The families of flowering plants

L. Watson and M.J. Dallwitz

Verbenaceae Jaume St-Hil.

Including Durantaceae J.G. Agardh, Nesogenaceae W. Marais, Petreaceae J.G. Agardh, Pyrenaceae Vent., Vitices (Viticaceae) Juss.; excluding Cyclocheilaceae, Dicrastylidaceae, Phrymataceae, Stilbaceae, Symphoremataceae.

Habit and leaf form. Trees, shrubs, and herbs, or lianas (many); bearing essential oils. ‘Normal’ plants and switch-plants; sometimes with the principal photosynthesizing function transferred to stems. Leaves well developed, or much reduced (occasionally). Self supporting, or climbing; the climbers stem twiners, or scrambling; Clerodendrum twining clockwise. Mesophytic and xerophytic. Leaves opposite (usually), or whorled, or alternate (rarely); petiolate to sessile; foetid, or without marked odour, or aromatic; simple, or compound; epulvinate; when compound, ternate to pinnate (e.g.Vitex), or palmate. Lamina dissected, or entire; when dissected, pinnatifid; pinnately veined; cross-venulate. Leaves exstipulate; leaf development not ‘graminaceous’. Domatia occurring in the family (recorded in 4 genera); manifested as pits, or pockets, or hair tufts.

Leaf anatomy. The leaf lamina dorsiventral, or bifacial (then isobilateral). Stomata mainly confined to one surface (abaxial), or on both surfaces; anomocytic (mostly), or diacytic (some species of Lippia, Clerodendrum and Stachytarpheta), or paracytic (rarely, but observed in Gmelina hystrix). Hairs present (with numerous kinds represented in the family); eglandular and glandular. Cystoliths present (rather frequently, especially associated with hair bases, and/or hair tips may also be calcified). The mesophyll with sclerenchymatous idioblasts, or without sclerenchymatous idioblasts; containing crystals. The crystals mostly solitary-prismatic (large and small needles and prisms being widely recorded, but druses go unmentioned). Minor leaf veins without phloem transfer cells (6 genera).

Axial (stem, wood) anatomy. Young stems tetragonal (often), or cylindrical, or oval in section. Cork cambium present; initially deep-seated (rarely, e.g., in Lantana and Lippia), or initially superficial (usually). Nodes unilacunar (1–several traces). Primary vascular tissues in a cylinder, without separate bundles; collateral. Internal phloem absent. Medullary bundles present (e.g., in in Teijsmanniodendron and Tectona), or absent. Secondary thickening developing from a conventional cambial ring. Primary medullary rays wide, or mixed wide and narrow (?), or narrow.

The wood ring porous to diffuse porous. The vessels generally small, or medium (commonly of two distinct sizes in climbers). The vessel end-walls nearly always exclusively simple (with rare reticulate or scalariform plates recorded only in a few species of Vitex). The vessels without vestured pits; with spiral thickening, or without spiral thickening. The axial xylem without fibre tracheids; with libriform fibres; including septate fibres (typically), or without septate fibres (rarely). The fibres without spiral thickening. The parenchyma typically exclusively paratracheal (rarely more or less apotracheal or absent). The secondary phloem not stratified. ‘Included’ phloem absent. The wood storied, or partially storied, or not storied. Tyloses present, or absent.

Reproductive type, pollination. Plants hermaphrodite (usually). Pollination entomophilous.

Inflorescence, floral, fruit and seed morphology. Flowers usually aggregated in ‘inflorescences’; in cymes, in racemes, in spikes, in heads, and in verticils. The ultimate inflorescence units cymose, or racemose. Inflorescences terminal, or axillary; with involucral bracts (often, these commonly coloured), or without involucral bracts; pseudanthial (sometimes), or not pseudanthial. Flowers bracteate; small to medium-sized; very irregular (usually), or regular to somewhat irregular. The floral irregularity involving the perianth and involving the androecium. Flowers (4–)5(–8) merous; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk present, or absent; when present, annular.

Perianth with distinct calyx and corolla; (7–)10(–16); 2 whorled; isomerous, or anisomerous. Calyx (2–)5(–8); 1 whorled; gamosepalous; entire, or lobulate, or blunt-lobed, or toothed. Calyx lobes markedly shorter than the tube to markedly longer than the tube. Calyx unequal but not bilabiate, or regular, or bilabiate (e.g. Phyla); persistent; when K5, with the median member posterior. Corolla (4–)5(–8); 1 whorled; gamopetalous. Corolla lobes markedly shorter than the tube, or about the same length as the tube. Corolla imbricate; tubular (usually), or campanulate (rarely); unequal but not bilabiate, or bilabiate, or regular (rarely).

Androecium (2–)4(–5). Androecial members adnate (to the corolla tube); markedly unequal (usually), or all equal (rarely); free of one another; 1 whorled. Androecium exclusively of fertile stamens, or including staminodes. Staminodes when present, 1–3; in the same series as the fertile stamens; representing the posterior median member, or the posterior median member and the posterior-lateral pair; non-petaloid. Fertile stamens representing the posterior-lateral pair and the anterior-lateral pair (usually), or the anterior-lateral pair, or the posterior median member, the posterior-lateral pair, and the anterior-lateral pair. Stamens (2–)4(–5) (the posterior member usually, and sometimes the three upper members, reduced or missing); inserted near the base of the corolla tube, or midway down the corolla tube, or in the throat of the corolla tube; usually didynamous; reduced in number relative to the adjacent perianth (usually), or isomerous with the perianth; oppositisepalous; alternating with the corolla members. Anthers connivent (in pairs), or separate from one another; dorsifixed; dehiscing via longitudinal slits; introrse; tetrasporangiate. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or isobilateral, or decussate. Anther wall initially with one middle layer; of the ‘dicot’ type, or of the ‘monocot’ type. Tapetum glandular. Pollen grains aperturate; (2–)3(–5) aperturate, or 6 aperturate; colpate, or colporate, or rugate; 2-celled (in 9 genera), or 3-celled (in 3 genera).

Gynoecium 2 carpelled (usually), or 4 carpelled, or 5 carpelled. Carpels reduced in number relative to the perianth (usually), or isomerous with the perianth. The pistil 2–10 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary 2 locular, or 4–5 locular (but the original locules (usually two) early becoming divided by a ‘false septum’ in each — cf. Labiatae). Locules secondarily divided by ‘false septa’ (usually), or without ‘false septa’. Gynoecium usually median; stylate. Styles 1; attenuate from the ovary, or from a depression at the top of the ovary (but the ovary apex no more than slightly lobed); apical, or lateral. Stigmas 1; 1 lobed, or 2 lobed; wet type; papillate; Group III type and Group IV type. Placentation basal to axile, or axile. Ovules 2 per locule (i.e. in the true locules, one each in the locelli); pendulous, or horizontal, or ascending (but always with the micropyle directed downwards); non-arillate; orthotropous, or hemianatropous, or anatropous; unitegmic; tenuinucellate. Endothelium not differentiated. Embryo-sac development Polygonum-type. Antipodal cells formed; 3; not proliferating; ephemeral (usually), or persistent. Synergids usually hooked (and beaked). Endosperm formation cellular. Endosperm haustoria present; chalazal and micropylar (the latter usually the less well developed). Embryogeny onagrad.

Fruit fleshy (usually), or non-fleshy; dehiscent (rarely), or indehiscent (mostly), or a schizocarp. Mericarps when schizocarpic, 4 (usually), or 8–10, or 2 (?); comprising nutlets, or comprising drupelets. Fruit when non-schizocarpic a drupe (usually), or a capsule. Capsules valvular (with 2–4 valves). The drupes with separable pyrenes, or with one stone. Seeds non-endospermic (except Nesogenes). Cotyledons 2 (expanded, flat). Embryo achlorophyllous (5/5); straight.

Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, phytochemistry. C3. C3 physiology recorded directly in Verbena. Anatomy non-C4 type (Cleodendron, Lantana, Premna, Stachytarpheta, Verbena, Vitex). Sugars transported as oligosaccharides + sucrose (the 8 genera screened all particularly rich in oligosaccharides). Cyanogenic, or not cyanogenic. Alkaloids present, or absent. Anthraquinones detected (Tectona); derived from shikimic acid. Verbascosides detected (5 genera, excluding Phyla). Cornoside detected (Phyla). Iridoids detected; ‘Route I’ type (normal, in some Verbena), or ‘Route II’ type (mostly, normal and decarb.). Saponins/sapogenins present, or absent. Proanthocyanidins absent. Flavonols absent. Ellagic acid absent (5 genera, 6 species). Ursolic acid present. Aluminium accumulation not found.

Geography, cytology. Temperate, sub-tropical to tropical (mainly). Very widespread temperate and tropical, but absent from central and Northern Eurasia. X = 5–12.

Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Lamiiflorae; Lamiales. Cronquist’s Subclass Asteridae; Lamiales. APG III core angiosperms; core eudicot; Superorder Asteranae; lamiid. APG IV Order Lamiales.

Species about 3000. Genera about 90; Acantholippia, Adelosa, Aegiphila, Aloysia, Amasonia, Archboldia, Asepalum, Baillonia, Bouchea, Burroughsia, Callicarpa, Caryopteris, Casselia, Chascanum, Citharexylum, Clerodendrum, Coelocarpum, Coelocarpum, Cornutea, Dimetra, Diostea, Dipyrena, Duranta, Faradaya, Garrettia, Geunsia, Glandularia, Glossocarya, Gmelina, Hierobotana, Holmskioldia, Hosea, Huxleya, Hymenopyramis, Junellia, Karomia, Lampaya, Lantana, Lippia, Monochilus, Nashia, Neorapinia, Neosparton, Nesogenes, Oncinocalyx, Oxera, Paravitex, Parodianthus, Peronema, Petitia, Petraeovitex, Petraea, Phyla, Pitraea, Premna, Priva, Pseudocarpidium, Recordia, Rehdera, Rhaphithamnus, Schnabelia (or Labiatae), Stachytarpheta, Stylodon, Surfacea, Tamonea, Tectona, Teijsmanniodendron, Tetraclea (or Labiatae), Teucridium, Tsoongia, Ubochea, Urbania, Verbena, Verbenoxylum, Vitex, Viticipremna, Xeroaloysia, Xolocotzia.

General remarks. For comment on the taxonomically unsatisfactory circumscription of Verbenaceae employed here, see remarks under Labiatae.

Economic uses, etc. Timber from Tectona grandis (teak); some notable ornamentals, e.g. Clerodendrum, Callicarpa, Vitex, Lantana, Verbena; also some noxious, notoriously photosensitizing weeds (Lantana).

Illustrations. • Le Maout and Decaisne: Verbena. • Vitex lutens, as V. littoralis: Hook. Ic. Pl. 5 (1842–3). • Le Maout and Decaisne: Vitex. • Callicarpa longifolia: Lindley. • Le Maout and Decaisne: Clerodendrum. • Stachytarpheta bicolor: Bot. Mag. 91 (1865). • Clerodendrum fragrans: as Clerodendron, Bot. Reg. XXIV, 41 (1838). • Clerodendrum splendens: as Clerodendron, Bot. Reg. 7, 1842. • Clerodendrum, Gmelina. • Premna mooiensis, as Vitex: Hook. Ic. Pl. 28 (1901). • Teucridium parvifolium: Hooker, Fl. Novae-Zelandiae (1853). • Verbena, Lippia, Stachytarpheta (Chittenden). • Foliar hairs of Lippia and Verbena, with those of assorted Labiatae and Dicrastylidaceae (El-Gazzar). • Foliar hairs of Clerodendron and Petraea, with Pityrodia (Dicrastylidaceae) and Avicennia (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: 5th March 2018.’.