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The families of flowering plants

L. Watson and M. J. Dallwitz

Annonaceae Juss.

Including Hornschuchiaceae J.G. Agardh, Monodoraceae J.G. Agardh

Habit and leaf form. Trees, or shrubs, or lianas; bearing essential oils; resinous, or not resinous. Self supporting, or climbing; when climbing, scrambling, or stem twiners, or petiole twiners. Leaves evergreen; alternate; distichous; non-sheathing; gland-dotted, or not gland-dotted; aromatic, or without marked odour; simple. Lamina entire; pinnately veined; cross-venulate. Leaves exstipulate. Lamina margins entire. Domatia occurring in the family (recorded in 3 genera); manifested as pockets (usually), or hair tufts (in 1/12 species).

Leaf anatomy. The leaf lamina dorsiventral. Abaxial epidermis papillose, or not papillose. Stomata paracytic. Adaxial hypodermis absent. Lamina with secretory cavities, or without secretory cavities. Secretory cavities containing oil, or containing mucilage, or containing resin. The mesophyll usually with spherical etherial oil cells (?); containing mucilage cells, or not containing mucilage cells; with sclerenchymatous idioblasts, or without sclerenchymatous idioblasts. Main veins vertically transcurrent. Minor leaf veins without phloem transfer cells (Annona).

Axial (stem, wood) anatomy. Young stems with solid internodes. Pith with diaphragms (commonly, comprising stone cells), or without diaphragms; heterogeneous (with groups of stone cells even in the absence of complete septa). Secretory cavities present; with resin. Cork cambium present; initially superficial. Nodes unilacunar (with three traces), or bilacunar (according to Lammers et al 1986). Primary vascular tissues in a cylinder, without separate bundles, or comprising a ring of bundles; collateral. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring. Primary medullary rays wide, or mixed wide and narrow, or narrow. The axial xylem with vessels (but these rather few).

The wood variously ring porous to diffuse porous. The vessels very small; solitary, radially paired, in radial multiples, and clustered. The vessel end-walls horizontal; simple. The vessels without vestured pits; with spiral thickening (rarely, reported in Asimena), or without spiral thickening. The axial xylem with fibre tracheids. The fibres without spiral thickening. The parenchyma apotracheal. The secondary phloem stratified into hard (fibrous) and soft (parenchymatous) zones. ‘Included’ phloem absent. The wood commonly partially storied (VP). Tyloses absent (?).

Reproductive type, pollination. Plants hermaphrodite, or monoecious (rarely), or dioecious.

Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’. The ultimate inflorescence units when flowers aggregated, racemose. Flowers regular; cyclic, or partially acyclic. Sometimes the androecium acyclic (spiralled). Free hypanthium absent. Hypogynous disk present.

Perianth with distinct calyx and corolla (usually P3+3+3, with the outer one or two whorls sepaloid); usually 9; usually 3 whorled; isomerous. Calyx 3, or 6; usually 2 whorled; polysepalous; valvate, or open in bud. Corolla 3; 1–2 whorled; polypetalous; imbricate, or valvate.

Androecium usually 25–100 (i.e. ‘many’). Androecial members when many, maturing centripetally; free of the perianth; all equal; free of one another; rarely 3 whorled, or 6 whorled (otherwise spiralled). Androecium exclusively of fertile stamens (usually), or including staminodes (e.g. in Uvaria spp., where the outer members may be imperfect). Staminodes when present, external to the fertile stamens; non-petaloid. Stamens 25–100 (‘many’). Anthers adnate; non-versatile; dehiscing via longitudinal slits, or dehiscing by longitudinal valves; extrorse; tetrasporangiate; appendaged (via expansion of the connective). Endothecium developing fibrous thickenings. Microsporogenesis successive, or simultaneous. The initial microspore tetrads tetrahedral, or isobilateral, or decussate. Anther wall initially with more than one middle layer; of the ‘dicot’ type. Tapetum glandular. Pollen monosiphonous; shed in aggregates (5 genera), or shed as single grains; when aggregated, in tetrads (usually), or in polyads (octads in Trigynaea). Pollen grains aperturate (usually), or nonaperturate; 1 aperturate (mostly), or 2 aperturate; (mono) sulcate (mostly, occasionally with two parallel furrows at the equator), or ulcerate (rarely); 2-celled.

Gynoecium usually 10–100 carpelled (or more — i.e. ‘many’). The pistil when syncarpous, 1 celled, or 2–15 celled (or more?). Gynoecium apocarpous (usually), or syncarpous (rarely); eu-apocarpous (the carpels spiralled or cyclic), or synstylovarious to eu-syncarpous (e.g. Monodora); superior. Carpel 1–10 ovuled. Placentation of free carpels basal. Ovary when syncarpous 1 locular, or 2–15 locular (or more — i.e. ‘multilocular’). Stigmas wet type; papillate; Group III type. Placentation when unilocular parietal, or basal; when plurilocular basal. Ovules in the single cavity when unilocular, 1–50; 10–50 per locule (i.e. ‘many’); ascending; apotropous; with ventral raphe; arillate, or non-arillate; anatropous; bitegmic; crassinucellate. Outer integument not contributing to the micropyle. Endothelium not differentiated. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization, or fusing only after one has been fertilized (?). Antipodal cells formed; 3; not proliferating; ephemeral. Synergids pear-shaped. Hypostase present, or absent. Endosperm formation cellular. Embryogeny onagrad.

Fruit fleshy; an aggregate (commonly an aggregate of berries). The fruiting carpels coalescing into a secondary syncarp, or not coalescing. The fruiting carpel indehiscent; baccate. Seeds endospermic. Endosperm ruminate (by contrast with Magnoliaceae); oily. Seeds with amyloid. Embryo achlorophyllous (4/5).

Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, phytochemistry. Anatomy non-C4 type (Annona). Sugars transported as sucrose (usually), or as oligosaccharides + sucrose (Annona squamosa). Cyanogenic, or not cyanogenic. Alkaloids present (commonly), or absent. Arbutin absent. Iridoids not detected. Proanthocyanidins present, or absent; when present, cyanidin. Flavonols present, or absent; when present, quercetin. Ellagic acid absent (2 genera, 3 species). Sieve-tube plastids P-type; type I (a).

Geography, cytology. Sub-tropical and tropical. Widespread, especially Old World. X = 7, 8, 9.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Magnoliiflorae; Annonales. Cronquist’s Subclass Magnoliidae; Magnoliales. APG 3 core angiosperms; Superorder Magnolianae; Order Magnoliales.

Species 1200. Genera 126; Afroguatteria, Alphonsea, Ambavia, Anaxagorea, Ancana, Annickia, Annona, Anomianthus, Anonidium, Artabotrys, Asimina, Asteranthe, Balonga, Bocagea, Bocageopsis, Boutiquea, Cananga, Cardiopetalum, Chieniodendron, Cleistochlamys, Cleistopholis, Cremastosperma, Cyathocalyx, Cyathostemma, Cymbopetalum, Dasoclema, Dasymaschalon, Deeringothamnus, Dendrokingstonia, Dennettia, Desmopsis, Desmos, Diclinanona, Dielsiothamnus, Disepalum, Duckeanthus, Duguetia, Ellipeia, Ellipeiopsis, Enicosanthum, Ephedranthus, Exellia, Fissistigma, Fitzalania, Friesodielsia, Froesiodendron, Fusaea, Gilbertiella, Goniothalamus, Greenwayodendron, Guamia, Guatteria, Guatteriella, Guatteriopsis, Haplostichanthus, Heteropetalum, Hexalobus, Hornschuchia, Isolona, Letestudoxa, Lettowianthus, Malmea, Marsypopetalum, Meiocarpidium, Meiogyne, Melodorum, Mezzettia, Mezzettiopsis, Miliusa, Mischogyne, Mitrella, Mitrephora, Mkilua, Monanthotaxis, Monocarpia, Monocyclanthus, Monodora, Neostenanthera, Neo-uvaria, Oncodostigma, Onychopetalum, Ophrypetalum, Oreomitra,Orophea, Oxandra, Pachypodanthium, Papualthia, Petalolophus, Phaeanthus, Phoenicanthus, Piptostigma, Platymitra, Polyalthia, Polyaulax, Polyceratocarpus, Popowia, Porcelia, Pseudartabotrys, Pseudephedranthus, Pseudoxandra, Pseuduvaria, Pyramidanthe, Raimondia, Reedrollinsia, Richella, Rollinia, Ruizodendron, Sageraea, Sapranthus, Schefferomitra, Sphaerocoryne, Stelechocarpus, Stenanona, Tetrameranthus, Tetrapetalum, Toussaintia, Tridimeris, Trigynaea, Trivalvaria, Unonopsis, Uvaria, Uvariastrum, Uvariodendron, Uvariopsis, Woodiellantha, Xylopia.

Economic uses, etc. Important commercial fruits from Annona spp. (atemoya, cherimoya, custard-apple, ilarma, sugar-apple, sweet sop, sour sop), Artabotrys.

Illustrations. • Technical details: Annona (Thonner). • Technical details: Annona (Lindley). • Technical details: Asimena. • Annona glabra: as A. laurifolia, Bot. Reg. 1328, 1830. • Uvaria narum: R. Wight (1840). • Leaf epidermis of Duguetia and Mitrephora, with crystals and hairs (Solereder, 1908).

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: 19th October 2016.’.