Caryopsis (grain) (255 31) Cross-section

In botany, a caryopsis (plural caryopses) is a type of simple fruit—one that is monocarpellate (formed from a single carpel) and indehiscent (not opening at maturity) and resembles an

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not ope ...

, except that in a caryopsis the pericarp is fused with the thin seed coat. The caryopsis is popularly called a

grain A grain is a small, hard, dry fruit (caryopsis) – with or without an attached hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and legum ...

and is the fruit typical of the family

Poaceae Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns an ...

(or Gramineae), which includes wheat, rice, and

corn Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. Th ...

. The term ''grain'' is also used in a more general sense as synonymous with

cereal A cereal is any Poaceae, grass cultivated for the edible components of its grain (botanically, a type of fruit called a caryopsis), composed of the endosperm, Cereal germ, germ, and bran. Cereal Grain, grain crops are grown in greater quantit ...

(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

bract In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of ...

Etymology

The name "caryopsis" is derived from the Greek words ''karyon'' and ''-opsis'', meaning "nut" and "having the appearance of", respectively. The term was first used by

Achille Richard Achille Richard was a French botanist, botanical illustrator and physician (27 April 1794 in Paris – 5 October 1852). Biography Achille was the son of the botanist Louis-Claude Marie Richard (1754–1821). He was a pharmacist in the Frenc ...

to refer to the dry, monospermic, indehiscent fruit commonly found in grasses. 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

s, utricles, berries, and nuts. However, others have suggested that these differing fruit structures are representative of caryopsis diversity rather than of entirely different structures. This diverse form of the caryopsis would include the follicle-like form of ''

Crypsis In ecology, crypsis is the ability of an animal or a plant to avoid observation or detection by other animals. It may be a predation strategy or an antipredator adaptation. Methods include camouflage, nocturnality, subterranean lifestyle and ...

'' 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.

References

{{Authority control Fruit morphology