Prunus Totally Explained

Everything about Prunus totally explained

Prunus is a genus of trees and shrubs, including the plums, cherries, peaches, apricots and almonds. It is traditionally placed within the rose family Rosaceae as a subfamily, the Prunoideae (or Amygdaloideae), but sometimes placed in its own family, the Prunaceae (or Amygdalaceae). There are around 430 species of Prunus, spread throughout the northern temperate regions of the globe.
The flowers are usually white to pink, with five petals and five sepals. They are borne singly, or in umbels of two to six or more on racemes. The fruit of all Prunus species is a drupe with a relatively large "stone". Leaves are simple and usually lanceolate, unlobed and toothed along the margin.

Classification

Historical

The first use of prunus as a genus name belongs to Linnaeus in Hortus Cliffortianus of 1737, which went on to become Species Plantarum. In that work Linnaeus attributes the word to "Varr.", who must be Marcus Terentius Varro. The word isn't very frequent in Latin. Pliny uses prunus silvestris to mean the blackthorn.
The Online Etymological Dictionary presents the customary derivations of plum

and prune

from Latin prunum, the plum, which is frequent in a number of authors, including Pliny. The word isn't native Latin, but is a loan from Greek prounos, from proumnos, origin unknown. Most dictionaries follow Hoffman, Etymologisches Wörterbuch des Grieschischen, in making it a loan from a pre-Greek language of Asia Minor, related to Phrygian.
This view can be botanically misleading. The origin of the word isn't the origin of the tree. A possible classical importation of some plum cultivated in Asia Minor doesn't mean that species classified under Prunus today were not in ancient Greece and Italy.
In 1737 Linnaeus used four genera to capture modern Prunus: Amygdalus, Cerasus, Prunus and Padus, but simplified to Amygdalus and Prunus in 1758. Since then various genera of Linnaeus and others have become subgenera and sections, as it clearer that all the Prunus species are more closely related. Liberty Hyde Bailey says: ť "The numerous forms grade into each other so imperceptibly and inextricably that the genus can't be readily broken up into species."

Modern

A recent DNA study of 48 species of Prunus concluded that Prunus is monophyletic and is descended from some Eurasian ancestor.
Historical treatments break the genus up into several different genera, but this segregation isn't currently widely recognised other than at the subgeneric rank. ITIS recognises just the single Genus Prunus, with an open list of species, all of which are shown in the box on the right.
One standard contemporaneous treatment of subgenera derives from the work of Alfred Rehder in 1940. Rehder hypothesized five subgenera: Amygdalus, Prunus, Cerasus, Padus and Laurocerasus. To them C. Ingram added Lithocerasus. The six contemporaneous subgenera are described as follows:

Prunus subgenera:
- Subgenus Amygdalus: almonds and peaches. Axillary buds in threes (vegetative bud central, two flower buds to sides). Flowers in early spring, sessile or nearly so, not on leafed shoots. Fruit with a groove along one side; stone deeply grooved. Type species Prunus dulcis (Almond).
- Subgenus Prunus: plums and apricots. Axillary buds solitary. Flowers in early spring stalked, not on leafed shoots. Fruit with a groove along one side; stone rough. Type species Prunus domestica (Plum).
- Subgenus Cerasus: cherries. Axillary buds single. Flowers in early spring in corymbs, long-stalked, not on leafed shoots. Fruit not grooved; stone smooth. Type species Prunus cerasus (Sour cherry).
- Subgenus Lithocerasus: dwarf cherries. Axillary buds in threes. Flowers in early spring in corymbs, long-stalked, not on leafed shoots. Fruit not grooved; stone smooth. Type species Prunus pumila (Sand cherry).
- Subgenus Padus: bird cherries. Axillary buds single. Flowers in late spring in racemes on leafy shoots, short-stalked. Fruit not grooved; stone smooth. Type species Prunus padus (European bird cherry).
- Subgenus Laurocerasus: cherry-laurels. Axillary buds single. Flowers in early spring in racemes, not on leafed shoots, short-stalked. Fruit not grooved; stone smooth. Mostly evergreen (all the other subgenera are deciduous). Type species Prunus laurocerasus (European cherry-laurel).

Another recent DNA study found that Amygdaloideae can be divided into two clades: Prunus-Maddenia, with Maddenia basal within Prunus, and Exochorda-Oemleria-Prinsepia. Prunus can be divided into two clades: Amygdalus-Prunus and Cerasus-Laurocerasus-Padus. Yet another study adds Empectocladus as a subgenus to the former.

Uses

The genus Prunus includes the almond, apricot, cherry, peach and plum, all of which have cultivars developed for commercial fruit production. The edible part of the almond is the seed; the almond fruit is a drupe and not a "nut". There are also a number of species, hybrids, and cultivars grown strictly as ornamental plants, usually for their profusion of flowers, occasionally for leaves and bark. These ornamentals include the group that may be collectively called flowering cherries (sakura). Other species are grown for hedging, game cover, and other utilitarian purposes. The wood of some species is a minor and specialised timber (cherry wood). Pygeum is a herbal remedy containing extracts from the bark of Prunus africana. It is used as to alleviate some of the discomfort caused by inflammation in patients suffering from benign prostatic hyperplasia.
Because of their considerable value as both food and ornamental plants, many Prunus species have been introduced to parts of the world to which they're not native. Many of the Old World species are grown for ornament or fruit, and have been planted throughout the world; and some have become naturalised beyond their native range. Prunus species are used as food plants for the larvae of a large number of Lepidoptera species (butterflies and moths) . .

Palaeobotanical models

The earliest fossil Prunus are wood, drupe and seed and a leaf from the middle Eocene of the Princeton Chert of British Columbia. Using the known age as calibration data, recent research by Oh and Potter reconstructs a partial phylogeny of some Rosaceae from a number of nucleotide sequences. According to this study Prunus and its "sister clade" Maloideae (apple subfamily) diverged at 44.3 mya (well before most of the Primates existed). This date is within the Lutetian, or older middle Eocene. Stokey and Wehr report: reports that the Rosaceae were more diverse at higher altitudes. The Okanagan formations date to as early as 52 mya, but the 44.3 mya data, which is approximate, depending on assumptions, might still apply. The authors assert: "... the McAbee flora records a diverse early middle Eocene angiosperm-dominated forest."

Further Information

Get more info on 'Prunus'.

External Link Exchanges

Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:

<a href="http://prunus.totallyexplained.com">Prunus Totally Explained</a>

Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned.