The families of flowering plants

L. Watson and M.J. Dallwitz

Atherospermataceae R. Br.

~ Monimiaceae.

Habit and leaf form. Trees, or shrubs. Leaves opposite; petiolate; often gland-dotted; aromatic; simple; exstipulate.

Leaf anatomy. The leaf lamina dorsiventral. Stomata present; mainly confined to one surface (abaxial); usually anomocytic. Hairs present; exclusively eglandular; unicellular (mostly). Unicellular hairs simple, or branched (sometimes 2-armed, sometimes tufted). Complex hairs seemingly absent. Adaxial hypodermis present, or absent. The mesophyll with spherical etherial oil cells (with clear or brown contents, sometimes manifested as transparent dots); not containing mucilage cells. Minor leaf veins without phloem transfer cells (Doryphora, Laurelia).

Axial (stem, wood) anatomy. Cork cambium present; initially superficial. Nodes unilacunar. 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.

The wood diffuse porous. The vessels mostly small; solitary, radially paired, and in radial multiples (mostly solitary, but always with a few small radial multiples). The vessel end-walls oblique; scalariform (with up to 100 bars in Atherosperma), or scalariform and simple. The axial xylem with fibre tracheids, or without fibre tracheids; with libriform fibres, or without libriform fibres; including septate fibres (but usually rather few). The fibres with spiral thickening. The parenchyma usually sparse, sometimes extremely so; wood not storied.

Reproductive type, pollination. Plants hermaphrodite, or monoecious, or dioecious, or polygamomonoecious.

Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’; when solitary, axillary; when aggregated, in cymes. The ultimate inflorescence units cymose. Flowers regular, or somewhat irregular; partially acyclic. The gynoecium acyclic. Floral receptacle markedly hollowed. Free hypanthium present.

Perianth with distinct calyx and corolla, or sepaline, or vestigial, or absent (‘apetalous’); when present, 4 (2 + 2), or 6–20 (?); 2(–3) whorled. Calyx 1 whorled. Corolla when present, 7–20 (or more); 1 whorled.

Androecium in male flowers 12–100 (? — ‘many’). Androecial members branched, or unbranched (?); when few, 1 whorled, or 2 whorled (in one or two ‘series’). Androecium exclusively of fertile stamens, or including staminodes (in the hermaphrodite flowers of Doryphora). Stamens (4–)6–100 (‘definite’ or ‘indefinite’); when ‘definite’, alternisepalous (when K and C determinable, or opposite the perianth segments). Filaments appendiculate (each with a pair of glandular scales at the base). Anthers adnate; dehiscing by longitudinal valves (the flaps attached at the tops of the thecae); extrorse; appendaged (by extension of the connective), or unappendaged. Pollen grains aperturate; 2 aperturate, or 3 aperturate; sulculate.

Gynoecium 3–100 carpelled (i.e. to ‘many’); apocarpous; eu-apocarpous; superior to inferior (the carpels sometimes sunk in the receptacle). Carpel with a lateral style, or with a gynobasic style; 1 ovuled. Placentation basal. Ovules ascending; anatropous.

Fruit non-fleshy; an aggregate. The fruiting carpel indehiscent; an achene. Seeds endospermic. Endosperm oily. Embryo well differentiated (small). Embryo straight.

Physiology, phytochemistry. Not cyanogenic. Iridoids not detected. Saponins/sapogenins absent. Proanthocyanidins absent. Flavonols present; kaempferol and quercetin. Ellagic acid absent. Aluminium accumulation not found. Sieve-tube plastids P-type; type I (a).

Geography, cytology. Temperate to tropical. Australia, New Guinea, New Zealand, New Caledonia, Chile. X = 22.

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

Species 12. Genera 6; Atherosperma, Daphnandra, Doryphora, Laurelia, Laureliopsis, Nemuaron.

Economic uses, etc. Edible fruits (Laurelia).

Illustrations. • Laurelia sempervirens, as L. serrata: Curtis Bot. Mag. 125 (1909). • Laurelia novae-zelandiae (= Atherosperma?): Hooker, Fl. Novae-Zelandiae (1853). • Glossocalyx longicuspis: Thonner. • Le Maout and Decaisne: Atherosperma moschatum, Doryphora sassafras: Lindley.

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: 15th April 2018.’.