The families of flowering plants
~ Scrophulariaceae sensu lato
Habit and leaf form. Trees, or shrubs, or lianas; non-laticiferous. Self supporting, or climbing. Leaves opposite, or alternate to opposite (alternate only in Buddleja alternifolia), or whorled; when whorled, 3 per whorl; petiolate to sessile; connate (in some Buddleja species), or not connate; simple. Lamina pinnately veined; cross-venulate. Leaves stipulate, or exstipulate (the stipules often reduced, but then represented by a stipular line linking the opposing leaf bases). Stipules interpetiolar; without colleters. Lamina margins entire, or serrate, or dentate.
Leaf anatomy. Hairs present; eglandular and glandular (glandular hairs usually present, contrasting with other Loganiaceae sensu lato); multicellular. Complex hairs usually present; peltate, or stellate, or capitate. The mesophyll without sclerenchymatous idioblasts. Minor leaf veins without phloem transfer cells (Buddlejaceae).
Axial (stem, wood) anatomy. Young stems cylindrical, or tetragonal. Primary vascular tissues collateral. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. Primary medullary rays mixed wide and narrow (mostly), or narrow (uniseriate and multiseriate).
The wood ring porous to diffuse porous (climate-related). The vessel end-walls oblique; simple. The vessels without vestured pits. The axial xylem with tracheids (e.g., commonly in Buddleja), or without tracheids; with fibre tracheids (occasionally), or without fibre tracheids; with libriform fibres, or without libriform fibres; including septate fibres (in some Buddleja species, Peltanthera, Nuxia), or without septate fibres. The parenchyma paratracheal (or absent). Included phloem absent. Tile cells present, or absent.
Reproductive type, pollination. Plants hermaphrodite (mostly), or dioecious (e.g., most American Buddleja species). Female flowers with staminodes. Gynoecium of male flowers pistillodial. Plants homostylous.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in inflorescences; in cymes, or in racemes, or in heads, or in panicles. The ultimate inflorescence units cymose (usually), or racemose (Gomphostigma). Inflorescences terminal, or axillary, or terminal and axillary; variable, mostly cymose and paniculate or capitate. Flowers bracteate (lower bracts sometimes leafy, otherwise bracts scale- or sepal-like); bracteolate; regular, or somewhat irregular. The floral irregularity (when irregular) involving the perianth (the sepals often unequal). Flowers 4 merous (mostly), or 5 merous (Peltanthera only); cyclic; tetracyclic. Hypogynous disk absent (usually), or present (Gomphostigma); intrastaminal; annular.
Perianth with distinct calyx and corolla; 8, or 10; 2 whorled; isomerous. Calyx 4; 1 whorled; gamosepalous; five, rarely four blunt-lobed, or toothed; unequal but not bilabiate, or regular; persistent; non-accrescent; imbricate. Corolla 4; 1 whorled; gamopetalous; imbricate, or valvate (with both conditions represented in Buddleja); variously shaped, hairy or glabrous within; regular; white, or yellow, or white to yellow, or orange, or purple, or blue (or violet).
Androecium 5 (Peltanthera), or 4. Androecial members adnate (epipetalous); all equal; free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 4; inserted midway down the corolla tube, or in the throat of the corolla tube; isomerous with the perianth; oppositisepalous; alternating with the corolla members; filantherous, or with sessile anthers. Anthers dorsifixed (or peltate); dehiscing via longitudinal slits; introrse; bilocular (mostly, although the locules are sometimes apically confluent), or four locular (Androya); tetrasporangiate. Tapetum glandular. Pollen grains aperturate; 3–4(–5) aperturate; colporate; 2-celled.
Gynoecium 2 carpelled, or 4 carpelled (ostensibly, in a few Buddleja species). The pistil 2 celled (usually), or 4 celled (in the berries of some Buddleja species). Gynoecium syncarpous; synstylovarious, or eu-syncarpous; superior. Ovary 2 locular, or 4 locular. Locules secondarily divided by false septa (accounting for occasional 4celled gynoecia in species of Buddleja?), or without false septa. Gynoecium median; stylate. Styles 1 (persistent); attenuate from the ovary; apical. Stigmas 1 (unbranched); wet type; papillate; Group III type. Placentation axile. Ovules 20–50 per locule (or more); pendulous, or ascending; hemianatropous; unitegmic; tenuinucellate. Endothelium differentiated (observed in several species of Buddleja), or not differentiated (?). Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; persistent. Synergids pear-shaped. Hypostase present. Endosperm formation cellular. Endosperm haustoria present; chalazal and micropylar. Embryogeny onagrad.
Fruit fleshy, or non-fleshy; dehiscent, or indehiscent; a capsule (usually), or a berry, or a drupe. Capsules loculicidal. Fruit 4–50 seeded (several to many). Seeds endospermic (the endosperm fleshy or starchy); winged, or wingless. Cotyledons 2. Embryo achlorophyllous (1/3); straight.
Seedling. Germination phanerocotylar.
Physiology, phytochemistry. Sugars transported as sugar alcohols + oligosaccharides + sucrose (in 5 Buddleja species). Not cyanogenic. Alkaloids present (e.g. Androya decaryi, Nicodemia, some Buddleja species), or absent. Verbascosides detected (3 genera). Cornoside not detected. Iridoids detected; Route II type (decarb.). Saponins/sapogenins present, or absent. Proanthocyanidins absent. Flavonols present, or absent; kaempferol (trace). Ellagic acid absent (2 genera).
Geography, cytology. Temperate to tropical. Widespread, tropical and warm temperate. X=7 (Gomphostigma)/19(Buddleja, Emorya, Nuxia). Supposed basic chromosome number of family: 7 and 19. Ploidy levels recorded: 2, 4, 6, 12, 16, and 38.
Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgrens Superorder Lamiiflorae; Scrophulariales. Cronquists Subclass Asteridae; Scrophulariales. APG 3 core angiosperms; core eudicot; Superorder Asteranae; lamiid; Order Lamiales (as a synonym of Scrophulariaceae).
Species 150. Genera 9; Androya, Buddleja, Emorya, Gomphostigma, Nicodemia, Nuxia, Peltanthera.
General remarks. See Leeuwenberg 1980, under Loganiaceae. Removal of Buddleja and related genera from Loganiaceae has long seemed justified. Their nearest neighbour in terms of the present descriptions is Scrophulariaceae, from which they may differ absolutely only in the equal stamens and perhaps in two biochemical characters (cornoside and transported sugars, representing esoteric characters which may have been inadequately screened). See comments under Loganiaceae re recent cladistic and molecular studies of Loganiaceae sensu lato. For discussion of broader classificatory problems posed by Scrophulariaceae, impinging on Bignoniaceae, Buddlejaceae, Callitrichaceae, Plantaginaceae, Hippuridaceae, Lentibulariaceae, and Hydrostachydaceae, and such problem genera as Paulownia and Schlegelia, see Olmstead and Reeves (1995), who provided preliminary insights from chloroplast gene sequencing.
Illustrations. • Buddleja colvilei: Hooker’s Illustrations of Himalayan plants (1855). • Buddleja globosa: Bot. Mag. 174, 1791. • Technical details: Nuxia (Thonner). • Leaf 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: 13th March 2017. delta-intkey.com/angio’.