''Pimelea microcephala'', commonly known as mallee rice-flower or shrubby rice-flower is a species of flowering plant in the family

Thymelaeaceae The Thymelaeaceae are a cosmopolitan family of flowering plants composed of 50 genera (listed below) and 898 species.Zachary S. Rogers (2009 onwards)A World Checklist of Thymelaeaceae (version 1) Missouri Botanical Garden Website, St. Louis. It ...

and is

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 ...

to mainland Australia. It is an erect shrub with compact heads of male or female, white to yellow or greenish flowers on separate plants, the heads surrounded by 2 or 4 leaf-like

involucral 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, ...

Description

''Pimelea microcephala'' is an erect,

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproducti ...

shrub that typically grows to a height of and has glabrous stems. Its leaves are arranged in opposite pairs, linear to more or less narrowly elliptic, mostly long and wide on a short petiole. The flowers are white to yellow or greenish and arranged on the ends of branches in compact heads on a

peduncle Peduncle may refer to: *Peduncle (botany), a stalk supporting an inflorescence, which is the part of the shoot of seed plants where flowers are formed *Peduncle (anatomy), a stem, through which a mass of tissue is attached to a body **Peduncle (art ...

long. The flowers are

glabrous Glabrousness (from the Latin '' glaber'' meaning "bald", "hairless", "shaved", "smooth") is the technical term for a lack of hair, down, setae, trichomes or other such covering. A glabrous surface may be a natural characteristic of all or part o ...

inside and usually densely curly-hairy on the outside, on a hairy

pedicel Pedicle or pedicel may refer to: Human anatomy *Pedicle of vertebral arch, the segment between the transverse process and the vertebral body, and is often used as a radiographic marker and entry point in vertebroplasty and kyphoplasty procedures ...

. Male flowers are in heads of 8 to 100 flowers, the floral tube long. Female flowers are in heads of 7 to 12, each long. The

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined ...

s are long and the

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

s of male flowers are shorter than the sepals. Flowering mainly occurs from April to September and the fruit is a succulent, red

nut Nut often refers to: * Nut (fruit), fruit composed of a hard shell and a seed, or a collective noun for dry and edible fruits or seeds * Nut (hardware), fastener used with a bolt Nut or Nuts may also refer to: Arts, entertainment, and media Com ...

Taxonomy

''Pimelea microcephala'' was first formally described by Robert Brown in ''

Prodromus Florae Novae Hollandiae ''Prodromus Florae Novae Hollandiae et Insulae Van Diemen'' (Prodromus of the Flora of New Holland and Van Diemen's Land) is a flora of Australia written by botanist Robert Brown and published in 1810. Often referred to as ''Prodromus Flora Nova ...

'' in 1810. In 1983 S. Threlfall described two subspecies of ''P. microcephala'' in the journal '' Brunonia'', and the names are accepted by the

Australian Plant Census The Australian Plant Census (APC) provides an online interface to currently accepted, published, scientific names of the vascular flora of Australia, as one of the output interfaces of the national government Integrated Biodiversity Information Syst ...

: * ''Pimelea microcephala'' subsp. ''glabra'' (

F.Muell. Baron Sir Ferdinand Jacob Heinrich von Mueller, (german: Müller; 30 June 1825 – 10 October 1896) was a German-Australian physician, geographer, and most notably, a botanist. He was appointed government botanist for the then colony of Vic ...

Tate Tate is an institution that houses, in a network of four art galleries, the United Kingdom's national collection of British art, and international modern and contemporary art. It is not a government institution, but its main sponsor is the U ...

J.M.Black John McConnell Black (28 April 1855 – 2 December 1951) was a Scottish botanist who emigrated to Australia in 1877 and eventually documented and illustrated thousands of flora in South Australia in the early 20th century. His publications assi ...

) Threlfall (previously known as ''Pimelea microcephala'' var. ''glabra'' F.Muell. & Tate ex J.M.Black) has 8 to 64 male flowers, the floral tube long and the flowers sparsely hairy on the outside and often becoming glabrous. * ''Pimelea microcephala'' R.Br. subsp. ''microcephala'' has 13 to 100 male flowers, the floral tube long and the flowers are covered with short, fine, curly hairs on the outside.

Distribution and habitat

Mallee rice-flower grows in shrubland, woodland and mallee, and is widespread in all mainland states of Australia and in the

Northern Territory The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an Australian territory in the central and central northern regions of Australia. The Northern Territory shares its borders with Western Au ...

. It is found in the north-west of Victoria, in inland New South Wales, in the south of the Northern Territory and in the

Avon Wheatbelt The Avon Wheatbelt is a bioregion in Western Australia. It has an area of . It is considered part of the larger Southwest Australia savanna ecoregion. Geography The Avon Wheatbelt bioregion is mostly a gently undulating landscape with low reli ...

, Carnarvon, Coolgardie,

Gascoyne The Gascoyne region is one of the nine administrative regions of Western Australia. It is located in the northwest of Western Australia, and consists of the local government areas of Carnarvon, Exmouth, Shark Bay and Upper Gascoyne. The Ga ...

Geraldton Sandplains Geraldton ( Wajarri: ''Jambinu'', Wilunyu: ''Jambinbirri'') is a coastal city in the Mid West region of the Australian state of Western Australia, north of the state capital, Perth. At June 2018, Geraldton had an urban population of 37,648. ...

Great Victoria Desert The Great Victoria Desert is a sparsely populated desert ecoregion and interim Australian bioregion in Western Australia and South Australia. History In 1875, British-born Australian explorer Ernest Giles became the first European to cross th ...

, Mallee, Murchison

Nullarbor The Nullarbor Plain ( ; Latin: feminine of , 'no', and , 'tree') is part of the area of flat, almost treeless, arid or semi-arid country of southern Australia, located on the Great Australian Bight coast with the Great Victoria Desert to its ...

Pilbara The Pilbara () is a large, dry, thinly populated region in the north of Western Australia. It is known for its Aboriginal peoples; its ancient landscapes; the red earth; and its vast mineral deposits, in particular iron ore. It is also a gl ...

and Yalgoo bioregions of Western Australia. Subspecies ''glabra'' is restricted to the north-west of South Australia.

References

{{Taxonbar, from1=Q7194615, from2=Q110751187, from3=Q51057245

microcephala ''Microcephala'' is a genus of Asian flowering plants in the chamomile tribe within the daisy family. ; SpeciesFlora of New South Wales Flora of the Northern Territory Flora of Queensland Flora of South Australia Flora of Victoria (state) Rosids of Western Australia Malvales of Australia Dioecious plants Plants described in 1810 Taxa named by Robert Brown (botanist, born 1773)