Scientific description of the Family Palmae

Palmae Juss.

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

Including: Borassaceae O.F. Cook, Chamaedoreaceae O.F. Cook, Geonomaceae O.F. Cook, Iriarteaceae O.F. Cook, Malortieaceae O.F. Cook, Manicariaceae O.F. Cook, Nypaceae (Engl. & Gilg) Tralau, Nipaceae Chadef. & Emberg., Phoenicaceae Schultz-Schultzenst., Phytelephant(ac)eae Mart., Phytelephasi(ac)eae Chadef. & Emberg., PPseudophoenicaceae O.F. Cook, Sabalaceae(`-ineae') Schultz-Schultzenst., Sagoaceae(`-goineae') Schultz-Schultzenst., Synechanthaceae O.F. Cook

Habit and leaf form. Trees, or `arborescent', or shrubs, or lianas (rarely diminutive undershrubs). 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 evergreen; small to very large; alternate; spiral; 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; without a persistent basal meristem (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). Accumulated starch other than exclusively `pteridophyte type'.

Leaf anatomy. Epidermis without differentiation into `long' and `short' cells; containing silica bodies, or without silica bodies. Stomata mostly tetracytic. The mesophyll contains calcium oxalate crystals. The mesophyll crystals raphides (usually), or solitary-prismatic (or as crystal sand). Minor leaf veins without phloem transfer cells (Chamaerops). Vessels present; end-walls scalariform.

Stem anatomy. Secondary thickening absent (or slight, and then not cambial but from divisions in the ground parenchyma). Xylem with vessels. Vessel end-walls mostly oblique; scalariform, or simple, or scalariform and simple. Sieve-tube plastids P-type; type II.

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

Reproductive type, pollination. 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). Anemophilous, or entomophilous (more often).

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in `inflorescences'; in panicles (usually, and usually complex). The terminal inflorescence unit 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 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.

Gynoecium 3(-10). Carpels isomerous with the perianth, or increased in number relative to the perianth. 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; multiple (occasionally), or not multiple. 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); 1 seeded. Seeds endospermic. Endosperm ruminate, or not ruminate; oily (usually), or not oily. Seeds usually without starch. Cotyledons 1. Embryo achlorophyllous (9/9).

Physiology, biochemistry. Not cyanogenic. Alkaloids present (occasionally, pyrimidine), or absent. Proanthocyanidins present (usually, abundantly), or absent (e.g. Livistona); cyanidin. Flavonols present (rarely), or absent; when present, kaempferol and quercetin (also tricin, luteolin, etc.). Saponins/sapogenins present (occasionally), or absent. C3. C3 recorded in Borassus, Cocos, Phoenix. Anatomy non-C4 type (Archantophoenix, Areca, Arenga, Borassus, Calamus, Caryota, Chrysalidocarpus [now Dypsis], Cocos, Cyrtostachys, Elaeis, Eugeissonia, Iguanura, Licuala, Livistona, Nypa, Oncosperma, Phoenix, Pinanga, Ptychosperma, Roystonea).

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

Taxonomy. Subclass Monocotyledonae. Superorder Areciflorae; Arecales. Species 2500. Genera 205; Areca, Borassus, Calamus, Caryota, Chamaedorea, Cocos, Daemonorops, Elaeis, Geonoma, Licuala, Livistona, Metroxylon, Nypa, Phoenix, Phytelephas, etc.

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

Text courtesy and copyright © 1998, L. Watson & Michael Dallwitz; reprinted here with permission. Full citation: Watson, L., and Dallwitz, M. J. (1992 onwards). `The Families of Flowering Plants: Descriptions, Illustrations, Identification, and Information Retrieval.' Version: 8th May 1998. URL: http://www.biodiversity.uno.edu/delta/angio/www/palmae.htm.

Go to http://www.biodiversity.uno.edu/delta/angio/www/chars.htm for an explanation of the characters used in this description.

Go to http://www.biodiversity.uno.edu/delta/angio/www/implicit.htm for a list and explanation of the implicit attributes used in the description.

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