''Teucrium racemosum'', also commonly referred to as either the grey germander or forest germander, is a species of flowering plant in the family

Lamiaceae The Lamiaceae ( ) or Labiatae are a family of flowering plants commonly known as the mint, deadnettle or sage family. Many of the plants are aromatic in all parts and include widely used culinary herbs like basil, mint, rosemary, sage, savory ...

. It 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 Australia and is found in all mainland states, the Northern Territory and the Australian Capital Territory. It grows in floodplains, dry lake beds and open woodlands. A perennial herb, it has four-sided, densely hairy stems, narrow egg-shaped leaves, and white flowers usually arranged singly in leaf axils. It grows to be between 15 and 40 cm tall.

Description

''Teucrium racemosum'' is a

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 ...

that grows to a height of between . It is a root suckering plant, meaning that it spreads by pushing up new shoots around the perimeter of its original base. Due to this root suckering ability, it is not uncommon for the ''Teucrium racemosum'' to spread to a diameter of several metres. The stems are white or greyish and densely covered with curved hairs pressed against the stem but that are usually lost from the stem's ridges. The leaves are a narrow oval shape, densely hairy, especially on the lower surface, usually long and wide. The edges of the leaves are sometimes somewhat lobed, rolled under or wavy. The flowers are usually arranged singly in leaf axils near the ends of branches on a

pedicel Pedicle or pedicel may refer to: Human anatomy *Pedicle of vertebral arch, the segment between the transverse process and the vertebral body, and is often used as a radiographic marker and entry point in vertebroplasty and kyphoplasty procedures ...

that is long. The pedicel is often horizontal near its far end with the flower held erect. 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 are long, densely hairy and fused at the base for about half of their length. The petals are long, with the lower middle lobe usually long, the four

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s long. Flowering occurs from September to June.

Taxonomy

''Teucrium racemosum'' was first described in 1810 by Scottish botanist Robert Brown in ''

Prodromus Florae Novae Hollandiae ''Prodromus Florae Novae Hollandiae et Insulae Van Diemen'' (Prodromus of the Flora of New Holland and Van Diemen's Land) is a flora of Australia written by botanist Robert Brown and published in 1810. Often referred to as ''Prodromus Flora Novae ...

''. ''Teucrium'' is a genus of the family Lamiaceae. The genus ''Teucrium'' was first described by

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

in his work ''

Species Plantarum ' (Latin for "The Species of Plants") is a book by Carl Linnaeus, originally published in 1753, which lists every species of plant known at the time, classified into genera. It is the first work to consistently apply binomial names and was the ...

'' in 1753. ''Teucrium'' has around 300 species, of which 13 are endemic to Australia.

Distribution and habitat

''Teucrium racemosum'' is found in all states and territories of Australia apart from Tasmania. It grows on floodplains, dry lake beds and open woodlands. It is also often found around ephemeral lakes or disturbed areas. also often found around ephemeral lakes or disturbed areas that are usually uninhabitable for most other plants.

Reproduction

As is the case with many Lamiaceae, ''Teucrium racemosum'' uses

gynodioecy Gynodioecy is a rare breeding system that is found in certain flowering plant species in which female and hermaphroditic plants coexist within a population. Gynodioecy is the evolutionary intermediate between hermaphroditism (exhibiting both fem ...

as a method of reproduction. Gynodioecy is a breeding system consisting of male and hermaphroditic plants in a population. Gynodioecy occurs as a consequence of genetic mutation that prevents a hermaphroditic plant from producing

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...

, while keeping the female reproductive parts intact. In gynodioecious species, female plants often have much smaller anthers (the part of the stamen where

is produced) and as a result produce little to no pollen, whilst in hermaphroditic flowers both male and female sexes are functional.''Recent Advances in the Study of Gynodioecy: the interface of theory and empiricism'', Bailey M. & McCauley D.E., 2009, Annals of Botany, 104(4), p, 611-620 Genetic conflict often arises in these plants, and it is a common observation for female plants to produce more seeds and healthier, higher quality seed than the hermaphroditic plants. This is thought to be because of the extra energy that female plants have access to as a result of not producing

. Gynodioecy is an extremely rare form of reproduction, with the ''Teucrium racemosum'' being part of just 1% of all plants that exhibit a gynodioecious mating system.''Pollen-Stigma interference in two Gynodioecious Species of Lamiaceae with Intermediate Individuals'', Rodriguez-Riano T. & Amots D., 2007, Annals of Botany, 100(2), p. 423-431 Flowering occurs from September to June.

Conservation

''Teucrium racemosum'' is listed as "not threatened" by the Western Australian Government

Department of Parks and Wildlife The Department of Parks and Wildlife (DPaW) was the department of the Government of Western Australia responsible for managing lands described in the ''Conservation and Land Management Act 1984'' and implementing the state's conservation and e ...

, and as "least concern" under the Queensland Government ''

Nature Conservation Act 1992 The ''Nature Conservation Act 1992'' is an act of the Parliament of Queensland, Australia, that, together with subordinate legislation, provides for the legislative protection of Queensland's threatened biota. As originally published, it prov ...

'' and the '' Northern Territory Government Territory Parks and Wildlife Conservation Act 1976''.

References