Obconic
Encyclopedia
In botany
Botany
Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...

, an obconic is an inverted cone shape. The term is most frequently applied to certain fruit or hypanthium
Hypanthium
A hypanthium is a floral structure consisting of the bases of the sepals, petals, and stamens fused together. Its presence is diagnostic of many families, including the Rosaceae, Grossulariaceae, and Fabaceae...

 structures with the apical end attached to the stem; however, less frequently the usage may apply to the pistil structure. In the case of fungi the designation is often made to the ascosphore. The use of obconic in botany dates to at least as early as the nineteenth century; however, some modern usage applies to an entire plant form, such as the shape of a whole shrub. More broadly, in geometry or design, the term can be assigned in an abstract manner to shapes in the natural or man-made world which show an inverted cone design.

Botanical examples

The carnivorous plant
Carnivorous plant
Carnivorous plants are plants that derive some or most of their nutrients from trapping and consuming animals or protozoans, typically insects and other arthropods. Carnivorous plants appear adapted to grow in places where the soil is thin or poor in nutrients, especially nitrogen, such as acidic...

 Nepenthes deaniana
Nepenthes deaniana
Nepenthes deaniana is a tropical pitcher plant endemic to the Philippines, where it grows at an altitude of 1180–1296 m above sea level. The species is known only from the summit region of Thumb Peak, a relatively small, ultramafic mountain in Puerto Princesa Province, Palawan.Nepenthes...

 has pitcher elements that are obconic in shape to capture insects. The hypanthium
Hypanthium
A hypanthium is a floral structure consisting of the bases of the sepals, petals, and stamens fused together. Its presence is diagnostic of many families, including the Rosaceae, Grossulariaceae, and Fabaceae...

 of the western USA plant Heuchera rubescens
Heuchera rubescens
Heuchera rubescens is a species of Heuchera. Its common name is pink alumroot. It is native to the western United States and northern Mexico.-External links:***...

 has one subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 with an obconic structure, while several other subspecies have alternative hypantium geometries, so that the obconic characteristic is a subspecies determinant and diagnostic. The hypanthium
Hypanthium
A hypanthium is a floral structure consisting of the bases of the sepals, petals, and stamens fused together. Its presence is diagnostic of many families, including the Rosaceae, Grossulariaceae, and Fabaceae...

 of the Toyon
Toyon
Heteromeles arbutifolia , and commonly known as Toyon, is a common perennial shrub native to California down to Baja California....

 shrub is also generally obconic in shape. The Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

n tree Eriobotrya
Eriobotrya
Eriobotrya is a genus of about ten species of large evergreen shrubs and small trees in the family Rosaceae, native to east and southeast Asia.-Species:By far the best known species is the Loquat, E...

 latifolia and several other species within the genus Eriobotrya
Eriobotrya
Eriobotrya is a genus of about ten species of large evergreen shrubs and small trees in the family Rosaceae, native to east and southeast Asia.-Species:By far the best known species is the Loquat, E...

 have an obconic calyx, although some individuals manifest clavate calices. The basal portion of the pistil of Pachypodium baronii
Pachypodium baronii
Madagascar palm , also known as bontaka, is a flowering plant in the Dogbane family Apocynaceae . It has the habit of a robust shrub with a spherical or bottle-shaped trunk...

 exhibits the obconic structural design.

As a fungal example the species Pocillum
Pocillum
Pocillum is a genus of fungi in the family Helotiaceae. The genus contains 2 or 3 species.-External links:* at Index Fungorum...

cesatii is noted to have an obconic ascosphore.

Etymology and historical usage

The derivation of the word obconic is based upon the Greek with the common prefix ob, meaning inverted, and the Greek word for angle gon or gonia, followed by the generic suffix ic. Historically botanists have used the designation obconic to describe elements of a plant such as the fruit, hypanthium, calyx or pistil base since at least as early as the nineteenth century, and in modern times the term has been generalized to also refer to an entire plant architectural shape.
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