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The families of flowering plants

L. Watson and M.J. Dallwitz

Celastraceae R. Br.

Alternatively Hippocrateaceae Juss.

Including Chingithamnaceae Hand.-Mazz., Leptolobaceae Dulac, Pottingeriaceae (A. Engler) Takhtajan (doubtfully), Salaciaceae, Tripterygiaceae; excluding Canotiaceae, Goupiaceae, Lepuropetalaceae, Lophopyxidaceae, Parnassiaceae, Siphonodontaceae.

Habit and leaf form. Trees, shrubs, and lianas; laticiferous, or with coloured juice, or non-laticiferous. ‘Normal’ plants (usually), or switch-plants. Leaves well developed (mostly), or much reduced (e.g. Psammomoya, with leaves represented by cataphylls). Self supporting, or climbing; when climbing, stem twiners (e.g. Hippocratea). Leaves alternate, or opposite; ‘herbaceous’, or leathery, or membranous (?); petiolate; non-sheathing; not gland-dotted; simple. Lamina entire; pinnately veined; cross-venulate. Leaves stipulate (stipules small), or exstipulate. Stipules when present, caducous. Leaf development not ‘graminaceous’. Domatia occurring in the family (recorded in one genus); manifested as pits.

General anatomy. Plants with laticifers, or without laticifers. The laticifers when present, in stems, or in leaves and in stems.

Leaf anatomy. The leaf lamina dorsiventral (mostly), or bifacial (then isobilateral). Mucilaginous epidermis present, or absent. Stomata mainly confined to one surface (usually, abaxial), or on both surfaces (occasionally); usually anomocytic, or anomocytic to anisocytic, or paracytic (recorded only in Bhesa), or cyclocytic (Mortonia). Hairs present to absent (seemingly infrequent); when present, eglandular; unicellular, or multicellular. Unicellular hairs branched (rarely, two armed), or simple. Multicellular hairs if present, uniseriate. Complex hairs absent. Adaxial hypodermis present, or absent. Lamina with secretory cavities, or without secretory cavities. The mesophyll with sclerenchymatous idioblasts, or without sclerenchymatous idioblasts. Minor leaf veins without phloem transfer cells (Euonymus, Maytenus).

Axial (stem, wood) anatomy. The cortex containing cristarque cells, or without cristarque cells. Secretory cavities present, or absent (?). Cork cambium present; initially deep-seated, or initially superficial. Nodes unilacunar. Primary vascular tissues in a cylinder, without separate bundles (mostly), or comprising a ring of bundles (Maytenus spp.); collateral. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring (usually), or anomalous. The anomalous secondary thickening when present, via concentric cambia (e.g. Salacia). Primary medullary rays usually narrow.

The wood ring porous to diffuse porous. The vessels small (typically very small, sometimes extremely so); exclusively solitary (in some genera), or radially paired to in radial multiples (in others). The vessel end-walls scalariform, or simple. The vessels without vestured pits; with spiral thickening, or without spiral thickening. The axial xylem with tracheids, or without tracheids; with vasicentric tracheids (rarely), or without vasicentric tracheids; with fibre tracheids (usually), or without fibre tracheids; with libriform fibres, or without libriform fibres; often including septate fibres (these rather short and thin walled with parenchyma-like distribution), or without septate fibres. The fibres with spiral thickening, or without spiral thickening. The parenchyma apotracheal, or paratracheal (or absent). ‘Included’ phloem present, or absent. The wood not storied.

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

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in cymes, or in fascicles. The ultimate inflorescence units cymose (usually), or racemose (rarely). Inflorescences terminal, or axillary, or epiphyllous (Polycardia); mostly cymes or fascicles. Flowers usually small; regular; 4–5 merous; cyclic; nearly always tetracyclic. Hypogynous disk usually present; intrastaminal; annular.

Perianth with distinct calyx and corolla; (4–)8–10; 2 whorled; isomerous. Calyx (2–)4–5; 1 whorled; polysepalous, or gamosepalous (basally); regular; imbricate, or valvate (rarely). Corolla (2–)4–5; 1 whorled; polypetalous; imbricate, or valvate; regular; not fleshy.

Androecium (2–)3, or (4–)5. Androecial members free of the perianth; free of one another, or coherent (sometimes connate at the base); when joined 1 adelphous; 1 whorled (usually), or 2 whorled. Androecium exclusively of fertile stamens (usually), or including staminodes. Staminodes sometimes (2–)3–5 (alternating with the stamens); internal to the fertile stamens; non-petaloid. Stamens (2–)3–5; isomerous with the perianth; oppositisepalous. Anthers dehiscing via longitudinal slits; extrorse, or introrse; unilocular to bilocular; bisporangiate, or tetrasporangiate. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or decussate. Anther wall initially with more than one middle layer. Tapetum glandular. Pollen shed in aggregates (often), or shed as single grains; when in aggregates in tetrads, or in polyads. Pollen grains aperturate; 3 aperturate; colporate; 2-celled (Celastrus), or 3-celled (Hippocratea, Maytenus, Salacia).

Gynoecium 2–5 carpelled (usually with all but one abortive). The pistil 1–5 celled. Gynoecium syncarpous; synovarious to eu-syncarpous; superior, or partly inferior (rarely). Ovary plurilocular; 2–5 locular. Gynoecium stylate, or non-stylate. Styles 1; attenuate from the ovary; apical. Stigmas 2–5 (same number as G); dry type; non-papillate; Group II type. Placentation axile. Ovules (1–)2 per locule (usually), or 3–50 per locule (rarely many); pendulous, or ascending; apotropous; with ventral raphe, or with dorsal raphe (when pendulous); often arillate; anatropous; bitegmic; tenuinucellate, or crassinucellate. Outer integument contributing to the micropyle, or not contributing to the micropyle. Endothelium differentiated. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; usually ephemeral. Synergids pear-shaped, or hooked (with filiform apparatus in (e.g.) Hippocratea). Endosperm formation nuclear. Embryogeny caryophyllad, or solanad.

Fruit fleshy, or non-fleshy; dehiscent, or indehiscent; a capsule, or capsular-indehiscent, or a berry, or a drupe, or a samara, or achene-like. Capsules loculicidal. Seeds endospermic (usually), or non-endospermic. Endosperm when present, ‘more or less’ oily. Seeds with a testa; winged, or wingless. Embryo well differentiated. Cotyledons 2; flat (large, foliaceous). Embryo chlorophyllous (3/19); straight.

Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, phytochemistry. C3 (?), or CAM. CAM recorded directly in Gymnosporia (non-succulent, and dubious). Sugars transported as oligosaccharides + sucrose, or as sugar alcohols + oligosaccharides + sucrose. Not cyanogenic. Alkaloids present (commonly), or absent. Arbutin absent. Iridoids not detected. Saponins/sapogenins present, or absent. Proanthocyanidins present (usually), or absent; when present, cyanidin and delphinidin. Flavonols present, or absent (Salacia); kaempferol and quercetin (mostly), or myricetin (Catha). Ellagic acid absent (9 species, 5 genera). Aluminium accumulation demonstrated (rarely).

Geography, cytology. Sub-tropical and tropical (most), temperate (fewer). Cosmopolitan.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Santaliflorae; Celastrales. Cronquist’s Subclass Rosidae; Celastrales. APG III core angiosperms; core eudicot; Superorder Rosanae; fabid. APG IV Order Celastrales.

Species 850. Genera about 85; Allocassine, Anthodon, Apatophyllum, Apodostigma, Arnicratea, Baequaertia, Bhesa, Brassiantha, Brexiella, Campylostemon, Cassine, Catha, Celastrus, Cheiloclinium, Crossopetalum, Cuervea, Denhamia, Dicarpellum, Elachyptera, Elaeodendron, Empleuridium, Euonymus, Evonymopsis, Fraunhofera, Glyptopetalum, Goniodiscus, Gyminda, Gymnosporia, Hartogiella, Hartogiopsis, Hedraianthera, Helictonema, Herya, Hexaspora, Hippocratea, Hylenaea, Hypsophila, Kokoona, Loeseneriella, Lophopetalum, Maurocenia, Maytenus, Menepetalum, Microtropis, Monimopetalum, Mortonia, Moya, Myginda, Nicobariodendron, Orthodphenia, Paxistima, Peripterygia, Peritassa, Perottetia, Platypterocarpus, Plenckia, Pleurostylia, Polycardia, Pottingeria(?), Prionostemma, Pristimera, Psammomoya, Pseudosalacia, Ptelidium, Pterocelastrus, Putterlickia, Quetzalia, Reissantia, Rzedowskia, Salacia, Salacighia, Salaciopsis, Salvadoropsis, Sarawakodendron, Schaefferia, Semialarium, Simicratea, Simirestis, Tetrasiphon, Thyrsosalacia, Tontelea, Torralbasia, Tripterygium, Tristemonanthus, Viposia, Wimmeria, Xylonymus, Zinowiewia.

General remarks. Intkey comparisons of the descriptions compiled in this package offer enough character differences to defend maintaining Lepuropetalaceae, Parnassiaceae, Siphonodontaceae and perhaps Lophopyxidaceae as separate families, but Canotiaceae and Goupiaceae seem poorly distinguished.

Economic uses, etc. A few genera cultivated as ornamentals (e.g. Catha, Celastrus, Elaeodendron, Euonymus). The toxic alkaloid maytansine (from Maytenus), when delivered by antibodies, may have application in treating colon cancers (New Scientist 31 August 1996).

Illustrations. • Le Maout and Decaisne: Euonymus. • Cassine crocea, as Elaeodendron croceum: Thonner. • Salacia dusenii: Thonner. • Loeseneriella arnottiana, as Hippocratea: Lindley. • Celastrus angulatus, as C. latifolius: Hook. Ic. Pl. 23 (1894). • Euonymus europaeus: Eng. Bot. 317, 1864. • Euonymus europaeus (B. Ent., 1827). • Euonymus japonicus: Bot. Reg. 1844, 6. • Fraunhofera multiflora: Martius, Nova Gen. et Spec. Pl. Brasiliensium 3 (1829). • Gymnosporia montana, as Celastrus: R. Wight, Ic. Pl. Indiae Orientalis 2 (1843). • Maytenus boaria: as M. chilensis, Bot. Reg. 1702, 1835. • Pleurostylia capensis: Hook. Ic. Pl. 23 (1894). • Polycardia lateralis, as P. baroniana: Hook. Ic. Pl. 23 (1894). • Pristimera grahami, as Hippocratea: R. Wight, Ic. Pl. Indiae Orientalis 2 (1843). • Salacia chinensis, as S. prinoides: Wight’s Figs. of Indian Plants 2 (1843). • Wimmeria concolor: Hook. Ic. Pl. 4 (1841).

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.’.