Coastal Bird's Foot Trefoil

Annual, Herbs, Taproot present, Nodules present, Stems erect or ascending, Stems or branches arching, spreading or decumbent, Stems prostrate, trailing, or mat forming, Stems less than 1 m tall, Stems solid, Stems or young twigs glabrous or sparsely glabrate, Leaves alternate, Leaves petiolate, Stipules inconspicuous, absent, or caducous, Stipules persistent, Stipules free, Stipules reduced to glands, Leaves compound, Leaves pinnately 3-foliolate, Leaves palmately 5-11 foliate, Leaves odd pinnate, Leaf or leaflet margins entire, Leaflets opposite, Leaflets alternate or subopposite, Leaflets 3, Leaflets 4, Leaflets 5-9, Leaves glabrous or nearly so, Flowers solitary in axils, or appearing solitary, Flowers in axillary clusters or few-floweredracemes, 2-6 flowers, Inflorescence umbel-like or subumbellate, Inflorescence axillary, Bracts conspicuously present, Flowers zygomorphic, Calyx 5-lobed, Calyx hairy, Petals separate, Corolla papilionaceous, Petals clawed, Petals orange or yellow, Banner petal ovoid or obovate, Wing petals narrow, oblanceolate to oblong, Wing tips obtuse or rounded, Keel tips obtuse or rounded, not beaked, Stamens 9-10, Stamens or anthers dimorphic, alternating large and small, Stamens diadelphous, 9 united, 1 free, Filaments glabrous, Style terete, Style persistent in fruit, Fruit a legume, Fruit unilocular, Fruit freely dehiscent, Fruit elongate, straight, Fruit or valves persistent on stem, Fruit coriaceous or becoming woody, Fruit exserted from calyx, Fruit internally septate between the seeds, Valves twisting or coiling after dehiscence, Fruit glabrous or glabrate, Fruit 2-seeded, Fruit 3-10 seeded, S eeds reniform, Seed surface smooth, Seeds olive, brown, or black.

Acmispon maritimus, synonym Lotus salsuginosus, is a species of legume native to Arizona, California and northwestern Mexico. It is known by the common name coastal bird's-foot trefoil. It grows in many types of mountain, desert, and scrub habitat, not necessarily near the coast. It is an annual herb quite variable in morphology, from petite to bushy, hairless to roughly hairy, and prostrate to erect in form. The slender stems are lined with leaves each made up of pairs of leaflets variable in shape and size. The inflorescence is a small array of 1 to 4 yellow flowers, each up to a centimeter long or so. The elongated flower corolla emerges from a tubular calyx of sepals. The fruit is a legume pod up to 3 centimeters long. Laboratory studies have shown this species, which occurs in wildfire-prone habitat such as chaparral, to have an increased rate of seed germination after exposure to heat.