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''Placospermum'' is a
''Placospermum coriaceum'' trees grow to 30 m (100 ft) tall in their native rainforests, and are likely to be much smaller in cultivation. Leaves on the youngest plants are simple and oblanceolate, but large lobed intermediate leaves soon appear. These are up to 90 cm (36 in) long with up to nine lobes up to 20 cm (8 in) long each. The adult leaves are once again simple, and are spathulate or oblanceolate and up to 17 cm (7 in) long and leathery. The pinkish flowers grow in
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of a single species of large trees, constituting part of the plant family Proteaceae
The Proteaceae form a family of flowering plants predominantly distributed in the Southern Hemisphere. The family comprises 83 genera with about 1,660 known species. Together with the Platanaceae and Nelumbonaceae, they make up the order Pro ...
. The species ''Placospermum coriaceum'' 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 elsew ...
to the rainforests of the wet tropics region of northeastern Queensland
)
, nickname = Sunshine State
, image_map = Queensland in Australia.svg
, map_caption = Location of Queensland in Australia
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, established_ ...
, Australia. Common names include rose silky oak and plate-seeded oak.
History
The genus and species were first formally scientifically described in 1924 by Cyril T. White andWilliam D. Francis
William Douglas Francis (6 March 1889 – 2 January 1959) was an Australian botany, botanist.
Born in Bega, New South Wales, at the age of 17 he moved with his father Alfred, and brother Frederick, from Wollongong, New South Wales, where he ...
. The precise relationships of the genus were unclear, though it was clear it was an early offshoot within the Proteaceae and retained primitive characteristics, until Lawrie Johnson
Lawrence Alexander Sidney Johnson Fellow of the Australian Academy of Science, FAA, (26 June 1925 – 1 August 1997) known as Lawrie Johnson, was an Australian Taxonomy (biology), taxonomic botany, botanist. He worked at the Royal Botanic Garden ...
and Barbara G. Briggs classified it in the subfamily Persoonioideae
The Persoonioideae are a subfamily of closely related genera within the large and diverse family Proteaceae and incorporates such genera as ''Persoonia'', ''Acidonia'', ''Garnieria'', ''Toronia'' and ''Placospermum''.
Like most Proteaceae, the g ...
in their 1975 monograph " On the Proteaceae: the evolution and classification of a southern family". They noted that it had large chromosomes, like those of ''Persoonia
''Persoonia'', commonly known as geebungs or snottygobbles, is a genus of about one hundred species of flowering plants in the family Proteaceae. Plants in the genus ''Persoonia'' are shrubs or small trees usually with smooth bark, simple leav ...
'' and allied genera, as well as sharing some other primitive features.
Description
''Placospermum coriaceum'' trees grow to 30 m (100 ft) tall in their native rainforests, and are likely to be much smaller in cultivation. Leaves on the youngest plants are simple and oblanceolate, but large lobed intermediate leaves soon appear. These are up to 90 cm (36 in) long with up to nine lobes up to 20 cm (8 in) long each. The adult leaves are once again simple, and are spathulate or oblanceolate and up to 17 cm (7 in) long and leathery. The pinkish flowers grow in raceme
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 s ...
s at the end of branches. Flattened oval fruit follow, which measure 3.5-4 by 3 cm. Each contains many seeds. Like other members of the Persoonioideae, ''Placospermum coriaceum'' lacks the cluster roots typical of most Proteaceae.
The large lobed immature leaves are an attractive feature, and ''Placospermum coriaceum'' has been cultivated as an indoor plant.
References
{{Taxonbar, from=Q3906158 Proteaceae Monotypic Proteaceae genera Ornamental trees Endemic flora of Queensland