Such plants usually grow into fairly erect shrubs; and sometimes the main stem thickens to become a trunk, resulting in a small tree.

Plants with a lignotuber, on the other hand, have many stems arising from the underground rootstock, usually resulting in smaller shrubs with a mallee habit.

[4][5] Unusually for members of the family Proteaceae, Adenanthos flowers are solitary, rather than clustered together in large showy inflorescences.

The peduncle has minute basal bracts at its base, and sometimes at its midpoint, providing evidence of the loss of some lateral axes.

Very rarely, an involucre may enclose two flowers rather than just one, providing further evidence of reduction from a complex, multi-flowered inflorescence.

The style-end is released, the style springs erect, and the flower's pollen is thus held aloft where it may be deposited on the face of a nectarivorous bird.

Unlike some other Proteaceae genera, the style-end of Adenanthos shows little evidence of adaption to either of its dual roles.

[9] There is no record in either case of specimens of Adenanthos being seen or collected, but A. cygnorum is fairly common at the Swan River, and A. acanthophyllus occurs at Shark Bay, albeit only at the southern end of Peron Peninsula, where neither expedition is likely to have visited.

The Vancouver expedition discovered King George Sound in September 1791, and during their stay there Menzies collected specimens of many plant species, including two Adenanthos species, A. sericeus[11] Jacques Labillardière, naturalist to Bruni d'Entrecasteaux's expedition in search of the lost ships of Jean-François de Galaup, comte de La Pérouse, visited Esperance Bay on the south coast of Western Australia in 1792, collecting A. cuneatus there.

[10] In December 1801 and January 1802, at the start of Matthew Flinders' famous circumnavigation of Australia, HMS Investigator visited King George Sound for several weeks.

The botanist to the voyage, Robert Brown, made an extensive plant specimen collection, including A. cuneatus, A. sericeus and A. obovatus.

As HMS Investigator was commencing its anticlockwise circumnavigation, a French expedition under Nicolas Baudin was exploring the coastline in a clockwise direction.

There, botanist Jean Baptiste Leschenault de la Tour, assisted by gardener's boy Antoine Guichenot, collected plant specimens including A. cuneatus, A. obovatus and A. sericeus.

Though he did not give an explicit etymology for the genus name therein, the type specimen for A. cuneatus contains annotations that show Labillardière experimenting with various Greek word stems, listing in each case the corresponding Latin transliteration and meaning.

He eventually settled on Adenanthos, formed from the Greek stems άδὴν (aden, glandula, "gland") and ανθος (anthos, flos, "flower").

Irish botanist E. Charles Nelson states that the name refers to the prominent and copiously productive nectaries.

However, neither A. obovatus nor the type subspecies of A. sericeus occurs at any location visited by Labillardière, suggesting that some of his specimens were obtained from some other collector whom he failed to credit.

On the basis of phylogenetic data it is further placed in tribe Leucodendreae, a morphologically heterogeneous group with no obvious diagnostic characters, and dominated by South African genera.

Two species were unusual in having flowers with one sterile stamen, and perianth tubes that are curved and swollen above the middle; these were placed in A. sect.

[20] A phenetic analysis of the genus undertaken by Ernest Charles Nelson in 1975 yielded results in which the members of A. sect.

The south coast of Western Australia, between the Stirling Range and the Fitzgerald River area, is particular diverse, with 17 species occurring on the Esperance Plains alone.

Eastwards along the south coast, the genus occurs in disjunct populations on isolated pockets of siliceous sand surrounded by the calcareous soils of the Great Australian Bight.