The Rhamnaceae are a large

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. They include all forbs (flowering plants without a woody stem), grasses and grass-like plants, a vast majority of ...

s, mostly trees, shrubs, and some vines, commonly called the buckthorn family. Rhamnaceae is included in the order

Rosales Rosales () is an order of flowering plants.Peter F. Stevens (2001 onwards). "Rosales". At: Trees At: Angiosperm Phylogeny Website. At: Missouri Botanical Garden Website. (see ''External links'' below) It is sister to a clade consisting of Faga ...

. The family contains about 55 genera and 950 species. The Rhamnaceae have a worldwide distribution, but are more common in the subtropical and tropical regions. The earliest fossil evidence of Rhamnaceae is from the Late Cretaceous. Fossil flowers have been collected from the Upper Cretaceous of Mexico and the Paleocene of Argentina. Leaves of family Rhamnaceae members are simple, i.e., the leaf blades are not divided into smaller leaflets.Flowering Plants of the Santa Monica Mountains, Nancy Dale, 2nd Ed. 2000, p. 166 Leaves can be either alternate or opposite. Stipules are present. These leaves are modified into spines in many genera, in some (e.g. '' Paliurus spina-christi'' and ''

Colletia ''Colletia'' is a genus of flowering plants in the family Rhamnaceae, with five species of spiny shrubs. All species of this genus are native to southern South America. They are non-legume nitrogen fixer Actinorhizal plants are a group of angios ...

cruciata'') spectacularly so. ''Colletia'' stands out by having two

axil A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ...

lary buds instead of one, one developing into a thorn, the other one into a shoot. Ceanothus cuneatus1

Helinus integrifolius, blom, Skeerpoort, b

Ziziphus mucronata, blomme, Roodeplaat NR, c

Rhamnus saxatilis (Felsen-Kreuzdorn) IMG 7432

The

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism ...

s are radially symmetrical. There are 5 (sometimes 4) separate sepals and 5 (sometimes 4 or none) separate petals. The petals may be white, yellowish, greenish, pink or blue, and are small and inconspicuous in most genera, though in some (e.g. ''Ceanothus'') the dense clusters of flowers are conspicuous. The 5 or 4

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

s are opposite the petals. The

ovary The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the bod ...

is mostly superior, with 2 or 3

ovule In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the '' integument'', forming its outer layer, the ''nucellus'' (or remnant of the megasporangium), and the f ...

s (or one by abortion). The

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in partic ...

s are mostly berries, fleshy

drupe In botany, a drupe (or stone fruit) is an indehiscent fruit in which an outer fleshy part ( exocarp, or skin, and mesocarp, or flesh) surrounds a single shell (the ''pit'', ''stone'', or '' pyrena'') of hardened endocarp with a seed (''kerne ...

s, or nuts. Some are adapted to wind carriage, but most are dispersed by mammals and birds. Chinese jujube is the fruit of the

jujube Jujube (), sometimes jujuba, known by the scientific name ''Ziziphus jujuba'' and also called red date, Chinese date, and Chinese jujube, is a species in the genus '' Ziziphus'' in the buckthorn family Rhamnaceae. Description It is a smal ...

tree (''Ziziphus zizyphus'') and is a major fruit in China. The American genus ''

Ceanothus ''Ceanothus'' is a genus of about 50–60 species of nitrogen-fixing shrubs and small trees in the buckthorn family (Rhamnaceae). Common names for members of this genus are buckbrush, California lilac, soap bush, or just ceanothus. ''"Ceanothus"' ...

'', which has several showy

ornamental Ornamental may refer to: *Ornamental grass, a type of grass grown as a decoration *Ornamental iron, mild steel that has been formed into decorative shapes, similar to wrought iron work *Ornamental plant, a plant that is grown for its ornamental qua ...

species, has

nitrogen-fixing Nitrogen fixation is a chemical process by which molecular nitrogen (), with a strong triple covalent bond, in the air is converted into ammonia () or related nitrogenous compounds, typically in soil or aquatic systems but also in industry. At ...

root nodule Root nodules are found on the roots of plants, primarily legumes, that form a symbiosis with nitrogen-fixing bacteria. Under nitrogen-limiting conditions, capable plants form a symbiotic relationship with a host-specific strain of bacteria know ...

s. Economic uses of the Rhamnaceae are chiefly as ornamental plants and as the source of many brilliant green and yellow

dye A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution and ...

s. The

wood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of ligni ...

of '' Rhamnus'' was also the most favoured species to make charcoal for use in

gunpowder Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, carbon (in the form of charcoal) and potassium nitrate ( saltpeter) ...

before the development of modern propellants. Alphitonia ponderosa (6691195369).jpg, ''Alphitonia ponderosa'' Mountain flower white flower.jpg, ''Ceanothus'' Ceanothus papillosus var roweanus 2.jpg, ''Ceanothus papillosus'' var. ''roweanus'' at the

Regional Parks Botanic Garden The Regional Parks Botanic Garden is a 10-acre (4 hectare) botanical garden located in Tilden Regional Park in the Berkeley Hills, east of Berkeley, California, in the United States. It showcases California native plants, and is open to the publi ...

, Berkeley, California

Genera

Systematics

Modern

molecular phylogenetics Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

recommend the following clade-based classification of Rhamnaceae:

References

External links

Rhamnaceae of Mongolia in FloraGREIF
{{Taxonbar, from=Q156083 Rosid families