''Cycas arenicola'' is a species of

cycad Cycads are seed plants that typically have a stout and woody (ligneous) trunk (botany), trunk with a crown (botany), crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants o ...

in the genus ''

Cycas ''Cycas'' is a genus of plants belonging to a very ancient lineage, the Cycadophyta, which are not closely related to palms, ferns, trees or any other modern group of plants. They are evergreen perennials which achieved their maximum diversity in ...

'', native to

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 ...

, in the far north of

Northern Territory The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an states and territories of Australia, Australian territory in the central and central northern regions of Australia. The Northern Territory ...

in the basin of the upper East Alligator River in

Arnhem Land Arnhem Land is a historical region of the Northern Territory of Australia, with the term still in use. It is located in the north-eastern corner of the territory and is around from the territory capital, Darwin. In 1623, Dutch East India Compan ...

. It grows in

Eucalyptus ''Eucalyptus'' () is a genus of over seven hundred species of flowering trees, shrubs or mallees in the myrtle family, Myrtaceae. Along with several other genera in the tribe Eucalypteae, including '' Corymbia'', they are commonly known as euca ...

woodlands on highly

siliceous Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one ...

soils (sandstone derived). They thrive in open situations. The stems reach 1.5 m (rarely 2.5 m) tall, with a diameter of 15–20 cm. The

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

are numerous, 0.9-1.6 m long, pinnate with 180-200 leaflets, glossy bright green above, pubescent beneath with brown pubescence, the leaflets are oriented 60-90 degrees forward without overlapping. The petiole is brown pubescent, 25–35 cm long, armed with spines. The female

cones A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex. A cone is formed by a set of line segments, half-lines, or lines conn ...

open, with

sporophyll A sporophyll is a leaf that bears sporangia. Both microphylls and megaphylls can be sporophylls. In heterosporous plants, sporophylls (whether they are microphylls or megaphylls) bear either megasporangia and thus are called megasporophylls, or mi ...

s 15–20 cm long, grey with orange hairs, each with 4-6 ovules. Margins toothed, with bright orange

sarcotesta The sarcotesta is a fleshy seedcoat, a type of testa. Examples of seeds with a sarcotesta are pomegranate and some cycad seeds. The sarcotesta of pomegranate seeds consists of epidermal cells derived from the integument In biology, an integu ...

when ripened. The male cones are solitary, spindle shaped, 25 cm long and 9 cm diameter. The name derives from Latin ''arena'' and ''-cola'', "sand dweller", the species growing in

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...

habitats. First described in 1993 by Hill, the plant is not thought to be threatened as its range occurs on Aboriginal land and is very remote. The plant is dependent on very dry, seasonally variable conditions, and is susceptible to crown rot.

References

Cycad Pages: ''Cycas arenicola''
{{Taxonbar, from=Q5197915 arenicola Cycadophyta of Australia Endemic flora of Australia Flora of the Northern Territory Near threatened flora of Australia