''Amorpha apiculata'' is a species of papilionate

leguminous A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock fo ...

shrub known commonly as the Baja California false-indigo. It is a very rare narrow

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found els ...

only found in the

Sierra de San Pedro Martir Sierra (Spanish for "mountain range" and " saw", from Latin '' serra'') may refer to the following: Places Mountains and mountain ranges * Sierra de Juárez, a mountain range in Baja California, Mexico * Sierra de las Nieves, a mountain range ...

and its western foothills. It is characterized by a white vexillum, a smooth, hairless fruit and spine-like glands. It is closely related to ''

Amorpha californica ''Amorpha californica'' is a species of flowering plant in the legume family known by the common name California false indigo. It is native to California, Arizona, and northern Baja California, where it grows in the California chaparral and woo ...

''.

Description

This plant is an erect, slender shrub that grows 2 to 5 m tall. On the petioles and rachises of the leaves are spine-like glands. The leaves appear in an ascendant to spreading manner, and are 10 to 20 cm long. The petioles are 1 to 2.5 cm long, and are usually equal to or longer than the width of the lowermost leaflet, with several to numerous of the amber-colored glands. There are 13 to 19 leaflets, each shaped elliptic to oblong-elliptic, mostly 1.5 to 3 cm long and 1 to 1.5 cm wide, and are usually 2.2 to 3.3 times as long as they are wide. The petiolules, which are the stalks that hold the leaflets, are 1.5 to 2.2 mm long. There are 1 to 7

racemes A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the sh ...

, which are 10 to 30 cm long. The

pedicels In botany, a pedicel is a stem that attaches a single flower to the inflorescence. Such inflorescences are described as ''pedicellate''. Description Pedicel refers to a structure connecting a single flower to its inflorescence. In the absenc ...

are 0.8 to 1.2 mm long. The

bracts In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or o ...

are shaped narrowly linear, and are 2.5 to 3 mm long. The

calyx Calyx or calyce (plural "calyces"), from the Latin ''calix'' which itself comes from the Ancient Greek ''κάλυξ'' (''kálux'') meaning "husk" or "pod", may refer to: Biology * Calyx (anatomy), collective name for several cup-like structures ...

tube is shaped narrowly funnelform, 2.5 to 3 mm long. The

vexillum The ''vexillum'' (; plural ''vexilla'') was a flag-like object used as a military standard by units in the Ancient Roman army. Use in Roman army The word ''vexillum'' is a derivative of the Latin word, ''velum'', meaning a sail, which con ...

is 5 to 7 mm long, and about 4 mm wide, broadly ovate and colored white. The

fruits In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particul ...

are about 6 mm long to 2.5 mm wide, and are mostly smooth and free of hair.

Taxonomy

This species was described by

Ira Loren Wiggins Ira Loren Wiggins (1 January 1899 – 28 November 1987) was an American botanist, Curator of the Dudley Herbarium, and Director of the Natural History Museum (1940–1962) at Stanford University. He was a Stanford faculty member from 1929 unti ...

in 1933. Botanist Robert L. Wilbur notes similarities to ''

'', as they

overlap Overlap may refer to: * In set theory, an overlap of elements shared between sets is called an intersection, as in a Venn diagram. * In music theory, overlap is a synonym for reinterpretation of a chord at the boundary of two musical phrases * ...

in range, although he states that both species can be distinguished each other based on vegetative or reproductive characteristics, such as the hairless fruit, white vexillum, and the longer

filaments The word filament, which is descended from Latin ''filum'' meaning "thread", is used in English for a variety of thread-like structures, including: Astronomy * Galaxy filament, the largest known cosmic structures in the universe * Solar filament, ...

on ''A. apiculata''.

Molecular phylogenetics Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

has supported their close relationship, with ''A. californica'' and ''A. apiculata'' creating a well-supported clade. The ''A. californica'' and ''A. apiculata'' clade appears to be the earliest diverging in the genus.

Distribution

This species is one of the rarest species of ''Amorpha'', and is only endemic to the

and its foothills west to

San Quintin San Quintín or San Quintin may refer to : Chile * San Quintín Glacier Mexico *San Quintín, Baja California ** San Quintín Volcanic Field Philippines *San Quintin, Abra *San Quintin, Pangasinan See also * Saint Quentin * Battle of St. Quentin ...

References

{{Taxonbar, from=Q12247807 apiculata Flora of Baja California Endemic flora of Mexico Natural history of the Peninsular Ranges Plants described in 1933