s i s EQUISETATAE
nom. nov. (classis Equiseta Endl. 1836, Gen. pl. 58).
Typus: Equisetum L. 1753.
6.

Divisio POLYPODIOPHYTA
div. nov. (classis Filices Endl. 1836; Gen. pl. 58).
Typus: Polypodium L. 1753.
C l a s s i s POLYPODIATAE
classis nov. (classis Filices Endl. 1836, Gen. pl. 58).
Typus: Polypodium L. 1753.
Subclassis PROTOPTERIDIDAE subclassis nov. (Primofilices Arber 1906, in Ann. Bot., Lond.,
20: 215; subclassis Primofilicidae Pichi-Sermolli 1958, in Uppsala Univ. Arsskr. 6: 80).
Typus: Protopteridium Krejci 1880.
Subclassis ARCHAEOPTERIDIIDAEstat. nov. (ordo Archaeopteridales F. Nemejc 1950, in Acta
Musei nat. Pragae 6(3): 80).
Typus: Archaeopteris Dawson 1871.
Subclassis OPHIOGLOSSIDAE
Takht. 1956, nomen subnudum, Telomophyta 1: 168 (ordo Ophioglossales Engl. 1898, Syllabus ed 2: 63).
Typus: Ophioglossum L. 1753.
Takht. 1956, Telomophyta 1: 77.
Subclassis NOEGGERATHIIDAE
Typus: Noeggerathia Sternb. 1822.
Subclassis MARATTIIDAE stat. nov. (ordo Marattiaceae Kaulfuss 1824, Enum. 31).
Typus: Marattia Swartz 1788.
Subclassis POLYPODIMDAEstat. nov. (fam. Polypodiaceae R. Brown 1810, Prodromus 145;

subclassis Filicidae Rothm. p.p. 1951, in Feddes Repert. 54: 262; subclassis Filicidae PichiSermolli 1958, in Uppsala Univ. Arsskr. 6: 83).

Typus: Polypodium L. 1753.
Subclassis MARSILEIDAE Pichi-Sermolli 1958, Uppsala Univ. Arsskr. 6: 83, nomen subnudum(ordo MarsileaceaeR. Brown 1810, Prodromus:166).
Typus: Marsilea L. 1753.

133

This content downloaded from 212.238.120.34 on Sat, 5 Apr 2014 08:26:21 AM
All use subject to JSTOR Terms and Conditions

Subclassis SALVINIIDAE
Pichi-Sermolli 1958, Uppsala Univ. Arsskr. 6: 83, nomen subnudum(fam. Salviniaceae Dumort. 1829, Anal. Fam.: 27).
Typus: Salvinia Adans. 1763.
7. Divisio PINOPHYTAdiv. nov. (classis Gymnospermae Lindl. 1830, Intr. Nat. Syst. Bot.: 245;
divisio Gymnospermae Prantl 1874, Lehrb. d. Bot. 131).
Typus: Pinus L. 1753.
A. Subdivisio CYCADICAE
nom. nov. (phylum Cycadophyta Bessey 1907, in Univ. Nebr. Stud.
7: 47; subdivisio Cycadophytina W. Zimm. 1959, Die Phylog. d. Pfl. ed. 2: 325. p.p., nomen
subnudum).
Typus: Cycas L. 1753.
C 1 a s s i s LYGINOPTERIDATAEnom. nov. (divisio Cycadofilices Potonie 1899, Lehrb. d. Pflanzenpaleont. 160; classis Pteridospermeae F. W. Oliver et D. H. Scott 1904, Phil. Trans. Roy.
Soc. Lond. B, 197: 239).
Typus: Lyginopteris Potonie 1899.
C 1 a s s i s CYCADATAE classis nov. (classis Zamiae Endl. 1836, Gen. pl. 70).
Typus: Cycas L. 1753.
C 1 a s s i s BENNETTITATAE
nom. nov. (classis Bennettitales Engl. 1892, Syllabus 61).
Typus: Bennettites Carruthers 1870 (Cycadeoidea Buckland 1828, a taxonomic synonym, but not a nomenclatural synonym).
B. Subdivisio PINICAEsubd. nov. (phylum Strobilophyta Bessey 1907, in Univ. Nebr. Stud.
7: 49; subdivisio Coniferophytina W. Zimm. 1959, Die Phylog. d. Pfl. ed. 2: 325, nomen
subnudum).
Typus: Pinus L. 1753.
C a ssis GINKGOATAEnom. nov. (classis Ginkgoales Engl. 1897, Engler und Prantl, Die
natiirl. Pflanzenfam., Nachtr. 341).
Typus: Ginkgo L. 1753.
C 1 a s s i s PINATAEnom. nov. (classis Pinoideae Bessey 1907, in Univ. Nebr. Stud. 7: 50).
Typus: Pinus L. 1753.
Subclassis CORDAITIDAE
nom. nov. (classis Cordaitales Engl. (1892, Syllabus 60).
Typus: Cordaites Unger 1850.
Subclassis PINDAE subcl. nov.T(ordo Coniferae Juss. 1789, Gen. pl.: 411, p.p.; ordo Coniferae
Prantl 1874, Lehrb. d. Bot. 134; classis Coniferae Engl. 1892, Syllabus 61).
C. Subdivisio GNETICAEsubd. nov. (classis Gnetales Engl. 1887, in Engler und Prantl, Die
natiirl. Pflanzenfam. II. 1: 2).
Typus: Gnetum L.
nom. nov. (classis Gnetales Engl. 1887, in Engler und Prantl, Die natiirl.
C 1 a s s i s GNETATAE
Pflanzenfam. II. 1: 2).
Typus: Gnetum L. 1767.
Subclassis EPHEDRIDAE
subcl. nov. (fam. Ephedraceae Dumortier 1829, Anal. Fam. pl.: 11).
Typus: Ephedra L. 1753.
Subclassis WELWITSCHIIDAEsubcl. nov. (fam. Tumboaceae Wettst., 1903, Handl. d. syst. Bot.
158; Welwitschiaceae Lotsy 1911, Bot. Stammesgesch. 3: 310).
Typus: Welwitschia Hook. f. 862.
Subclassis GNETIDAE subcl. nov. (fam. Gnetaceae Lindl. 1834, Bot. Reg. 1686).
Typus: Gnetum L. 1767.
8. Divisio MAGNOLIOPIIYTAdiv. nov. (divisio Angiospermae A. Br. et Doell 1857, ex Doell, Fl.
Baden. 1: 104).
Typus: Magnolia I. 1753.
classis nov. (classis Dicotyledoneae DC. 1818, Syst. 1: 123).
C a ssis
MsAGNOLLATAE
Typus: Magnolia 1753.
C 1 a s s i s LILIATAEclassis nov. (classis Monocotyledoneae DC 1818, Syst. 1: 122).
Typus: Lilium L. 1753.
134

This content downloaded from 212.238.120.34 on Sat, 5 Apr 2014 08:26:21 AM
All use subject to JSTOR Terms and Conditions