''Caladenia cremna'', commonly known as Don's spider orchid, is a plant in the orchid family Orchidaceae and is endemic to a small area in Victoria. It is a rare ground orchid with a single hairy leaf and a single yellow flower with red striations.

Description

''Caladenia cremna'' is a terrestrial, perennial, deciduous,

herb In general use, herbs are a widely distributed and widespread group of plants, excluding vegetables and other plants consumed for macronutrients, with savory or aromatic properties that are used for flavoring and garnishing food, for medicinal ...

with an underground tuber. It has a single, dull green, hairy leaf, long and wide with purple blotches at the base. A single yellow flower in diameter and with fine red striations is borne on a spike tall. The

petal Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...

s and sepals are long. The dorsal sepal is erect, wide at the base and tapers to a thread-like end with a dark, purple-red glandular tip long. The lateral sepals are wide at the base and taper to a thread-like end with a tip like that on the dorsal sepal, although shorter. The petals are wide, slightly shorter than the sepals and lack the glandular tip. The petals and sepals spread widely apart and have drooping tips. The labellum is lance-shaped to egg-shaped, long and wide when flattened and curves downward at the tip. It is mostly yellowish with a dark reddish tip. Red teeth on the margins are about long but decreasing in size towards the front. There are four to six rows of well-spaced, foot-shaped calli along the centre of the labellum, decreasing in size towards the front. Flowering occurs in October.

Taxonomy and naming

This species was first formally described by David L. Jones in 2006 and given the name ''Arachnorchis cremna''. The description was published in ''Australian Orchid Research'', based on a specimen found near Whitfield. In 2007, Gary Backhouse changed the name to ''Caladenia cremna'', publishing the name change in ''The Victorian Naturalist''. Jones derived 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 ...

(''cremna'') from "the Greek ''cremnos'', steep, in reference to the steep slope where this species occurs".

Distribution and habitat

Don’s spider orchid grows in eucalypt forest, with an understorey of heath and '' Rytidosperma pallidum'' on steep

slaty Slate gray is a gray color with a slight azure tinge that is a representation of the average color of the material slate. As a tertiary color, slate is an equal mix of purple and green pigments. Slaty, referring to this color, is often used ...

hillsides. It is only known from the area where the

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * Ty ...

specimen was found.

Conservation

Between 18 and 35 plants have been counted in the area of occupation. The species is listed as "Endangered" under the Victorian Government ''

Flora and Fauna Guarantee Act 1988 The ''Flora and Fauna Guarantee Act 1988'', also known as the ''FFG Act'', is an act of the Victorian Government designed to protect species, genetic material and habitats, to prevent extinction and allow maximum genetic diversity within the Au ...

'' and as "Critically Endangered" under the Commonwealth Government '' Environment Protection and Biodiversity Conservation Act 1999'' (EPBC) Act. The main threats to the species are activities associated with road use and maintenance and weed invasion.

References

{{Taxonbar, from=Q15287521 cremna Plants described in 2006 Endemic orchids of Australia Orchids of Victoria (state) Taxa named by David L. Jones (botanist)