{{Short description|Fruit of the grasses (Poaceae)}} {{Use dmy dates|date=April 2017}} thumb|An assortment of different caryopses. [[File:Spiklet.jpg|thumb|Wheat spikelet with the three anthers sticking out.|right]] thumb|Caryopsis cross-section.|right In botany, a '''caryopsis''' ({{plural form|'''caryopses'''}}) is a type of simple fruit—one that is monocarpellate (formed from a single carpel) and indehiscent (not opening at maturity) <ref>{{cite web|title=Caryopsis|url=http://www.merriam-webster.com/dictionary/caryopsis|publisher=Merriam Webster|access-date=31 August 2014}}</ref> and resembles an achene, except that in a caryopsis the pericarp is fused with the thin seed coat.
The caryopsis is popularly called a grain and is the fruit typical of the family Poaceae (or Gramineae), which includes wheat, rice, maize,<ref>{{cite web|title=caryopsis|url=http://www.britannica.com/EBchecked/topic/97667/caryopsis|website=Encyclopædia Britannica|access-date=31 August 2014}}</ref> and oat.<ref>{{cite journal |last1=Pomeranz |first1=Y |last2=Sachs |first2=I. B. |date=February 1972 |title=Scanning electron microscopy of the oat kernel |url=https://www.cerealsgrains.org/publications/cc/backissues/1972/Documents/chem49_20.pdf |journal=Cereal Chemistry |volume=49 |issue=1 |pages=11-13, 20-22 }}</ref>
The term ''grain'' is also used in a more general sense as synonymous with cereal (as in "cereal grains", which include some non-Poaceae). Considering that the fruit wall and the seed are intimately fused into a single unit, and the caryopsis or grain is a dry fruit, little concern is given to technically separating the terms ''fruit'' and ''seed'' in these plant structures. In many grains, the "hulls" to be separated before processing are flower bracts.
==Etymology== The name ''caryopsis'' is derived from the Greek words {{lang|grc-Latn|karyon}} and {{lang|grc-Latn|-opsis}} ({{wikt-lang|grc|κάρυον}} and {{wikt-lang|grc|ὄψις}}), meaning 'nut' and 'having the appearance of', respectively. The term was first used by Achille Richard to refer to the dry, monospermic, indehiscent fruit commonly found in grasses.<ref>{{cite book |title=Analyse botanique des embryons endorhizes ou monocotylédonés, particuliérement de celui des Graminées : suivie d'un examen critique de quelques mémoires anatomico-physiologico-botaniques de M. Mirbel |last1=Richard |first1=Louis-Claude |author1-link=Louis Claude Richard |author2=Charles-François Brisseau de Mirbel |author2-link=Charles-François Brisseau de Mirbel |publisher=Courcier |year=1811 |oclc=15141724 }}</ref>
This definition of fruit for the Gramineae family has persisted to the modern day, but some botanists have challenged the idea that the dry caryopsis is a defining characteristic of the family. The other forms of fruit proposed to be borne by grasses include achenes,<ref name=Felix>{{cite journal |title=Les graminées (Poaceae) d'Afrique tropicale. 1. Généralités, classification, description des genres |last=Jacques-Félix |first=Henri |author-link=Henri Jacques-Félix |year=1962 |publisher=IRAT |journal=Bulletin Scientifique |issue=8 |url=https://agritrop.cirad.fr/369161/ }}</ref> utricles,<ref name=Felix/> berries,<ref>{{cite journal |url=https://academic.oup.com/transactionslinneanbot/article-abstract/6/9/401/2410680 |title=On the Fruit of ''Melocanna bambusoides'', Trin., an Endospermless, Viviparous Genus of ''Bambuseae'' |last=Stapf |first=Otto |journal=Transactions of the Linnean Society of London |volume=6 |number=9 |pages=401–425 |year=1904 |publisher=Oxford University Press }}</ref> and nuts.<ref>{{cite book |title=The world's grasses: their differentiation, distribution economics and ecology |last=Bews |first=John William |year=1929 |publisher=Longmans, Green and Co. }}</ref> However, others have suggested that these differing fruit structures are representative of caryopsis diversity rather than of entirely different structures.<ref>{{cite journal |title=Zlaki SSSR |trans-title=Cereals of the USSR |last=Tsvelev |first=N.N. |journal=Science, Leningrad |year=1976 }}</ref> This diverse form of the caryopsis would include the follicle-like form of ''Crypsis'' and ''Eleusine'' where a free pericarp adjoins the seeds which are extruded when moistened (as in an achene or utricle), the berry-like form found in some bamboo genera including ''Dinochloa'' and ''Olmeca'' where the pericarp is more thick and fleshy, and the nut-like form found in ''Dendrocalamus'' and ''Schizostachyum''. By this definition, the caryopsis is truly the only fruit type found in the Gramineae. The types of caryopsis are often distinguished by the terms "modified caryopsis", referring to caryopses with a pericarp not wholly adnate to the seed coat, and "true caryopsis", referring to those with a pericarp totally adherent to the seed coat.<ref>{{cite book |title=A Survey of Modified Caryopses in the Gramineae |last=Brandenburg |first=D.M. |publisher=American Journal of Botany |volume=72 |number=6 |page=943 |year=1985 }}</ref>
==References== {{Reflist}}
{{fruits}} {{Authority control}}
Category:Fruit morphology