''Corybas trilobus'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of terrestrial

orchid 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 ...

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 ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

. It is part of the ''C. trilobus''

aggregate Aggregate or aggregates may refer to: Computing and mathematics * collection of objects that are bound together by a root entity, otherwise known as an aggregate root. The aggregate root guarantees the consistency of changes being made within the ...

, whose members are characterized by a funnel or dish-shaped labellum and an often heart or kidney-shaped solitary leaf.

Description

''Corybas trilobus'' is a variable 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 ...

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 ...

whose boundaries continue to be further delineated. The following description adheres to its 2016 delineation ''sensu stricto.'' ''C. trilobus'' has a single reniform (kidney-shaped) leaf born on a petiole that is 13–24 mm long. The leaf itself is at least 18 mm in diameter and is longer than it is wide; its apex is broad but ends ends with a sudden sharp point, and its base is distinctly two-lobed. The single flower is held on a peduncle with a small, slender floral bract; the ovary is pale yellow-green and ribbed. The flower is characteristically mostly pale-colored except for its labellum margins. The dorsal

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 ...

arches over the labellum and is broadly rounded at the apex; it is green and does not extend past the labellum. It presses firmly against the apex of the labellum and does not fold backwards. The lateral sepals are long and filiform (thread-like), often crimson at the base and fading to crystalline pink or white near the tips. The petals are similar though noticeably shorter; they still exceed 43 mm. The labellum is translucent green, but its borders tend to be streaked or splotched with crimson-maroon. It is strongly downturned and rounded. Flowering occurs from September to November. The peduncle elongates greatly as the capsule ripens. ''Corybas trilobus'' can be confused with several other species, some in the ''C. trilobus'' species complex and some not. Its distinguishing features include its dorsal sepal, which must not extend past the labellum or be reflexed, its strongly reniform leaves, which are wider than they are long, its mostly pale, elliptic flowers but with slightly pigmented labella, and its long petiole and petals.

Taxonomy

''Corybas trilobus'' was first described by Joseph Hooker in 1853 as ''Nematoceras trilobum''. Its name was subsequently changed by Hooker in 1864 to ''Corysanthes triloba''. In 1871, Heinrich Gustav Reichenbach changed its name to ''Corybas trilobus''. Since then, multiple similar species have been described and placed within the ''C. trilobus'' aggregate. In 2016, Carlos Lehnebach split off 5 new species from ''C. trilobus'': '' C. confusus'', '' C. obscurus'', '' C. sanctigeorgianus'', '' C. vitreus'', and '' C. walliae''. Furthermore, using Bayesian analyses and maximum parsimony analyses, Lehnebach found that not all of the newly described species may fall within a single clade.

Distribution and habitat

''Corybas trilobus,'' like its close relatives, primarily inhabits the understories of southern beech forests consisting of '' Nothofagus''.

References

{{Taxonbar, from=Q10261100

trilobus ''Trilobus'' Bruennich, 1781 is a disused genus of trilobites, the species of which are now all assigned to other genera. * ''T. caudatus'' = '' Dalmanites caudatus'' * ''T. punctatus'' Bruennich, 1781 = '' Encrinurus punctatus'' ''Trilobus'' ...

Endemic orchids of New Zealand