Excluding Nelsoniaceae, Mendonciaceae, Thunbergiaceae
Habit and leaf form. Shrubs, or herbs, or trees (rarely). `Normal' plants, or switch-plants (rarely). Leaves well developed (usually), or much reduced. The herbs annual to perennial; with a basal aggregation of leaves, or with neither basal nor terminal aggregations of leaves. Self supporting (mostly, by contrast with Thunbergiaceae), or epiphytic, or climbing (sometimes, e.g Adhatoda); when climbing, stem twiners, or root climbers (?), or scrambling (?). Trees leptocaul. Hydrophytic, or helophytic (including a few mangroves), or mesophytic (many in damp places in tropical forests), or xerophytic. Leaves opposite (decussate); flat; gland-dotted, or not gland-dotted; simple. Lamina dissected, or entire; pinnately veined; cross-venulate. Leaves exstipulate. Lamina margins entire, or crenate, or serrate, or dentate; flat, or revolute, or involute. Domatia recorded (from 3 genera); represented by hair tufts.
Leaf anatomy. Abaxial epidermis papillose, or not papillose. Mucilaginous epidermis absent. Stomata mainly confined to one surface, or on both surfaces; diacytic. Hairs present; eglandular, or glandular; unicellular, or multicellular. Unicellular hairs branched, or unbranched. Multicellular hairs branched, or unbranched.
Adaxial hypodermis present (rarely), or absent. Lamina dorsiventral, or isobilateral (rarely); without secretory cavities. Cystoliths very commonly present (showing as streaks in the lamina). The mesophyll containing calcium oxalate crystals, or without calcium oxalate crystals. The mesophyll crystals raphides (rarely), or solitary-prismatic. Main veins embedded. Minor leaf veins with phloem transfer cells (Ruellia), or without phloem transfer cells (9 genera).
Stem anatomy. Cork cambium present; initially deep-seated (sometimes), or superficial. Nodes unilacunar. Primary vascular tissue bicollateral, or centrifugal. Cortical bundles absent. Medullary bundles present (rarely), or absent. Internal phloem present, or absent. Secondary thickening developing from a conventional cambial ring. `Included' phloem absent. Xylem with fibre tracheids; with libriform fibres; with vessels. Vessel end-walls simple. Vessels without vestured pits. Primary medullary rays narrow. Wood diffuse porous; not storied; parenchyma paratracheal.
Reproductive type, pollination. Hermaphrodite. Entomophilous. Pollination mechanism conspicuously specialized (commonly exhibiting a loose-pollen mechanism, cf. Scophulariaceae etc. - e.g. the large bee-flowers of Acanthus), or unspecialized.
Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in `inflorescences'; in cymes, in racemes, and in verticils. The terminal inflorescence unit cymose (in about 75%), or racemose. Inflorescences commonly dichasial cymes, becoming monochasial in the ultimate branches, and frequently condensed in the leaf axils, cf. Labiatae; pseudanthial, or not pseudanthial. Flowers bracteate; bracteolate (the bracts and bracteoles often showy); somewhat irregular to very irregular (in about 75% of the genera), or regular; usually more or less zygomorphic. The floral asymmetry involving the perianth and involving the androecium. Flowers 4 merous, or 5 merous; tetracyclic. Free hypanthium absent. Hypogynous disk present.
Perianth with distinct calyx and corolla; (6-)8, or 10; 2 whorled; isomerous, or anisomerous. Calyx (3-)4, or 5; 1 whorled; gamosepalous; variously entire, or lobulate, or lobed. Degree of gamosepaly, maximum length joined/total calyx length 0.5-0.9. Calyx imbricate, or valvate, or contorted, or open in bud; when K5, with the odd member posterior. Corolla 4, or 5; 1 whorled; gamopetalous (at least basally). Degree of gamopetaly 0.5-0.75. Corolla imbricate, or contorted; bilabiate, or unequal but not bilabiate (the upper lip sometimes suppressed).
Androecium 2, or 4(-5). Androecial members adnate (usually exserted, the filaments inserted on the corolla tube); all equal, or markedly unequal; free of one another, or coherent; when coherent, 2 - adelphous (partially connate, in pairs); 1 - whorled. Androecium exclusively of fertile stamens, or including staminodes. Staminodes when present, 1-3. Stamens 4(-5), or 2; didynamous (in about 75% of the species), or not didynamous, not tetradynamous; reduced in number relative to the adjacent perianth, or isomerous with the perianth; oppositisepalous. Anthers separate from one another, or connivent; dorsifixed (often with one lobe reduced or abortive); dehiscing via longitudinal slits; unilocular to bilocular; tetrasporangiate; appendaged (the connective often long, cf. Salvia), or unappendaged. Endothecium developing fibrous thickenings (usually), or not developing fibrous thickenings (e.g. Barleria, Justicia, Ruellia). Anther epidermis persistent. Microsporogenesis simultaneous. Anther wall initially with one middle layer; of the `dicot' type. Tapetum glandular. Pollen monosiphonous; shed as single grains. Pollen grains aperturate, or nonaperturate (rarely); 2-8 - aperturate; colpate, or porate, or colporate, or foraminate; 2-celled, or 3-celled.
Gynoecium 2; syncarpous; synstylovarious to eu-syncarpous; superior. Ovary 2 locular. Gynoecium median. Ovary sessile. Styles 1; attenuate from the ovary; apical; much longer than the mature ovary (usually). Stigmas 2 (the posterior often smaller); dry type; non-papillate; Group II type. Placentation axile. Ovules 2-50 per locule (i.e., 2 to many); non-arillate, or arillate (occasionally exhibiting what may be a funicular aril - cf. Corner); anatropous to campylotropous; unitegmic. Endothelium not differentiated. Embryo-sac development Polygonum-type. Polar nuclei fusing only after one has been fertilized. Antipodal cells formed; when not proliferated, 3; proliferating (occasionally, to 4-18 cells), or not proliferating; ephemeral (usually), or persistent. Synergids pear-shaped. Endosperm formation cellular. Endosperm haustoria present; chalazal and micropylar (`terminal', the latter usually the more aggressive). Embryogeny onagrad, or solanad.
Fruit non-fleshy; dehiscent; a capsule. Capsules loculicidal. Fruit elastically dehiscent. Dispersal unit the seed. Seeds non-endospermic; borne on minute, hook-like outgrowths (`retinacula'); conspicuously hairy, or not conspicuously hairy; with amyloid, or without amyloid. Embryo well differentiated. Cotyledons 2. Embryo achlorophyllous (3/3); large. Testa sometimes covered with hairs or scales which become sticky or slimy when wet. Polyembryony recorded (and common).
Seedling. Germination phanerocotylar.
Physiology, biochemistry. Cyanogenic (rarely), or not cyanogenic. Alkaloids present, or absent. Iridoids recorded; seco-compounds. Proanthocyanidins absent. Flavonols present (rarely), or absent; when present, kaempferol and quercetin (traces). Ellagic acid absent (8 species, 7 genera). Saponins/sapogenins present (rarely), or absent. Aluminium accumulation not found. C3, or C4. C3 recorded in Adhatoda, Barleria, Beleropone, Fittonia, Graptophyllum, Justicia, Lepidogathis. C4 recorded in Blepharis. Anatomy non-C4 type (Acanthopale, Acanthus, Adhatoda, Asystasia, Barleria, Crabbea, Crossandra, Dyschoriste, Echolium, Eremomastax, Hypoestes, Isoglossa, Justicia, Lepidagathis, Monechma, Monothecium, Peristrophe, Phaulopsis, Rhinacanthus, Ruellia, Ruttya, Whitfieldia), or C4 type (Blepharis).
Peculiar feature. The seeds on elongated, indurated, hook-shaped funicles (`retinacula').
Geography, cytology. Holarctic, Paleotropical, Neotropical, Cape, and Australian. Temperate to tropical (mainly tropical). Centred on Indomalaysia, Africa, Brazil and central America. X = 7-21.
Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren's Superorder Lamiiflorae; Scrophulariales. Cronquist's Subclass Asteridae; Scrophulariales. Takhtajan's Subclass Asteridae; Lamianae; Scrophulariales. Species 2500. Genera about 250; Acanthopale, Acanthopsis, Acanthostelma, Acanthura, Acanthus, Achyrocalyx, Adhatoda, Afrofittonia, Ambongia, Ancistranthus, Ancistrostylis, Andrographis, Angkalanthus, Anisacanthus, Anisosepalum, Anisostachya, Anisotes, Apassalus, Aphanosperma, Aphelandra, Aphelandrella, Ascotheca, Asystasia, Asystasiella, Ballochia, Barleria, Barleriola, Beloperone, Benoicanthus, Blechum, Blepharis, Borneacanthus, Boutonia, Brachystephanus, Bravaisia, Brillantasia, Buceragenia, Calacanthus, Calophanoides, Calycacanthus, Camarotea, Carlowrightia, Celerina, Cephalacanthus, Chaetacanthus, Chalarothyrsus, Chameranthemum, Championella, Chileranthemum, Chlamydocardia, Chlamydostachya, Chroesthes, Clinacanthus, Clistax, Codonacanthus, Conocalyx, Corymbostachys, Cosmianthemum, Crabbea, Crossandra, Crossandrella, Cyclacanthus, Cylindrosolenium, Cyphacanthus, Dactylostegium, Danguya, Dasytropis, Dichazothece, Dicladanthera, Dicliptera, Didyplosandra, Dipteracanthus, Dischistocalyx, Dolichostachys, Drejera, Drejerella, Duosperma, Dyschoriste, Ecbolium, Echinacanthus, Elytraria, Encephalosphaera, Epiclastopelma, Eranthemum, Eremomastax, Eusiphon, Filetia, Fittonia, Forcipella, Forsythiopsis, Gastranthus, Geissomeria, Glossocheilus, Golaea, Graphandra, Graptophyllum, Gymnophragma, Gymnostachyum, Gynocraterium, Gypsacanthus, Habracanthus, Hansteinia, Haplanthodes, Harpochilus, Henrya, Herpetacanthus, Heteradelphia, Holographis, Hoverdenia, Hulemacanthus, Hygrophila, Hypoestes, Indoneesiella, Ionacanthus, Isoglossa, Isotheca, Jadunia, Juruasia, Justicia, Kalbreyeracanthus, Kalbreyeriella, Kosmosiphon, Kudoacanthus, Lankesteria, Lasiocladus, Leandriella, Lepidagathis, Leptostachya, Liberatia, Linariantha, Lindauea, Lophostachys, Louteridium, Lychniothyrsus, Mackaya, Marcania, Megalochlamys, Megalostoma, Megaskepasma, Melittacanthus, Mellera, Metarungia, Mexacanthus, Mimulopsis, Mirandea, Monothecium, Morsacanthus, Neohallia, Neriacanthus, Neuracanthus, Odontonema, Odontonemella, Ophiorrhiziphyllon, Oplonia, Oreacanthus, Orophochilus, Pachystachys, Pelecostemon, Pentstemonacanthus, Perenideboles, Pericalypta, Periestes, Peristrophe, Petalidium, Phaulopsis, Phialacanthus, Phidiasia, Phlogacanthus, Physacanthus, Podorungia, Poikilacanthus, Polylychnis, Pranceacanthus, Pseuderanthemum, Pseudodicliptera, Pseudoruellia, Psilanthele, Ptyssiglottis, Pulchranthus, Pupilla, Razisea, Rhinacanthus, Rhombochlamys, Ritonia, Rostellularia, Ruellia, Ruelliopsis, Rungia, Ruspolia, Ruttya, Salpinctium, Salpixantha, Samuelssonia, Sanchezia, Santapaua, Sapphoa, Satanocrater, Sautiera, Schaueria, Schwabea, Sciaphyllum, Sclerochiton, Sebastiano-schaueria, Siphonoglossa, Spathacanthus, Sphacanthus, Sphinctacanthus, Spirostigma, Standleyacanthus, Steirosanchezia, Stenandriopsis, Stenandrium, Stenostephanus, Streblacanthus, Streptosiphon, Strobilanthes, Strobilanthopsis, Styasasia, Suessenguthia, Synchoriste, Taeniandra, Tarphochlamys, Teliostachya, Tessmanniacanthus, Tetramerium, Theileamea, Thomandersia, Thyanostigma, Tremacanthus, Triaenanthus, Trichanthera, Trichocalyx, Ulleria, Vavara, Vindasia, Warpuria, Xantheranthemum, Xerothamnella, Yeatesia, Zygoruellia.
Economic uses, etc. A few cultivated ornamentals: Acanthus, Aphelandra, Fittonia, Beloperone, Justicia, etc.
Illustrations. acant605.gif acant606.gif acant503.gif
Additional, to be intercalated. The twiners twining clockwise.
