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The families of flowering plants

L. Watson and M.J. Dallwitz

Palmae Juss.

Alternatively Arecaceae Schultz-Schultzenst. (nom. altern.)

Including Acristaceae O.F. Cook, Borassaceae O.F. Cook, Caryotaceae O.F. Cook, Ceroxylaceae O.F. Cook, Chamaedoreaceae O.F. Cook, Coryphaceae Schultz-Schultzenstein, Geonomaceae O.F. Cook, Iriarteaceae O.F. Cook, Lepidocaryaceae O.F. Cook, Malortieaceae O.F. Cook, Manicariaceae O.F. Cook, Nipaceae Brongniart ex Martinet, Nipaceae Chadef. & Emberg., Nypaceae (Engl. & Gilg) Tralau, Phoenicaceae Schultz-Schultzenst., Phytelephanteae (Phytelephantaceae) Mart., Phytelephasieae (Phytelephasiaceae) Chadef. & Emberg., Pseudophoenicaceae O.F. Cook, Sabalineae (Sabalaceae) Schultz-Schultzenst., Sagoineae (Sagoaceae) Schultz-Schultzenst., Synechanthaceae O.F. Cook

Habit and leaf form. Trees, or ‘arborescent’, or shrubs (rarely diminutive undershrubs), or lianas. Plants green and photosynthesizing. Self supporting, or climbing; often scrambling (by means of hooks on prolonged rachides, leaflets modified as spines, armed sterile inflorescence axes, etc.). Pachycaul. Mesophytic, or xerophytic. Leaves persistent; small to very large; alternate; spiral, or distichous; leathery; petiolate; sheathing. Leaf sheaths tubular; with joined margins (but often splitting at maturity). Leaves nearly always compound; epulvinate; (falsely) pinnate, or palmate, or bipinnate (rarely). Lamina without cross-venules. Leaves ligulate (often, in palmate and costa-palmate forms), or eligulate; leaf development not ‘graminaceous’ (presumably). Vernation conduplicate. Leaves becoming compound by ontogenetically predetermined splitting.

General anatomy. Plants with ‘crystal sand’ (occasionally), or without ‘crystal sand’. Plants with silica bodies (hatshaped, spheroidal or ellipsoidal, occurring universally).

Leaf anatomy. Epidermis without differentiation into ‘long’ and ‘short’ cells; containing silica bodies, or without silica bodies. Stomata mostly tetracytic. The mesophyll containing crystals. The crystals raphides (usually), or solitary-prismatic (or as crystal sand). Foliar vessels present; with scalariform end-walls. Minor leaf veins without phloem transfer cells (Chamaerops).

Axial (stem, wood) anatomy. Secondary thickening absent (or slight, and then not cambial but from divisions in the ground parenchyma).

The vessel end-walls mostly oblique; scalariform, or simple, or scalariform and simple.

Root anatomy. Root xylem with vessels (mostly with transverse end walls); vessel end-walls nearly always simple.

Reproductive type, pollination. Plants hermaphrodite (rarely), or monoecious, or dioecious, or polygamomonoecious. Floral nectaries present, or absent. Nectar secretion when produced, from the gynoecium (via septal nectaries), or from the androecium (via nectaries associated with the stamen bases). Pollination anemophilous, or entomophilous (more often).

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in panicles (usually, and these usually complex). The ultimate inflorescence units cymose. Inflorescences axillary (usually), or terminal; usually complex panicles; usually spatheate. Flowers small; more or less regular; 3 merous; cyclic (usually), or partially acyclic. Rarely the perianth acyclic, or the androecium acyclic. Perigone tube present, or absent.

Perianth with distinct calyx and corolla, or of ‘tepals’, or vestigial to absent (rarely); 6 (usually), or 4, or 4–9 (rarely, when spiral); free, or joined; 2 whorled (usually 3+3, occasionally 2+2), or 1 whorled (rarely); isomerous (but the two whorls usually more or less dissimilar); sepaloid, or petaloid, or sepaloid and petaloid; when biseriate, usually different in the two whorls; usually white, or cream.

Androecium 3, or 6, or 9, or 10–900 (i.e. occasionally very numerous). Androecial members free of the perianth, or adnate (to the perianth); free of one another, or coherent; 1 adelphous (filaments often united into a tube or cup); 2 whorled, or 3 whorled (or acyclic). Androecium exclusively of fertile stamens, or including staminodes (? — assuming that references to staminodes refer to male-fertile flowers). Stamens 3, or 6, or 9, or 10–900 (or more); isomerous with the perianth, or diplostemonous (usually), or triplostemonous to polystemonous. Anthers dehiscing via longitudinal slits; latrorse; tetrasporangiate. Endothecium developing fibrous thickenings. The endothecial thickenings spiral. Anther epidermis persistent. Microsporogenesis successive, or simultaneous. The initial microspore tetrads tetrahedral, or isobilateral, or T-shaped, or linear. Anther wall initially with more than one middle layer. Tapetum glandular. Pollen grains aperturate; 1 aperturate (usually), or 2 aperturate; sulcate (usually, sometimes trichotomosulcate), or sulculate (2-sulculate); 2-celled (in 8 genera).

Gynoecium 3(–10) carpelled. Carpels isomerous with the perianth, or increased in number relative to the perianth. The pistil when syncarpous, 1 celled, or 3(–10) celled. Gynoecium apocarpous, or syncarpous (occasionally pseudomonomerous); eu-apocarpous, or synovarious to synstylovarious. Ovary when syncarpous 1 locular (rarely, by abortion of the other locules), or 3(–10) locular. Gynoecium non-stylate, or stylate. Styles 1, or 3(–10); when not completely joined, free to partially joined. Stigmas dry type; papillate; Group II type. Placentation sub apical, or basal (or ‘lateral’). Ovules 1 per locule; non-arillate; orthotropous, or anatropous, or campylotropous, or hemianatropous; bitegmic; crassinucellate. Outer integument contributing to the micropyle. Embryo-sac development Polygonum-type (usually), or Allium-type (rarely). Polar nuclei fusing prior to fertilization. Antipodal cells formed, or not formed (then the three nuclei degenerating early); when formed, 3; not proliferating; ephemeral, or persistent. Synergids pear-shaped. Endosperm formation nuclear. Embryogeny onagrad, or asterad.

Fruit fleshy, or non-fleshy; an aggregate (occasionally), or not an aggregate. The fruiting carpel when apocarpous (i.e. rarely), indehiscent; drupaceous. Fruit indehiscent (usually), or dehiscent (rarely); nearly always a berry, or a drupe (sometimes with a fibrous mesocarp). The drupes with one stone (often having the seed united with the endocarp). Fruit 1 seeded. Seeds endospermic. Endosperm ruminate, or not ruminate; oily (usually), or not oily. Seeds usually without starch. Cotyledons 1. Embryo achlorophyllous (9/9). Testa without phytomelan.

Seedling. Germination cryptocotylar (regardless of the structure of the cotyledon). Hypocotyl internode absent. Mesocotyl absent. Seedling collar not conspicuous. Cotyledon hyperphyll elongated to compact; non-assimilatory. Coleoptile present, or absent. Seedling cataphylls absent. First leaf dorsiventral. Primary root persistent, or ephemeral.

Physiology, phytochemistry. C3. C3 physiology recorded directly in Borassus, Cocos, Phoenix. Anatomy non-C4 type (Archantophoenix, Areca, Arenga, Borassus, Calamus, Caryota, Chrysalidocarpus, Cocos, Cyrtostachys, Elaeis, Eugeissonia, Iguanura, Licuala, Livistona, Nypa, Oncosperma, Phoenix, Pinanga, Ptychosperma, Roystonea). Accumulated starch other than exclusively ‘pteridophyte type’. Not cyanogenic. Alkaloids present (occasionally, pyrimidine), or absent. Saponins/sapogenins present (occasionally), or absent. Proanthocyanidins present (usually, abundantly), or absent (e.g. Livistonia); cyanidin. Flavonols present (rarely), or absent; when present, kaempferol and quercetin (also tricin, luteolin, etc.). Sieve-tube plastids P-type; type II.

Geography, cytology. Sub-tropical to tropical. Pantropical and subtropical. X = 13–18. Ploidy levels recorded: only in Areca.

Taxonomy. Subclass Monocotyledonae. Dahlgren et al. Superorder Areciflorae; Arecales. APG III core angiosperms; Superorder Lilianae; commelinid Monocot. APG IV Order Arecales.

Species about 2500. Genera about 205; Acanthophoenix, Acoelorrhaphe, Acrocomia, Actinokentia, Actinorhytis, Aiphanes, Allagoptera, Alloschmidia, Alsmithia, Ammandra, Antongilia, Aphandra, Archontophoenix, Areca, Arenga, Asterogyne, Astrocaryum, Attalea, Bactris, Balaka, Barcella, Basselinia, Beccariophoenix, Bentinckia, Bismarckia, Borassodendron, Borassus, Brahea, Brassiophoenix, Brongniartikentia, Burretiokentia, Butia, Calamus, Calospatha, Calyptrocalyx, Calyptrogyne, Calyptronoma, Campecarpus, Carpentaria, Carpoxylon, Caryota, Catoblastus, Ceratolobus, Ceroxylon, Chamaedorea, Chamaerops, Chambeyronia, Chelyocarpus, Chrysalidocarpus, Chuniophoenix, Clinosperma, Clinostigma, Coccothrinax, Cocos, Colpothrinax, Copernica, Corypha, Cryosophila, Cyphokentia, Cyphophoenix, Cyphosperma, Cyrtostachys, Daemonorops, Deckenia, Desmoncus, Dictyocaryum, Dictyosperma, Drymophloeus, Dypsis, Elaeis, Eleiodoxa, Eremospatha, Eugeissona, Euterpe, Gastrococos, Gaussia, Geonoma, Goniocladus, Gronophyllum, Guihaia, Gulubia, Halmoorea, Hedyscepe, Heterospathe, Howeia, Hydriastele, Hyophorbe, Hyospathe, Hyphaene, Iguanura, Iriartea, Iriartella, Itaya, Jessenia, Johannesteijsmannia, Juania, Jubaea, Jubaeopsis, Kentiopsis, Kerriodoxa, Korthalsia, Laccospadix, Laccosperma, Latania, Lavoixia, Lemurophoenix, Leopoldinia, Lepidocaryum, Lepidorrhachis, Licuala, Linospadix, Livistona, Lodoicea, Louvelia, Loxococcus, Lytocaryum, Mackeea, Manicaria, Marojejya, Masoala, Mauritia, Mauritiella, Maxburretia, Maximiliana, Medemia, Metroxylon, Moratia, Myrialepis, Nannorrhops, Nenga, Neodypsis, Neonicholsonia, Neophloga, Neoveitchia, Nephrosperma, Normanbya, Nypa, Oenocarpus, Oncocalamus, Oncosperma, Orania, Oraniopsis, Orbigyna, Palandra, Parajubaea, Pelagodoxa, Phloga, Phoenicophorium, Phoenix, Pholidocarpus, Pholidostachys, Physokentia, Phytelephas, Pigafetta, Pinanga, Plectocomia, Plectocomiopsis, Podococcus, Pogonotium, Polyandrococos, Prestoea, Pritchardia, Pritchardiopsis, Pseudophoenix, Ptychococcus, Ptychosperma, Raphia, Ravenea, Reinhardtia, Retispatha, Rhapidophyllum, Rhapis, Rhopaloblaste, Rhopalostylis, Roscheria, Roystonea, Sabal, Salacca, Satakentia, Scheelea, Schippia, Sclerosperma, Serenoa, Siphokentia, Socratea, Sommieria, Syagrus, Synechanthus, Tahina, Tectiphiala, Thrinax, Trachycarpus, Trithrinax, Veillonia, Veitchia, Verschaffeltia, Voanioala, Vonitra, Wallichia, Washingtonia, Welfia, Wendlandiella, Wettenia, Wodyetia, Ynesa, Zombia.

Economic uses, etc. Pantropically of great economic importance: coconut products, oils, dates, ivory nuts, carnauba wax, house building materials, rattan cane, raffia, etc.


(The male palm marries the female palm) ‘by gentle sighings, tender looks, and the dispersion of a powder’
(Pliny’s ‘Natural History’ (First Century A.D.). Fifteen wasted centuries later, Parkinson (1640) accounts this belief ‘of the ancient writers . . . among the rest of their fables’. See Gilmour’s ‘British Botanists’ (1956, Collins))

Illustrations. • Le Maout and Decaisne: Chamaerops. • Le Maout and Decaisne: Areca (betel), Caryota, Metroxylon. • Caryota cumingii: Bot. Mag. 95 (1869). • Chamaedorea linearis, as Morenia fragrans: Bot. Mag. 91 (1865). • Fruit structure: Cocos, Cucifera (= Hyphaene), Saguerus (= Arenga). • Habit and inflorescence: Chamaedorea, Livistonia, Seaforthia. • Fruit and seed details: Phoenix dactylifera. • Rhapis flabelliformis: Le Maout and Decaisne. • Raphia laurentii: Thonner. • Raphia laurentii: Thonner. • Rhopalostylis sapida (as Areca): Hooker, Fl. Novae-Zelandiae (1853). • Trachycarpus fortunei, as Chamaerops: Bot. Mag. 86 (1860).

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 5th March 2018.’.