Lupinus L.

Scientific Description

Family Papilionaceae. Genisteae.

Habit and leaf form. Shrubs (often with long- and short-shoots), or herbs; deciduous; not resinous. Plants unarmed. The herbs annual; plants with neither basal nor terminal concentrations of leaves. Helophytic, or mesophytic. Leaves small to large; fasciculate, or not fasciculate; alternate; spiral; ‘herbaceous’; not imbricate; petiolate; non-sheathing; not gland-dotted; compound (usually, always in ours); more or less peltate, or not peltate; pulvinate to epulvinate; palmate. Leaflets 5–17; not stipellate; epulvinate; flat, or folded; without lateral lobes. Leaf blades dorsiventral. Leaves with stipules. Stipules intrapetiolar; adnate to the petiole; free of one another; usually subulate; persistent. Leaves without a persistent basal meristem. Stem anatomy. Nodes tri-lacunar, or penta-lacunar. Secondary thickening absent, or developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; not crowded at the stem bases; in racemes. Inflorescences simple. The terminal inflorescence unit racemose. Inflorescences terminal. Flowers pedicellate; bracteate. Bracts deciduous (caducous). Flowers bracteolate. Bracteoles persistent. Bracteoles adnate to the receptacle (or to the base of the calyx, usually), or not adnate to the receptacle. Flowers small to medium-sized; very irregular; zygomorphic. The floral asymmetry involving the perianth and involving the androecium. Flowers papilionaceous (imbricate-descending, with the posterior petal outside and forming a ‘standard’); basically 5 merous. Floral receptacle with neither androphore nor gynophore. Free hypanthium present, or absent. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; (3–)5; 1 -whorled; gamosepalous (often bassally gibbous); more or less five lobed; imbricate, or valvate; exceeded by the corolla; bilabiate (deeply so, the posterior lip 2-lobed to entire, the anterior entire or shallowly 2 or 3 lobed); persistent; non-accrescent; with the median member anterior. Epicalyx present (representing adnate bracteoles), or absent. Corolla present; 5; 1 -whorled; appendiculate, or not appendiculate. Standard not appendaged. Corolla partially gamopetalous. 4 of the petals joined (the two ventral petals connivent to form the ‘keel’, and the wings apically adnate to enclose it). The joined petals anterior (and lateral). The wings of the corolla adherent to the keel (via their claws), or free from the keel; not laterally spurred. Standard ‘normally’ developed (the limb circular, ovate or oblong); entire; not sericeous. Keel conspicuously exceeded by the wings to about equalling the wings (but enclosed by them); long-acuminate and beaked (straight or upturned); neither coiled nor spiralled; not bent and beaked. Corolla imbricate (descending); plain (the standard sometimes eye-spotted), or with contrasting markings; white, or cream, or yellow, or purple, or violet, or blue; deciduous; non-accrescent. Petals clawed. Androecial members definite in number. Androecium 10. Androecial sequence determinable, or not determinable. Androecial members free of the perianth; all equal, or markedly unequal; coherent (the filaments united basally into a usually closed tube); 1 - adelphous. The staminal tube free from the keel petals. Androecial members 1 -whorled. Androecium exclusively of fertile stamens. Stamens 10; distinctly dissimilar in shape (the anthers alternately long basifixed, short dorsifixed); diplostemonous; both opposite and alternating with the corolla members. Anthers separate from one another, or connivent; dimorphic (long-basifixed, minute- or short-dorsifixed); alternately dorsifixed and basifixed; alternately versatile and non-versatile; dehiscing via pores, or dehiscing via longitudinal slits; latrorse, or introrse; tetrasporangiate. Pollen shed as single grains. Gynoecium 1 carpelled. The pistil 1 celled. Carpels reduced in number relative to the perianth. Gynoecium monomerous; of one carpel; superior. Carpel stylate; apically stigmatic. Style upwardly curved, or bent, or sigmoid (rarely ‘convolute’). Style bearded via an apical tuft to bearded via an apical ring (somewhat), or glabrous. Stigmatic tissue terminal. Carpel 2–50 ovuled (i.e. to ‘many’). Placentation marginal (along the ventral suture). Gynoecium median (the placenta posterior, on the ventral suture). Ovary sessile to stipitate. Ovules pendulous to ascending; biseriate; arillate, or non-arillate; anatropous, or campylotropous to amphitropous, or hemianatropous.

Fruit and seed features. Fruit sessile; non-fleshy; hairy (densely pilose when young). The fruiting carpel dehiscent; a legume. Pods somewhat elongated, or much elongated; not triangular; straight; not becoming inflated; more or less flat to somewhat compressed; regularly constricted between adjacent seeds, or irregularly constricted; transversely septate between the seeds; wingless. Valves of the dehisced pod twisted, or not twisted. Fruit 1 celled; elastically dehiscent, or passively dehiscent. Dispersal unit the seed (usually), or the fruit. Fruit 2–12 seeded. Seeds reniform or circular; endospermic, or non-endospermic; not mucous; usually more or less compressed; small to large; non-arillate (at least,no large, persistent aril). Cotyledons 2; if radicle flexed, accumbent. Embryo chlorophyllous; straight, or curved, or bent. Testa non-operculate. Micropyle zigzag, or not zigzag. Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, biochemistry. Nitrogen-fixing root nodules present. Aluminium accumulation not found. Photosynthetic pathway: C₃.

Geography, cytology, number of species. Adventive (and cultivated). A genus of 150–200 species; 6 species in Western Australia.