''Calothamnus quadrifidus'' subsp. ''petraeus'' is a plant in the myrtle

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Myrtaceae Myrtaceae, the myrtle family, is a family of dicotyledonous plants placed within the order Myrtales. Myrtle, pōhutukawa, bay rum tree, clove, guava, acca (feijoa), allspice, and eucalyptus are some notable members of this group. All spe ...

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 the

south-west The points of the compass are a set of horizontal, radially arrayed compass directions (or azimuths) used in navigation and cartography. A compass rose is primarily composed of four cardinal directions— north, east, south, and west—eac ...

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 ...

. It is similar to other subspecies of ''Calothamnus quadrifidus'' except that its leaves are linear and somewhat rough and scaly and the stamen bundles are relatively long. (Subspecies ''seminudus'' is similar to ''petraeus'' but has smaller fruit.)

Description

''Calothamnus quadrifidus'' subsp. ''petraeus'' is an erect or spreading shrub which sometimes grows to a height of and lacks a

lignotuber A lignotuber is a woody swelling of the root crown possessed by some plants as a protection against destruction of the plant stem, such as by fire. Other woody plants may develop basal burls as a similar survival strategy, often as a response t ...

. Its leaves are crowded, flat and linear with the outer part slightly expanded, long and wide. The leaves, when mature, are either covered with long soft hairs or they are rough and scaly. The flowers are red and arranged in clusters, usually on one side of the stem amongst the older leaves. 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 are arranged in 4 claw-like bundles, each about long. The outer surface of the floral cup (the

hypanthium In angiosperms, a hypanthium or floral cup is a structure where basal portions of the calyx, the corolla, and the stamens form a cup-shaped tube. It is sometimes called a floral tube, a term that is also used for corolla tube and calyx tube. It ...

) and 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 hairy. Flowering mainly occurs from August to October and is followed by fruits which are woody, roughly spherical capsules, long when mature.

Taxonomy and naming

''Calothamnus quadrifidus'' subsp. ''petraeus'' was first formally described in 2010 by

Alex George Alexander or Alex George may refer to: * Alex George (botanist) (born 1939), Australian botanist *Alexander L. George (1920–2006), American political scientist *Alexander George (philosopher), American philosopher * Alex George (motorcyclist), Sc ...

in ''

Nuytsia ''Nuytsia floribunda'' is a hemiparasitic tree found in Western Australia. The species is known locally as moodjar and, more recently, the Christmas tree or Western Australian Christmas tree. The display of intensely bright flowers during the ...

'' from a specimen collected near Yellowdine. The epithet is said to be from the Greek ''petraeus'', meaning "rocky", in reference to the occurrence on rock outcrops. The proper word in ancient Greek for "rocky" is however ''petraios'' (πετραῖος).Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. Revised and augmented throughout by Sir Henry Stuart Jones with the assistance of Roderick McKenzie.''Oxford: Clarendon Press.

Distribution and habitat

''Calothamnus quadrifidus'' subsp. ''petraeus'' occurs in the area between

Karroun Hill Nature Reserve The Karroun Hill Nature Reserve is a 3097 km2 nature reserve in the Mid West region of Western Australia, about 310 km north-east of Perth. Description The reserve lies at an altitude of 300–480 m above sea level in pastoral ...

, Merredin and Yellowdine 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 ...

, Coolgardie and Mallee biogeographic regions. It grows in sand derived from

granite Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies und ...

quartzite Quartzite is a hard, non- foliated metamorphic rock which was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tec ...

Conservation

''Calothamnus quadrifidus'' subsp. ''petraeus'' is classified as "not threatened" by the Western Australian Government

Department of Parks and Wildlife The Department of Parks and Wildlife (DPaW) was the department of the Government of Western Australia responsible for managing lands described in the ''Conservation and Land Management Act 1984'' and implementing the state's conservation and en ...

References

{{Taxonbar, from=Q20817723 quadrifidus Myrtales of Australia Plants described in 2010 Plant subspecies