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The families of flowering plants

L. Watson and M.J. Dallwitz

Thymelaeaceae Juss.

Including Daphnoideae (Daphnaceae) Vent., Phalerieae (Phaleriaceae) Meissn.; excluding Aquilariaceae, Gonystylaceae.

Habit and leaf form. Shrubs (most), or shrubs, or lianas (rarely), or herbs (rarely). ‘Normal’ plants. Self supporting (usually), or climbing. Mesophytic, or xerophytic. Leaves small to medium-sized; alternate, or opposite, or whorled; commonly spiral; flat, or rolled; ‘herbaceous’, or leathery (sometimes ericoid); petiolate to sessile; gland-dotted, or not gland-dotted; simple. Lamina entire; pinnately veined; cross-venulate. Leaves exstipulate; leaf development not ‘graminaceous’.

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

Leaf anatomy. The leaf lamina dorsiventral (usually), or bifacial to centric (in occasional species of several genera). Mucilaginous epidermis present. Stomata anomocytic, or cyclocytic. Hairs present; seemingly exclusively eglandular; supposedly always unicellular. Unicellular hairs branched (then 2-armed), or simple. Complex hairs absent. Adaxial hypodermis present (of mucilaginous cells, in Daphne), or absent. The mesophyll with sclerenchymatous idioblasts, or without sclerenchymatous idioblasts; containing crystals, or without crystals. The crystals when found, druses, or solitary-prismatic. Minor leaf veins without phloem transfer cells (Daphne, Pimelea).

Axial (stem, wood) anatomy. Cork cambium present; initially superficial. Nodes unilacunar. Primary vascular tissues in a cylinder, without separate bundles; bicollateral (mostly), or collateral (rarely). Internal phloem present (nearly always), or absent (e.g. in the moss-like Drapetes and the ericoid Kelleria). Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring (mostly), or anomalous (in forms with interxylary phloem). The anomalous secondary thickening when present, via concentric cambia (Wikstroemia), or from a single cambial ring.

The wood semi-ring porous (Dirca, Passerina), or diffuse porous. The vessels small (typically, sometimes extremely so). The vessel end-walls simple. The vessels with vestured pits (usually), or without vestured pits (then vestures confined to fibre pits, e.g. in Dirca, Daphne, Wikstroemia); with spiral thickening, or without spiral thickening. The axial xylem with tracheids; with vasicentric tracheids (often), or without vasicentric tracheids; typically with fibre tracheids; with libriform fibres, or without libriform fibres; without septate fibres. The fibres without spiral thickening. The parenchyma paratracheal (and often with terminal bands). ‘Included’ phloem of various configurations present (several genera), or absent. The wood partially storied, or not storied.

Reproductive type, pollination. Plants hermaphrodite, or monoecious, or dioecious, or gynodioecious (with much variation in Pimelea).

Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’; when aggregated, in racemes, or in heads, or in fascicles. The ultimate inflorescence units racemose. Inflorescences racemes or heads, very condensed; with involucral bracts (often), or without involucral bracts; pseudanthial, or not pseudanthial. Flowers bracteolate, or ebracteolate; regular to somewhat irregular; 4–5 merous; cyclic. Floral receptacle markedly hollowed (often forming a deep tube of leafy consistency). Free hypanthium nearly always conspicuously present (but ‘more or less absent’ in Synandrodaphne). Hypogynous disk present, or absent; when present, of separate members, or annular.

Perianth with distinct calyx and corolla, or sepaline (the corolla sometimes missing or interpretable as staminodes, then the ‘calyx’ commonly more or less petaloid); 4–5, or 8–10, or 11–17; 2 whorled, or 1 whorled; isomerous, or anisomerous. Calyx 4–5; 1 whorled; gamosepalous (usually, variously laciniate or represented by lobes on the hypanthium), or polysepalous (rarely); unequal but not bilabiate, or regular; (tube) persistent; imbricate. Corolla when present, (3–)4–5(–12) (scale-like); 1 whorled; polypetalous (inserted on the hypanthial tube or at its mouth); imbricate.

Androecium 2 (rarely — Pimelea), or 4–5, or 8, or 10, or 11–100 (usually the same number as the calyx lobes, sometimes double them or ‘many’). Androecial members branched (?), or unbranched; free of the perianth (at the mouth of the hypanthium), or adnate (to ‘calyx tube’); free of one another; 1 whorled (when 4–5), or 2 whorled (when 8 or 10). Androecium exclusively of fertile stamens, or including staminodes (depending on interpretation). Staminodes if so interpreted, 3–12; petaloid (the scalelike ‘petals’ being interpretable as staminodes). Stamens 2, or 4, or 5, or 8, or 10, or 11–35; reduced in number relative to the adjacent perianth (rarely), or isomerous with the perianth, or diplostemonous, or polystemonous; oppositisepalous (when one whorled), or alternisepalous (when 2 whorled?); filantherous, or with sessile anthers. Anthers dehiscing via longitudinal slits; introrse; tetrasporangiate. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or isobilateral. Anther wall initially with one middle layer, or initially with more than one middle layer (1 or 2); of the ‘monocot’ type. Tapetum glandular. Pollen grains aperturate; (3–)4–30 aperturate (to ‘many’); (oligo- to poly-) foraminate; 3-celled (in 5 genera).

Gynoecium 2–5(–12) carpelled. Carpels isomerous with the perianth, or reduced in number relative to the perianth, or increased in number relative to the perianth. The pistil 1 celled, or 2–5 celled. Gynoecium syncarpous (but occasionally pseudomonomerous when G2); eu-syncarpous; superior. Ovary 1 locular (occasionally, when G2), or 2–5 locular, or 2 locular. Gynoecium non-stylate, or stylate. Styles 1 (the simple style sometimes with small ‘parastyles’ at the base); apical, or lateral. Stigmas dry type; papillate; Group II type. Placentation when unilocular parietal, or apical; when plurilocular (i.e.usually) axile, or apical. Ovules in the single cavity when unilocular, 1; 1 per locule; pendulous; epitropous; with ventral raphe; arillate (or carunculate); anatropous, or hemianatropous; bitegmic; crassinucellate. Outer integument not contributing to the micropyle. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; proliferating (usually, forming up to 30 or more cells), or not proliferating. Synergids hooked (sometimes with filiform apparatus). Hypostase usually present. Endosperm formation nuclear. Embryogeny asterad.

Fruit fleshy, or non-fleshy; indehiscent; achene-like, or a berry, or a drupe. Seeds endospermic, or non-endospermic. Cotyledons 2. Embryo achlorophyllous (2/3); straight.

Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, phytochemistry. C3. C3 physiology recorded directly in Thymelaea. Anatomy non-C4 type (Daphne, Dendrostelleria, Thymelaea). Sugars transported as sucrose (in Daphne). Not cyanogenic. Alkaloids present, or absent. Arbutin absent. Iridoids not detected. Proanthocyanidins absent (mostly), or present; cyanidin (in one Daphne sample). Flavonols present, or absent; quercetin, or kaempferol and quercetin. Ellagic acid absent (5 species, 2 genera). Aluminium accumulation not found.

Geography, cytology. Temperate to tropical. Very widespread, tropical to temperate - more diverse in the Southern hemisphere. X often = 9.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Malviflorae; Thymelaeales. Cronquist’s Subclass Rosidae; Myrtales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; malvid; Order Malvales.

Species 500. Genera 44; Aetoxylon, Amyxa, Arnhemia, Atemnosiphon, Craterosiphon, Cryptadenia, Dais, Daphne, Daphnemorpha, Daphnopsis, Deltaria, Diarthron, Dicranolepis, Dirca, Drapetes, Edgeworthia, Enkleia, Eriosolena, Funifera, Gnidia, Goodallia, Jedda, Kelleria, Lachnaea, Lagetta, Lasiadenia, Lasiosiphon, Lethedon, Linodendron, Linostoma, Lophostoma, Oreodendron, Ovidia, Passerina, Peddiea, Phaleria, Pimelea, Rhamnoneuron, Schoenobiblus, Stellera, Stephanodaphne, Struthiola, Synandrodaphne, Synaptolepis, Thecanthes, Thymelaea, Wikstroemia.

General remarks. Gonystylaceae (q.v.) are excluded with good reason, but Aquilariaceae (q.v.) seem to differ only in habit and in having dehiscent, capsular fruits.

Economic uses, etc. Cultivated ornamental shrubs from Daphne, Dais, Dirca (leatherwood), Pimelea (rice flower), etc.; incense, from Wikstroemia; bark fibre for paper from Daphne, Edgeworthia, Thymelaea, etc. The family is said to include some of the few plants poisonous to camels.

Illustrations. • Technical details: Daphne, Drimyspermum (= Phaleria), Drapetes, Gyrinopsis. • Technical details: Lachnaea (Thonner). • Calyptrostegia intermedia: as Pimelea intermedia, Bot. Reg. 1439 (1831). • Daphne cneorum: Bot. Mag. 313, 1795. • Daphne laureola and D. mezereum: Eng. Bot. 1246 and 1247, 1868. • Daphne laureola (B. Ent.). • Daphne laureola (J. E. Sowerby, 1861). • Daphne mezereum (B. Ent.). • Daphne mezeruem (J. E. Sowerby, 1861). • Daphne cf. sericea: as D. australis, Bot. Reg. XXIV, 56 (1838). • Dais cotinifolia: Bot. Mag. 147, 1791. • Goodallia guianensis: Hook. Ic. Pl. 13 (1877–79). • Pimelea glauca: Bot. Reg. 1268, 1829. • Pimelea filiformis: Hooker, Fl. Tasmaniae (1860). • Pimelea nivea: as P. incana, Bot. Reg. XXIV, 24 (1838). • Pimelea physodes: Hook. Ic. Pl. 9 (1852). • Pimelea rosea: inflorescence. • Pimelea rosea: habit. • Pimelea spectabilis: Bot. Reg. 33, 1841. • Struthiola lineariloba: Bot. Mag. 222, 1793. • Synaptolepis kirkii: Hook. Ic. Pl. 11 (1867–71).

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: 20th June 2017.’.