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The families of flowering plants

L. Watson and M. J. Dallwitz

Monimiaceae Juss.

Including Hortoniaceae A.C. Smith; excluding Atherospermataceae, Siparunaceae.

Habit and leaf form. Shrubs and herbs; bearing essential oils; resinous (often), or not resinous. Mesophytic. Leaves opposite; leathery; petiolate; gland-dotted (often), or not gland-dotted; aromatic (often, resiniferous), or without marked odour; simple. Lamina entire; pinnately veined; cross-venulate. Leaves exstipulate. Lamina margins entire, or serrate. Leaf development not ‘graminaceous’. Domatia occurring in the family (recorded in Tetrasynandra); manifested as pockets.

Leaf anatomy. The leaf lamina dorsiventral. Stomata present; mainly confined to one surface (abaxial); commonly paracytic. Hairs present; exclusively eglandular; unicellular (mostly), or multicellular. Unicellular hairs branched (sometimes 2-armed, or tufted), or simple. Complex hairs present, or absent (usually); when present, peltate (in several genera). Adaxial hypodermis usually present. Lamina often with secretory cavities. Secretory cavities containing resin. The mesophyll with spherical etherial oil cells (frequently seen as transparent dots in the leaves); not containing mucilage cells; containing crystals. The crystals chiefly in the form of very numerous, small needles, frequenty occurring throughout the mesophyll. Minor leaf veins without phloem transfer cells (Peumus).

Axial (stem, wood) anatomy. Cork cambium present; initially superficial. Nodes unilacunar (with one to several traces). Primary vascular tissues in a cylinder, without separate bundles; collateral. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring. Primary medullary rays narrow, or wide (expanded distally in Peumus).

The wood diffuse porous. The vessels small, or small to medium; solitary, radially paired, and in radial multiples (mostly solitary, but always with a few small radial multiples). The vessel end-walls slightly to very oblique; scalariform, or reticulately perforated, or simple (rarely). The vessels without vestured pits; with spiral thickening, or without spiral thickening. The axial xylem with tracheids; with fibre tracheids, or without fibre tracheids; with libriform fibres, or without libriform fibres; seemingly aways including septate fibres. The fibres without spiral thickening. The parenchyma apotracheal, or paratracheal, or apotracheal and paratracheal (very variable). The secondary phloem not stratified. ‘Included’ phloem absent. The wood not storied. Tyloses present, or absent.

Reproductive type, pollination. Plants hermaphrodite (?), or monoecious, or andromonoecious, or gynomonoecious, or dioecious, or androdioecious, or androdioecious, or polygamomonoecious, or polygamodioecious (? — ‘commonly unisexual’). Female flowers with staminodes, or without staminodes.

Inflorescence, floral, fruit and seed morphology. Flowers solitary (sometimes), or aggregated in ‘inflorescences’; when aggregated, in cymes. The ultimate inflorescence units cymose. Inflorescences axillary, or terminal (rarely); helicoid cymes, cymose or racemose. Flowers small to medium-sized; calyptrate, or not calyptrate; regular, or somewhat irregular (then somewhat oblique); cyclic, or partially acyclic. The gynoecium acyclic. Floral receptacle markedly hollowed. Free hypanthium present.

Perianth with distinct calyx and corolla, or sequentially intergrading from sepals to petals, or sepaline, or vestigial to absent; 4–50 (to ‘many’, often shedding the tips from the bud as a ‘calyptra’); free, or joined; 2–3 whorled; anisomerous; fleshy, or non-fleshy; persistent, or deciduous. Calyx when recognisable 4; sometimes 2 whorled; polysepalous; regular; fleshy; calyptrate, or not calyptrate; imbricate (decussate). Corolla 7–20(–30); polypetalous.

Androecium 10–150 (usually ‘many’). Androecial members free of the perianth; free of one another; 1 whorled, or 2 whorled. Androecium including staminodes (possibly staminodal basal nectaries, and staminode(s) between A and G). Staminodes 1–50 (? — to ‘many’); internal to the fertile stamens. Stamens 10–150 (usually ‘many’?); filantherous (the filaments short, often flattened). Filaments not appendiculate (without glands). Anthers basifixed; non-versatile; dehiscing via longitudinal slits, or dehiscing by longitudinal valves; extrorse, or introrse; tetrasporangiate. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral. Anther wall initially with more than one middle layer. Tapetum glandular. Pollen shed in aggregates, or shed as single grains; when aggregated, in tetrads (e.g. Hedycarya). Pollen grains nonaperturate (mainly), or aperturate (perhaps, in Macrotorus); when detectable, 1 aperturate; when aperturate, sulcate (perhaps, in Macrotorus); 2-celled (in Peumus).

Gynoecium (1–)3–100 carpelled (to ‘many’). The pistil when monomerous, 1 celled. Gynoecium monomerous, or apocarpous; of one carpel, or eu-apocarpous; superior to partly inferior (the carpels sometimes partly sunk in the receptacle). Carpel apically stigmatic; 1 ovuled. Placentation apical. Stigmas dry type; papillate; Group II type. Ovules ascending (usually), or pendulous (rarely); anatropous; bitegmic; crassinucellate. Embryo-sac development Allium-type (seemingly). Polar nuclei fusing prior to fertilization. Antipodal cells formed; proliferating (to 5–20 cells, in Peumus boldus). Endosperm formation cellular. Embryogeny asterad.

Fruit (i.e. the carpel) non-fleshy; an aggregate (in a head). The fruiting carpels coalescing into a secondary syncarp (often often partially embedded in the fleshy receptacle and/ enclosed by the hypanthium), or not coalescing. The fruiting carpel indehiscent; an achene. Fruit enclosed in the fleshy receptacle to enclosed in the fleshy hypanthium (often), or without fleshy investment external to the original ovary. Dispersal unit the flower. Fruit 1 seeded. Seeds endospermic. Endosperm not ruminate; oily. Embryo achlorophyllous (1/1); straight.

Seedling. Germination phanerocotylar.

Physiology, phytochemistry. Sugars transported as sucrose (in Peumus). Not cyanogenic. Alkaloids present (commonly), or absent. Iridoids not detected. Saponins/sapogenins present (rarely), or absent. Proanthocyanidins present, or absent; when present, cyanidin. Flavonols present; kaempferol and quercetin. Ellagic acid absent (3 genera, 3 species). Aluminium accumulation demonstrated. Sieve-tube plastids P-type and S-type; type I (a and b).

Geography, cytology. Temperate to tropical. Chiefly southern tropical - Central and South America, Southwest and Southeast tropical africa, tropical and Eastern Australia, Polynesia, New Zealand.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Magnoliiflorae; Laurales. Cronquist’s Subclass Magnoliidae; Laurales. APG 3 core angiosperms; Superorder Magnolianae; Order Laurales.

Species 150. Genera 26; Austromatthaea, Decarydendron, Dryadodaphne, Ephippiandra, Faikea, Hedycarya, Hennecartia, Hortonia, Kairoa, Kibara, Kibaropsis, Lauterbachia, Levieria, Macropeplus, Macrotorus, Matthaea, Mollinedia, Monimia, Palmeria, Parakibara, Peumus, Steganthera, Tambourissa (Ambora), Tetrasynandra, Wilkiea, Xymalos.

Economic uses, etc. Some cultivated as ornamentals (Hedycarya, Peumus), edible fruits from Peumus, commercial timbers from many members (e.g. Chilean boldo wood from Peumus boldus).

Illustrations. • Technical details: Hedycaria, Peumus (Lindley). • Technical details: Ephippiandra, Tambourissa. • Hedycarya arboria: Cheeseman, Ill. Fl. of New Zealand (1914). • Peumus fragrans: Bot. Mag. 114 (1888). • Hortonia floribunda: R. Wight, Ic. Pl. Indiae Orient. 6 (1863). • Hortonia acuminata and H. ovalifolia: R. Wight, Ic. Pl. Indiae Orient. 6 (1863).

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: 19th October 2016.’.