''Discocactus'' 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
tropical
The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...
cacti
A cactus (: cacti, cactuses, or less commonly, cactus) is a member of the plant family Cactaceae (), a family of the order Caryophyllales comprising about 127 genera with some 1,750 known species. The word ''cactus'' derives, through Latin, ...
. ''Discocactus'' plants are endemic to southern Brazil, eastern Bolivia, and northern Paraguay.
These species are in the risk of extinction in the wild.
Description
The species of the genus ''Discocactus'' are depressed spherical to spherical and usually solitary plants, with mostly numerous, at the base somewhat broadened ribs and well-developed warts. The
areole
In botany, areoles are small light- to dark-colored bumps on cactus, cacti out of which grow clusters of Thorns, spines, and prickles, spines. Areoles are important diagnostic features of cactus, cacti, and identify them as a family distinct fr ...
s are usually covered by strong thorns. At the apex of the adult plants, there is a wooly
cephalium
A Cephalium is generally defined as the dimorphism between Sexually mature and immature cacti, often with the confluence of areoles, production of hairs, or periderm development at or underneath the areoles after flowering. The area of which dense ...
, white or shaded with yellow or grey. The terminal cephalium, up to 4 centimeters high, is slightly depressed. It consists of white, yellowish to grayish white wool and may have bristly spines.
The fragrant, white, funnel- or tray-shaped flowers arise at the edge of the cephalium and open at night. Their pericarpel, glabrous at the base, is covered with scales higher up. There is no wool or hair. The slender flower-tube is also covered with scales.
The spherical to club-shaped to oblong, white to pink to bright red fruits are glabrous and slightly fleshy. They open at a vertical slit and have a perennial flower remnant. The fruits contain broadly oval to almost spherical, shiny black seeds that are 2 to 2.5 millimeters long.
Taxonomy
The genus was first described in 1837 by Ludwig Georg Karl Pfeiffer.
The name comes from 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 ...
' (=disc) because of its shape.
Species
All species are listed under Appendix I of
CITES
CITES (shorter acronym for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of inte ...
meaning commercial international trade is prohibited and non-commercial international trade is regulated.
[
, ]Plants of the World Online
Plants of the World Online (POWO) is an online taxonomic database published by the Royal Botanic Gardens, Kew.
History
Following the Convention on Biological Diversity, the Royal Botanic Gardens in Kew launched Plants of the World Online i ...
accepted the following species:
References
Bibliography
* Edward F. Anderson : ''The Cactus Family''. Timber Press: Portland (Oregon), 2001, p. 218-221
* N. L. Britton, J. N. Rose: ''The Cactaceae. Descriptions and Illustrations of Plants of the Cactus Family''. Washington, 1920
External links
*
*
*
photos on www.AIAPS.org
*
photos on www.cactiguide.com
{{Clear
Cacti of South America
Flora of Brazil
Flora of Bolivia
Flora of Paraguay
Cereeae genera
Night-blooming plants