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The families of flowering plants

L. Watson and M.J. Dallwitz

Ehretiaceae Lindl.

~ Boraginaceae.

Including Cordiaceae R.Br., Sebestanae (Sebestenaceae) Vent.

Habit and leaf form. Trees, or shrubs, or herbs (rarely). Plants green and photosynthesizing. Mesophytic. Leaves alternate (rarely sub-opposite); spiral; non-sheathing; simple. Lamina dissected (sometimes, in Cordia), or entire (usually); pinnately veined; cross-venulate. Leaves exstipulate. Lamina margins entire, or crenate, or serrate, or dentate. Leaf development not ‘graminaceous’. Domatia occurring in the family (found in Cordia and Ehretia); manifested as pits, or hair tufts.

General anatomy. Plants with ‘crystal sand’, or without ‘crystal sand’.

Leaf anatomy. The leaf lamina dorsiventral, or bifacial, or centric. Stomata present; anomocytic, or anisocytic. Adaxial hypodermis absent. Cystoliths present (at least sometimes, in Cordia), or absent. The mesophyll with sclerenchymatous idioblasts, or without sclerenchymatous idioblasts; containing crystals. The crystals druses, or solitary-prismatic (and sometimes with crystal-sand). Minor leaf veins without phloem transfer cells (Ehretia).

Axial (stem, wood) anatomy. Cork cambium present; initially superficial. Primary vascular tissues in a cylinder, without separate bundles; collateral. Secondary thickening developing from a conventional cambial ring. Primary medullary rays narrow.

The wood ring porous to diffuse porous. The axial xylem with tracheids (at least sometimes), or without tracheids (?); with vasicentric tracheids (often, in Ehretia), or without vasicentric tracheids; with fibre tracheids, or without fibre tracheids; with libriform fibres, or without libriform fibres; including septate fibres (at least sometimes), or without septate fibres. The fibres with spiral thickening, or without spiral thickening. The parenchyma apotracheal, or paratracheal. The secondary phloem stratified into hard (fibrous) and soft (parenchymatous) zones (at least in Cordia and Ehretia).

Reproductive type, pollination. Plants hermaphrodite (usually), or andromonoecious (sometimes, in Cordia).

Inflorescence, floral, fruit and seed morphology. Flowers solitary (in Cordia, Halgania), or aggregated in ‘inflorescences’; in cymes, in spikes, in heads, in corymbs, and in panicles. The ultimate inflorescence units cymose. Inflorescences terminal, or axillary, or leaf-opposed; cymose, sometimes spiciform or capitate. Flowers regular; (4–)5(–8) merous; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk present.

Perianth with distinct calyx and corolla; (9–)10(–13); 2 whorled; isomerous, or anisomerous. Calyx (4–)5; 1 whorled; gamosepalous; lobulate, or blunt-lobed, or toothed; campanulate, or tubular; unequal but not bilabiate, or regular; persistent; accrescent (sometimes, inflated and enclosing the fruit), or non-accrescent. Corolla (4–)5(–8) (lobed); 1 whorled; gamopetalous; imbricate (usually), or valvate (sometimes); regular; pink, or purple, or blue.

Androecium 5. Androecial members adnate (epipetalous); all equal; free of one another (usually), or coherent (joined by the anthers in Halgania); 1 whorled. Androecium exclusively of fertile stamens. Stamens 5; usually isomerous with the perianth; oppositisepalous; alternating with the corolla members. Anthers separate from one another (usually), or cohering (forming a tube enclosing the style, in Halgania); dehiscing via longitudinal slits; introrse; tetrasporangiate. Endothecium developing fibrous thickenings. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or isobilateral, or decussate. Anther wall initially with one middle layer; of the ‘dicot’ type. Tapetum glandular. Pollen grains aperturate; 3 aperturate; 2-celled.

Gynoecium 2 carpelled. Carpels reduced in number relative to the perianth. The pistil 2–4 celled. Gynoecium syncarpous; synovarious to eu-syncarpous; superior. Ovary 2 locular (morphologically, but the locules sometimes with incomplete false septa). Locules secondarily divided by ‘false septa’, or without ‘false septa’. Gynoecium median. Styles 1, or 2, or 4; partially joined; apical. Stigmas 2–4 lobed. Placentation axile to basal. Ovules (1–)2 per locule; ascending (usually), or pendulous (rarely); non-arillate; hemianatropous; unitegmic; tenuinucellate, or crassinucellate. Embryo-sac development Polygonum-type, or Allium-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral. Synergids hooked. Endosperm formation cellular. Endosperm haustoria present; chalazal and micropylar. Embryogeny asterad, or chenopodiad.

Fruit fleshy, or non-fleshy; indehiscent (usually), or a schizocarp (Coldenia). Mericarps in Coldenia, 4; comprising nutlets. Fruit a drupe (often enclosed in the persistent calyx); (1–)2–4 seeded. Seeds endospermic, or non-endospermic. Embryo achlorophyllous (1/2).

Seedling. Germination phanerocotylar.

Physiology, phytochemistry. C3. C3 physiology recorded directly in Ehretia. Sugars transported as sucrose (in 9 Cordia and Gerascanthus species, and one Ehretia). Inulin not found. Not cyanogenic. Alkaloids present. Iridoids not detected. Saponins/sapogenins absent.

Geography, cytology. Sub-tropical to tropical. Pantropical, centring on Central and South America.

Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Solaniflorae; Boraginales. Cronquist’s Subclass Asteridae; Lamiales. APG III core angiosperms; core eudicot; Superorder Asteranae; lamiid. APG IV Order Boraginales (as a synonym of Boraginaceae).

Species 400. Genera about 13; Bourreria, Coldenia, Cordia (including Gerascanthus), Cortesia, Ehretia, Halgania, Menais(?), Rhabdia.

General remarks. Exhibiting stratified secondary phloem (i.e., a character relying on limited sampling), otherwise poorly distinguished in terms of these compiled descriptions from Boraginaceae (q.v.).

Illustrations. • Le Maout and Decaisne: Ehretia. • Cordia myxa: R. Wight 2 (1850). • Le Maout and Decaisne: Cordia myxa and C. gerascanthus. • Cordia senegalensis: Thonner. • Cordia sebestena, and Rotula aquatica as Rhabdia lycioides: Lindley. • Ehretia serrata, probably = Ehretia acuminata: Bot. Reg. 1097, 1827. • 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: 5th March 2018.’.