''Lasthenia'', commonly known as goldfields, is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of flowering plants in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Asteraceae Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchi ...

. The genus is named after Lasthenia of Mantinea, a

cross-dressing Cross-dressing is the act of wearing clothes traditionally or stereotypically associated with a different gender. From as early as pre-modern history, cross-dressing has been practiced in order to disguise, comfort, entertain, and express onesel ...

female pupil of the

ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

philosopher

Plato Plato ( ; Greek language, Greek: , ; born BC, died 348/347 BC) was an ancient Greek philosopher of the Classical Greece, Classical period who is considered a foundational thinker in Western philosophy and an innovator of the writte ...

Description

The goldfield genus comprises annual (rarely perennial) herbs that are either

glabrous Glabrousness () is the technical term for a lack of hair, down, setae, trichomes, or other such covering. A glabrous surface may be a natural characteristic of all or part of a plant or animal, or be due to loss because of a physical condition, ...

or hairy. Stems are typically branched and erect, attaining a height of less than . Their opposite leaves, up to in length, have entire margins and

pinnate Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and ...

venation.

Inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

s are characterized by solitary heads (sometimes in

cymes In botany, an inflorescence is a group or cluster of flowers arranged on a plant's stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a main axis ( ped ...

), with

phyllaries In botanical terminology, a phyllary, also known an involucral bract or tegule, is a single bract of the involucre of a composite flower. The involucre is the grouping of bracts together. Phyllaries are reduced leaf-like structures that form one o ...

free or partly fused. The receptacle may present as naked and narrowly conic to

hemispherical A sphere (from Ancient Greek, Greek , ) is a surface (mathematics), surface analogous to the circle, a curve. In solid geometry, a sphere is the Locus (mathematics), set of points that are all at the same distance from a given point in three ...

. The normally yellow ray florets may number 4 to 16, and the

ligule A ligule (from "strap", variant of ''lingula'', from ''lingua'' "tongue") is a thin outgrowth at the junction of leaf A leaf (: leaves) is a principal appendage of the plant stem, stem of a vascular plant, usually borne laterally above g ...

s are typically yellow as well. The numerous disk florets typically have yellow, 5-lobed corollae. Anther tips manifest as acuminate to triangular. Style tips may be triangular or round and are typically hair-tufted. Fruits are less than across, cylindric to obovoid in shape, and black or gray in color. The pappus may present awns or scales, or infrequently neither. The genus is mostly cross-pollinated, with some

insects Insects (from Latin ') are hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed ...

serving as pollinators.

Ecology and horticulture

Goldfield species occur over a range of

habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...

, such as meadows, shrubland and open forest, but tend towards

semiarid A semi-arid climate, semi-desert climate, or steppe climate is a dry climate sub-type. It is located on regions that receive precipitation below potential evapotranspiration, but not as low as a desert climate. There are different kinds of sem ...

conditions. They are commonly found at ephemeral pools and are important plants in coastal regions. They are visited by

Sciaridae The Sciaridae are a family of fly, flies, commonly known as dark-winged fungus gnats. Commonly found in moist environments, they are known to be a pest of mushroom farms and are commonly found in household plant pots. This is one of the least s ...

fungus gnats for nectar, and it is possible that these animals are key pollinators at least for Contra Costa Goldfields (''L. conjugens''). In

horticulture Horticulture (from ) is the art and science of growing fruits, vegetables, flowers, trees, shrubs and ornamental plants. Horticulture is commonly associated with the more professional and technical aspects of plant cultivation on a smaller and mo ...

, most make hardy

ornamental plant Ornamental plants or ''garden plants'' are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars th ...

s, suitable for flower-beds or borders. Autumn is the best time for sowing the seed, but it may also be sown early in the spring.

Species

There are a total of eighteen

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

, seventeen are

endemic Endemism is the state of a species being found only 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 foun ...

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

and one species is only found in

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

. Of the seventeen species found in

, most are endemic to

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

. *'' Lasthenia burkei'' – Burke's goldfields (endemic to California,

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...

) *'' Lasthenia californica'' ::'' Lasthenia californica subsp. californica'' – California goldfields (found in northern California and

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

) ::'' Lasthenia californica subsp. bakeri'' – Baker's goldfields (endemic to California) ::'' Lasthenia californica subsp. macrantha'' – perennial goldfields (endemic to California) *'' Lasthenia chrysantha'' – alkali sink goldfields (endemic to California) *''

Lasthenia conjugens ''Lasthenia conjugens'', commonly known as Contra Costa goldfields, is an endangered species of wildflower endemic to a limited range within the San Francisco Bay Area of the state of California, USA. Specifically this rare species occurs in Na ...

'' – Contra Costa goldfields (endemic to California,

) *'' Lasthenia coronaria'' – crowned goldfields, royal goldfields (found in California and northern

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

) *'' Lasthenia debilis'' – Greene's goldfields (endemic to California) *'' Lasthenia ferrisiae'' – Ferris's goldfields (endemic to California) *'' Lasthenia fremontii'' – Fremont's goldfields (endemic to California) *'' Lasthenia glaberrima'' – smooth goldfields (found in California, Oregon,

Washington Washington most commonly refers to: * George Washington (1732–1799), the first president of the United States * Washington (state), a state in the Pacific Northwest of the United States * Washington, D.C., the capital of the United States ** A ...

, and

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

) *'' Lasthenia glabrata'' ::'' Lasthenia glabrata subsp. glabrata'' – yellow-ray goldfields (endemic to California) ::'' Lasthenia glabrata subsp. coulteri'' – Coulter's goldfields (endemic to California) *'' Lasthenia gracilis'' – common goldfields (found in California,

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

, the

Channel Islands of California The Channel Islands () are an eight-island archipelago located within the Southern California Bight in the Pacific Ocean, off the coast of California. They define the Santa Barbara Channel between the islands and the California mainland. The ...

, and northern

) *'' Lasthenia kunthii'' – Chilean goldfields (found in

vernal pools Vernal pools, also called vernal ponds or ephemeral pools, are seasonal pools of water that provide habitat for distinctive plants and animals. They are considered to be a distinctive type of wetland usually devoid of fish, and thus allow the saf ...

)Ornduff (1966) *'' Lasthenia leptalea'' – Salinas Valley goldfields (endemic to California) *'' Lasthenia maritima'' – maritime goldfields, seaside goldfields (found along the coast and offshore islands and islets from California to British Columbia) *'' Lasthenia microglossa'' – small-ray goldfields (endemic to California) *'' Lasthenia minor'' – coastal goldfields (endemic to coastal and inland California) *'' Lasthenia ornduffii'' – Ornduff's goldfields (endemic to Oregon) *'' Lasthenia platycarpha'' – alkali goldfields (endemic to California)

References

* (2006)
''Lasthenia.'' In ''Flora of North America North of Mexico, Vol. 21: Asteraceae.'' Flora of North America Editorial Committee (eds.). Oxford University Press, New York, New York.
* (1966): A biosystematic survey of the goldfield genus ''Lasthenia'' (Compositae: Helenieae). ''University of California Publications in Botany'' 40: 1-92. * (2004)
Gardening for the Million.
{{Authority control Asteraceae genera