''Orites acicularis'', commonly known as yellow bush, is an angiosperm endemic to

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

and is a member of the genus ''

Orites ''Orites'' is a genus of 9 known species, 7 endemic to Australia (4 of which occur in Tasmania) and 2 in South America; 1 in the Chilean Andes and 1 in Bolivia. Species This listing was sourced from the ''Australian Plant Name Index'' and ot ...

'' within the 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 was first described in 1810 by Scottish botanist Robert Brown in ''Transactions of the

Linnean Society of London The Linnean Society of London is a learned society dedicated to the study and dissemination of information concerning natural history, evolution, and taxonomy. It possesses several important biological specimen, manuscript and literature colle ...

.''

Description

''Orites acicularis'' is a yellow-green coloured, woody, rounded shrub growing to approximately 1–1.5 m (3.28–4.92 ft) in height and 0.5–1 m (1.64–3.28 ft) in width, with many ascending branches. The leaves are of a conspicuous yellow-green colour; they are glabrous,

sclerophyll Sclerophyll is a type of vegetation that is adapted to long periods of dryness and heat. The plants feature hard leaf, leaves, short Internode (botany), internodes (the distance between leaves along the stem) and leaf orientation which is paral ...

ous, approximately 10-35mm long, and rounded. They taper to a sharp point, which is typically more yellow than the rest of the leaf. The adaxial surface of the leaf has a shallow central groove, and the leaf margins are entire. Leaves attach to the woody stem by a 2–5 mm petiole. Flowering occurs in December, and presents upon a rachis which can be terminal or axillary. The perianth is homochlamydeous; it comprises four white-cream

tepal A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated (i.e. of very ...

s with a groove running along the centre, and curling under to display the pink style. The immature fruit is a green similar to that of the leaves. The fruits are glabrous and oblong, with an elongated tip of reddish brown. When mature, the follicle is lignified and erect, approximately 15 mm long, and boat-shaped. The boat shape is due to the seeds having been released immediately upon maturity.

Habitat and distribution

''Orites acicularis'' commonly occurs in Tasmanian sub-alpine mountain plateaus, heaths, and boulder fields with a geology of

dolerite Diabase (), also called dolerite () or microgabbro, is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. Diabase dikes and sills are typically shallow intrusive bodies and often exhibit fine-grained ...

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 undergro ...

, and

diorite Diorite ( ) is an intrusive igneous rock formed by the slow cooling underground of magma (molten rock) that has a moderate content of silica and a relatively low content of alkali metals. It is intermediate in composition between low-silic ...

. Dolerite's slow rate of erosion results in shallow, low-nutrient soils with an abundance of rock fragments. In sub-alpine plateaus, depressions form in the boulder fields. There, vegetable and mineral matter accumulate, creating

bog A bog or bogland is a wetland that accumulates peat as a deposit of dead plant materials often mosses, typically sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, mosses, quagmire, and muskeg; a ...

s or smaller areas of deep

soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former te ...

. Similarly,

bolster heath Bolster heath or cushion moorland is a type of vegetation community that features a patchwork of very low growing, tightly packed plants found at the limits of some alpine environments. The cushion plants form a smooth surfaced 'cushions' from sever ...

impedes drainage, creating shallow

peat Peat (), also known as turf (), is an accumulation of partially decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, moors, or muskegs. The peatland ecosystem covers and is the most efficien ...

s. Other species of plants that commonly grow in this habitat include: ''

Gleichenia alpina ''Gleichenia alpina'', commonly known as alpine coral-fern, is a small fern species that occurs in Tasmania and New Zealand. It grows in alpine and subalpine areas with moist soils and is a part of the Gleichrniaceae family. The species was fir ...

'', ''

Astelia alpina ''Astelia alpina'' called pineapple grass, silver astelia, or perching lily is a commonly found species in alpine and subalpine areas of Tasmania and the Australian Alps.Pickering, C.M., Jordan, M., and Hill, W. (2004) "Sexual dimorphism and sex ...

'', ''

Baeckea gunniana ''Baeckea gunniana'', commonly known as alpine baeckea, is a species of flowering plant in the family Myrtaceae and is endemic to alpine and sub-alpine areas of south-eastern Australia. It is a densely-branched shrub with egg-shaped to oblong l ...

'', ''

Bauera rubioides ''Bauera rubioides'', commonly known as river rose, dog rose or wiry bauera, is a species of flowering plant in the family Cunoniaceae and is endemic to south-eastern Australia. It is a scrambling, tangled shrub with wiry branches, wikt:trifoliat ...

'', '' Orites revoluta'', ''

Richea sprengelioides ''Richea sprengelioides'' is a species of flowering plant in the family Ericaceae. It is one of the 11 species within the genus ''Richea'' that are endemic to Australia, of which 9 are found only in Tasmania. The species was first formally descr ...

'', ''

Tasmannia lanceolata ''Tasmannia lanceolata'' ( syn. ''Drimys lanceolata''), commonly known as Tasmanian pepperberry or mountain pepper, is a shrub native to woodlands and cool temperate rainforest of south-eastern Australia. The shrub varies from 2 to 10 m high. T ...

'', and ''

Eucalyptus coccifera ''Eucalyptus coccifera'', commonly known as the Tasmanian snow gum, is a small to medium-sized tree endemic to Tasmania. It has smooth, grey and cream-coloured bark, elliptic to lance-shaped adult leaves, flower buds in groups of between three a ...

''.

Adaptations to solar radiation

''Orites acicularis'' has evolved a number of characteristics to assist with protection from solar radiation in excess of its photosynthetic requirements. Two such adaptations are its abaxial pseudohypodermis and its bundle sheath extensions. Bundle sheath extensions are formed when sclerenchyma and/or collenchyma cells around a bundle sheath extend to both the adaxial and abaxial epidermis layers of a leaf. The evolution of these bundle sheath extensions in species restricted to open vegetation in the family Proteaceae suggests that it is a recurring adaptation to provide protection against the high levels of solar radiation present. The ''Orites''-type abaxial pseudohypodermis is defined as multiseriate, elongate sclerids forming a reticulum around the sub-stomatal cavities (Jordan et al. 2005) and acts as a further barrier to solar radiation that lies just below the

cuticle A cuticle (), or cuticula, is any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticle" are non- homologous, differing in their origin, structu ...

of the plant.

Etymology

The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

, , is derived from

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

and means "needle-shaped".

References

{{Taxonbar, from1=Q18078527 acicularis Endemic flora of Tasmania Plants described in 1810