''Acacia cochlearis'', commonly known as the rigid wattle, is a shrub of the genus ''

Acacia ''Acacia'', commonly known as the wattles or acacias, is a large genus of shrubs and trees in the subfamily Mimosoideae of the pea family Fabaceae. Initially, it comprised a group of plant species native to Africa and Australasia. The genus na ...

'' and the subgenus ''Plurinerves''. It is native to an area along the coast from the Goldfields-Esperance to the

Mid West The Midwestern United States, also referred to as the Midwest or the American Midwest, is one of four Census Bureau Region, census regions of the United States Census Bureau (also known as "Region 2"). It occupies the northern central part of ...

regions of

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

Description

The bushy erect pungent shrub typically grows to a height of with branchlets that are ribbed, glabrous or sparsely appressed-puberulous with straight hairs.

Stipule In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole). Stipules are considered part of the anatomy of the leaf of a typical flowering plant, although in many speci ...

s are present only on young fresh shoots. The trunk and branches have smooth green or brown bark. The leathery leaves have

phyllode Phyllodes are modified petioles or leaf stems, which are leaf-like in appearance and function. In some plants, these become flattened and widened, while the leaf itself becomes reduced or vanishes altogether. Thus the phyllode comes to serve the ...

s or are

sessile Sessility, or sessile, may refer to: * Sessility (motility), organisms which are not able to move about * Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant * Sessility (medicine), tumors and polyps that ...

, patent to ascending, inequilateral basally, subulate-linear, elliptic in shape and straight to recurved. They are mostly in length and wide. It blooms from July to October and produces yellow flowers. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

s are simple with 1–3 per axil and peduncles which are long, Heads are globular with a diameter, containing 30-50-flowers that have a deep golden color. The flowers are

pollinated Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds, ...

by many different species of

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...

s. A moderate number of seeds will be produced during favourable seasons. The green-brown pod which forms later is a linear shape and is slightly raised over the seeds. The pod is approximately long and contains between 10 and 15 of mostly viable black seeds. The valves of the pod will recurve once the seed is shed, usually in December.

Taxonomy

The species was first formally described by the botanist

Jacques Labillardière Jacques-Julien Houtou de Labillardière (28 October 1755 – 8 January 1834) was a French biologist noted for his descriptions of the flora of Australia. Labillardière was a member of a voyage in search of the Jean-François de Galaup, comte ...

in 1807 as ''Mimosa cochlearis'' as part of the work ''

Novae Hollandiae Plantarum Specimen ''Novae Hollandiae Plantarum Specimen'' is a two-volume work describing the flora of Australia. Facsimiles of the originals can be found in the onlinBiodiversity Heritage Library (Vol.1)anVol 2) The author was the French botanist Jacques Labillar ...

''. It was then reclassified as ''Acacia cochlearis'' by Heinrich Wendland in 1820 as part of the work ''Commentatio de Acaciis aphyllis''. It was reclassified in 2003 by

Leslie Pedley Leslie Pedley (19 May 1930 – 27 November 2018)IPNILeslie Pedley/ref> was an Australian botanist who specialised in the genus ''Acacia''. He is notable for bringing into use the generic name ''Racosperma'', creating a split in the genus, which r ...

as ''Racosperma cochleare'' then transferred back to genus ''Acacia'' in 2006. The species can be confused with '' Acacia melanoxylon''.

Distribution and habitat

''A. cochlearis'' grows in sandy soils and is found in coastal areas on sandplains and sand dunes. It grows in coastal areas from Lancelin to

Israelite Bay Israelite Bay is a bay and locality on the south coast of Western Australia. Situated in the Shire of Esperance local government area, it lies east of Esperance and the Cape Arid National Park, within the Nuytsland Nature Reserve and the Grea ...

, where it is found growing as solitary plants or in dense thickets.

Uses

The shrub is sold as a suitable medium size shrub for gardens in coastal regions or areas with sandy soils. It is also used to stabilise dune or coastal areas. ''A. cochlearis'' establishes quickly and reliably in stabilised soils. Although it is must be protected from high winds it is utilised in mixed plantings with other species such as '' Acacia rostellifera'' and ''

Scaevola crassifolia ''Scaevola crassifolia'' is a shrub in the family Goodeniaceae, native to Western Australia and South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most ar ...

''. It is an indicator of good quality dunes as the species is vulnerable to disturbance once established.

Cultivation

''A. cochlearis'' can be grown from seed. The seeds should be soaked in hot water or lightly abraded with fine sandpaper prior to planting. They should be sown in free draining soil and can benefit from the addition of disease-free soil from existing plants to transfer the ''Rhizobium'' bacteria that are important in nitrogen fixation. Plants require a position in full sun.

References