In botany, the term obconic refers to an inverted cone shape. The term is most frequently applied to certain fruit or hypanthium 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 ascospore. 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.[Annette J.G. Wilson, Alexander S. George, Anthony E. Orchard (2001) Flora of Australia, Published by ABRS/CSIRO ] 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
Nepenthes deaniana has pitcher elements that are obconic in shape to capture insects.
[M.R. Cheek and M.H.P. Jebb (1999) Nepenthes (Nepenthaceae) in Palawan, Philippines. Kew Bulletin 54(4): 887–895. ] The
hypanthium of one plant found in the western United States,
Heuchera rubescens, has one
subspecies with an obconic structure, while several other subspecies have alternative hypanthium geometries, so that the obconic characteristic is a subspecies determinant and diagnostic.
[Willis Linn Jepson and James C. Hickman (1993) The Jepson Manual: Higher Plants of California, Published by University of California Press, 1400 pages ] The
hypanthium of the
Toyon shrub is also generally obconic in shape.
[C. Michael Hogan (2008) Toyon (Heteromeles arbutifolia), GlobalTwitcher, ed. Nicklas Stromberg ] The
tree
Eriobotrya latifolia and several other species within the genus
Eriobotrya have an obconic calyx, although some individuals manifest
clavate calices.
[Joseph Dalton Hooker (1879) The Flora of British India, Great Britain India Office, Published by L. Reeve] The basal portion of the pistil of
Pachypodium baronii exhibits the obconic structural design.
As a fungal example the species Pocillum cesatii is noted to have an obconic ascospore.[George Massee (1895) British Fungus-flora: A Classified Text-book of Mycology]
Etymology and historical usage
The derivation of the word
obconic is based upon the
Greek language with the common prefix
ob, meaning
inverted, and the Greek word for angle
gon or
gonia, followed by the generic suffix
ic.
[Laurence Urdang, Alexander Humez and Howard G. Zettler (1982) Suffixes and Other Word-final Elements of English, Contributor Laurence Urdang, Published by Gale Research Co.] 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.
See also
