''Caladenia tessellata'', commonly known as the thick-lip spider-orchid, is a plant in the orchid family

Orchidaceae Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowering ...

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 elsew ...

to south-eastern

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 ...

. It is a ground orchid with a single hairy leaf and one or two yellowish-green flowers with dark red markings.

Description

''Caladenia tessellata'' is a terrestrial,

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...

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 and a single, sparsely hairy, linear to lance-shaped leaf, 50–100 mm long and 4–9 mm wide. Up to three yellowish-green flowers with dark red marks are borne on a thin, wiry stalk 20–150 mm tall. 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 b ...

s and

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 taper to fine, short, thread-like tips. The dorsal sepal is erect at its base, then curves forward and is 15–25 mm long and 2–3 mm wide. The lateral sepals are 15–25 mm long and 3–5 mm wide, curve downwards and are nearly parallel to each other. The petals are 15–25 mm long and about 2 mm wide and also curve downwards. The labellum is cream-coloured to green, often with a dark red tip and is heart-shaped, 8–9 mm long and wide. The sides of the labellum often have a few short, blunt teeth, the tip is curled under and there are four to six rows of shiny black calli in the lower central part. Flowering occurs in September and October.

Taxonomy and naming

''Caladenia tessellata'' was first formally described by

Robert Fitzgerald Robert Stuart Fitzgerald (; 12 October 1910 – 16 January 1985) was an American poet, literary critic and translator whose renderings of the Greek classics "became standard works for a generation of scholars and students".Mitgang, Herbert (Janua ...

in 1876 and the description was published in his book ''Australian Orchids'' from a specimen collected in Hunters Hill. 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 ...

(''tessellata'') is a

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 ...

word meaning "inlaid with small square stones" or "mosaic" in reference to the labellum appearing to be paved with short, thick calli.

Distribution and habitat

This caladenia is found in near-coastal areas from

Swansea Swansea (; cy, Abertawe ) is a coastal city and the second-largest city of Wales. It forms a principal area, officially known as the City and County of Swansea ( cy, links=no, Dinas a Sir Abertawe). The city is the twenty-fifth largest in ...

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

Westernport Bay Western Port, (Boonwurrung: ''Warn Marin'') commonly but unofficially known as Western Port Bay, is a large tidal bay in southern Victoria, Australia, opening into Bass Strait. It is the second largest bay in the state. Geographically, it is ...

in Victoria although there is a more inland population near Braidwood. It usually grows in grassy woodland.

Conservation

''Caladenia tessellata'' is known from about 19 populations containing a total of 450 plants. Six of these populations are in New South Wales, and in some, no plants have been observed for more than 20 years. The largest N.S.W. population is in the Morton National Park and in Victoria the largest is in the Wilsons Promontory National Park. The species is classified as "vulnerable" under the Australian Government '' Environment Protection and Biodiversity Conservation Act 1999''. The main threats to the species are habitat disturbance caused by activities such as road maintenance, trampling as many plants are near walking tracks, altered fire regimes and browsing by kangaroos and wallabies.

References

{{Taxonbar, from=Q9673993 tessellata Plants described in 1876 Endemic orchids of Australia Orchids of New South Wales Orchids of Victoria (state)