Including Bougainville(ac)eae J.G. Agardh, Mirabilidaceae W.R.B. Oliv., Pisoniaceae J.G. Agardh
Habit and leaf form. Trees, shrubs, and herbs, or lianas (sometimes, in Pisonia). Self supporting (mostly), or climbing (sometimes, in Pisonia). Mesophytic. Leaves alternate (sometimes), or opposite (usually, members of the pair often unequal); petiolate to sessile; non-sheathing; simple. Lamina entire; pinnately veined; cross-venulate. Leaves exstipulate.
General anatomy. Plants with `crystal sand', or without `crystal sand'.
Leaf anatomy. The mesophyll usually containing calcium oxalate crystals. The mesophyll crystals raphides. Minor leaf veins without phloem transfer cells (Bougainvillea, Oxybaphus, Pisonia).
Stem anatomy. Cork cambium present; initially deep-seated (rarely), or superficial. Nodes unilacunar. Internal phloem absent. Secondary thickening mostly anomalous; mostly via concentric cambia. `Included' phloem present. Xylem with libriform fibres; with vessels. Vessel end-walls simple. Wood partially storied (VP); parenchyma apotracheal, or paratracheal (usually very sparse). Sieve-tube plastids P-type; type III (a).
Reproductive type, pollination. Hermaphrodite (usually), or monoecious, or andromonoecious, or gynomonoecious, or polygamomonoecious (?).
Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in `inflorescences'; in cymes, in panicles, in spikes, and in umbels. The terminal inflorescence unit usually cymose. Inflorescences terminal, or axillary; with involucral bracts (frequently, these often brightly coloured), or without involucral bracts; pseudanthial (sometimes, especially when reduced to a single flower - the involucre then calyx-like, the calyx corolla-like), or not pseudanthial. Flowers bracteate (usually with several bracts); small, or medium-sized; regular; usually cyclic; tricyclic. Free hypanthium absent. Hypogynous disk often present (around G); annular.
Perianth sepaline, or petaline (but then generally regarded as representing `petaloid sepals'); (3-)5(-10); joined; 1 whorled. Calyx (i.e. the perianth) (3-)5(-10); 1 whorled; gamosepalous; tubular; regular; base persistent (and usually remaining around the fruit); valvate, or plicate in bud.
Androecium (1-)5(-30). Androecial members when numerous, maturing centrifugally; adnate (to the perianth tube, occasionally), or free of the perianth (usually); all equal, or markedly unequal; free of one another, or coherent; when coherent, 1 - adelphous (the filaments basally connate); 1 - whorled. Androecium exclusively of fertile stamens. Stamens (1-)5(-30); typically alternisepalous; inflexed in bud. Anthers dehiscing via longitudinal slits; introrse; tetrasporangiate. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or isobilateral. Anther wall initially with more than one middle layer (2); of the `basic' type. Tapetum glandular. Pollen grains aperturate; 3(-4) - aperturate, or 6-15 - aperturate; colpate (3-4), or foraminate, or rugate (6-polyrugate); usually 3-celled.
Gynoecium 1. Carpels reduced in number relative to the perianth. Gynoecium monomerous; of one carpel; superior. Carpel stylate; apically stigmatic, or with a lateral style; 1 ovuled. Placentation basal. Stigmas dry type; papillate; Group II type. Ovules ascending; non-arillate; campylotropous, or hemianatropous; unitegmic, or bitegmic; crassinucellate. Outer integument not contributing to the micropyle. Embryo-sac development usually Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; proliferating (sometimes, to a limited extent), or not proliferating; persistent. Synergids hooked. Endosperm formation nuclear. Embryogeny asterad.
Fruit non-fleshy. The fruiting carpel indehiscent; an achene, or nucular. Fruit usually enclosed in the persistent base of the perianth; 1 seeded. Seeds endospermic (the endosperm forming a cap over the radicle), or non-endospermic. Perisperm present. Seeds with starch. Embryo well differentiated (large). Cotyledons 2. Embryo chlorophyllous (2/2); curved (usually), or straight, or bent.
Seedling. Germination phanerocotylar.
Physiology, biochemistry. Not cyanogenic. Alkaloids present, or absent. Iridoids absent. Proanthocyanidins present, or absent; when present, cyanidin. Flavonols present; kaempferol, or kaempferol and quercetin (usually both, abundant). Ellagic acid absent (5 species, 4 genera). Betalains present. Saponins/sapogenins present, or absent. Plants often accumulating free oxalates. C3 and C4. C3 recorded in Bougainvillea, Mirabilis. C4 recorded in Allionia, Boerhaavia. Anatomy C4 type (Allionia, Boerhaavia, Okenia), or non-C4 type (Boerhaavia, Bougainvillea, Commicarpus, Mirabilis).
Geography, cytology. Temperate (a few), or sub-tropical to tropical. Pantropical and subtropical. X = 10, 13, 17, 29, 33 (or more).
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren's Superorder Caryophylliflorae; Caryophyllales. Cronquist's Subclass Caryophyllidae; Caryophyllales. Takhtajan's Subclass Caryophyllidae; Caryophyllanae; Caryophyllales. Species 290. Genera 33; Abronia, Acleisanthes, Allionia, Ammocodon, Andradea, Anulocaulis, Belemia, Boerhavia, Bougainvillea, Caribea, Cephalotomandra, Colignonia, Commicarpus, Cryptocarpus, Cuscatlania, Cyphomeris, Gaupira, Grajalesia, Izabalaea, Leucaster, Mirabilis, Neea, Neeopsis, Nyctaginia, Okenia, Phaeoptilum, Pisonia, Pisoniella, Ramisia, Reichenbachia, Salpianthus, Selinocarpus, Tripterocalyx.
Economic uses, etc. A few popular ornamentals, e.g. the annual Mirabilis and the subtropical vine Bougainvillea.
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