Loganiaceae R.Br. ex Mart.

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

Distribution

Its distribution is pantropical with a centre of diversity in Australia and New Caledonia

Morphology General Habit

Some species of Strychnos can be trees, especially in Africa, but all collections of the New Guinea taxa are described climbers or lianas.

Ecology

Annual and perennial herbs, climbers, epiphytes, shrubs and trees.

Recognition

Branch tendrils and spines may be present (Strychnos). Stipules present, interpetiolar or sometimes intrapetiolar, may be inconspicuous. Leaves simple, opposite, rarely whorled, entire, venation pinnate, 3–5-nerved from the base (Strychnos) or curvinerved. Colleters frequently present in leaf axils. Inflorescences terminal or axillary, cymose. Flowers 4–5-merous, usually bisexual, rarely unisexual; calyx lobes acute, fused at the base or free; corolla tubular with 4–5 lobes; stamens the same number as petals, alternating with them, inserted on the corolla tube, usually included; ovary superior, rarely semi-inferior, placentation axile, frequently peltate, ovules 1–many, style 1–2. Fruit superior, capsular, berry-like or drupaceous. Seeds 1–many, endosperm well developed, embryo straight with small cotyledons. Loganiaceae is not an easy family to define and is often confused with Rubiaceae (especially Geniostoma), from which it can be distinguished by its superior ovary

Loganiaceae, A. J. M. Leeuwenberg. Flora Zambesiaca 7:1. 1983

Morphology General Habit

Woody or less often herbaceous plants

Morphology Leaves

Leaves mostly opposite, less often ternate (often in Nuxia, sometimes in Strychnos), occasionally quaternate (sometimes in Nuxia), or sometimes subopposite or alternate (sometimes in Buddlejeae, especially in Buddleja and Nuxia)

Morphology Leaves Stipules

Stipules true or false, present, reduced to lines connecting the petiole bases, or absent; in some cases leaves connate–perfoliate (in some Buddleja spp. with opposite leaves); lamina simple, variously shaped, pinnately veined, entire, incised, or less often lobed; sometimes with 1–3 pairs of basal secondary veins larger and curved along the margin, rendering the leaves seemingly 3–7–veined (most Strychnos spp.)

Morphology Reproductive morphology Inflorescences

Inflorescence usually thyrsoid or otherwise cymose, or 1–flowered, rarely a raceme (Gomphostigma)

Morphology Reproductive morphology Flowers

Flowers regular, mostly hermaphrodite, homo– or (in Mostuea) heterostylous, mostly 4– or 5–merous (corolla and androecium 8–16–merous in Anthocleista), mostly actinomorphic but then often with subequal or unequal sepals, less often subactinomorphic or zygomorphic

Morphology Reproductive morphology Flowers Calyx

Sepals usually green, free or united, usually persistent, imbricate, valvate, or apert in bud

Morphology Reproductive morphology Flowers Corolla

Corolla usually coloured, sympetalous, variously shaped; lobes valvate, imbricate, or contorted in bud

Morphology Reproductive morphology Flowers Androecium

Stamens as many as corolla lobes and alternating with them or sometimes less; filaments free from each other, from much shorter to much longer than the anthers; anthers basifix, often versatile; cells 2 or (outside FZ area) 4, discrete or confluent at the apex, parallel or divergent at the base, dehiscent throughout by a longitudinal slit

Morphology Reproductive morphology Flowers Gynoecium

Pistil simple; ovary superior or sometimes slightly inferior, mostly 2–celled, but sometimes 1–, or 4–celled; style simple, terminal, persistent or ; stigma simple or sometimes branched; ovules 2–many, on an axile placenta attached to the septum or in a unicellular ovary to the bottom (Strychnos spinosa) or parietal

Morphology Reproductive morphology Fruits

Fruit a capsule or a berry, 1–many–seeded

Morphology Reproductive morphology Seeds

Seeds variously shaped, small or large, sometimes winged, with fleshy, starchy, or horny (Mostuea, Strychnos) endosperm surrounding a rather small or large straight embryo

Loganiaceae, C.F.A. Onochie & A.J.M. Leeuwenberg. Flora of West Tropical Africa 2. 1963

Morphology General Habit

Mostly trees and shrubs; stem usually woody

Morphology Leaves

Leaves opposite, simple; stipules present or absent

Morphology Reproductive morphology Flowers

Flowers hermaphrodite, usually actinomorphic, paniculate, corymbose or in globose heads

Morphology Reproductive morphology Flowers Calyx

Calyx-lobes valvate or imbricate

Morphology Reproductive morphology Flowers Corolla

Corolla tubular, lobes 4-16, contorted, imbricate or valvate

Morphology Reproductive morphology Flowers Androecium

Stamens epipetalous, as many as the corolla-lobes and alternate with them, or rarely reduced to 1; anthers 2-celled, opening lengthwise

Morphology Reproductive morphology Flowers Gynoecium

Ovary superior, 2-4-celled; style single; ovules several to numerous, rarely solitary, axile or ascending from the base of each cell

Morphology Reproductive morphology Fruits

Fruit a capsule, berry or drupe

Morphology Reproductive morphology Seeds

Seeds sometimes winged; embryo straight, in the middle of fleshy or cartilaginous endosperm

Loganiaceae, E. A. Bruce and J. Lewis. Flora of Tropical East Africa. 1960

Morphology General Habit

Trees or shrubs (in our area; also herbs elsewhere) with opposite simple leaves; stipules interpetiolar, sometimes reduced to a mere line; latex absent

Morphology Reproductive morphology Inflorescences

Inflorescences usually cymose and moderately branched but sometimes of numerous cymules racemosely arranged

Morphology Reproductive morphology Flowers

Flowers regular, usually hermaphrodite, sometimes heterostylous, usually 4–5-merous (corolla-lobes up to 20 in Anthocleista)

Morphology Reproductive morphology Flowers Calyx

Calyx shortly joined, ± campanulate

Morphology Reproductive morphology Flowers Corolla

Corolla with a short or long tube; lobes imbricate or valvate

Morphology Reproductive morphology Flowers Androecium

Stamens equal in number to and alternate with the corolla-lobes (in our area; more or less numerous elsewhere), the filaments often short

Morphology Reproductive morphology Flowers Nectaries

Disc absent or slight

Morphology Reproductive morphology Flowers Gynoecium

Ovary superior or half-inferior, 2 (rarely 1 or 4)-locular; style 1, rarely divided above; stigmas 1, 2 or 4; ovules usually numerous, sometimes few (rarely 1) on axil placentas, anatropous or amphitropous

Morphology Reproductive morphology Fruits

Fruit a usually septicidally dehiscent capsule (loculicidally dehiscent in >i>Mostuea), berry or drupe

Morphology Reproductive morphology Seeds

Seeds various, sometimes flattened or winged; endosperm present; embryo usually straight; radicle usually inferior