Lauraceae Juss.

Timothy M. A. Utteridge and Laura V. S. Jennings (2022). Trees of New Guinea. Kew Publishing. Royal Botanic Gardens, Kew

Distribution

The Lauraceae are a major tropical and subtropical family, particularly in tropical South-East Asia and tropical America, with 45 genera and 2000–2500 species. In New Guinea, the family is represented by 15 genera, consisting of c. 225–265 species, including the two New Guinea species of the parasitic twining vine Cassytha L. and the introduced species Persea americana Mill. (the avocado).

Ecology

Members of the family are found growing in primary or secondary vegetation, mainly in lowland to mid-montane forests.

Recognition

Lauraceae can be recognised by alternate or spiral leaves which are often glaucous below, no stipules, relatively small 3-merous flowers, often pale yellow or white without conspicuous tepals, anthers opening by flaps, and the pedicel/receptacle often enlarging and enclosing the single seeded fruit. Species of Lauraceae remain poorly known and difficult to identify, mainly because fruits or flowers are unknown for many species, making generic placement uncertain, since most genera are defined by floral characters. A second problem is that identification is often almost impossible as both flower and fruit characters are needed in most generic keys, but specimens almost never bear both flowers and fruits!

Morphology General Habit

Trees or shrubs (Cassytha a twining parasitic vine with reduced leaves)

Morphology General Bark

Bark and foliage usually aromatic. Stipules absent

Morphology Leaves

Leaves usually alternate, occasionally subopposite or pseudo-verticillate, simple, margin entire, mostly penninerved or often triplinerved

Morphology Reproductive morphology Inflorescences

Inflorescences usually axillary, occasionally subterminal, panicles, spikes, racemes, or pseudo-umbels

Morphology Reproductive morphology Flowers

Flowers generally bisexual, sometimes unisexual and plants dioecious, actinomorphic, (2–)3-merous, small; perianth in 2 whorls, usually of 4 or 6 basally connate, usually undifferentiated sepal-like segments, deciduous or persistent; perianth tube usually persisting as a cupule at base of fruit; stamens usually in 4 whorls of 3, adnate to perianth tube, innermost whorl rarely united, usually reduced to staminodes; filaments usually free, third whorl usually bearing 2 usually sessile and distinct basal glands; anthers basifixed, 2- or 4-celled at anthesis, those of 2 outer whorls mostly introrse, inner third whorl extrorse, dehiscing by flap like valves opening upward; ovary superior, sometimes appearing inferior (Cryptocarya), 1-loculed; ovule solitary, anatropous, pendulous, placentation parietal; style 1; stigma 1, occasionally 2- or 3-lobed

Morphology Reproductive morphology Fruits

Fruit a drupe or berry, sometimes surrounded at base by persistent perianth or seated on a large cupule-like receptacle or pedicel, or surrounded entirely by accrescent pedicel (Cryptocarya)

Morphology Reproductive morphology Seeds

Seed with large straight embryo; endosperm absent.

Lauraceae, Hutchinson and Dalziel. Flora of West Tropical Africa 1:1. 1954

Morphology General Habit

Trees or shrubs, very rarely twining parasitic herbs, all parts with aromatic oil-glands

Morphology Leaves

Leaves alternate, rarely opposite or subopposite, coriaceous and evergreen, variously nerved; stipules absent

Morphology Reproductive morphology Flowers

Flowers small, greenish or yellowish, usually cymose or racemose, hermaphrodite, polygamous or dioecious, actinomorphic

Morphology Reproductive morphology Flowers Calyx

Calyx usually inferior; tube sometimes enlarging in fruit; lobes usually 6, imbricate

Morphology Reproductive morphology Flowers Corolla

Petals absent

Morphology Reproductive morphology Flowers Androecium

Stamens typically in 4 whorls, often the fourth row suppressed or reduced to staminodes; filaments sometimes glandular at the base, very rarely the glands fused into a disk; anthers continuous with the filament, 2–or 4-valved, cells superposed or more or less collateral, opening from the base upwards by flaps, introrse or sometimes the third whorl extrorse

Morphology Reproductive morphology Flowers Gynoecium

Ovary superior, rarely inferior, 1-celled; style terminal, simple; stigma small Ovule solitary, pendulous

Morphology Reproductive morphology Fruits

Fruit baccate or drupaceous

Morphology Reproductive morphology Seeds

Seed pendulous, without endosperm; testa membranous; embryo straight; cotyledons thick, fleshy; radicle superior

Gemma Bramley, Anna Trias-Blasi & Richard Wilford (2023). The Kew Temperate Plant Families Identification Handbook. Kew Publishing Royal Botanic Gardens, Kew

Recognition

Characters of similar families: Annonaceae: flowers large, stamens numerous, anthers linear, fruit compound. Convolvulaceae (Cuscuta): flowers are needed: fused corolla with 5 lobes (Cassytha with free tepals in 3s). Fagaceae: stipules present, flowers tiny, wind pollinated, fruit a single-seeded nut subtended by a woody cupule. Magnoliaceae: stipules present, petals large and showy, fruit many-seeded.

Morphology General Habit

Trees or shrubs (Cassytha a twining parasite); cut parts often aromatic- Sap absent

Morphology General Hair

Hairs where present, simple

Morphology Leaves Stipules

Stipules absent

Morphology Leaves

Leaves simple; usually alternate, rarely subopposite (especially in Cinnamomum) or apparently whorled; margins entire, leaves sometimes lobed (e.g. Sassafras); often coriaceous, young leaves sometimes red, glaucous below; tripli- or trinerved, lower venation orthogonally arranged; aromatic when crushed

Morphology Reproductive morphology Inflorescences

Inflorescences axillary, occasionally pseudoterminal; usually branched: thyrsoid or pseudo-umbellate with several umbels of flowers; often enveloped in bracts (Litsea, Lindera and Neolitsea)

Morphology Reproductive morphology Flowers

Flowers bisexual and/or unisexual, actinomorphic, very small, yellowish, greenish or white; 3-merous (rarely 2-merous), 2 equal whorls of 3 tepals each; 3 whorls of fertile stamens, 1 inner whorl of sterile staminodes; anthers 2- or 4-locular opening by flaps (valves); ovary unicarpellate, superior, with a single ovule

Morphology Reproductive morphology Fruits

Fruit a berry or drupe with the receptacle or pedicel enlarged surrounding the base of, or entirely enclosing, the fruit

Morphology Reproductive morphology Seeds

Seed 1.

Note

Trees or shrubs. Leaves alternate or spiral, glaucous below, stipules absent. Flowers 3-merous, small, tepals undifferentiated, anthers opening by flaps; ovary superior; pedicel/receptacle often enlarging and enclosing the single-seeded fruit.

Distribution

A pantropical group with approximately 55 genera and at least 2,500 species. Generic delimitation is problematic, and many taxa are in need of revision. The family is an important component of tropical forests, but its diversity extends into temperate regions; for example, there are ca. 140 species in Australia and ca. 450 species in China.

Description Author

Timothy Utteridge

Lauraceae, Bernard Verdcourt. Flora of Tropical East Africa. 1996

Morphology General Habit

Mostly evergreen trees (often tall with buttresses), shrubs or, in Cassytha, parasitic twiners with scale-like leaves

Morphology Leaves

Leaves simple, alternate or occasionally opposite, entire to slightly undulate or, in about six SPECIES, lobed, usually coriaceous; stipules absent

Morphology Reproductive morphology Flowers

Flowers usually small, mostly green or yellow, regular, unisexual or hermaphrodite, in cymes, false umbels, heads, spikes, panicles or occasionally solitary; bracts small or absent or, in a few genera, forming an involucre at the base of the inflorescences or partial inflorescences

Morphology Reproductive morphology Flowers Perianth

Perianth-lobes usually ± equal, in 2 whorls of (2-)3, imbricate or in ± one whorl

Morphology Reproductive morphology Flowers Androecium

Stamens and staminodes usually twice as many as perianth-segments, in 4 (rarely more) whorls; innermost whorl and occasionally 2 outer whorls reduced to staminodes; filaments of third whorl usually with 2 ± stalked or sessile glands on either side, the stalk sometimes adnate to the filament, rarely all or none with glands; anthers with 2-4 thecae opening by valves, those of the outer stamens introrse, those of the third series often extrorse

Morphology Reproductive morphology Flowers Gynoecium

Ovary unicarpellate, sessile, free or in a few genera adhering to the calyx-tube and appearing inferior, 1-locular; ovule 1, pendulous, anatropous

Morphology Reproductive morphology Fruits

Fruit a 1-seeded berry or dry but indehiscent

Morphology Reproductive morphology Seeds

Seeds with endosperm; cotyledons large

Timothy Utteridge & Gemma Bramley (2020). The Kew Tropical Plant Families Identification Handbook, Second Edition. Kew Publishing Royal Botanic Gardens, Kew

Note

Leaves alternate or spiral, glaucous below, stipules absent. Flowers 3-merous, small, tepals undifferentiated, anthers opening by flap; ovary superior; pedicel/receptacle often enlarging and enclosing the 1-seeded fruit.

Recognition

Characters of similar families: Annonaceae: flowers large, stamens numerous, anthers linear, compound fruit. Magnoliaceae: petals large and showy, fruit many-seeded. Monimiaceae: leaves opposite or subopposite, compound fruit of many fruitlets on a swollen axis. Myristicaceae: red sap when cut, fruit leathery, dehiscent, seed surrounded by an aril. Icacinaceae: cut parts not aromatic, often climbing, anthers not opening with flaps, ovary with 2 ovules.

Morphology General Habit

Trees or shrubs (Cassytha, a twining parasite); cut parts often aromatic. Sap lacking

Morphology General Hair

Hairs where present, simple

Morphology Leaves Stipules

Stipules lacking

Morphology Leaves

Leaves simple; usually alternate, rarely subopposite (especially Cinnamomum) or apparently whorled; margins entire; often coriaceous, young leaves sometimes red, glaucous below; tripli- or trinerved, smaller veins arranged orthogonally (‘boxy’); aromatic when crushed

Morphology Reproductive morphology Inflorescences

Inflorescences axillary, occasionally pseudoterminal; usually branched: thyrsoid or pseudo-umbellate with several umbels of flowers; inflorescences often enveloped in bracts (Litsea, Lindera and Neolitsea)

Morphology Reproductive morphology Flowers

Flowers bisexual and/or unisexual, actinomorphic, very small, yellowish, greenish or white; 3-merous (rarely 2-merous), 2 equal whorls of 3 tepals each; 3 whorls of fertile stamens, 1 inner whorl of sterile staminodes; anthers 2- or 4-locular opening by flaps (valves); ovary unicarpellate, superior, with a single ovule

Morphology Reproductive morphology Fruits

Fruit a berry with receptacle or pedicel enlarged surrounding the base of, or entirely enclosing, the fruit

Morphology Reproductive morphology Seeds

Seed 1.

Distribution

A pantropical group with c. 50 genera and 2,500–3,500 species. Generic delimitation is problematical, and many groups are in need of revision. Main centres of diversity are Asia and South America; Africa is relatively poor in species.

Ecology

Often an important component of tropical montane forests, but diversity is greater in the lowland rain forest.

Description Author

Timothy Utteridge

George R. Proctor (2012). Flora of the Cayman Isands (Second Edition). Royal Botanic Gardens, Kew

Morphology General Habit

Trees, shrubs, or leafless parasitic herbs; leaves alternate and simple; stipules lacking

Morphology Reproductive morphology Flowers

Flowers perfect or dioecious, axillary panicles or (in Cassytha) in spikes; perianth segments usually 6, in 2 whorls, fused below into a short tube that develops into a cupule at the base of the fruit

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens in a double ring, an outer ring of 6 perfect stamens and an inner ring of which 3 are perfect, all opening by valves, alternating with 3 staminodes that are often very small or apparently lacking

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary superior, free from the perianth tube, 1-celled with 1 pendulous ovule

Morphology Reproductive morphology Fruits

Fruit a 1-seeded berry (drupe), with the persistent perianth tube usually forming a cupule at the base, or else enveloped by the fleshy receptacle; seed relatively large, without endosperm, the cotyledons thick and fleshy.

Distribution

A chiefly pantropical family of about 32 genera and more than 1,100 species, especially common in S. America and southeast Asia.

Lauraceae, B.L. Stannard. Flora Zambesiaca 9:2. 1997

Morphology General Habit

Evergreen monoecious, or dioecious polygamous trees or shrubs, rarely leafless twining parasitic herbs with haustoria (Cassytha), all parts usually with aromatic oil glands

Morphology Leaves

Leaves alternate, rarely opposite or subopposite, entire, coriaceous, rarely membranaceous, pinnately nerved or 3–5-nerved from near the base, usually net-veined, leaves reduced to small scales in Cassytha; stipules lacking

Morphology Reproductive morphology Inflorescences

Inflorescences of cymes or paniculately arranged cymes, racemes or heads; flowers rarely solitary, axillary, usually subterminal; bracts simple, involucrate, deciduous; bracteoles present or lacking

Morphology Reproductive morphology Flowers

Flowers hermaphrodite, unisexual by abortion, greenish, yellowish or reddish, actinomorphic

Morphology Reproductive morphology Flowers Receptacle

Receptacle campanulate, cup-shaped or urceolate, rarely oblong, sometimes accrescent after flowering

Morphology Reproductive morphology Flowers Perianth

Perianth (2)3-merous in 2 whorls, not differentiated into calyx and corolla; tepals (4)6(8) free or ± connate, all similar or the outer ones smaller than the inner, imbricate or valvate in bud, deciduous or persistent

Morphology Reproductive morphology Flowers Androecium

Stamens usually in 4 whorls inserted in the throat of the receptacle, or at the base of and opposite to the tepals, usually the fourth whorl, and sometimes the third whorl staminodal; filaments usually present and free, ± flattened, varying from very short to much longer than the anthers, those of the inner whorls mostly with a pair of globose glands at the sides or at the base (less often the glands attached to the receptacle, or sometimes the outer stamens with glands at the base); anthers basifixed, 2–4-celled, rarely 1-celled by confluence, cells ± collateral, or superposed (in 4-celled anthers), dehiscing from the base upwards; staminodes tepaloid, sagittate or ligulate

Morphology Reproductive morphology Flowers Gynoecium

Ovary superior, rarely inferior (in Africa, Hypodaphnis), 1-locular; ovule solitary, anatropous from near the apex; style terminal; stigma small, discoid, pointed or unilaterally widened, rarely 2–3-lobed

Morphology Reproductive morphology Fruits

Fruit baccate or drupaceous, indehiscent, free or ± surrounded by the accrescent receptacle, or completely enclosed within it, often borne on a thickened fruiting pedicel

Morphology Reproductive morphology Seeds

Seed 1; testa membranaceous to coriaceous, sometimes adnate to the pericarp and indistinct; endosperm lacking; embryo straight; radicle superior, cotyledons fleshy, sometimes connate

Use

Many species are important as timber trees, whereas others contain aromatic spices of commercial value. Examples of the latter are those producing cinnamon (Cinnamomum zeylanicum) and camphor (C. camphora).