Ornithopus L.

Scientific Description

Family Papilionaceae. Loteae (Coronilleae).

Habit and leaf form. Slender, prostrate or ascending herbs; not resinous. Annual; plants with neither basal nor terminal concentrations of leaves. Helophytic, or mesophytic. Leaves small to medium-sized; alternate; spiral; ‘herbaceous’; not imbricate; petiolate to sessile; non-sheathing; compound; epulvinate; pinnate; imparipinnate. Leaflets (7–)10–37 (‘3–18 pairs’, plus 1); 2–15 cm long; not stipellate; pulvinate, or epulvinate; flat, or folded. Leaf blades dorsiventral. Leaves with stipules. Stipules intrapetiolar; adnate to the petiole; free of one another; scaly. Leaf blade margins entire (small). 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 heads, or in umbels, or in fascicles. Inflorescences simple. The terminal inflorescence unit cymose, or racemose. Inflorescences axillary (pedunculate); pedunculate, few-flowered ‘cymose heads’, compact clusters or ‘umbels’; not pseudanthial. Flowers pedicellate; bracteate, or ebracteate (‘small or absent’, but inflorescences often ‘subtended by floral leaves’); bracteolate, or ebracteolate (‘small or absent’); small; very irregular; zygomorphic; not resupinate. The floral asymmetry involving the perianth and involving the androecium. Flowers papilionaceous (imbricate-descending, with the posterior petal outside and forming the ‘standard’); basically 5 merous. Floral receptacle with neither androphore nor gynophore. Free hypanthium present to absent. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; 5; 1 -whorled; gamosepalous; (five) lobed. Calyx lobes markedly shorter than the tube to about the same length as the tube. Calyx imbricate, or valvate; regular, or unequal but not bilabiate, or bilabiate (then the posterior pair of lobes more connate); non-fleshy; persistent; non-accrescent. Epicalyx absent. Corolla present; 5; 1 -whorled; appendiculate, or not appendiculate (the wings at least sometimes auriculate). Standard not appendaged (but the claw with infolded margins). Corolla partially gamopetalous. 2 of the petals joined (the two ventral petals connivent to form the ‘keel’). The joined petals anterior. The wings of the corolla free from the keel; laterally spurred, or not laterally spurred. Standard ‘normally’ developed; not sericeous. Keel conspicuously exceeded by the wings (almost straight); not long-acuminate/beaked (blunt); neither coiled nor spiralled; not bent and beaked. Corolla imbricate (descending); white, or yellow, or pink; deciduous; non-accrescent. Petals clawed (the claws slender). Fertile stamens present. Androecial members definite in number. Androecium 10. Androecial sequence determinable, or not determinable. Androecial members free of the perianth; markedly unequal (the filaments alternately long and short); coherent (with filaments united basally into a tube); 2 - adelphous (the posterior, vexillary member free of the rest); 1 -whorled (even though diplostemonous). Androecium exclusively of fertile stamens. Stamens 10; distinctly dissimilar in shape (the alternate, longer filaments dilated distally); diplostemonous; both opposite and alternating with the corolla members. Filaments alternately filiform and club-shaped. Anthers separate from one another, or connivent; all alike; dorsifixed; versatile; dehiscing via pores, or dehiscing via longitudinal slits; latrorse, or introrse; tetrasporangiate. Pollen shed as single grains. Fertile gynoecium present. 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 (in-) bent (above the ovary, then straight). Style glabrous. Stigmatic tissue terminal. Carpel 7–50 ovuled (‘many’). Placentation marginal (along the ventral suture). Gynoecium median. Ovary sessile. Stigmas capitate. Ovules pendulous to ascending; biseriate; arillate, or non-arillate; anatropous, or campylotropous to amphitropous, or hemianatropous.

Fruit and seed features. Fruit 20–35 mm long; sessile; non-fleshy; hairy, or not hairy; not spinose. The fruiting carpel indehiscent; a loment. Pods much elongated; not triangular; straight to curved; not becoming inflated; somewhat compressed, or terete; regularly constricted between adjacent seeds; transversely septate between the seeds; wingless. Fruit 1 celled. Dispersal unit the loment segments. Fruit 7–25 seeded (‘many’). Seeds endospermic; not mucous; compressed to not compressed (globular to lenticular); small; non-arillate. Cotyledons 2; accumbent. Embryo chlorophyllous; curved, or bent (the radicle inflexed). Testa non-operculate. Micropyle zigzag, or not zigzag. Seedling. Germination phanerocotylar (the plumule suppressed, with shoots developing from the axils of the cotyledons).

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

Geography, cytology, number of species. Adventive. 2n=14. A genus of 6 species; 3 species in Western Australia.