Ciato

The cyato (from the Greek: κύαϑος, 'cup') is a special type of inflorescence consisting of a pseudoanthan, that is to say a structure that appears to be a single flower, but actually consists of several flowers. This type of inflorescence occurs only in the Euphorbiaceae family, specifically in the Euphorbia genus, which is one of the most diverse genera within the Plantae kingdom.

Features

The solitary flower-like characteristics of the ciatus are highlighted by brightly colored nectaries often surmounted by petaloid appendages attached to the aforementioned nectaries, or by colored bracts located below the cyathus. These bracts are called cyatophylls in the section Goniostema of the genus Euphorbia.

The cyathi are rarely solitary, but are mostly found forming biparous cymes or compound inflorescences like the pseudoumbela (cyme with an umbel arrangement, but with centrifugal flowering from the center to the periphery).

In a group of the Malagasy species of the section Goniostema of the genus Euphorbia (E. aueoviridiflora, E. capmanambatoensis, E. iharanae, E. leuconeura, E. neohumbertii, E. viguieri) there is a tendency to form an additional pseudonym that grows from the top. Possibly as an adaptation to ornithophilous pollination, the cyathi have specialized in such a way that the cyathophylls are upright, encircling the axis protectively, but rendering the nectaries inaccessible. By way of compensation, among these cyathi there are other naked and sterile ones whose only function is to produce nectar.^{[citation required]}

Structure

A ciato is made up of:

• Five (rarely four) bracteolas, which are small and are united with the free apex, and form a cup-shaped involuc. Alternate with the bracteolas are five nectarios, which are sometimes merged.
• An extremely small female flower located in the center of the base of the involucro. The flower consists of an ovary on a short stem, with pistilo and surrounded by five groups (one at the base of each bracteola) of monandras male flowers (with a single stamen) extremely reduced.

The following is a table showing the various parts of a cyath.

Cutting a stool Tridental euphorbia.:
b →
i → Inflorescence
g → Nectario
ag → Appendice of the obituary
bo → Bracteola
mf → Male flower
a → Antera
ff → Female flower
or → Ovary
s →
pm → Men's flower stick

Footnote