An updated angiosperm. classification

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1 Botanical Journal qf the Linnean Sociery (1989), 100: With figure An updated angiosperm. classification GERTRUD DAHLGREN Department of Systematic Botany, University of Lund, 6. Vallgatan 20, S Lund, Sweden Received July 1988, revised and accepted for publication November 1988 DAHLGREN, G., An updated angiosperid classification. A new two-dimensional diagram, reflecting the system of classification of the angiosperms, is presented. t combines the dicotyledon diagram in G. Dahlgren ( 1989) and an adapted monocotyledon diagram after that in Dahlgren ( 1985) in a single diagram. An updated monocotyledon taxonomy is presented and the classification is appended. ADDTONAL KEY WORDS:-Magnoliidae (dicotyledons)- Liliidae (monocotyledons). CONTENTS The revised classification Acknowledgements References Appendix THE REVSED CLASSFCATON A revised system of classification of the angiosperms, with the orders shown in a two-dimensional diagram, was published by Dahlgren (1980). The taxonomy of the monocotyledons was revised in Dahlgren, Clifford & Yeo ( 1985) and an updated system of classification of the dicotyledons appeared in G. Dahlgren ( 1989). The diagram of 1980 has been used by many scientists in different fields to illustrate the distribution of various character states in the angiosperms. The diagrams that have resulted from the revisions of 1985 and 1989 will now replace that of The dicotyledon diagram has already been used to illustrate the distribution of various coffee acid compounds (Molgaard & Ravn, 1988), embryological characters (G. Dahlgren, in press) and forms and types of sieveelement plastids (Behnke, in press). The fact that the monocotyledons and dicotyledons appear in different diagrams is not entirely satisfactory, and there have been repeated requests for a combination of these groups in a single diagram. Such a diagram, together with an updated treatment of the taxonomy of the monocotyledons is presented here, Fig. 1. The diagram corresponds with the previous diagrams in that the orders are represented as bubbles, whose size is relative to the number of species in the order, and their relative positions reflect phylogenetic affinities. The orders are {89{ $03.00/ The Linnean Society of London

2 Velloziales \~_.---_j " OZin~iberales \ _ Cyperales ' O}chidales Fa bales g 0 Triuridales D Polygonalas Alismatales " ~,., ' -- --'-~- _ 1, ~ / 0/ 0 Batsam nales /. ' \ ; / Arales -... \ -..._ Plumbag1nales. ' ' \. ' '.,. Burmanniaies '/ \ '1 (J' \- Nvmphaeal / Papaverales. '0' " -- ' ' --,, \ ',.- /~...,_ / Ranuncul~les, / PotJga!ales-' / Piperales '\..,.../,-Dillen ales ""-, Rhi'i'oPhoraies. \0,., _,., Paeoniales ~, Vitales 1. 1 Theales...,,. /----- ~ /c'ornales Gooden ales CB rs Lecylhtdales - Santalales\., \ ~ - _..,..., / OEucommtales QLoasales Ebenales ( PRjlttosporales ', -G-t anales ~ Brunoal~es \ en 1, / \ Sarracentale _ ~7~ \ Balanophorales, Fouqu eriale- '. \ 'Q \ Styhdiales Encales l!,~ \ Arallales ~lales ~-~\ 1 Primulales \ Figure. Diagram of angiosperm classification, showing orders, combined into superorders. <.0 CX> 0 ~ ::!:"" C'l :;; t'l z ',

3 AN UPDATED ANGOSPERM CLASSFCATON 199 combined into superorders thus forming bubble complexes as in the diagrams of 1980 and 1989, while diverging from the monocotyledon diagram of 1985 in which each order is represented by a separate bubble. The dicotyledons are divided into 25 superorders (G. Dahlgren, 1989), the monocotyledons into ten (Dahlgren, 1985 and appendix). The ending -florae for the superorders has been changed to -anae in agreement with the classification of the dicotyledons (G. Dahlgren, 1989). For the classification of the monocotyledons the reader is referred to Dahlgren et al. (1985) where an updated treatment of the taxonomy is presented. Only a few changes are suggested here in relation to this work: Acoraceae are recognized as a family in Arales. Rhipogonaceae have been accorded family rank in Dioscoreales. Behniaceae, Lanariaceae, Johnsoniaceae and Simethidaceae are treated as families in Asparagales. Geosiridaceae are included in ridaceae, Thismiaceae in Burmanniaceae and Sparganiaceae in Typhaceae. Finally Neuwiediaceae form a separate family in Orchidales. These changes will be commented on below, but for the sake of consistency the monocotyledon taxonomy adopted here will also be compared with that in Dahlgren (1980). Alismatanae. Compared with that in previous works a somewhat simplified ordinal division is proposed, viz. into two orders: Alismatales with Aponogetonaceae, Butomaceae, Hydrocharitaceae, Limnocharitaceae and Alismataceae, and Najadales with Scheuchzeriaceae, Juncaginaceae, N ajadaceae, Potamogetonaceae, Zosteraceae, Posidoniaceae, Cymodoceaceae and Zannichelliaceae. t is to be noted that Limnocharitaceae have been separated from Alismataceae to form a new family. Aranae. Acoraceae, with the single genus Acorus, are now a family separated from Araceae (previous family rank C. A. Agardh, 1822). The genus is distinct in a number of attributes (Walker, 1986; French, 1987), and may not be particularly close to Araceae at all. Among distinguishing features are the ensiform leaves, the presence of cells with essential oils, the glandular tapetum, the type of endothecial cells, and the endosperm type. Lilianae. Smilacaceae and Petermanniaceae have been transferred from Asparagales to Dioscoreales on the basis of leaf morphology and floral characters, but can be said to form a bridge between the two orders (Dahlgren et a!., 1985). The monogeneric Rhipogonaceae form a family in Dioscoreales, distinct from Smilacaceae and differing from it in the opposite leaves, lack of tendrils, bisexual flowers, anatropous ovules and endosperm with starch. Family rank for Rhipogonaceae has been discussed by Huber ( 1969, 1977). n Asparagales the monotypic genus Behnia, endemic to South Africa, has previously been treated in the family Luzuriagaceae. Contrary to other genera of that family Behnia has a campanulate perianth with fused tepals, and also differs in microcharacters of the seed. t is here recognized as a separate family. Another South African montypic genus, Lanaria, has generally been placed in Haemodoraceae but was included in Tecophilaeaceae in Dahlgren et al. (1985) on the basis of embryological characters. t agrees with Hypoxidaceae in seed and stomata characters. Lanariaceae have now been described as a separate family in Dahlgren & van Wyk ( 1988). Calectasiaceae and Blandfordiaceae are distinct from Dasypogonaceae, and xioliriaceae is distinct from Amaryllidaceae.

4 200 G. DAHLGREN The tribe Johnsoniae Benth., placed in Anthericaceae by Dahlgren et al. ( 1985), includes genera endemic to the Australasian region. t is considered to be a heterogeneous group by Keighery (1984). He proposes to restrictjohnsoniae to the genus Johnsonia and four related genera, while remaining genera are placed in the tribes Boryeae and Sowerbeae. The evidence for this revised classification lies in differences in cytologic, morphologic and ecologic characters. The genera referred to the tribe Boryeae would probably fit better in Dasypogonaceae according to Dahlgren et al. ( 1985). The tribes have also been treated as a separate family, Johnsoniaceae (Lotsy, 1911; Sato, 1942 and others). Since they seem to be distinct from other families of Asparagales family rank S recommended here. The western European genus Simethis has sometimes been placed in An thericaceae (on embryological similarities) sometimes in Asphodelaceae (on chemical and seed characters). t is here treated as a separate family, Simethidaceae. Eriospermaceae are treated as a separate family distinct from Anthericaceae (Dahlgren & Clifford, 1982; Bond & Goldblatt, 1984). Dianellaceae have been included in Phormiaceae and Geitonoplesiaceae in Luzuriagaceae. Hanguanaceae have, with some reservation, been excluded from Asparagales (see under Arecanae). Some of the families proposed in Asparagales have not been formally described as far as know, and the rank must be seen as a recommended until more data are available. The family taxonomy in this order is in great need of revision, and the present tendency to split may lead, by secondary fusion of some of these families, to a balanced taxonomy that agrees with evolutionary concepts. n Liliales, Geosiridaceae agree with the family ridaceae in inflorescence and floral construction as well as embroyological characters and have been included in this family as the single genus Geosiris originally was (Baillon, 1984). The family Uvulariaceae have been set up to accommodate some genera previously placed in Convallariaceae, Colchicaceae or Tricyrtidaceae, the last family name now being included in Uvulariaceae as a synonym, for priority reasons. Melanthiaceae together with Campynemaceae, here recognized as a distinct family, are treated as an order, Melanthiales, having few of the distinctive features of true Liliales. Orchidales should actually be included in Liliales, with which it shares most distinctive features, but has nevertheless been treated as an independent order. Garay ( 1972) considers that the two genera of Apostaciaceae, Neuwiedia and Apostasia, are not closely related. They differ in number of stamens and the occurrence of a rhizome, and they have no advanced characters in common. Apostaciaceae are here split up into two families, Neuwiediaceae and Apostasiaceae, which together with Cypripediaceae and Orchidaceae form the order. n Burmanniales, Thismiaceae, with six incompletely known achlorophyllous genera, seem to be connected with Burmanniaceae and are included in this family (Bentham & Hooker 1883) and also by Cronquist (1981). Bromelianae. This superorder includes the orders Velloziales, Bromeliales, Haemodora1es, Philydrales, Pontederiales and Typhales. Within Typhales, Sparganiaceae are included in Typhaceae (Miiller-Doblies, 1977). Zingiberanae. Here the family circumscriptions are retained, even though the

5 AN UPDATED ANGOSPERM CLASSFCATON 201 families Musaceae, Heliconiaceae and Strelitziaceae are particularly closely related. Commelinanae. Commelinales has been extended to include the families Xyridaceae, Rapateaceae and Eriocaulaceae of the former order Eriocaulales. Hydatellales has been accorded order rank and comprises the family Hydatellaceae only. The genera of this family were previously treated m Centrolepidaceae (Poales). Arecanae, Cyclanthanae and Pandananae. These are recognized as discrete superorders, at least Pandananae probably having a distant relationship with the other two superorders. Cyclanthanae and Pandananae comprise one order and family each, while Arecanae, with hesitation, has been allowed to include the monogeneric Hanguanaceae (formerly in Asparagales), placed in a separate order, Hanguanales. t is striking that, in addition to the starchy endosperm, Hanguana shows a number of similarities with palms, although this may be a result of convergence. ACKNOWLEDGEMENTS wish to thank the artist, Mr Bent Johnsen, who has kindly drawn the diagram for me. REFERENCES AGARDH, C. A., Aphorismi Bothanici. Lunde: Literis Belingianis. BALLON, H., Histoire des plantes. Monographic des Amaryllidades, Bromeliacies et lridades. Paris: Libraire Hachette. BEHNKE, H.-D., Distribution and evolution of forms and types of sieve-element plastids in the dicotyledons. Aliso, in press. BENTHAM, G. & HOOKER,]. D., Genera Plantarum, 3 (2). London: Reeve & Co. BOND, P. & GOLDBLATT, P., Plants of the Cape Flora. A descriptive catalogue. Journal if South African Botany, Supplement 13. CRONQUST, A., An lntergrated System of Classification if Flowering Plants. New York: Columbia University Press. DAHLGREN, G., The last Dahlgrenogram. System of classification of the dicotyledons. n the Davis and Hedge Festschrift: Edinburgh University Press. DAHLGREN, G., Steps towards the natural system of the dicotyledons: embryological characters. Aliso, in press. DAHLGREN, R., A revised system of classification of the angiosperms. Botanical Journal if the Linnean Society, 80: DAHLGREN, R. & CLFFORD, T., The Monocotyledons: a Comparative Study. London & New York: Academic Press. DAHLGREN, R., CLFFORD, H. T. & YEO, P. F., The Families of the Monocotyledons. Heidelberg: Springer Verlag. DAHLGREN, R. & VAN WYK, A. E., Structures and relationships of families endemic to or centered in Southern Africa. n P. Goldblatt, & P. P. Lowry, (Eds), Modern Systematic Studies in African Bola'?)'. St. Louis: Missouri Botanical Garden. FRENCH, J. C., Systematic anatomy if the Araceae. Symposium 5:24 at the XV:e nternational Botanical Congress, Berlin. GARAY, L. A., On the origin of Orchidaceae, 2. Journal of the Arnold Arboretum of Harvard University, 53: HUBER, H., Die Samenmerkmale und Verwandtschaftverhiiltnisse der Liliifloren. Mitteilungen Botanisches Staatsammlung Muenchen, 8: HUBER, H., The treatment of monocotyledons in an evolutionary system of classification. Plant Systematics and Evolution, Supplement 1: KEGHERY, G. J., The Johnsonieae (Liliaceae); biology and classification. Flora, 175: 103-!08. LOTSY, J. P., Vortriige iiber botanische Stammesgeschichte. Cormophyta siphonogamia, 3. Jena: Fischer.

6 202 G. DAHLGREN MULLER-DOBLES, D. & MULLER-DOBLES, U., Ordnung Typhales. n G. Hegi (Ed.), lllustrierte Flora von Mitte{europa. Bd, Teill: Berlin, Hamburg. M0LGAARD, P. & RAVN, H., Evolutionary aspects of caffeoyl ester distribution in dicotyledons Pfrytochemistry, 27: SATO, D., Karyotype alteration and phylogeny in Liliaceae and allied families. Japanese Journal of Botany, 12: WALKER, J. W., Classification and Evolution if the Monocotyledons. 37th Annual ABS Meeting, University of Massachusetts, Amherst. Alismatanae APPENDX System of Classification qf the Monocotyledons Alismatales: Aponogetonaceae, Bu tomaceae, H ydrochari taceae, Limnocharitaceae, Alismataceae Najadales: Scheuchzeriaceae, Juncaginaceae, Najadaceae, Potamogetonaceae, Zosteraceae, Posidoniaceae, Cymodoceaceae, Zannichelliaceae Triuridanae Triuridales: Triuridaceae Aranae Arales: Araceae, Acoraceae, Lemnaceae Lilianae Dioscoreales: Trichopodaceae, Dioscoreaceae, Stemonaceae, Taccaceae, Trilliaceae, Rhipogonaceae, Petermanniaceae, Smilacaceae Asparagales: Philesiaceae, Luzuriagaceae, Behniaceae, Convallariaceae, Dracaenaceae, Asparagaceae, Ruscaceae, Herreriaceae, Nolinaceae, Asteliaceae, Dasypogonaceae, Calectasiaceae, Blandfordiaceae, Xanthorrhoeaceae, Agavaceae, Hypoxidaceae, Tecophilaeaceae, Lanariaceae, xioliriaceae, Cyanastraceae, J ohnsoniaceae, Phormiaceae, Doryanthaceae, Eriospermaceae, Asphodelaceae, Simethidaceae, Anthericaceae, Aphyllanthaceae, Hemerocallidaceae, Funkiaceae, Hyacinthaceae, Alliaceae, Amaryllidaceae Liliales: Colchicaceae, Uvulariaceae, ridaceae, Alstroemeriaceae, Calochortaceae, Liliaceae Melanthiales: Melanthiaceae, Campynemaceae Burmanniales: Burmanniaceae, Corsiaceae Orchidales: Neuwiediaceae, Apostasiaceae, Cypripediaceae, Orchidaceae Bromelianae Velloziales: Velloziaceae Bromeliales: Bromeliaceae Haemodorales: Haemodoraceae Philydrales: Philydraceae Pontederiales: Pon tederiaceae Typhales: Typhaceae Zingiberanae -?,ingiberales: Lowiaceae, Musaceae, Heliconiaceae, Strelitziaceae, Zingiberaceae, Costaceae, Cannaceae, Marantaceae

7 AN UPDATED ANGOSPERM CLASSFCATON 203 Commelinanae Commelinales: Mayacaceae, Commelinaceae, Xyridaceae, Rapateaceae, Eriocaulaceae Hydatellales: H yda tellaceae Cyperales: Juncaceae, Thurniaceae, Cyperaceae Poales: Flagellariaceae, J oinvilleaceae, Restionaceae, Centrolepidaceae, Poaceae Arecanae Hanguanales: Hanguanaceae Arecales: Arecaceae Cyclanthanae Cyclanthales: Cyclan thaceae Pandananae Pandanales: Pandanaceae