Including Cassythaceae Bartl. ex Lindl.
Habit and leaf form. Trees, shrubs, and `arborescent'; bearing essential oils, or without essential oils. Leaves well developed (usually), or much reduced (Cassytha). Autotrophic (usually), or totally parasitic (Cassytha). When parasitic, on roots of the host. Self supporting (usually), or climbing (Cassytha); the climbers stem twiners. Leptocaul. Mesophytic. Leaves evergreen; alternate (usually), or opposite (rarely), or whorled (rarely); usually spiral; leathery (usually), or membranous (in Cassytha); petiolate; non-sheathing; gland-dotted; aromatic; simple. Lamina entire (usually), or dissected (lobed in e.g. Sassafras); when lobed, pinnatifid; pinnately veined; cross-venulate. Leaves exstipulate; without a persistent basal meristem. Domatia recorded (14 genera); represented by pits (mostly), or pockets, or hair tufts.
Leaf anatomy. Stomata absent; mainly confined to one surface (abaxial); paracytic. Hairs present; mostly unicellular (and mostly thick walled).
Adaxial hypodermis very often present. Lamina dorsiventral; without secretory cavities. The mesophyll usually with spherical etherial oil cells; containing mucilage cells, or not containing mucilage cells (less common than oil cells). Minor leaf veins without phloem transfer cells (Cinnamomum, Laurus, Persea).
Stem anatomy. Cork cambium present; initially superficial (usually), or deep-seated. Nodes unilacunar (with two traces). Internal phloem absent. Secondary thickening developing from a conventional cambial ring. `Included' phloem absent. Xylem with tracheids, or without tracheids; with fibre tracheids, or without fibre tracheids; with libriform fibres, or without libriform fibres. Vessel end-walls scalariform, or simple, or scalariform and simple. Vessels without vestured pits. Wood partially storied (VPI), or not storied; parenchyma paratracheal. Sieve-tube plastids P-type, or S-type; when P-type type I (b).
Reproductive type, pollination. Hermaphrodite, or monoecious, or dioecious, or polygamomonoecious.
Inflorescence, floral, fruit and seed morphology. Flowers solitary (rarely), or aggregated in `inflorescences'. The terminal inflorescence unit racemose, or cymose. Inflorescences axillary; often umbelliform; with involucral bracts (often), or without involucral bracts. Flowers small; often fragrant; regular; usually 3 merous; cyclic. Free hypanthium present (well developed, like a calyx tube). Hypogynous disk present, or absent.
Perianth sepaline (usually), or with distinct calyx and corolla (notably in Cassytha); 6 (usually), or 4; joined (there being a well developed hypanthium); (1-)2(-3) whorled; when more than one whorl, isomerous; green, or cream, or yellow; fleshy, or non-fleshy; persistent, or deciduous; accrescent, or non-accrescent. Calyx 3 (Cassytha), or (4-)6. Corolla when clearly identifiable as such, in Cassytha, 3; 1 whorled; fleshy.
Androecium (3-)9(-26). Androecial members free of the perianth (on the hypanthium); free of one another; (1-)3 - whorled, or 4 - whorled. Androecium exclusively of fertile stamens, or including staminodes (the innermost members often staminodal, and sometimes there are paired, nectariferous ?staminodal appendages on the filaments). Stamens (3-)9(-26); diplostemonous to polystemonous (usually), or reduced in number relative to the adjacent perianth to isomerous with the perianth. Filaments appendiculate (the appendages paired, nectariferous), or not appendiculate. Anthers basifixed; non-versatile; dehiscing by londitudinal valves (opening from base to apex), or dehiscing via pores (in Hexapora); introrse (usually), or introrse and extrorse (with the latter state confined to the third whorl); bilocular, or four locular; bisporangiate, or tetrasporangiate, or bisporangiate and tetrasporangiate. Endothecium developing fibrous thickenings (or the cell walls become much thickened). Anther epidermis persistent. Microsporogenesis successive. The initial microspore tetrads tetrahedral, or isobilateral, or T-shaped, or linear. Tapetum amoeboid, or glandular. Pollen grains nonaperturate; 2-celled.
Gynoecium 1 (ostensibly), or 3 (theoretically); ostensibly monomerous; of one carpel (or at least, ostensibly so); superior (usually), or inferior (Hypodaphnis). Carpel stylate; apically stigmatic; 1 ovuled. Placentation apical. Stigmas dry type; papillate; Group II type. Ovules pendulous; non-arillate; anatropous; bitegmic; crassinucellate. Outer integument contributing to the micropyle (usually), or not contributing to the micropyle. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed, or not formed (then the three nuclei degenerating early); when formed, 3; proliferating (rarely), or not proliferating. Synergids commonly exhibiting filiform apparatus. Endosperm formation cellular, or nuclear. Embryogeny onagrad, or asterad (or with no clear pattern).
Fruit fleshy (usually), or non-fleshy (very rarely). The fruiting carpel indehiscent; drupaceous, or baccate (usually), or nucular ((?) -rarely). Fruit enclosed in the fleshy receptacle, or enclosed in the fleshy hypanthium, or without fleshy investment; 1 seeded. Seeds non-endospermic. Embryo well differentiated (even in the parasitic Cassytha). Embryo achlorophyllous (5/6); straight.
Seedling. Germination phanerocotylar, or cryptocotylar.
Physiology, biochemistry. Not cyanogenic. Alkaloids present (commonly), or absent. Iridoids absent. Proanthocyanidins present (usually), or absent; when present, cyanidin. Flavonols present; kaempferol and quercetin. Ellagic acid absent (8 species, 7 genera). Arbutin absent. Saponins/sapogenins absent. Aluminium accumulation demonstrated. Inulin recorded.
Geography, cytology. Temperate to tropical. Pantropical and subtropical, extending into the temperate regions. X = 12.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren's Superorder Magnoliiflorae; Laurales. Cronquist's Subclass Magnoliidae; Laurales. Takhtajan's Subclass Magnoliidae; Magnolianae; Laurales. Species 2000-2500. Genera 54; Actinodaphne, Adenodaphne, Aiouea, Alseodaphne, Anaueria, Aniba, Apollonias, Aspidostemon, Beilschmiedia, Brassiodendron, Caryodaphnopsis, Cassytha, Chlorocardium, Cinnadenia, Cinnamomum, Clinostemon, Cryptocarya, Dehaasia, Dicypellium, Dodecadenia, Endiandra, Endlicheria, Eusideroxylon, Gamanthera, Hexapora, Hypodaphnis, Iteadaphne, Kubitzkia, Laurus, Licaria, Lindera, Litsea, Mezilaurus, Nectandra, Neocinnamomum, Neolitsea, Nothaphoebe, Ocotea, Paraia, Persea, Phoebe, Phyllostemonodaphne, Pleurothyrium, Potameia, Potoxylon, Povedadaphne, Ravensara, Rhodostemonodaphne, Sassafras, Syndiclis, Triadodaphne, Umbellularia, Urbanodendron, Williamodendron.
Economic uses, etc. Some important economic plants, including fruit from Persea americana (Avacado pear), cinnamon and camphor from Cinnamomum spp., aromatic oils oils from Lindera (benzoin) and Sassafras, and fragrant woods used in cabinet-making.
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