Prunus

{{Taxobox | image = Frühling blühender Kirschenbaum.jpg | image_width = 250px | image_caption = Prunus cerasus (Sour Cherry) in bloom | regnum = Plantae | divisio = Magnoliophyta | classis = Magnoliopsida | ordo = Rosales | familia = Rosaceae | subfamilia = Prunoideae or Spiraeoideae

Within the rose family Rosaceae, it was traditionally placed as a subfamily, the Prunoideae (or Amygdaloideae), but was sometimes placed in its own family, the Prunaceae (or Amygdalaceae). More recently it has become apparent that Prunus evolved from within subfamily Spiraeoideae.

Classification

Linnean classification

In 1737 Linnaeus used four genera to include the species of modern Prunus—Amygdalus, Cerasus, Prunus and Padus—but simplified it to Amygdalus and Prunus in 1758. Since then the various genera of Linnaeus and others have become subgenera and sections, as it is clearer that all the species are more closely related. Liberty Hyde Bailey says: :"The numerous forms grade into each other so imperceptibly and inextricably that the genus cannot be readily broken up into species."

Modern classification

A recent DNA study of 48 species 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 is not 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 below, under "Species".

One standard modern treatment of the 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 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. 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

Uses

The genus Prunus includes the almond, apricot, cherry, peach and plum, all of which have cultivars developed for commercial fruit and nut production. The edible part of the almond is the seed; the almond fruit is a drupe, not a true nut. Many other species are occasionally cultivated or used for their seed and fruit.

There are also a number of species, hybrids, and cultivars grown as ornamental plants, usually for their profusion of flowers, sometimes for ornamental foliage and shape, occasionally for their bark. These ornamentals include the group that may be collectively called flowering cherries (including sakura, the Japanese flowering cherries).

Other species such as blackthorn are grown for hedging, game cover, and other utilitarian purposes.

The wood of some species is a minor and specialised timber (cherry wood), usually from larger tree species such as the wild cherry.

Many species produce an aromatic resin from wounds in the trunk; this is sometimes used medicinally. There are other minor uses including dye production.

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 are not native, some becoming naturalised.

Prunus species are food plants for the larvae of a large number of Lepidoptera species (butterflies and moths); see List of Lepidoptera which feed on Prunus.

Toxicity

Many species are cyanogenic; that is, they contain compounds called cyanogenic glucosides, notably amygdalin, which, on hydrolysis, yield hydrogen cyanide (HCN). Although the fruits of some may be edible by humans and livestock (in addition to the ubiquitous fructivory of birds), seeds, leaves and other parts may be toxic, some highly. The plants contain no more than trace amounts of HCN but on decomposition after crushing and exposure to air or on digestion poisonous amounts may be generated. The trace amounts may give a characteristic taste ("bitter almond") with increasing bitterness in larger quantities, less tolerable to people than to birds, which habitually feed on specific fruits.

Species

The lists below are incomplete, but include most of the better known species.

Eastern Hemisphere

Prunus africana

Prunus apetala

Prunus armeniaca

Prunus avium

Prunus bifrons

Prunus buergeriana

Prunus campanulata

Prunus canescens

Prunus cerasifera

Prunus cerasoides

Prunus cerasus

Prunus ceylanica

Prunus cocomilia

Prunus cornuta

Prunus crassifolia

Prunus davidiana

Prunus domestica

Prunus dulcis

Prunus fruticosa

Prunus geniculata

Prunus glandulosa

Prunus gracilis

Prunus grayana

Prunus incana

Prunus incisa

Prunus insititia

Prunus italica

Prunus jacquemontii

Prunus japonica

Prunus korshinskyi

Prunus laurocerasus

Prunus laxinervis

Prunus lusitanica

Prunus maackii

Prunus mahaleb

Prunus mandshurica

Prunus maximowiczii

Prunus minutiflora

Prunus mume

Prunus murrayana

Prunus myrtifolia

Prunus nipponica

Prunus occidentalis

Prunus padus

Prunus persica

Prunus pleuradenia

Prunus pseudocerasus

Prunus prostrata

Prunus rivularis

Prunus salicina

Prunus sargentii

Prunus serrula

Prunus serrulata

Prunus sibirica

Prunus simonii

Prunus sogdiana

Prunus speciosa

Prunus spinosa

Prunus spinulosa

Prunus ssiori

Prunus subhirtella

Prunus tenella

Prunus tomentosa

Prunus triloba

Prunus ursina

Prunus vachuschtii

Prunus verecunda

Prunus × yedoensis

Prunus zippeliana

Western Hemisphere

Prunus alabamensis

Prunus alleghaniensis

Prunus americana

Prunus andersonii

Prunus angustifolia

Prunus besseyi

Prunus buxifolia

Prunus caroliniana

Prunus emarginata

Prunus eremophila

Prunus fasciculata

Prunus fremontii

Prunus havardii

Prunus hortulana

Prunus huantensis

Prunus ilicifolia

Prunus integrifolia

Prunus maritima

Prunus mexicana

Prunus munsoniana

Prunus nigra

Prunus pensylvanica

Prunus pumila

Prunus rigida

Prunus serotina

Prunus sphaerocarpa

Prunus subcordata

Prunus texana

Prunus umbellata

Prunus virginiana

Palaeobotanical models

(Prunus persica) over a 7½ month period, from bud formation in early winter to fruit ripening in midsummer.]] The earliest known 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 (or 43 million years ago, 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 state: "... the McAbee flora records a diverse early middle Eocene angiosperm-dominated forest."

Etymology

The Online Etymology Dictionary presents the customary derivations of plum and prune from Latin prūnum, the plum fruit. The tree is prūnus; however, Pliny also uses prūnus silvestris to mean the blackthorn. The word is not native Latin, but is a loan from Greek προῦνον (prounon) which is a variant of προῦμνον (proumnon), origin unknown. The tree is προύμνη (proumnē). Most dictionaries follow Hoffman, Etymologisches Wörterbuch des Griechischen, in making some form of the word a loan from a pre-Greek language of Asia Minor, related to Phrygian.

The first use of Prunus as a genus name was by Linnaeus in Hortus Cliffortianus of 1737, which went on to become Species Plantarum. In that work Linnaeus attributes the word to "Varr.", who it is assumed must be Marcus Terentius Varro.

Notes

References

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External links

Category:Prunoideae Category:Rosaceae Category:Spiraeoideae