ON THE ORlGIN OF PLUMS: A STUDY OF SLOE, DAMSON, CHERRY PLUM, DOMESTIC PLUMS AND THEIR INTERMEDIA TE FORMS

H. WOLDRING Gral/il/ger 11/.\'/i/1I11i voor Arche% gie, Grol/il/gel/, Ne/her/al/ds

ABSTRACT: In this paper the origin of plums is investigated through a study of intelmediate forms of sloe and damson. Furthelmore the role of cherry plum in connection with the evolution of plums is discussed, as well as the various opinions on the origin of husbanded and feral damson. There is general agreement that damson is the ancestor of our dornestic plums. The cultivation of Prul1us insititia since the Neolithic era, as well as the subsequent development and spread of domestic plums, have led to the emergence of several local varieties in both groups. In order to be informed on the multitude of varieties and range of distribution, the author has collected great numbers of stones of damson varieties and related groups in various parts of Eurore and Anatolia. Fruit stones of both damson and domestic plums are shown to have characteristic varietal differences. This studY has revealed several morphologically intermediate f Olms of sloe and damson. The features of these f Olm s indicate that they result from hybridization between sloe and damson, which implies a close relationship between the species. The conclusions in this study are principally based on results from breeding tests of varieties of damson, sloe, cherry plums and the intermediates, perforrnedduring the years 1989-1997. The tests demonstrate that fruit stones of black­ fruited damson varieties gelminate readily and that the seedlings usually develop into normal shrubs or trees. By contrast, fruit stones obtained from damson specimens with yellow, green Ol' red fruits show seed sterility Ol' produce seedlings characterized by pOOl' growth and viability. These features suggest hybridization and such specimens probably originate from crossings between damson and domestic plums. The characteristics found in the progeny of black-fruited damsons suggest that this group represents the original, botanical species. Fruit stones of cherry plums, irrespective of the colour of the fruits, show high germination capacity while the growth of their seedlings is remarkably homogeneous and vigourous. The strikingly similar features of sloe and black­ fruited damsons, the evidence of their close relationship derived from the hybrid forms and the absence of cherry plum features have led to the conclusion that (black-fruited) damson plums developed directly from forms of sloe. The extreme rareness of intermediates between damson and cherry plum and the striking differences in features between these species indicate that cherry plum did not play a role in the ancestry of the damson.

KEYWORDS: Botany, species, hybridization, intermediates, Prul1us, sloe, damson, cherry plum, origin of domestic plums.

I. INTRODUCTION wild plums in Eurasia include PI'lII1US brigal1tina, an endernicplum with inedible fmits of the southwestern The genus Prunus (Prunoidae subfamily, Rosaceae Alps (France, Italy) and two species related to cherry family) is generally subdivided into four subgenera: plum, which occur locally in theMediterranean: Prullus Prunophora (plums), Cerasus (cherries), Amygdalus cocomilia (Italy, Greece, Turkey) and PI'III1US ursina (almond) and Padus (cherries with f10wers in terminal (Israel to southern Turkey). Russian researchers racernes 'bird cherries '). The genus as a whole comprises distinguish several species related to cherry plum in the 150-200 species, depending on the definition of spe­ Caucasus and centJ'al Asia (Komarov, 1941). cies. Damson (Prunus insititia) is considered the main Within the Prunophora group sloe, cherry plum, progenitor of the large-fruited domestic plums. This damson and domestic plum constitute four closely species is thought to have originated in westernAsia Ol' related species. Sloe is a widely distributed natural southern Russia (e.g. Caucasus; Rybin, 1936) and species of the temperate parts of Europe and Asia. subsequently to have spread over Europe and much of Cherry plums (Prul1us cerasife ra ssp. divaricata) occur Asia by cultivation. Its simple reproduction from wild in central and western Asia and probably also on rootsuckers, plants which develop from roots at some the Balkans. Cultivated and naturalized cherry plums distance from the primm'y tree, has certainly assisted its (Pn/nlls cerasife ra ssp. cerasife ra) are widespread in distribution in the past. Though the fruits of most Europe and Anatolia. Related to these species but illSititia varieties are economically worthless, damsons geographically distant is the Prl/IIIIS sa/icina/trijlora are still much present in gardens, farm-yards, old group, cultivated in east Asia (China, Japan). Other orchards etc. Feral and possibly wild specimens occur

535 536 H. WOLDRING throughout Europe, North Africa and Anatolia. In France Columella (Roach, 1985). Illustrations of plum fmits the species is common in hedgerows and waste places are available from the beginning of book printing. nearvillages. Rikli (1943-1948: p. 675) mentions Prunus Konrad Gesnel' iIIustrated the yellow-fruited 'Ziparte' insititia as a component of holm oak forest in the Tell of central Europe in H istoria Plantartlfl/ (1516-1565), Atlas, Algeria (altitude 1030-1150 m). Another more Ol' while the 'Gelbe Spilling', also a yellow-fruited insititia less natural habitat of the plant inc1udes open places in variety, is illustrated by lTh.Tabernaemontanus (1588). the jungle vegetation that has developed on former Carolus Clusius (1583) published the earliest illustration dunes along the southern coast of the Caspian Sea. All of cherry plums (see also Korber-Grohne, 1996). Other the same, Russian researchers state that in the former old plum varieties, such as the English damsons, are USSR no plums occur in a wild state (Komarov,1 941). illustrated by John Gerard (1597). It is not impossible that wild populations have Studies with the aim to survey the number and value disappeared through cross-breeding with cultivated of plum varieties were canied out in the 18th and 19th specimens. centuries. One of the earliest inventories was drawn up The foregoing means that the origin of damson by Jahn et al. (1850- 1 875). The described fruit varieties plums is unclear. As a polyploid species, damson plums inc1ude almost 300 plum varieties, occurring in Germany probably evolved from another species or from crossings alone. Dutch fmit varieties were listed by Berghuis between Prunus species. According to Rybin (1936) (1868). In the first half of this centuI'Y some specialized plums originate from crossings between sloe (Prunus handbooks were published in the U.S. (Hedrick, 1911), spinosa L.) and cherry plums (Prunus cerasifera Ehrh.). in Britain (Taylor, 1949) and in Sweden (Dahl, 1943). Rybin performed experimental crossings between these Peyre (1945) describes the'w ild' and cultivated plums species, which in one case produced a polyploid plum of France. Mostof these works provide also illustrations resembling the damson. Werneck (1961) assumes a and descriptions of the stones, which aiready indicates great contribution of sloe in the parentage of some the significance the various authors attribute to this part Austrian damson varieties, whereas in others (e.g. of the fruit as a means of identification. In general, 'Weinkrieche') he found dominating features of cherry however, it is difficult to identify unfamiliar varieties plum. His conc1usions were based chiefly on the features from the illustrated stones alone (with the exception of of the fruit stones. Zohary & Hopf (1988) suggest that Dahl, 1943). dam son plums evolved directly from polyploid cherry The folIowing publications highlight the importance plums; they reject the role of sloe in the ancestry of of the fruit stones as identifying features. Roder (1940) damson plums. On the other hand, Korber-Grohne found that the identification of plum varieties is greatly (1996) attributes a significant role to sloe in the facilitated by the characteristics of the stones. His work development of Prunus insititia. inc1udes several plates with fruit stones of (mostly) Prunus fruit stones have morphologically distinct domestic plums. A table with indices of the fruit stones and genetically fixed features, which enables the (and fruits) completes the study. Exceptfor two varieties identification of species and even most varieties of belonging to the var. pomariorum, Roder did not inc1ude plums. This is of special advantage in insititia plums, the insititia plums in his research. In Austria,Werneck since within this group other varietal differences are (1958; 1961) studied the latter group for two reasons. small (fruits 20-25 mm in size, usually round/oval, and First,the rapid decrease of damsons and related groups blue to violet in colour). at the time of research; and secondly, the proven Since 1989 the author has collected fmit stones of hardiness ofthese nongrafted plums to winter conditions damson and related groups in various parts of Europe in Austria. In Austria domestic plums were killed offby and Anatolia with the folIowing objectives: several severe winters this century, so that selected - To trace the unknown origin of dam son and other varieties of illsititia might be of great economic plums; advantage. - To expand the rather scanty knowledge of the Monographs on cherry plums are scarce; an number and geographical distribution of insititia infolmative study is that of Stika & Frank (1988) which varieties; deals with the variability and distribution of modern - To perform basic research in the f Olm of breeding chen'y plums (wild, economic and ornamental) inc1uding tests in order to com pare seedlings of cherry plum, sloe pictures of fruit stones. and dam son varieties with the maternal plants; A thorough study of ancient plum varieties in - To obtain reference material to facilitate iden­ Germany and adjacent regions (Alsace, France and the tification of plum stones from archaeological assem­ north of Switzerland) has been published recently by blages. Korber-Grohne (1996). The origin of the ancient, non­ grafted v-arietiesof plums and prunes, but also of cherry plums, large-fruited forms of sloe and hybrids between 2. STUDIES ON PLUMS sloe and PrLlnusinsititia is discussed in connection with their respective histories as revealed from archaeological The earliest writfen information on fmit and fruit assemblages. cultivation comes from Roman authors, e.g. Pliny and It is impossible to enumerate here all the papers On the origin of plums 537 which discuss and illustrate ancient plum stones. The characteristics. A group that c\em'ly shows features of folIowing are mentioned (see also Korber-Grohne, ssp. insititia and ssp. domes/iea are the typical English 1996): damsons. By their properties,the small-fruited English damson vm'ieties m'e rightly c\assified in the insititia Prunus illsititia group., The small-fruited forms, even though some Neolithic Hopf, 1968 varieties produce pyriform fruits,are no doubt identical Bertsch & Bertsch,1947 to the continental insititia varieties (in terms of the size Bronze Age Jacquat,1988 and shape ofthe fruits and fruit stones). Yet this country Roman Period Baas, 1936; 195 1 also produces varieties with large fruits and stones, e.g. Frank & Stika, 1988 Damson MelTyweather and Bradley's King,which given Maier, 1988 the size of their fruits should be c\assified as domestica Middle Ages Behre, 1978 plums. Their fruits show some resemblance to prunes. Gregor, 1995 In this case it is easier to name the variety than the Knorzer, 1979; 1987 subspecies under which it is c\assified. The presence of KroII, 1980 features of insititia as well as those of domestica in a Opravil, 1976; 1986a; 1986b group with such typical properties as damsons is in all Van Zeist, 1994 probability the consequence of crossings between dam­ 16th/17th centUl'y Behre, 1978 sons and different groups of plums. According to Taylor Van Zeist, 1988 (1949) vm'ieties like Damson Merryweather probably Prunus eerasife ra resulted from such crossings, but the typical dam son Baas, 1936 flavour and bitterness of the fruits were decisive for Kiihn, 1995 their c\assification under the insititia group. Stika & Frank,1988 The identification of vm'ieties is often complicated, PrullUS spinosa ssp. l7IaeroearpalPrunus fr u/ieans firstly because of the number of varieties, and secondly (intermediates) because the properties of these varieties are not always Kiihn, 1995 as constant as is often suggested. Properties such as Opravil,1976 fragrance and taste, the size of the fruits, their time of Van Zeist, 1988; 1994 ripenjng, the degree to which the flesh c\ings to the stone and the presence of pubescence on young twigs are decisive factors used in the identification of insititia 3. SOME NOTES ON THE VALUE OF and domestica varieties (see for instance Hogg, 1884). IDENTIFICATION CRITERIA IN PRUNUS But these features may vary considerably. Some of these properties depend greatly on the weather in the In general the identification of the discussed P/'IInus growing season and on early Ol' late harvesting. Large species does not present difficulties. Untypical cherry yields generally produce smaller fruits (and stones). plums, e.g. specimens with shorter pedicels, may at first The degree of pubescence on one-year-old twigs depends sight be confused with damson plums. Some local greatly on habitat and possibly also on the nature of PrulllIs species in the eastern Mediterranean, such as individuals. As an example we might consider 'St. Prul1us eoeomilia in Greece and Turkey and PrUl1l1S Julien', a well-defined French variety. Pubescent and ursina in western Syria and Lebanon, may be confused glabrous specimens of this variety have been collected with the related cherry plum because of their likeness in in equal numbers in the Morvan region in central foliage and fruits. France. The identification of groups at lower levels (sub­ A general feature in young Prullus specimens is species, varieties) is usually more complicated. Such is spinescence. This is of special significance in cherry the case with cherry plums: cultivated cherry plums plums; in floristic works, the absence of spines is a (PrUI1I1S eerasife ra ssp. cerasife ra) and wild cherry discriminating identification mark of this species. Yet, plums (Prul1us cerasifera ssp. divariea/a) of western of som e 100 specimens raised from stones of various and central Anatolia differ only in minute detail. The origin,al most all developed an abundance of immense subspecies insititia and subspecies dOl1lestiea inc\ude spines in the third or fourth yem' of growth. This such a wide range of forms with so many overlapping spinescence apparently decreases at an older age. Even features that it is hardly possibie to point out diagnostic old specimens of sloe often lose their characteristic features which c\early distinguish the two groups. spmescence. Recently,Korber-Grohne ( 1996) has included the 'Roter Of all the identification marks, the features of the Spilling' in the group of prunes (ssp. oeeonomiea) on stones seem the most stable characteristics. Hedrick the basis of the features of the fruits and fruit stones. Up (1911) notes: "In describing the several hundred f Olm s till then, this variety had been regarded as an in si/i tia of plums for The Plums ofNelll York, the stone has been plum. This indicates that the present division of the quite as satisfactory if not the most satisfactory, of any subspecies is not (Ol' cannot be) settled on well-defined of the organs of this plant for distinguishing the various 538 H. WOLDRING species and varieties". In fact the size of the fruit stones and hybrids of Pnll1l1s spinosa x Prunlls insititia. This is the sole feature that may vary to some extent. division is in some cases supported by chromosome Experience teaches us that the dimensions of the stones research. Large-fruited specimens with 2n = 32:4x slightly decrease in fertile years, especiaIly in the large­ chromosomes belong to P/'unus spinosa, which has the fmited commercial plums. The value of fmit stones as same number of chromosomes. Accordingly, speci­ a means of identification is affirmed by various authors mens with 2n=40:5x chromosomes should originate (Roder, 1940; Werneck, 1961). They state that the from crossings between sloe and the hexaploid characteristics of the stones are constant, providing a (2n=48:6x) damson (see also section 4). decisive identification criterion, not only for the As a consequence of their problematie defini tion, the identification of the species, but particularly for nomenclature of the intermediates and botanical spe­ determining varieties. This is true especiaIly for the cies is quite confusing. A summary of scientific and commercial plum varieties. In a 'blindfold' test, Roder vernacular names is presented in table l, while (1940) could correctly identify 95 out of 100 varieties, characteristics of the groups are described in section 5. just by examining the stones. For a clear understanding of the term' intermediates': these plants display features of sloe as well as damson. Plants with fruits that are larger than sloe, but with other 4. THE INTERMEDIATES characteristics which fully match that species, are considered as intern1ediates. Similarly insititia-type During the present investigation it became evident that plants with for instance wry fmits have also been quite a number of plants with insititia-type fruits have included as intermediates. also features which are not typical of this species, but In this study the term damson refers to the group of bear closer resemblance to sloe, e.g. in the properties of varieties with round Ol' oval, small plums (Prunus fruit stones, leaves, taste of fruits ancVor length of dOl1lestica ssp. insititia) which occur throughoutEurope. pedicels. By contrast, intermediate forms of damsonl In faet, some of the true English insititia varieties from domestic plum and cherry p1um are rare and were found which the noun damson is taken differ slightly from the only in Italy, while no specimens intermediate to sloe continental insititias in their typical flavour and necked and cherry plum were recorded. The morphology and (pyriform) fruit shape. Well-known and widespread the properties of fruit and fruit stones of these typical insititia varieties are the Gern1an 'Krieche' and intermediate forms suggest a relationship between sloe the French 'St. Julien'. In everyday language the term and damson, which lends this group a particular interest 'bullace' is often applied to the entire group of insititia in the discussion onthe origin and historicaI development varieties. ll1e author is of the opinion that the bullace, of plums. eventhough it is considered an (English) insititia variety, Opinions differ on the taxonomical status of the has so many features in common with sloe, that this intelmediates. Reference works assume the intelmediate name is unsuitable to cover all the insititia varieties. specimens to be hybrids of sloe and damson plums, Other plums, often larger-fruited (Reine Claude, oval Prunus xfruticans (Tutin et a1., 1968), or include them plums, round plums, pmnes, etc.), have beencategorized as large-fruited varieties of sloe (Prunus spinosa var. under 'domestic' ordomestica plums (Prunusdomestica macrocarpa) (Hegi, 1906 ff.), Prunus spinosa ssp. ssp. domestica). megalocarpa and Prunus spinosa ssp. ovoideoglobosa More than 30 intelmediate specimens (see Appen­ (Werneck, 1961). Fournier (1977) includes the inter­ dix) discussed here demonstrate a seemingly random mediate specimens in sloe as possibIe intra-specific variation in size and shape of the leaves, length of the hybrids. Apart from PnlllllS frl/ticans, Peyre (1945) fruit stalks, tannin and sugar content of the fmits and distinguishes five large-fmited f Olms at species level. growth habit, properties which display traits of sloe or Korber-Grohne (1996) divides the intermediates into damson plums. In practice, features of either sloe Ol' large-fruited fOlmsof PnlllLlS spin osa (var.lllacrocarpa) damson predominate in most specimens. From the

Table I. Scientific

Latin n

Prl/nIlS xfrlllicans Internle diate Prunellier il fruits Wilde Kriech, Sallkriech, Groolvruchtige Prl/nIlS spinosa specimens gros Ganenschle he, Kultur- slee doorn var. lIlacrocarpa sch lehe (Werneck 1961) Prl/nIlS spinosa Sloe, blackthorn Pnl llell ier, epine-noir Schwarzdorn, Schlehe Sleedoolll Prl/nIlS insiriria Damson, bu llace Pruneolier, prune Zipane, Krieche, Kroosjes, kriekpruim, sauvage, creque Haferpflaume wichteries Prl/nlls ceras(f'era Cherry plum Prune-ce rise Kirschpflaume Ke rspntim Oll the origin o/plums 539 varying and interspecific features of the specimens, the an attempt to increase the range of grown fruit varieties, author conc1udes that the specimens originate from members of a Dutch pomological society (Noordelijke crossings between sloe and damson. Pomologische Vereniging) requested Russian col­ leagues to send over fruit stones of such specimens. The 4.l. Geographical distribution and habitats of inter- sent samples contained a variety of spinosa stones, but mediates hardly any exceeded IO mm length, the minimum size for fruit stones of large-fruited specimens. The regions Written accounts indicate that intermediate specimens where intelmediate specimens have been documented are distributed throughout central and western Europe fall within the range of distribution of sloe and damson. (Domin, 1944; Peyre, 1945; Werneck, 1961; Woldring, Interestingly, intermediates seem to be absent in the 1993) and as far north as Småland in the south of southern European countries, although sloe and damson Sweden (Weimarck, 1942). They are particularly plums are widespread there. Davis (1956-1988) and common in France (Dordogne, Normandy, Morvan). Pignatti (1982) do not specifically mention these fonns Most of the discussed intermediates were collected in in their floras. Searches by the present author for this country. According to Peyre (1945), particularly intermediates in central and western Turkey, the Othris large numbers, comprising several types (according to mountains in Greece and Tuscany in Italy, however, Peyre: species), occur around the cities of Lyon and were indeed unsuccessful. Bordeaux. Reports of extremely large-fruited (spillosa?) The discussed intermediates were mostly found in specimens occurring in Russia could not be verified. In man-made habitats, such as hedgerows, along roadsides,

o 400 km

_.,r": .' . I \. ..., ,, "\:'J'� , .� '...' .... ) , ,,

• 1

* o

O *

Fig. l. Distribution ol' intennediates. The nllmbers indicate the occllrrences of the discussed intennediates. l. Dordogne, France, IO types; 2. Cate d'Or, France, 5 types; 3. MOI"Van, France, 4 types; 4. Nomlandy, France, 5 types; 5. Northern Netherlands, 9 types; 6. COlswold, UK, 2 lypes. The Roman nlll11erals represent the record s ol' intennediates/hybrids from literature: I. Bodensee (Korber-Grohne, 1996); II. Northem AlIstria (Werneck, 1958; 1961); Moravia (KUhn, 1995); IV. SOllthern Sweden (Wei11larck, 1942). The asterisks indicate regions which lack intermediates. 540 H. WOLDRING edges of gardens,etc. They always grow near habitations 5.3. Cherry plum (Prunus cerasife ra Ehrh.) or in the cultural landscape surrounding villages and Chromosome number usually (x=8) 2n=16 (2x), but hamlets. Seemingly spontaneous specimens appeal' to also 3x (2n=24), 4x (2n=32), 6x (2n=48) (Watkins, grow in the same habitats as sloe,such as hedgerows. 1976). Sometimes it was clear that the specimens had been Many-stemmed shrubs 01' trees,up to 8 m. Rootsuckers planted. In France, cultivated specimens were encoun­ absent. tered amidst different domestic fruit trees. FaImers in Leaves (mostly) serrate, (ob)ovate, elliptic, oval. Normandy state that the wry fruits of these shrubs are Shoots thin, glabrous and smooth, usually unaI·med. consumed directly. Cultivated intermediates are also Flowers borne singly. Blossoming (in northwestern mentioned for Austria (Werneck, 1961). According to Europe) c. 2-3 weeks before the other groups. Werneck, the fruits are among other things used for the Pedicels (IO) 15-22(25) mm long, diameter => I mm, production of alcoholic beverages. often betweenO.6 and 0.9 mm, green orreddish,glabrous . Fruits red Ol' yellow, more rarely black-violet, green, orange, brownish; drooping, ripening early,bloom thin 5. CHARACTERISTICS OF SLOE, DAMSON AND if present: June (Mediterranean), July, August. CHERRY PLUM Fruit stones 10-22(27) mm long. Ventral suture shaI'p­ angled. Lateral gro oves shallow, indefinite and mostly 5.1. Sloe (Prunlls spinosa L.) smooth lateral faces. In some Mediterranean cherry plums elevated lateral ridges are found. Chromosome number usually (x=8) 2n=32 (4 x), but Citric acid present. Tannin absent (Komarov, 1941). als02x (2n=16),3x (2n=24),5x (2n=40) and 6x (2n=48) (Watkins, 1976). Shrubs or small trees, up to 3(5) m, spiny. Rootsuckers. 5.4. Characteristics of the intermediates and compa- Leaves (ob)lanceolate, elliptic,(ob)ovate, 3-5 cm long. rison with sloe, damson and cherry plum Flowers 13-18 mm in diameter, borne singly. Pedicels (3)5-10(15) mm long, diameter => l mm, The folIowing features describe the discussed pubescent ar glabrous. intermediates: shrub Ol' small tree, spiny Ol' unarnled. A Fruits 10-15 mm in size, (sub)globose, ovoid, conoid, common feature of intermediates, sloe and damson black( -violet), astringent taste, borne in rigid, non­ plums is the abundant development of rootsuckers. A drooping position. Mostly heavily bloomed. Ripe by seemingly random variation exists in the size and shape end of August/September. of the leaves, which either resemble those of sloe Ol' Fruit stones c. 7-10(12) mm long. The size separates damson plums. Flowers,single Ol' in pail's, 18-25 mm in spinosa stones fairly well from the other groups. Large diameter (measurements provided from specimens in spinosa stones overlap with the smallest in the other the Netherlands), and frequently equalling those of groups. dam son in size. Intermediates blossom at the same time Tannin present. Citric acid absent (Komarov,1941). as sloe and damson (in the Netherlands, aI'ound mid­ April). The fruits, c. 15-25 mm in size, are mostly globose or oval, occasionally subglobose or ovoid. This 5.2. Damson (Pr/lilliS dOl1lesticcl ssp. insititia) suggests a considerable variation,but broadly speaking Chromosome number (x=8) 2n=48 (6x) (Watkins, 1976). one could say that the fruits of the intermediates are Shrubs 01' small trees attaining 4-8 m, spiny 01' unarmed. round Ol' oval,c. 20 mm in size, purpIe to almost black Rootsuckers. and mostly with thick bloom (like the fruits of sloe). The Leaves elliptic, (ob)ovate 01' almost circular, 5-8(-10) features of the fruits largely match those of damson and cm long. differ from those of sloe only in the larger dimensions. - Flowers c. 25 nmi- in diameter, frequently in pail's, Ripe fruits often tend to droop, like those of damson ai-ising from one bud. plums. The taste is variable: sweet,sour or astringent, Pedicels (5) l 0-15(20) mm long, diameter > l mm, depending on the tannin and sugar content of the fruits. pubescent 01' glabrous. The chromosome number of the intermediates is Fruits ( 1 5)20-25(30) mm in size,drooping, (sub)globose, discussed in 6.2. ovoid or oval, usually bluish-black, but also yellow,red The dimensions of the fruit stones ofthe intelmediates or green. Bloom mostly thin. Ripe in August-October. (length c. 10-15 mm) generally exceed those of sloe. In Fruit stones (10)12-16(20) mm long. Ventral suture size, stones of the intermediates largely overlap with fairly complex, often broadened and with lateral grooves damson and cherry plum stones. A frequent feature of and ridges. Several types can be distinguished according intermediates aI-e the irregular indentations on the dOl'sal to the varieties. side of the stones (fig. 1). The stones of intermediates Tannin and citric acid present (Komarov, 194 1). range in chaI'acteristics between true spinosa type stones On the origin ofplums 541

Table2. Su mmary ofthedime nsion s (in mm) of so memorphological features ofthediscus sed in term ed iates and tile botanical species; * deri ved from Dutch specimens only.

Diameter of Length of Length of flUit Length of Diameter of flowers* fruits stones pedicels pedicels

Inteml ediates 18-25 15-25(28) 10-15(18) 4-12(18) (0.8)0.9-IS(1 .8) Slo e . (13)I 5(20) 10-15(17) �10(12) (2)4-12(I S) (0.7)0.9-I.S(1 .9) Dam son ( 18)20-25(28) ( 17)20-25(30) 10-18(20) IO-IS �I Ch erry plum (20)25-(28) 20-30(35) �IO (IO)I 5-20(25) (OA)0.S-0.9(1.1)

and il/sititia type. In the majority af the stones spil/osa 6. GENETICS AND THE POSSIBLE ORIGIN OF features dominate e.g. heavy sculpture, domed lateral INTERMEDIATE SPECIMENS sides, rounded outline (e.g. plate I, appendix), whereas in other types insititia features predominate, e.g. Theoretically, four genetic processes might lead to elongated, relatively flat stones, aften with more ar less forms that are morphologically intermediate to sloe and pronounced s-shape (e.g. plate V, appendix). Stones af damsan. the last type resemble those af damsans so much that in many cases other features, such as spinosa-type leaves 6.1. Autopolyploidy ar wry fruits,must be used to distinguish the specimens from true damsans. Nevertheless, with same specimens In this process, ane, several ar all chromosomes af a it remained unclear whether ane was dealing with an genome are duplicated ar multiplicated. Morphologi­ intermediate ar with a true damsan. It SilOUld be noted cally, autopolyploidy may take shape in the enlargement here that same insititia varieties exist such as the Dutch af same ar all parts of the plant. Thus, larger fruits might kroosjes, of which sculpture and shape of the stones are result from such a process in sloe. Retarded growth, basically identical with the general characteristics af decreased amountofbranching, longer time of flowering, spin osa stones (see also KrolI, 1980). later flowering and reduction af seed fertil it Y are features The properties af the intemlediates described here which may distinguish autopolyploids from the original indicate a close relationship with sloe and damsan. The species. During the study, no differences af this nature intermediates lack the typical features af cherry plums between sloe and the intermediates were noticed. In (glabrous,thin and lang pedicels, shape and serration af addition, sloe is a polyploid (4x), while the occurrence the leaves, glabrous twigs and the lack af rootsuckers). af autopolyploidy seems to be a regular feature in These differences indeed suggest that cherry plums are diploids only (Stebbins, 1960). The presence af insititia not involved in the ancestry af tlle West-European features in most intermediates also suggests a different intermediates. arigin. Two identical large-fruited specimens from This does not imply that crossings between sloe and Sainte Marie-en-Anglais in Normandy (see Appendix) cherry plums do not occur. Sterile triploid hybrids might represent autopolyploids af sloe. These speci­ (2n=24; 3x) between those species seem to be common mens differ from the common sloe only in the strongly in the Caucasus (Rybin, 1936). Zohary & Hopf (1988) enlarged fruits and stones. note that "dolllestica and il1sititia plums apparently intercross and intergrade with cerasifera-divaricata forms". The present authar found three almost identical 6.2. Hybridization trees which showed a true mixture af bat h aggregates Spontaneaus and experimentally obtained interspecific near Tuaro, nortll af the Lago di Trasimeno in central (and even intergeneric) hybrids are fairly common in Italy (cerasife ra features: early flowering, fruits, foliage; the Prunophora. Same examples: insititia/dolllestica features: fruit stones, pubescent - Crossings between sloe and cherry plum have been twigs, ane specimen with rootsuckers). The intermediate experimentally achieved by Rybin (1936). He also traits suggest that these specimens originate from states that hybrids af these species are common in the crossings between cerasife ra and il/sititia/domestica Caucasus; plums. - According to Hegi (1906 ff.), mirabelle (Prul1us il/sititia var. cerut) arose from crossings between cultivated plums and cherry plum; - A peculiar specimen collected by tlle author in the mountains south af Isparta, southwestern Turkey, was 542 H. WOLDRING identified by Professor Browicz (Poznan,Poland) as a species in members of the Rose family (Rosaceae). hybrid between Amygdalus cOl1ll1lunis and a PrUlIl/S Fairly com mon is apomixis,a reproductive process in species (probably nearby-growing cherry plum); which fertilization takes place without transfer of the - Numerous experimentally obtained hybrids have genetic material of the pollinator. The progeny or the F, resulted from efforts to improve the quality of fruits, population is therefore identical to the maternal plant. adaptation of trees to environment and resistance to Reproduction by apomixis is usual in e.g. blackberries diseases, especiaIly in America, e.g. crossings of (RI/bus jruticosus s.I.), Lady's mantIe (Alchemil/a Japanese plums (Prunus trif/ora) x native American vulgaris agg.) and cinquefoil or tormentil (Potentil/a species (Hedrick,191 I). species). The morphological features suggest that the inter­ Chance cross-fertilizations in apomictic species pro­ mediate specimens result from crossings between sloe duce F, plants which are morphologically intermediate and damson. Chromosome research on two specimens to the parent plants. Continued apomictic reproduction has confilmed hybridization between these species. (F ) of the intermediate plants leads to a new micro­ 2 Analysis of an intermediate specimen near Lake species. Although these F? plants differ only slightly - Constance in southernGennany showed a chromosome from the parent species, authorities rank such new number of 2n=40 (5x), intelmediate to that of sloe and forms at species level, e.g. in RubI/S jruticosus (Hegi, damson (Korber-Grohne,1996). The same chromosome 1906 ff.). number was found by Weimarck (1942) in hybrids A comparable proces s occurs in the usually self­ between sloe and the so-called 'terson' or 'tersen' , an pollinating dog rose and its siblings (Rosa canina insititia variety of southern Sweden. complex). Again cross-pollination between related (sub)species occasionally alternates with the usual process of self-pollination. Because of its dominating 6.3. Sexual reproduction genetic influence, the progeny of cross-breeding spe­ Downing,a nurseryman from New York (1896),notes: cies in the Rosa canina complex differs only slightly "When reared from seeds, our fru it trees always show from the maternal plant. Continued repi:oduction of the the tendency to returnto a wilder form". This trait hints progeny by means of self-pollination leads to the that our fruit trees are domesticates which would not formation of a new subspecies or micro-species. occur in nature. Generally,seedlings of damson have a The great number of varieties and strains in sloe and more spiny habitus than the parent plants. Notwith­ damson and the minor differences between them might standing their 'wild' appearance, seedlings of damson suggest similar processes in these species. Such is not plums retain the diagnostic features of the species, the case. It is stated in the literatLlI·e that cross- and self­ above all in their fruit stones. Evidence for this state­ pollination are common (Taylor, 1949), whereas ment may be found in the 'SI. Julien',a variety that in reproduction by apomixis is nowhere considered a the last centuries has been the chief rootstock for serious possibility. graf ting plums in France. Until recently, its reproduction occurred from seed. In spite of this long tradition the fruit stones have remained quite uniform in their 7. SOME RESULTS OF BREEDING EXPERIMENTS appearance. Another example is represented by the German 'Krieche',which according to Korber-Grohne A great number of seedlings have been grown from (1996) has not changed significantly. Modern fru it several varieties of the discussed species and inter­ stones of the 'Krieche' are identical to those found in mediate forms, in order to provide insight into the excavations in southern Germany and in Swiss lake­ reproductive capacities of varieties,the characteristics dwelling settlements. of the offspring, and possibIe differences in fruits and However, the mix of sp inosa and insititia features in fruit stones, viability, rate of growth and growth habit most intermediates make it unlikely that we are dealing among seedlings and between the seedlings and the here with 'reverting' insititia specimens, since the mother plants. The experiments were undertaken also emergence of features of a different species (sloe) in to test a statement in the literature (e.g. Werneck,1961: those plants would be impossible. The origin of the p. 25) to the effect that the fruit stones of seedlings of intermediates must therefore be a different one. The PrtlllUS varieties are morphologically identical to those possibIe origin of some questionable insititia specI­ of the maternal plant. AIso segregating progeny would mens is discussed in section 8. 1. be evidence of hybridization between species and might therefore provide significant infOImation on the origin of the intelmediates. 6.4. Apomixis Stohes for sowing were selected from reference Specific pollinating processes have contributed to a samples. It was decided to sow Iimited numbers of great variability and the establishment of several micro- stones from a range of varieties. Because of their an the origin ofplums 543 complex nature, priority was given to the sowing of and several yellow-fruited FI specimens. Seedlings intermediates,but the experiments also included several from a black-fmited specimen in the Jura (France) have varieties of cherry plum, damson and some strains of so far produced fruits in several colours: red, brown­ sloe. The tests started in 1989 and notes were made on orange and bright yellow, but none having the black germjnation capacity,via bility and growth. Part of the fmits of the parent. Shape and size of the fmits also seedlings of the starting years have blossomed and, differ from those of the parent. The fmit stones are notably the cherry plums; also set fruit. In cherry plums, copies of those which were sown. first fmits appeared in the fourth or fifth year of growth, but in the same timespan fmiting succeeded also in 7.3. Damson plum some specimens of sloe. In general, fmiting occurs in the second Ol' third year of flowering. No fmiting has yet Germination rate: 0-70% (Grisez, 1974: 89%). A most been achieved in damsons and intermediates. prominent feature observed in the offspring of insititia A conspicuous feature revealed by the breeding tests varieties is the variability in growth,not only between is the variation in (rate of) growth among seedlings varieties and strains, but also among seedlings of the from the same plant. This variation has been noted same plant. The dissi milar development of the seedlings chiefly in illsititia progeny, but also in seedlings of is most pronounced at the end of the first growing some spillosa strains. This heterogeneous growth season. One-year-old seedlings of the same origin may suggests heterozygosity and is defined in genetics as the vary in height between a few centimetres and one metre. effect of the fusion of genomes of genetically different The smallest specimens often show little viability and genotypes (cross-breeding plants). Each plant has part of them perish in the winter season. The variable thousands of genetic factors,genes which determine the growth is attributed to a heterozygous origin of the individual characteristics. Cross-fertilization therefore offspring. gives an almost infinite number of potential recom­ Interesting contrasts are found between dark blue­ binations (the seedlings). By contrast, self-fertilizing purple-fmited varieties and those with differently plants produce homozygous progeny, which only shows coloured fruits (green, yellow, red Ol' two-coloured), the genetic variation ofthe parent plant. The appearance especiaIly with regard to the germinative capacity of the of heterozygous progeny is therefore evidence of cross­ stones and growth capacities of the seedlings. Usually, breeding. the stonesof the dark-fmitedcategory genninate read ily. By contrast, stones of varieties with light-coloured fmits show failing or pOOl' germination while the 7.1. Sloe seedlings show poor growth. The straggling growth is Average germinative capacity: c. 60-80% (Grisez, 1974: frequently accompanied by characteristic growth c. 90%). Seedlings of the same origin show moderate to deficiencies,such as multifold branching,easi ly breakjng fairly vigorous and uniform growth, but the progeny of twigs and insufficient development of roots. Two- to some strains shows more variation in growth andJor four-year-old specimens died back almost to ground growth habit. The height of the different breeds varies surface in the co Id winter of 1995/ 1996. Such between 20-30 to 60-80 cm by the end of the first characteristics are very likely to be a consequence of growing season. Variation in growth between breeds is hybridization. thus more pronounced in this species than in cherry The folIowing cases suggest that hybridization has plums (see below). This apparently is due to the wide resulted in seed sterility. As reference material, fmit range of fOl'ms (low to tall shrubs,small trees) existing stones were collected from c. 150 insititia plants, the in sloe. identification of which was based particularly on the In sloe the first flowers appear 4-5 years af ter characteristics of the fruit stones. Only two of these gelmination. samples were collected from specimens with two­ coloured fruits. One large tree with purple-and-yellow fmits was fOlInd in Groningen, the Netherlands, the 7.2. Cherry plum second specimen grew in Les Piards, a village in the Germination rate: c. 70-80% (Grisez, 1974: 58%). One­ Jura, eastern France. Both specimens produce fmits year-old seedlings measure 50-100 cm or more and which are somewhat larger than the average damson show uniform growth. Many specimens flower and fmits. Other peculiarities are the king-size leaves (up to fmit after 4-5 years. The first results show that fruit Il cm) of the Groningen specimen (insititia leaves stones of the seedlings confOlm fajrly well to the usualJy measure 5-7 cm) and the many-stemmed, maternal plant. This does not hold for the colour and dwarfish habitus of the Jura specimen. Stones from both shape of the fmits, whjch either differ from or are specimens were sown. Fifty stones of the Groningen identical to the maternal plant. A yellow-fmited speci­ specimen, sown in two successive seasons, failed to men from S616z (Iznik G6lii,Turkey) yielded one red germinate. Later examination of fresh fmit stones from 544 H. WOLDRING

this tree confilmed the absence of viable endosperm. Features of autopolyploidy, as pointed out by Stebbins Twenty stones ofthe blue-and-yellow-fruited Jura spe­ (1960) are mostly lacking in the intermediates. Besides cimen yielded five very similar and seemingly healthy the absence of these fe atures, the specimens were all seedlings, but the height of c. 50 cm which these found at sites in man-made habitats, such as hedgerows, specimens attained in six growing seasons illustrates an orchm·ds and waste places near human habitation. By unusual stunted growth (a height of 2 or 3 m in the same contrast, intermediates are conspicuously lacking in period is common in most dark-fruited varieties). natural and isolated plant communities with sloe. This Considering the characteristics, these specimens also argues against an autopolyploid origin from sloe, might be crossings between dark-fruited insitifia speci­ for in that case lm·ge-fru ited specimens would also arise mens and a category of plums with larger and light­ in places where only sloe occurs. Features of damson in coloured fm its such as greengages (Reine Claude), a most intermediates also make autopolyploidy unlikely. group that inc1udcs several varieties with large and The presence of traits of sloe in most intermediates green to yellow fruits. also seems to exc1ude the possibility of 'regressive' According to Stebbins (1960) failing germination insififia seedlings, but some questionable specimens and inhibited growth are pronounced features of with dominating insififia fe atures may actually be hybridization between related species and between seedlings of dam son plums. Apart from these particular groups (populations, varieties) within a species. They cases, the interspecific and variable morphological might result from the lack of homology between fe atures and other traits suggest that the specimens chromosomes of the parents of the hybrid. Judging by originate from crossings between sloe and damson. the listofexampIescited by Stebbins, this is a widespread The vm·iable morphology ofthe hybridslintermediates phenomenon in the plant kingdom. contrasts strongly with the mostly homogeneous progeny produced by individual plants. The plants grown from fru it stones of intermediates in many cases resemble the 7.4. Intelmediates parent. Th is fe ature of the progeny conflicts with Germination rate: 20 to 80%. The progeny of man y Mendelian rules of hybridization, which say that F1 inteIlllediate types shows vigorous growth, and seedlings hybrids of the same parent plants are quite uniform, but of the same parent are usually remarkably uniform in that F2 progeny segregates into types which partI y morphology. So far, segregating fe atures, which re semble the parent plants. The value of progeny tests characterize hybrid offspring, have only been observed in providing evidence of hybridization is clem·ly in the progeny of an intermediate form near Gieten, the demonstrated by Stebbins (1960: p. 25) and others. Netherlands (GIE-90-2). Two specimens (out of 30) They found evidence for segregation of the progeny of have leaves resembling those ofdamson plums. Several hybrids of two species or other genetically distant seedlings show slightly smallerflowers than the hybrid, groups, segregations wh ich include types resembling suggesting the involvement of sloe in the parentage of the hybrid and types resembling the pm·ents of the this specimen. Variable progeny, pointing to hetero­ hybrid. WllY the progeny of the hybrids does not zygosity, is not common in this group. The progeny of segregate can only be guessed at. The homogeneous some inteIlllediate types is slightly heterozygous, but growth of the progeny suggests homozygosity and less markedly than in seedl ings of damson plums. would indicate self-fertilizing hybrids. In that case the Seedlings first blossomed at the age of 5-6 years. progeny is identical and varies only within the genetic Fruiting has not yet been observed. limits of the parent plant. Self-fertilization is, however, unlikely to be a much more pronounced fe ature of hybrids than it is in the parents. If that were the case it 8. DISCUSSION would be mitur a I for larger numbers of identical intermediates to occur in regions where intermediates are common. 8. 1. The ohgin of the intermediate specimens It seems al most impossible to regard the intelmediate As has been explained in the preceding section, the fOIlllS as an isolated group, or as one ar more subspecies characteristics ofthe intermediate specimens resemble or varieties of either sloe or damson, because of their those of sloe and damson. The properties of the fru its, diffe rent and variable phenotypes. It was found for the presence of rootsuckers, fl owering time, the instance that intermediates with identical stones mostly frequency of pubescent twigs, length of pedicels, etc. have a highly differentiated morphology (growth, contrastsharply with the ch aracteristics ofcherry plums. fo liage, wry or sweet fruits), whereas morphologically This suggests that sloe and dam son are involved in the identi�al plants may produce differe nt types of stones. parentage of the interspecific forms. The processes that The nature of this variation does not comply with the theoretically might have produced them have been definition of any taxonomical group; (sub)species, considered in section 6 and will be briefly reviewed vm·ieties, populations etc. are similar or diffe r in fixed here. Oll the origin of plums 545 characteristics. The variability found among the appeared to be so similar to t1lOse of certain insititia intermediates can only be expected in hybrids ofdi verse varieties (viz. two local Dutch varieties ('kroosjes' and origin, and in the case of sloe and damson is probably 'blauwtjes'), t11e 'SI. Julien', and a 'Spilling') as to the consequence of the wide range of specific spinosa clearly indicate the involvementofthese varieties in the and insititia varieties between which crossings may origin of tlle hybrid. In regions where a specific insititia produce a great number of recombinations. The chance variety predominates one would expect this variety to of obtaining F I types wirh unique properties in that case be a main contributor in the parentage of the seems more probable than the creation offully identical intermediates. Proof for this statement is not available. intermediate specimens. Indeed, in practice fu lly The region between Lormes and Avallon, in the identical specimens are rare, if any occur at all. northwestern MOl'van, central France, is studded with Despite the morphological variation offru its, leaves, the French damson variant, the 'St. Julien'. Curiously, growth, etc. in sloe and damson, written accounts none of the samples secured from supposed hybrid emphasize the morphological invariability of the fruit specimens in this area shows the typical morphology of stones in successive generations; in other words, the a 'St. Julien' stone. parent and its offspring will have morphologically AIso remarkable is the occurrence ofspecimens with identical stones, not only in self-pollinating, but also in stones of identical type, but which on account of the cross-breeding lines. A significant implication of this other morphological fe atures should be divided into mechanism is that the matemal plant as the producer intermediates and true damsons. Such was found in a controls the morphological configuration of the stones. series of specimens from the above-mentioned Morvan There are indications that the mechanism works in the region. Besides the identical stones in this series, some same way in crossings at species level (interspecific ofilie specimens show fe atures ofboth sloe and damson, hybrids). A practical case, discussed by Hedrick (191 1), and have therefore been interpreted as intermediates, concerns the beach plum, PnlllllS lIIaritillla, a low whereas other specimens display dominating fe atures shrubby species from the east coast of the U nited States. of damson plums. It seems as if this phenomenon The shrubs produce prolific crops, but the fruits are particularly shows up in areas where plums ancIJorsloe small and of an inferior quality. To improve the latter are abundant. The presence of such intermediate speci­ properties, the renowned Cal ifornian fru itgrower mens with identical stones and variable other Burbank fe rtilized a selected l1laritil1la specimen with characteristics is quite confusing, but on the other hand ' pollen of Japanese plums. A quotation: "The very first might equally point to hybridization. generation produces a plum which is an astonishing According to the Mendelian rules, interspecific grower for a l1Iaritil1la, al most equal to trijlora, with hybrids (F) of the same origin are similar and uniform, large, broad, glossy foliage almost of the exact shape of whereas the progeny ofFI specimens wi Il segregate into lIIaritillla ,maritillla blossoms, and fru its weighing nearly types wh ich partIy resemble the parent plants (PI )' On a quarter of a pound each, with an improved, superior the other hand, Stebbins (1960) argues that in general lIIaritil1la flavour, maritima pit in form, but enlarged". back-crossing between hybrids and the parental species The domination of maternalgenes wou Id explain the is much more likely (because of the greater I1Llmber of occurrence of intermediates with spinosa type stones the latter) than the chance of intercrossing hybrid spe­ and with insititia type stones. The diffe rent types of cimens. Back-crossing also leads to types which in part stones of the intermediates are very likely the result of resemble the Ol'iginal parent plants. Specimens with crossings between diffe rent insititia and spinosa dominating insititia fe atures like those from the Mor­ varieties. The dominance of the maternal plant in the van might thus originate from back-crossing processes formation of the stones in crossings would make it rather than from segregating progeny of FI specimens, possibie to identify the maternal plant,orvariety involved Th is would not be so important, were it not that back­ in the parentage ofthe intermediates. The actual practice crossing may have a significant side effect, namely an is mostly diffe rent. Owing to the number of varieties, exchange of genes or genomes between the parental and the small variability and size of spinosa stones, it is species. Th is process is sometimes termed introgressive not possibIe to deduce specific varieties or strains from hybridization (Stebbins, 1960). Indicators of such the fe atures of intermediate stones. Stones of insititia introgression might be the insititia specimens with varieties display more diffe rentiation owing to their bitter, inferiOl' fruits, which are frequent in France, but larger size, and more diverse shape and slllface sculpture. occur also in other parts ofEurope (Shiskin, in: Komarov , Th is makes it possibIe in some cases to trace an 194 1), intermediate's ancestry from the characteristics of its Iiybridization and subsequent back-Cl'ossing, and stones. The author compaJ'ed types of stones of inter­ possibly also segregating F2 progeny, leads to t11e esta­ mediates with similar stone types of insititia varieties, blishment of a variable aggregate of intermediates which were apparently involved in their parentage including types which approach the original parent (Woldring, 1993). Stones of four intermediate types species in likeness. Such hybrid swarms can be seen in 546 H. WOLDRING other woody members of the rose family (Crataegus, Table 3. Evolulion of lhe dirfe re nl groups of plums. Sorbus). In undisturbed natural situations these hybrid groups are found where genetically different and Spil/osa (Black-fruiled) imi/i/ia DCJ/I/es/iea geographically isolated populations come into contact Spil/osa x il/si/ilia lnlennediales (hybrids) or where ecologically diffe rent habitats occur side by ll/sililia x dOlllesliea? Red/yellow/green-fruiled imililia varielies side. The distribution of interspecific types of sloe and damson, which seems to concentrate in central and western Europe, might be an indication that dam son only recently intruded into previously sloe-dominated in reproduction and growth between the two insititia areas. groups may have important consequences and suggests The em'liest palaeobotanical evidence of damson that the group of black-fruited insititia varieties plums in Europe consists of fruit stones recovered from represents the original 'botanical' species, which Swiss lake-dwelling sites (Heer, 1866). Palaeobotanists morphologically and genetically does not depart disagree whether these were indigenous plums, as has significantly from its wild ancestors. been suggested for Austria by Werneck(196 1), Ol' were Zohary & Hopf (1988) conc1ude thatPrunus insititia introduced by migrating farmers. PrUllllS instititia is a might have evolved from (polyploid specimens of) the light-demanding species; it does not thrive in forest. cerasijera-divaricata complex, as insititia and The c1earance of woodland and the exploitation of the cerasifera-divaricata intergrade and apparently inter­ environment may have encouraged the expansion of cross with one another. In addition they state that sloe, indigenous plums Ol' the escape and running wild of with its wry and small fruits, is isolated cytologically cultivated specimens. InFrance, seemingly spontaneous and reproductively from the domestica-cerasijera­ il/sititia plums are still found in substantial numbers in divaricata complex. Hybrids between sloe and the hedgerows neal' villages and waste places. complex would be sterile; a statement which is however Disturbed habitats also support the light-demanding countered by the results of the progeny tests of and pioneering sloe. Because of its thorniness and rapid intermediates, performed by the autho!'. These tests reproduction from rootsuckers, th is species was popular reveal a complex of fe rtile hybrid forms between sloe as a cattie fe nce and was planted on the ramparts of early and damson. The present study also found that towns. The open conditions developing since the interspecific forms of damson and cherry plum are Neolithic caused two related species to invade identical uncommon. Viable crossings betweeri the latter species habitats, which greatly increased the chances of would be expected if damson plums indeed arose from hybridization. hybridization between sloe and cherry plum, as Rybin (1936) conc1uded from his investigations. The morphological resemblance of sloe and black­ 8.2. The genetic origin of damson plums fru ited damsons, the global characteristics of the fruit The resu1ts of the breeding tests (section 5.3) show stones and the occurrence of hybrids indicate a c1ase striking diffe rences between black-fruited il/sititia spe­ re lationship between those two species. Contemporary cimens and those with other fruit colours. In most cases flowering, the characteristic development of rootsuckers, the black-fruited specimens produce fe rtile seeds, which and the pubescence of twigs and fru i t stalks are further develop into normal, be it heterozygous plants, whereas traits which sloe and damson have in common. These green-, yellow- Ol' red-fru ited insititia specimens show fe atures do not occur or are of a different nature in the a universal seed sterility Ol' inferior and aberrant growth cerasife ra-divaricata aggregate of Zohary & Hopf, of seedlings. The latter might therefore represent hybrids which diametrically opposes the interrelated sloel between damson (for the stones) and a Pmnlls group damson c1uster to ceraslfe ra-divaricata . These with variously coloured fru its, probably domestic plums, discrepancies imply that an evolution ofil/sititiald ol1les­ but also Prunus cerasife ra plums may be considered tiea directly from the eerasiferaldivaricata complex as potential parents. The inability of these hybrids to suggested by Zohary & Hopf must be considered produce viable progeny suggests a genetic distance Ol' improbable. The absence of fe atures of eerasiferal banier between il/sititia plums and cultivated domestica divarieata in insititialdolllestica also suggests that plums or cerasife ra plums. Apparently these groups Pmnlls il/sititia did not evolve from crossings between represent genetically diffe rent units. sloe and cherry plums as c1aimed by Rybin (1936), but The above suggests a genetic separation between could have evolved directly from (hexaploid?) spil/osa black-fruited insititia varieties and the multi-coloured specImens. insititia group. TI1e heterozygous growth of black­ fru ited insititias, infened from the breeding tests, can 8.3. The geographic origin of damson plums have itsorigin only incross-fertilization between il/sititia varieties. The discovery of the pronounced differences Unlike domestic plums, feral insititia specimens Oll the origill of plums 547 maintain themselves quite eas ily in Europe. Seemingly though it is maintained now by cultivation. naturaloccurrences are frequent. Climatic aspects also indicate that illsififia plums are at home in Europe. Its 8.4. The importance of grafting for the development range of distribution inc1udes various c1imates, but it of domestic plums seems that the species prefers the temperate parts of Europe and western Asia. The (English) dam son and The genetic range of domestic plums and the fact that bullace thrive in, the cool and hum id Atlantic c1imate of most varieties are self-incompatible (and thus need to Britain, as do the mirabelles and other insififia varieties be cross-fertilized to set fru it) readily give rise to new in temperate France. l!JSititia plums are highly adjusted types. Liegel, an Austrian who lived in the 19th century, to the continental winters of central Europe. They have in his life ob tai ned c. 50 new plum varieties from fru it survived mass destruction among plums in severe win­ stones; some of which still exist. Many of our modem ters, e.g. the loss of almost all prune trees in Germany commercial plums date from the 19th century and were in 1 860 (Jahnet al., 1861) and the large-scale devastation fo und as chance seedlings in gardens and hedges, such of domestic varieties in Austria in 19281 1 929, 1940/ as Reine Claude d'Ouillins, Reine Victoria and Dia­ 1941 and 1956 (Werneck, 1961). This hints that mond, or have resulted from breeding tests at nurseries, prehistoric fru it stones repOl·ted for central Europe e.g. Czar, River's Early Prolific, Jefferson and BeJle de (Heer, 1866; Hopf, 1968; Werneck, 1958; Bertsch, Louvain. Bud sports, spontaneous mutations in bodY 1947) concern this species. Interestingly, such early (somatie) cells, usually in buds or tips of shoots, are records are practically missing in western Asia, e.g. the another source of new types, e.g. PurpIe Pershore, Caucasus, the region where insififia plums are thought which is a budsport of the yellow-fruited Pershore. to have their roots. (Admittedly , divaricafa plums and Most of these forms would be shortlived, if not a new other Prunus species, at home in western Asia by method of propagation - grafting - had emerged in nature, are also absent in early archaeobotanical Roman times. Technically, grafting is the method by assemblages.) Palaeobotanists (Hopf, 1968; Korber­ which a part of the desired plant, the graft or scion, is Grohne, 1996) suggest that insififia was not indigenous inserted upon a related (purposely selected) rootstock. but was introduced in central Europe by the Neolithic If successful, scion and rootstock will unite and grow up farmers. According to Zohary & Hopf (1988), who cite as one plant. This method ensures replication of specific Werneck & Bertsch (1959), pre-Neolithic remains of features and therewith the preservation and continuation carbonized stones discovered in the Upper-Rhine and of varieties. Crops are often increased by grafting. The Danube regions c10sely resemble the stones of present­ discovery of grafting with its advantages has been an day spontaneous domesfica plums (= Prunus iIIsififia?). essential condition for the development of dOl11esfica According to Zohary & Hopf these finds suggest that varieties. Its importance is emphasized in the so-calle d Prullus il/Sitifia could have predated agriculture and Pelzbuch (Gottfried von Franken, 1380), a treatise on should be regarded as an indigenous element in central the various aspects of grafting. Europe. But not all plums depend on grafting. It is interesting This food resource, whether present or introduced to note that most insififia varieties produce acceptable into central Europe, has certainly been taken into crops when grown on their own roots. This goes also for cultivation and improved by fu rther selection. Wild prunes (Prunus domesfica var. pruneauliana) and some archetypes may eventually have disappeared through other domesfica plums such as Pershore, Aylesbury destruction of their habitats, competition and merging prune and Warwickshire drooper, varieties which are with the newly husbanded forms, a proces s that has simply raised from rootsuckers. Th is method af been ascertained in vaJ'ious wild plants af which reproduction might in part explain the expansion of domesticated forms became widespread. For instance, insififia plums since the Neolithic era. the wild form of olive is not exactly known. In France Grafting usually does not produce new fruit types, and Italy, a great number of semi-wild forms of apple even though there are same ex am pie s of 'grafting and pear show fr uits which to some extent depart from hybrids', such as the two Crataegomespilus species, the small-fruited, wild specimens. These specimens which arose from the union of Mespilus grafted on the apparently result from intercrossing with domestic rootstock ofCrafaeglls(C. dan/ari, C. aSllieresii; Boom, relatives. On the other hand, it has been demonstrated 1965). Most of the (often local) apple, pear and plum by Korber-Grohne (1996) that modem fru it stones of varieties have arisen from the age-Iong tradition af the German 'Krieche' are ide nt icai to those found in growing fru it trees from seed, a practice that is still excavations of Swiss lake-dwelling sites and other successfully exercised by some people nowadays. In Neolithic sites, e.g. Ehrenstein (c. 4000 BC) in central general, it is not possibIe to reproduce modernbreeds Europe. The millennia-Iong unaltered stone morphology from rootsuckers, cuttings or seeds, since these methods would lead one to consider this black-fruited plum to be do not succeed or the plants produce poor yields and (one of) the elementary wild formes) of iIIsififia, even seedlings do not have the desirable qualities of the 548 H. WOLDRING parent plants. In these cases grafting has proved to be an Mediterranean climate zone of Greece and Italy. This adequate method of reproduction. plum probably spread in southern Europe through cuJtivation, possibly contemporarily with the so-called damascenes. It is not mentioned specifically in Roman 8.5. The value of written historicaI evidence accounts, even though it is in some respect superior to Roman written accounts point to Syria as the place damson. The plants are extremely disease-resistant and where damsons (damason, damascenes: from Damas­ are early and prolific croppers. Several strains produce cus), but also mirabelles (Prunus insititia ssp. cerut) excellentfmits. Disadvantageous (in northern countries) and greengages or Reine Claudes (Prunus domestica is its early flowering, which means that the flowers are ssp. italica) were thought to have originated. At present, often subject to frost damage. plums are extensively cultivated in the coastal areas of Prunus insititia andP. cerasifera show much likeness. Syria. Further inland, arid conditions in the growing Authoritative researchers (compare Korber-Grohne, season prohibit plum cultivation (Damascus average 1984; 1992) initially had difficulty separating the spe­ rainfall <200 mm per year). At the time of Roman cies. Even pomologists ofthe Noordelijke Pomologische hegemony in this area, various fm it types including the Vereniging, who trace old fruit varieties in the plum varieties mentioned by Pliny (23-79 AD; see Netherlands and are used to identifying fm it forms with Roach, 1985: p. 145) were introduced in Rome', where mi nor diffe rences, occasionally confuse forms ofdamson fmit growing was a popular hobby among prominent and cherry plum. It is possibIe that the Romans did not Romans. Marcus Lerentius Varro (116-27 BC) distinguish these plums as different groups. We may deligh tedly notes that the fOlmer woodland is so bestrewn assume that paI"!: of the plums mentioned in Roman with fm it trees from the Orient (Greece, Syria) in his accounts belong to the cerasife ra group, such as the so­ time, that the landscape resembles a large fmit garden called barley plum (Prunus 'hordearium '). According (Reinhardt, 191 1: p. 86). to Theophrastus this plum was so named because it There are various statements by Roman writers on ripens at the time of the barley harvest, approximately plums. Some ofthese raise questions aboutthe taxonomy May-June. In the Mediterranean, only cherry plums of the Roman damascenes, in the sense that these ripen so eaI·ly. probably diffe red from the modem damsons which Questions are raised also by the Roman 'wax plum', belong to the insititia group. The statements ofPliny on a type thought tobe identical with the modern mirabelle. the conservation of damascene plums makejt clear that If this is tme, it would be one of the oldest known these plums were preserved by drying in the sun, but, varieties. At present, the mirabelle is classified as a judging by the texts, with indiffe rentresuJts - "they miss subspecies Ol' vaI'iety of Prunus insititia, but some the sun of their homeland" - and concerningqualit y - au thors (Hegi, 1906 ff.) assume it to be a hybrid be­ "the fru its have larger stones and are less fleshy than in tween plum and cherry plum. Indeed, leaves, fm its and their homeland". Another author commeilts: "The best growth of the mirabelle show much resemblance to sorts of plums are damascenes, this testimony of Syria" (yellow-fmited) forms of cherry plums. It is not (in: Reinhardt, 1911). At present the French 'St. Julien' impossible that the noun 'myrobalan', a common is the only known insititia variety that can be suitably synonym for cherry plums, and 'mirabel ' became dried (Iike pmnes). Of course, comparison of aspects confused in later translations of Latin texts. Written such as taste remains hazardous; the perception of taste records are almost the only information on fm it in Roman times probably greatly differed from ours. cultivation in ancient Rome. In contrast to the ample Comments as - 'the best sort of plums ' - may indeed written documentation, archaeobotanical evidence such refer to conserving properties, but taking one thing with as fru its Ol' seeds is virtually lacking in Roman Italy. another, the descriptions of damascenes in Roman texts do not evoke the small and infe rior insititia plums! English historical records mention various authorsl 9. CONCLUSION fruit growers, e.g. Gerard (16th cent.), Evelyn (17th cent.), Hogg (19th cent.), who distinguish between ResuJts of breeding tests by the present author lead to 'Damasq ' or 'Damaszen Plums' and damson varieties the fo llowing conclusions (table3): (Greenoak, 1983: p. 80), which suggests differentgroups. l. The intermediate forms (Pnll1us xfruticans in the Cherry plum is another frequently cultivated Prullus Flora Europaea) investigated in this study are mostly species in the western part of Syria. According to Post hybrids ofPrunus spinosa x P. insititia. These crossings (1932) it is also found wild in hedges. Cherry plums aI'e usually fe rtile and imply a close relationship be­ thrive in the WaIm (sub-)Mediterranean climate, e.g. in tween the paI'ent species; western Anatolia, where the species in places dominates 2a. As a mIe, black-fruited illsititia varieties readily the arboreal vegetation of fore st steppes. Husbanded produce viable progeny from seed. By contrast, seed and seemingly natural specimens are frequent in the sterility or growth deficiencies are common in insititia On the origin o/plums 549 fOlms with other fruit colours; Spilling' specimen from Stromberg near Stuttgart. F. 2b. It is inferred from these data (2a) that black­ Ertug (Istanbul, Turkey) collected a large number of fru ited insititia specimens form the original species. edible plants in central Anatolia (Mamasun Barajl, east Insititia specimens with differently coloured fruits of Aksaray) including fruits of Prunus divaricata and probably result from hybridization between insititia Prul1us cocomilia. She also acted as a guide during and other groups of plums, e.g. dOl1lestica; sampling in private gardens in the villages ofGuyunkaya 3. The relationship 'between spinosa and insititia is and KlZIlkaya. During an excursion in the Othris manifested in the frequency of intermediates, the mountains (Greece) with Prof. H.R. Reinders (Gronin­ morphological resemblance ofthe fruits, identical (often gen) I became acquainted with the Thessalian form of shrub-like) growth, synchronic flowering, luxuriant Prul1us cocomilia. At the same time several samples of development of rootsuckers, etc. This suggests that cherry plums were collected in the adjacent plains. Prunus insititia evolved from certain strains of Prul1us Thanks are also due to Mr J. Venernaand the Cazemier spinosa. There are no indications for the involvement of family both from Lettelbert, Mr C. Couvert (secretary cherry plums in the development of insititia plums; of the N.P.V., Assen) and all those who provided plums 4. The constancy of many domestica plums depends from their garden and to those owners of plum trees who on grafting, since seedlings produce plants with differ­ are ignorant of their having contributed to this study. ent qualities. Seed sterility and low viability of man y The complex matter was extensively discussed with domestica varieties suggestheterozygosity and an origin Prof. U. Kbrber-Grohne and Prof. S. Bottema. Gene­ from genetically different groups. Crossings between tics, in particular in relation to the behaviour of the insititia varieties may have been the principal ancestry seedlings, have been discussed with Dr. L.P. Pynacker of domestica varieties. (Haren). Mrs G. Entjes-Nieborg processed the manu­ The conclusions mentioned here are strongly based script. The English text was improved by Ms A.C. on the results of the breeding tests. The underlying idea Bardet. in undertaking this project, the comparison offruits and fru it stones of seedlings with those of the respective ll. GLOSSARY OF TECHNICAL TERMS parent plants, is still to be worked out. Withthe exception of a number ofcherry plum seedlings, most offspring of 8100111 the other Prul1us species and intermediates has not yet Waxy layer on the surface of PrUllllS fruits, giving the impression fruited. The author hopes to present the results of this of a blue or whitish coloured fruit Cifric acid research in a future paper. Chemical component causing the sour taste of e.g. oranges and grape fru its Dorsallvellfral slIflIre 10. ACKNOWLEDGEMENTS Opposite sharp-angled parts ofthe fruit stone. The ventral suture nms parallel and is located at the same side as the line of jllnction visible on the exterior of the fruit Several people have, in one way or another, contributed Chrolllosollles to this study. They collected fru its during their travels or Linear bands in cells that carry the genes mentioned locations ofinteresting trees. Mr R. Bengtsson Cross/selfjerfiliZllfiol1 (Alnarp, Sweden) provided cuttings from rootsuckers Fusion ofmale and female gametes. Self-fertilization is the fusion ofthe hybrid sloe x terson. The cuttings were brought to of male and female gametes from the sanle individllal F, The first filial generation Holland by Mr Rob Leopold and his wife (Niebert). Frllif sfolles Thanks are due to Prof. H.T. Waterbolk, who traced a The pits or seeds of Pnllllls fru its hybrid form of sloe and damson located near Gieten CWllefe (province ofDrenthe). In fact, the problematic nature of Haploid reproductive cell Cem/s this specimen provided the starting point of the re­ Taxonomic group of c10sely related species. Genera are grouped search. He also provided fru its of cherry plums from into fa milies France and Holland. Drs C.A.G. Lagerwerf (Jipsing­ Cell huizen) trace d two old local insititia varieties in the Basic unit of inheritance by which hereditary characteristics are transmitted from parent to offspring sandy region in the east of the province of Groningen CellO/ile & (type GRO- l ; see Van Zeist Woldring, this volume). The haploid genetic set of a Iiving (diploid) organism Prof. A.T. Clason located this type in Rasquert, in the Crajfillg same province. Mr 1. de Boer (Lageland) provided Insertion ofscion (graft) onto stod:, usually of an other organism fru its from cherry plums and domestic plums in Den­ HOIIIOlogolls chrolllosollles -Contain the same sequence of genes, but deri ved from different mark. Dr U. Baruch (Jerusalem, Israel) made available parents Prul1us lIrsina, fru its from a native species in the north LlIrge-jmifed of Israel. Prof. U. Kbrber-Grohne (Wiesensteig, Indicates specimens with the nomlal morphology of the type Germany) kindly contributed fru it stones of the 'Roter species, but with larger fruits as the type species 550 H. WOLDRING

Pediceh GRISEZ, T.J., 1974. Seeds of 1V0ody p/ailIS ill Ihe UI/iled SI{/(e�·. Fruit stalks Agriculture Handbook No. 450. Forest Service, U.S. Department Po/yp/oid of Agriculture, Washington D.C. (reviewed March 1989 by Plants having more than two chromosome sets persomatic (bod y) technical coordinator C.S. Schopmeyer). celi HEER, O., 1866. Die Pflanzen der Pfahlbauten. Nelljahrsb/iiller der Pnllles Nalll/for.l'ch. Gesel/schajr Ziirich 68, pp. 3-53. HEDRICK, U.P., 1911. The 1'111111.1' of New York. Albany. Group of domestic plums with specific drying qualities. Typical HEGl, G., 1906 ff. llIlIslrierre Flora VOI/ Milleleuropa. 1., 2. und 3. varieties: Gernlan prune ('Zwetsche'), 'Stanley', 'Prune 'd Ente Auflage., 7 Bande, zum Te il in Teilbanden. Miinchen, spatel' (d'Agen)', 'Italian prune', 'Hungarian' (date) plunl. The term Berlin und Hanlburg. 'prune' is used here to distinguish the group from other domestic HOGG, F.M., 1884. Th ejrllil mW/lla/. 5th edition, London. plums. HOPF, M., 1968. Friichte undSanlen. In: H. Ziim, Dasjungst einzeitliche Sp ecies Dorf Ehrenstein (Kreis Ulm). Verojj: Slaall. AIIII. Dellkma/pjl. Taxonomic unit which normaliy does not interbreed with other SllIlIgarr, Reihe A 1012, pp. 7-77. such groups; related species are grouped into genera JACQUAT, c., 1988. Les plantes de I'age du Bronze. Catalogue des Variery fru its et graines. Hauterive - Champreveyres I. Arcllli% gie Taxonomic group below the species level Nellchfile/oise 7, pp. 9-47. JAHN, F., E. LUCAS & J.G.c. OBERDIECK, 1861. lIllIsIrierIes Hal/dbllch der Obslkll/u/e. Band III. Ebner & Seubart, Stuttgart. 12. NOTE KNORZER, K.-H., 1979. Spatmittelalterliche Pflanzenreste aus der Burg Briiggen, Kr. Viersen. BOIll/er Jahrbllch 179, pp. 595-6 1.1 . KNORZER, K.-H., 1987. Geschichte der synantropen Vegetation I. The sharp increase of plum, apple and pear varieties in Pliny's von Koln. KO/I/er Jahrbllch 20, pp. 27 1 -388. time, the first century AD, is not necessarilydue to the introduction KOMA ROV, V.L. (ed.), 194I.Flora oflhe U.S.S.R. Vol. IO: Rosaceae­ of 'foreign' varieties in Rome. The Romans' passion for fru it Rosoidae, Prunoidae. Moscow-Leningrad. growing must have led to the development ofnew fru it varieties. KORBER-GROHNE, U., 1984. Uber die Notwendigkeit einer A recent equivalent ofrapid accumulation ofvarieties is fo und in Registrierung und Dokumentation wilder und primitiver the very young States ofAmerica, where plum cultivation started Fruchtbaume, zu deren Erhaltung und zur Gewinnung von c. 1750. By 1828, Prince Nurseries, New York, were offering 140 Vergleichsmaterial fUrpalao-e thnobotanische Funde. In: W. van plum varieties for sale, including several American varieties' Zeist & W.A. Casparie (eds.), P/al/Is andAI/cielll Mali. Balkema, Rotterdam, pp. 237-24 1. KORBER-GROHNE, U., 1992. Kirschpflaume PrullllS cerasifera 13. REFERENCES und einige seltene Varietiiten der PflaumePmnlls domesliea L. Prasentation und Reservate. In: H. Kroli & R. Pastemak (eds.), BAAS, J., 1936. Die Kulturpflanzen aus den frii hgeschichtlichen Imemaliollal Work Grrlllpfo r PalaeoelhllobolllllY, Proceedillgs Burgen von Zantoch bei Landsberg a.d. Warthe. Nalur III/d Vo/k of lhe Nil/lh Symposillll/ Kiel 1992, pp. 87-99. 66, pp. 46 1 -468. KORBER-GROHNE, U., 1996. Pj la lili/eli, Kirschpjla llll/ell IIl1d BAAS, J., 1951. Die Obstarten aus der Zeit des Romerkastelis Schlehell. Helllige Pj lallzel/ lI/ltl ihre Geschichle seil der Friihzeil. Saalburg im Taunus bei Bad Homburg v.d.H. Bericlll des Stuttgart. Saa/bllrgmllseums IO, pp. 14-28. KROLL, H., 1980. Mittelalterlich/Friihneolithisches Steinobst aus BAAS, J. (ed.), 1971. Pj lanzenresle aliS romerzeillichel/ Sied/lIl/gel/ Liibeck. Liibecker Schriften illr Archii% gie III/d KII/lllrgeschichle von Mainz-Wiesel/au lIl/d Mail/z-II/nensradl lll/d ihr ZlIsalllmen­ 3, pp. 167- 1 73. hang lIIil Pj lal/zel/-FIII/del/ alis vor- III/d jriihgeschichl/ichen KUHN, F., 1991. Nålez semen ze stredoveke Johlavy, ze zvlåstnim Sralionen Mille/ellropas. Mainz. zretelem k peckåmsliv (Ein Fund von Sanlen aus dem Mittelalter BEHRE, K.-E., 1978. Formenkreise von Pnlllus dOllleSlica L. von der aus Iglau, mit besonderer Hinsicht auf Steinkerne von PruIlIlS. Wikingerzeit bis in die frii he Neuzeit nach Fruchtsteinen aus Darin: Bestimmungsschliissel fii r Steinkeme von PrullllS ssp. pp. Haithabu und Alt-Schleswig. Bericlue der Delllschen BOlanischen 33-35). V/aslivedllysbomik vymcillY Oddil ved prirodllich I O, pp. Gese//schajr 91, pp. 45-82. 17-36. BERGHUlS, S., 1868. De Neder/al/dsche Boomgaard. Groningen. KUHN, F., 1992. Altere Typen von Pnll/IIS sect. Pnllllls in Mahren BERTSCH, K. & F., 1947. Geschichle /II/serer K,dlllrpj lal/zen. und die Moglichkeiten ihrer Erhaltung. Vorl. Pj lal/zel/ziichllll/g Wissenschaftliche Verlagsgeselischaft, Stuttgart. 25, pp. 1 17- 120.

BOOM, B.K., 1965. Neder/al/dse del/dr% gie (= Flora der cultuur­ KUHN, F., 1995. Ein neuerFund mittelalterlicher Samen und Friichte gewassen van Nederland, I). 5e druk. Wageningen. ausJihlava. In: H. Kroli & R. Pastemak (eds.),1l/lemaliol/a/ Work DAHL, c.G., 1943. Pom% gi. Stockholm. GroIII' fo r Pa/aeoelllllObolaIlY, Proceedillgs of lhe Nil/lh Sympo­ DA VIS, P.H. (ed.), 1956- 1988. The jlora of Tllrkey alld Ihe Easl sill/I/ Kiel 1992, pp. 145- 148. Aegeal/ i.�/al/ds. I O vols. Edinburgh Univ. Press, Edinburgh. MAlER, S., 1988. Botanische Untersuchung romerzeitlicher DOMIN, 1944. De varia bi/ila le Pmlli spil/osae L. Praha. Pflanzenreste aus dem Brunnen der romischen Zivilsiedlung DOWNING, c., 1896. Fruil alldjrllil Irees af America. New York­ Kongen (Landkreis Esslingen). In: H. Klister (Hrsg.), Der London. priihislorische Mellsch III/d seille UI/Mell (= FeschriftU. Korber­ FOURNIER, P., 1977. Les qllalres jlores de Fral/ce. Paris. Grohne, Forschungen und Berichte zur Vor- und Friihgeschichte FRANK, K.-S. & R-P. STIKA, 1988. Bearbeitung der makros­ in Baden-Wiirttemberg 31), pp. 29 1 -324. kopischen Pflanzen und einiger Tierreste des Romerkastelis OPRAVIL, E., 1976. Archeo-botanicke nålezy z mestskeho jådra Sablonetum (Eli ingen bei Weissenburg in Bayern).Maleria/ hejie Uherskeho Brodu (Archaobotanische Funde aus dem Stadtkem Zllr Bayerischen Vorgeschichle, Reihe A, pp. 5-99. von UhersJ,,-y Brod). Sil/die arche% gickeho UI{(lvII CeskoI/ovem'ke GOTTFRIED VON FRANCKEN, 1380. Pe/zbllch. Akadelllie ved v Brne 3 (4), pp. 3-59. ' GREENOAK, Fr., 1983. Forgollel/jrllil. London. OPRAVIL, E., 1986a. Rostlinne makrozbytky z historickeho jadra GREGOR, R-J., 1995. Mittelalterliche Pflanzenreste von Bad Prahy (Pflanzliche Makroreste a.u s dem historischen Stadtkem Windsheim. In: W. Janssen, Der Wil/dsheimer Sp ira!flll/d aw' der von Prag). Arche% gica Pragel/Sis 7, pp. 237-27 1. Zeil llm 1500. Verlag des Germanischen Nationalmuseums, pp. OPRA VIL, E., 1986b. Archeobotanicke nahlezy z arealu bråny v 123- 1 34. Opave (bYv. Hotel Komna) (Archaobotanische Funde aus dem Oll the arigin af plums 55 1

Areal Jaktarer Tor in Opava). Ces. S/n Mllz. OpavlI (A) 35, pp. TUTIN, T.G., V.H. HEYWOOD, N.A. BURGES, D.M. MOORE, 227-253. D.H. VALENTINE, S.M. WALTERS & O.A. WEBB, 1968. PEYRE, P., 1945.Lespnllles mIlvages el eli/lives. Clermont-Ferrand, F/ora Ellropaea. 2 Vols. Canlbridge University Press, Cambridge. Paris. WATKINS, R., 1976. Cherry, plum, peach, apricot and almond. In: PIGNATI I,S., 1982. F1orc/ {1' Ila/iea.3 Volumes. Edagricole, Bologna. N. W. Simmonds (ed.), EVO/lllioll oJcrop p/ailIs. Longman, London POST, G.E., 1932. F/ora of Syria, Pa/eslille alld Sillai. American and New York, pp. 242-247. Press, Beirut. WEIMARCK, H., 1942. Bidrag till Skånes Flora. En spontan hybrid REINHARDT, L., 191 1. KII/Illrgesehiehle der Nlllzpjlallzell. mellem slan och terson. BOlalliska NOliser LIlIId, pp. '2 1 8-226. Miinchen. WERNECK, H.L., 1958. Die Fomlenkreise der bodenståndigen RIKLI, M., 1943- 1948. Das Pj lallzellk/eid der Mille/llleer/iillder. Pflaumen in Oberosterreich. Ihre Bedeutung fur die Systematik Hans Huber, Bem. und Wirtschaft der Gegenwart. Milleilllllgell der H6heren ROACH, F.A., 1985. ell/livaled Fmils of Brilaill. Their Origill alld Blllldes/ehr- IIl1d VerSllehsallsla/'ell fiir Weill-, Obsl- lind HisIOI·Y. Oxford. Garlenball (K/oslernellbllrg), Ber. B ObSI II. Ganen 8, pp. 59-82. RODER, K., 1940. Sortenkundliche Untersuchungen an Pmnlls WERNECK, H.L., 1961. Die wurzel- und kemechten Stammforrnen dOlllesliea. Kiillll-Arehiv 41, pp. 1-132. der Pflaumen in Oberosterreich. Nalllrklllulliches Jarhbllch der RYBIN, W.A., 1936. Spontane und experimentell erzeugte Bastarde S'ad, Linz, pp. 7- 129. zwischen Schwarzdom und Kirschpflaume und das Abstam­ WOLDRING, H., 1993. Over tussenvomlen van sleedoom en kriek­ mungsproblem der Kulturpflaume. P/allla-Arehiv Jiir lVissell­ pruim. Paleo-akllleel 4, pp. 85-89. sehafi/iehe Bolallik 25, pp. 22-58. ZEIST, W. VAN, 1988. Zaden en vruchten uit een zestiende-eeuwse STEBB1NS, G., 1960. Varialiollalld eVO/lllioll illp/ailIs (4th plinting). beerkuil. In: P.H. Broekhuizen, A. Camliggeit, H. van Gangelen G. Ledyard and Stebbins Jr, New York. & G.L.G.A. Kortekaas (eds.), Kallendiep dellrgravell, pp. 140- STIKA, H.-P. & K.-S. FRANK, 1988. Die Kirschpflaume: Systematik, 160. Groningen. Morphologie, Verbreitung, Verwendung, Genetik und archiio­ ZEIST, W. VAN, H. WOLDRING & R. NEEF, 1994. Plant husbandry and vegetation of early medieval Douai, northern France. logische Funde. Der priihislori�'che Memch IIl1d seille Ul/live/I (= FeslscI/rijl U. Korber-Grohlle zusammengestellt von Hansjorg Vegelalion History and Arclweobolany 3, pp. 191-218. Klister), Forschungen und Berichte zur Vor- und Friihgeschichte ZOHARY, D. & M. HOPF, 1988. DOllleslicalion oJp lalll,\' in lhe Old in Baden-Wiirttemberg 31, pp. 65-7 1. World. Clarendon Press, Oxford. TA YLOR, H.V., 1949. The p/lilliS of Ellg/alld. London. 552 H. WOLDRING

APPENDIX l. Intermediate forms of Prunus insititia BONG-91-1: Bunnerveen, near Peize, province of Drenthe, the Netherlands, 28th September 1992 and Prunus spinosa. Old plantings between sandy track and arable land. Small to medium­ sized tree with abundant secondary, extremely spiny vegetation, In this Appendix, Prunlls fonns intemlediate to insiririo and spinosa are described and depicted. The selection ofthe specimens is based on height c. 4 m. Summer shoots pubescent. Leaves appr. oval, 4-4.Sx3- the characteristics ofUle stones; each specimen represents a different 3.5 cm. Leaves of lateral spurs oblanceolate-obovate, 3-4x 1.6-2.3 type of stone. Locations of specimens with identical stones are cm. Fruits oval, more or less drooping, with or without bloom. Taste mentioned under the type-specimen. very acid. Pedicels thinly pubescent, length 7- 1 1 mm, dianleter 0.8- The type description includes location, date ofcollection, habitat, 1.2 mm. Insiriria fe atures: fruits. Sp inosa fe atures: size and anange­ character and measurements ofthe treeIshrub, leaves, pedicels, fruit ment ofleaves, habitus. Stones with predominantly spinosa fe atures. and fruit stones. Ln many cases measurements of leaves of summer shoots and the fruit-bearing lateral spurs are indicated separately. ESBR-93-2: Esbruyere, between Amay-Ie-Duc and Autun, C6te Some of the types were used in the breeding tests. Where this is the d'Or, France, 3rd September 1993 case, germination and growth rate are indicated. Next to SPIN-ESBR-93-1, from which it mioht be a seedlino The tables present the average, minimum and maximum (originating from fertilization with insiriria polle�). Both specimen� measurements oflength, thickness and breadth ofthe fruits andfru it located in pasture. Shrub with five stems, height c. 3 m. Summer stones. The dimensions offruits and fruit stones show much overlap, shoots pubescent. Leaves obovate, 4-6.Sx2.3-3.S cm. Leaves of for which reason proportional indices have been omitted. The lateral spurs lanceolate (small ones) or obovate (larger ones), 2.5- 6x2.3-3.S cm. Fruits almost round, drooping. Taste acid to wry. measurements of fruits and stones of modem insiriria vaJieties presented in Van Zeist and Woldring (this volume) may serve as a Pedicels al most smooth, sometimes in pairs, length 7- 12 mm, diame­ reference. ter 1.0- 1.5 mm. Insiriria features: fru its, leaves. Sp inosa features: Owing to their fairly similar appearance (usually black to purpie stones, taste of fruits. Gemlination rate c. 60%. Seedlings display or bluish colour, round or almost round-shape), black-and-white homogeneous growth. Indices fru its: BIL. I OO� I 04, TIL.l 00�98, photographs of the fruits also were deemed to be of little value. TIB. 1 00�94; indices stones: B/L. 100�S6,T/L. 100�84, TIB .IOO� 151

HELP.Z-92- 1: Helpman, suburb of the town of Groningen, the Netherlands, September 1992 HELP.z-92- 1 VAG-9 1-2 Small-sized tree with many root suckers in planting alongside road, Fruits height c. 4 m. Leaves al most circular to obovate, 7x4.S cm. Summer Number 15 12 shoots glabrous. Fruits subglobose with much bloom. Taste sweet but Length 16.6( 15.5- 1 7.7) 17.S( 1 4.5-20.5) not pleasant. Pedicels smooth, length 5- 10 mm, diameter c. 1.0 mm. Thickness 18.1( 1 6.5-19.4) 16.7(1 4.0-19.1) General impression of imiriria, but shape of the plums resembles Breadth 18.8( 1 7.4-20.2) 17.5(14.5-2 1.3) spinosa. Sp ino,l'lI-type stones. Gemination rate c. 70%, seedlings Stones fairly homogeneous. Moderate growth. Number 23 24 Length 9.8(9.0- 10.9) 10.5(9.2- 1 2.0) VAG-91-2: Nietap, province of Drenthe, the Netherlands, 5th Sep­ Thickness 8.6(8.0-9.4) 8.3(7.0-9.6) tember 1991 Breadth 6.7(6.3-7.2) 6.3(5.6-7. 1 ) Large shrub with few stems and many rootsuckers, height upto 5 m. Summer shoots thinly pubescent. Leaves quite large, oval to elliptic, 7x4cm. Fruits almost round to oval, drooping, blackish, glossy. Taste DOM-9S- 1 BARN-96- 1 wry. Pedicels thinly pubescent to glabrous, length 8- 18 mm, diameter Fruits unknown. lnsiriria fe atures: general fru it characteristics, leaves. Number IO 16 Sp inosa fe atures: stones, wry fruits, habitus(?). Gemination rate Length 19.8( 19.0-21.1) 20.9( 1 8.5-23. 1) 20%. Seedlings display heterogeneous growth. Thickness 20.0( 18.0-2 1 .3) 19.7( 1 7.7-2 1 .9) NB. In newly planted, c. 25-year-old forest, but possibly part of a Breadth 20.2( 1 8.0-22.5) 20.S( 1 8.3-23.0) fo nner hedgerow. A second specimen, with different stones (not Stones shown), grows at a distance of only 50 m. This specimen flowers Number 20 15 abundantly each year, with large insiriria-type flowers (diameter 2.5 Length 12.0( 10.7- 1 3.0) 12.7(1 1 .7- 1 3.7) cm), but fru it setting is extremely poor. Thickness 9.7(8.7- 10.8) 9.4(8.8- 10. 1) Breadth 6.7(6. 1-7.3) 7.4(6.9-8.8) DOM-9S- I: Domecy-sur-Cure, Morvan, France, 31st August 1995 Many-stemmed shrub in front ofthe local chateau, as broad as high, BONG-9 1-1 ESBR-93-2 c. 3 m. Summer shoots smooth. Leaves oval to elliptic, 6x3.S cm at Fru its maximum. Fruits slightly drooping, overspread with thick bloom, Number II 20 round to subglobose, sweet and tasty, free stone. Pedicels thinly Length 18.1(17. 1-19.9) 18.7( 1 6.2-20.9) pubescent to glabrous, lengU1 9- 14mm,diameter 1.0-1.1 mm.lnsiriria Thickness 16.6( 15.6-18.1 ) 18.3( 15.7- 19.7) fe atures: leaves, taste of fruit. Sp inosa fe atures: stones, habitus, bloom? Breadth 16.7( 15.4-18.4) 19.5( 1 6.5-2 1 .3) Stones BARN-96-I : Bamsley, Cotswold Hills, Gloucestershire, GreatBritain, Number 19 25 8th September 1996 Length 12.5(1 1.4- 13.6) 12.7(1 1 .5- 1 3.7) Productive shrub in a hedgerow dominated by sloe, height 3 m. Thickness 9.8(8.7- 10.8) 10.7(9.5- 11.6) Summer shoots pubescent. Leaves oval, c. 4x2.S cm. Leaves of fruit Breadth 6.3(5.7-7.3) 7. 1 (6.5-7.6) spurs larger(!), oval (sometimes obovate), c. 4.Sx3 cm. Fruits round, drooping. Taste sugary, free stone. Pedicels glabrous, length 4- 11 mm, diameter 1.1-1.3 mm. lnsiriria fe atures: fru its. Sp inosll fe atures: stones, lea ves. NB. Another specimen with the sanle type of stones (BARN-96-2) has leaves identical to sp inosa leaves. On the origin of plums 553

HELP. Z -92 - 1

VAG - 91 - 2

DOM-95-1

BARN- 96-1

BONG - 91-1

ESBR -93-2

o 2cm I . ' I 554 H. WOLDRING

SPIN-ESBR-93- 1: Esbruyere, between Amay-Ie-Duc and Autun, SPIN-ESBR-93- 1 GERAUD-92- 1 Cote d'Or, France 10th September 1993 Fru its Next to ESBR-93-2, spreading shrub, not very spiny, height c. 3 m. Number 15 II Summer shoots pubescent. Leaves oblanceolate-elliptic-obovate, Length 13.8(12.S- 1 4.8) 24.8(22.5-27 .8) length c. 4x 1.S-2.0 cm. Leaves of lateral spurs (ob)lanceolate, 3- TIlickness 13.S(1 2.8-14.1) 22.6( 19.7-26.0) Sx 1.0- 1.8cm. Fruits round, non-drooping. Taste wry. Pedicels smooth, Breadth 14.1(12.9-15.1) 24.2(2 1 .2-27.4) length 4-S mm, diameter 0.9- 1.0 mm. Indices fruits: BIL. l OO� I 02, Stones T/L.IOO�98, T/ B.100�96; indices stones: B/L.100�64, T/L.100�84, Number 2S 20 T/B.IOO� 132 Length 8.8(8.1-9.4) 1 4.3( 12.6- 15.3) NB. Indices offruit and fru it stones show remarkable correspondence Thickness 7.4(6.7-8. 1) 10.5(8.6- 11.4) with ESBR-93-2, whose (maternal) parent this spil/osa specimen is assumed to beo Breadth 5.6(5.0-6.2) 6.8(6.4-7.3)

GERAUD-92- 1: La Chapelle Saint Geraud, Dordogne, France, Sth GIE-90-2 GIE-91-4 September 1992 Fruits Slender, spinescent shrub in hedgerow, height C. S m. Summer shoots Number 16 12 densely pubescent. Leaves elliptic to oval, 9xS cm or smaller. Fruits Length 1 8.6( 1 5.0-21 .0) 26. 1 (22.7-28.8) appr. round, drooping. Tasteacid. Pedicels pubescent, length 4-8 mm, Thickness 18.2( 14.8-20.3) 24.6(2 1.2-27.3) diameter 1.0-1.2( I.S) mm. ll/si/i/ia fe atures: drooping, large fruits. Breadth 1 8.4( 15.2-21.1) 25.6(2 1 .S-28.2) Sp il/osa fe atures: stones, leaves, spinescence. Stones Number 26 25 GIE-90-2: Gieten, provinee of Drenthe, the Nelherlands, 31sI July Length 12.7(1 1.5- 14. 1) 14.7( 13.S-16.6) 1990 Thickness I 1.3(9.9- 12.4) 12.5(1 1.1- 14.4) Spiny shrubs and rootsuckers over tens of metres under tall oaks, Breadth 7.8(6.5 -8.9) 8.5(7.7-9.3) height 2-3 m. Summer shoots sparsely pubescent. Leaves oval, 6x4.S cm. Somedead stems occurwith a diameterofc. 10cm at I m height. ST.GERM-9S- 1 Flower diameter C. 2.5 cm, fru its resemble large sloe fruits, sem i­ ONLAY-95- 1 drooping. Taste wry. Pedicels smooth, lengU1 8- 13 mm, diameterO.8- Fruits 1.3 mm. /lISi/i/ia fe atures: leaves. Sp il/osa fe atures: habitus, type and Number IO II taste of fru it. Gennination rate SO%. Seedlings display vigorous Length 21.4( 1 9.3-22.7) 20.5( 1 7.5-23.2) homogeneous growth. Thickness 20.S( 17.7-21.9) 19.3( 1 6.8-22. 1) NB. TIle characteristics ofthe Gieten specimen, in particular those of Breadth 21.1(18.0-23.0) 20.3( 1 8.5-22.9) the stones, suggest an origin from a crossing of' kroosjes' and sloe (cf. Stones Woldring, 1993 ). Number 22 22 Length 13.3( 12.2- 13.9) 13.0( I I.S- 14.3) GIE-9 1 -4: Gieten, provinceofDrenthe, the Netherlands, 22nd October Thickness 11.3( I 0.4- 12.0) 10.5(9.2- 11.4) 1991 Breadth 8.S(7.7-9.3) 6.6(5.8-8.1) Shrub with few rootsuckers at the edge ofa fo rest (chiefly oaks) and plantation ofspruce, height C. 3 m. Summershoots pubescent. Leaves elliptic-oval, S-7x2.S-S cm. Fruits resemble GIE-90-2, but slightly more oval, slightly drooping. Taste acid. Pedicels pubescent, length 7- 13 mm, diameter 1.0- 1.4 mm, stones resembling the previous type. ll/si/i/ia features: fru its, leaves. Sp il/osa fe atures: shrubby growth. Gemlination rate 100%. Seedlings display mostly homogeneous, moderate growth. Stones with predominantly spil/osa features.

ST.GERM-9S-I: St. Germain des Champs, Morvan, France, 31st August 1995 Large, very productive tree in hedgerow between meadows, height 6- 7 m. Summershoots pubescent. Leavesoblanceolate-obovate, S.Sx3.3 cm at maximum. Leaves of lateral spurs smaller, elliptic to (ob)lanceolate. Fruits round, drooping. Taste wry. Pedicels glabrous, also in pairs, length 9- IS mm, diameter 1.0- 1.2 mm. ll/si/i/ia features: habitus, size of fru its. Sp il/osa fe atures: leaves, stones, taste of fruits. Types with identical stones: Esbruyere, Dracy Chalas (Cote d'Or), Brazey-en-Morvan, Dalmazane (Dordogne), possibly also Rasquert (Groningen, the Netherlands). Most common type of stone in the intermediates.

ONLA Y -9S- I: Onlay, Morvan, east-central France, 7th September 1995 Two identical trees near the village, height C. Sm. Summer shoots glabrous. Leaves oval, 7xS.5 cm Ol'smaller. Fruits globular, drooping. Taste sweet. Pedicels most ly glabrous, length 7- 10 mm, diameter 1.0 mm. lnsi/i/ia fe atures: size and tasteoffruits, habitus and size oftrees, lea ves. Sp il/osa fe atures: stones. Oll the origin of plums 555

SPIN-ESBR-93 - 1

GERAUD- 92-1

GIE -91-2

G I E -91 - 4

ST.GERM-95-1

ONLY- 95- 1

o 2 cm I I 556 H. WOLDRING

LESS-94- 1: Lessard-et-Ie-Chene, Normandy, France, 7th September LESS-94- 1 MASS-92-2 1994 Fruits Medium-sized, somewhat spiny shrub with few rootsuckers at the Number 16 1\ edgc ofagarden, height almost3 m. Summershoots thickly pubescenl. Length 25.2(22.0-29. 1 ) 27.5(25.3-29.5) Leaves (oblanceolate) elliptic toobovate, 4-7x2.5-4 cm. Fruits round­ Thickness 22.3( 19.0-25.6) 26.6(24.0-28.3) tnll1cate, drooping?Taste acid to sweel. Pedicels pubescent, length 7- Breadth 23.8(20.9-27.0) 28.5(26.0-30.2) 14 mm, diameter 1.4- 1.8 mm. /lIsi/i/ia fe atures dominant, except for Stones habitus and leaves. Number 21 25 Length I S.O( 1 2.9- 1 7.5) 14.9( 13.5- 16.3) MASS-92-2: Massalve, Dordogne, France, 3rd September 1992 Thickness 10.5(9. 1-1 1.8) 11.3( 10.1-12. 1) Thickets at the fringeofforest and meadow, fo rming a hedgerowover Breadth 6.9(6.2-7.5) 7.5(6.7-8.3) tens ofmetres, up to S m in heighl. Summershoots densely pubescenl. Leaves oval to broad elliptic, appr. Sx3 cm. Fruits subglobose to ST.MARIE-94- 1 SERVE-93- 1 round, large, bloom not removable. Taste acid to wry. Pedicels Fruits pubescent, often in pairs Ol' in clusters, length 6- 13 mm, diameter 1.1- Number 20 16 2.2 mm. /I/si/i/ia features: drooping, large fru its. Sp il/osa features: Length 20.3( 17.4-23.4) 23.0( 1 9.7-24.6) stones, tasteoffruits, habitus, leaves. Gemlination rate 50%. Seedlings Thickness 20.2( 16.9-23. 1) 21.0( 1 7.8-22.6) display slightly heterogeneous growtll. Breadth 20.5( 1 7.0-23.3) 22.6( 19.8-24.6) Stones ST.MARIE-94- 1: Sainte Marie-en-Anglais, Nomlandy, France, 31st Number 23 25 August 1994 Length 12.9( 10.7- 1 4.6) 15. 1(12.9-16.1) Shnlb on short stem, cultivated in garden, height 2m, breadth c. 2 m. Thickness 10.5(8.2- 12.0) I 1.1(9.6- 1 1.9) Summer shoots thickly pubescenl. Leaves uniform oval to al most Breadth 7.0(6.0-8.2) 7.8(6.7-8.8) circular, 3x2.S cm. Leaves of lateral spurs elliptic or lanceolate, 2- 4.Sx 1.0-2.0 cm. Fruitsround, semi-drooping, bloom. Taste wry (but MAGNY-94 ST.PAIR-94- 1 not very ripe). Pedicels pubescent, length 4-6 mm, diameter 1.2-1.9 Fruits mm. Sp illOm fe atures in every aspect, except for the extremely large Number IS IS fruits and stones. Might be a 'macrocarpa' fo rm or result from Length 22.6(20. 1-24. 1 ) 20. 1 (18.1-22.4) cultivation. Thickness 21.2( 19.1-23.8) 18. 1 ( 16.7- 19.4) NB. Six round-topped shrubs, height c. 3 m, cultivated in a garden Breadth 22.0( 1 9.8-25. 1 ) 19.3(1 7.4-20.7) near Lassery, Monteille (Normandy) display identical morphological Stones fe atures, fru its and stones. Six stones of this type rendered three Number 19 24 heterogeneous seedlings. Lengtll 14.6( 1 3.5- 1 5.5) 13.1(1 1.3- 14.7) Thickness 10.4(9.3- 11.5) 9.2(8.2- 10.0) SERVE-93- 1: Serve, between Arnay-Ie-Ducand Autun, Cate d'Or, Breadth 7.7(6.9-8.6) 6.5(5.6-7.2) France, 6th September 1993 Round-shaped, productive tree with shrubby rootsuckers, in (abandoned?) farmyard, height c. 4 m. Summer shoots pubescenl. Leaves obovate, 8x3.S-4 cm. Leaves of lateral spurs S-8x3-3.S cm. Fruits slightly ovate, drooping. Taste acid to wry. Pedicels thinly pubescent, length 6- 10 mm, diameter (1.2) IA-I.S( 1.8) mm. /llsi/i/ia fe atures: fruit alTangement, size of fru its, leaves. Sp il/osa fe atures: stones, wry taste. Germination rate 85%. Homogeneous, vigorous growth of seedlings.

MAGNY-94: Magny-Ie-Freu le, Nomlandy, France, 5th September 1994 Trimmed(!) spiny hedge over c. 20 m, bel\veen road and arable land, height c. I,S m. Summer shoots thickly pubescenl. Leaves elliptic Ol' obovate, 4-6.Sx2.S-3.Scm. Leaves of lateral spurs (ob)lanceolate to elliptic, 2.S-Sx 1.0-3.0 cm. Fruits round, slightly drooping, thick bloom, fru it setting fro m about 30cm above the ground. Taste sugary. Pedicels pubescent, length 3-9 (mostly 6) mm, diameter 1.3- 1.8 mm. /lIsi/i/ia fe atures: fruitcharacteristics, stones. Sp illosa fe atures: shrubby habitus (evident fro m some free-standing specimens), leaves.

ST.PAIR-94- 1: Saint Pairdu Mont, Nomlandy, France, 28th August 1994 Large, almost spineless tree with vigorous branches growing in a hedgerow, height c. S m. Summer shoots pubescenl. Leaves appr. oval, c. 6x3.S cm. Leaves of lateral spurs oblanceolate-obovate, 2.5- Sx 1.5-2.5 cm. Fruits roundish or truncate, drooping. Taste wry. Pedicels glabrous, length 6- 10 mm, diameter 1.0- 1.4 mm. /lIsi/i/ia fe atures: stones, size of fruits, habitus. Sp illosa fe atures: leaves, taste of fru its. Oll rhe origin of plums 557

LESS - 94-1

MASS - 92-2

ST. MARIE -94-1

SERVE -93-1

MAGNY -94

ST. PAI R-94-1

o 2cm I , . I 558 H. WOLDRING

LASS-94-3: Lassery, nearMonteille, Nomlandy, France, 31st August LASS-94-3 PONC-93- 1 1994 Fruits Small-sized, almost spineless tree with some rootsuckers, in hedgerow, Number 14 17 height 3-4 m. Summer shoots pubescent. Leaves elliptic to Length 22.5( 1 8.3-24.6) 21.8(20.3-24.0) (ob)lanceolate, c. 3x 1.5 cm. Leaves of lateral spurs almost the same Thickness 19.3(1 4.7-2 1.2) 18.6( 1 7.2-2 1.4) size. Fruits oval, drooping, thickly bloomed. Taste wry. Pedicels Breadth 20.3( 16. 1-22.3) 19.7(1 7.9-22.6) pubescent, length 4-8 mm, diameter 1.1-1.5 mm. II/sililia fe atures: Stones size offmits and stones, habitus. Sp il/osa fe atures: sculpture ofstones, Number 14 25 leaves, taste of fruits. Length 14.1(1 1 .6- 15.6) 15.1(13.7- 16.3) Thickness 8.8(7.0-9.3) 9.9(9.2- 10.8) PONC-93- 1: Poncey, between Arnay-Ie-Duc and Autun, Cate d'Or, Breadth 6.2(4.9-6.9) 6.4(5.8-6.8) France, 5th September 1993 Spiny shmbs in hedgerow between spil/osa specimens, at the edge of LAB-92- 1 LEUT-9 1-1 a meadow, many rootsuckers, height up to 3 m. Summer shoots thinly Fruits pubescent. Leaves elliptic-obovate, 5x2.5 cm. Leaves oflateral spurs Number 15 20 oblanceolate, 3-4.5x 1.6-2.5 cm. Fruits drooping, ovate, sometimes Length 21.9(20.7-23.7) 17.1 (15.5- 18.4) oval. Taste WIY. Pedicels glabrous, length 6-9 mm, diameter 0.9- Thickness 22.8(2 1.8-24.3) 16.1(15.1-18.0) 1.2( 1.4) mm. II/sililia fe atures: stones, most fruit characteristics. Breadth 23.5(22.2-25.2) 16.8(15.2- 17.8) Spil/osa features: leaves, habitus, taste of fru its. Gennination rate Stones 50%. Seedlings display homogeneous growth. Number 22 20 Length 11.9( 1 1.0- 13.1) 12.9(1 1 .7- 13.8) LAB-92- I: Laboureyrie, south of Le Pecher, Dordogne, France, 11th Thickness 9.3(8.7- 1 0.0) 9.4(8.4- 10.0) September 1992 Breadth 6.0(5.6-6.7) 6.7(6.0-7.4) Shrub in hedgerow, height c. 3 m. Summer shoots smooth. Leaves elliptic to oval-obovate, 7x3.5 cm at maximum. Leaves of lateral GR.ST-92-6 GERAUD-92-2 spurs smaller, elliptic-Ianceolate. Fru its drooping, subglobose. Taste Fruits sweet. Pedicels al most smooth, sometimes in pairs, length 5-12 mm, Number II IO diameter 1.0- 1.5 mm. II/sililia fe atures: fru its. Spil/osa fe atures: Length 19.6(18.1-21.1) 24.5(23.4-26.6) stones, habitus, leaves. Specimens with identical stones: St.-Julien­ Thickness 1 7.0( 15.3- 1 8.0) 21.9( 1 9.8-25.0) Maumont, Dordogne; St.-Pair-du-Mont, Nornlandy, France. Breadth 17.6( 15.8- 1 8.5) 23.2(2 1 .3-24.4) Stones LEUT-9 1-1: Leutingewolde, province of Drenthe, the Netherlands, Number 22 21 5th October 1991 Length 13.4(1 1 .8- 1 4.5) 13.8( 1 3.0- 14.8) Shrub with many rootsuckers, in hedgerow alongside road, height c. Thickness 9.0(8.0- 10.1) 8.6(8.0-9.3) 3 to 4 mu. Leaveselliptic to lanceolate, 6x2.5-3 cm. Fruits ovate. Taste Breadth 6.3(5.7-7.0) 6.4(5.9-7.6) wry. Pedicels smooth, length 5-10 mm, dianleter 1.1-1.6 mm. Except fo r the size of the fru its, fe atures of sloe predominate. Large-fruited form of sloe? Gennination rate C. 50%. Seedlings demonstrate homogeneous, quite vigorous growth. A specimen with identical stones was found in a plantation in the nearby village of Peize.

GR.ST-92-6: Groningen 'Stadspark', the Netherlands, 18th August 1992 Many-stemmed spiny shrub, with many rootsuckers, height c. 4 m. Summer shoots pubescent. Leaves oval, 8x4-4.5 cm. Fruits ovate, blackish-brown. Taste acid to wry. Pedicels length I l-IS mm, diameter 1.3 mm. Imilitill fe atures: leaves, large drooping fruits. Spil/osa fe atures: shnlb habitus, taste offruits, stones(?) 1l1ree specimens with similar stones were found in the park.

GERAUD-92-2: La Chapelle Saint Geraud, Dordogne, France, 5th September 1992 Small-sized tree in garden, height c. 3 m. Summer shoots sparsely pubescent. Leaves oblanceolate-elliptic, 6x3 cm at maximum. Fruits drooping, ovate to oval. Taste sweetJsugary. Pedicels in pairs, pubescent, length 5-9 mm, diameter 1.1-1.4 mm. Stones identical to a specimena in the nearby hamlet of Croisille, Dordogne, France. 0/1 the arigin af plums 559

LASS -94 -3

PONC- 93-1

LAB-92- 1

LEUT-91-1

GR. S T-92-6

GERAUD-92-2

o 2cm I I 560 H. WOLDRING

STROM-95-2: Sainl Romain, near Beaune, C6le d 'Or, France, 1995 STROM-95-2 STBONNET-92- 1 Shrub on caslle ram parts, heighl 2 m. Summer shools pubescenl. Leaves mosl ly obovale, some (ob)lanceolale, 2.5-5x 1.3-3.0 cm. Fru ils FruilS almosl blad:, drooping, oval-ovale. Tasle almosl wry. Pedicels Number 15 II smoolh, lenglh 7- 1 mm, diameler 1.0- 1.4 mm. Moslly iID'ililia I Lenglh 21.6( 1 8.9-24.4) 23.0(2 1 .7-25.4) fe alures, excepl for ils shrubby habilus and small slones. The leaves Thickness 17.6( 1 5.2-2 1.1) 21.6(20.5-24.2) of lhis specimen are much smaller bul similar in shape lo a nem'by­ Breadlh 18.2(15. 1-21.1) 22.6(2 1 .6-25.3) growing il/sililia specimen of lhe variely ·Sl.-JlIlien'. Slones Number 20 ST.BONNET-92- I: Sainl Bonnel near Sexcles, Dordogne, France, 21 3rd Seplember 1992 Lenglh I 1 .5( I 0.3- 1 3.0) 12.6( 11.8- 1 3.5) Shrub, heighl llnrecorded. Summer shOOlS pubescenl. Leaves elliplic TIlickness 7.5(6.7-8.4) 8.9(8. 1 -9.7) lO almOSl oval, 5x2.5-3.5 cm. Fruils roundish wilh bloom. Tasle sweel Breadlh 5.4(4.8-6. 1) 5.8(5.5-6.3) wilh acid aflertasle. Pedicels pubescenl, lenglh 6-9 mm, diameler 1 .0- 1.4 mm. Imililia fe alures: lasle and size of fru ils. Sp il/osa fe alures: LE PECH-92- 1 CHAL-95- 1 slones, leaves, habilus. Idenlical lype: Le Pecher, Dordogne, France. Fruils Number 5 14 LE PECH-92- I: Le Pecher, Dordogne, France, Illh Seplember 1992 Lenglh 26.4(25.4-27.0) 22.9{ 1 9.8-26.0) Small, spineless lree in meadow, heighl 3-4 m. Summer shools . Thickness 24.6(23.6-25.5) 21.4( 1 8.2-24.7) densely pubescenl. Leaves elliplic-oblanceolale. Leaves of laleral Breadlh 25.9(25. 1 -26.8) 21.1( 1 8.4-23.8) spurs glossy ,elliplic-oval, 6x3.5 cm. Fruils roundish, drooping. Tasle Slones sweel. Pedicels pubescenl, lenglh 6- 10 mm, diameler 1.3- 1.7 mm. Number 18 20 II/sililia fe alures: size and lasle of fruils, slones, habilus. Sp il/osa Lenglh 14.2( 13.1-14.9) 13.6(1 1.2- 15.5) fe atures: leaves. Idenlical lype: Massalve, Dordogne. TIlickness 10. 1 (9.3- 1 0.7) 10.5(8.9- 12.2) Breadlh 6.5(6.2-6.9) 7.2(6.2-9.0) CHAL-95- 1: Chalaux, Morvan, France, 3rd Seplember 1995 Very produclive lree wilh abundanl roolsuckers al lhe edge of lhe ROB-92- 1 village, heighl 5 m. Summer shoolS al mOSl glabrous. Leaves oval or GR.ST-92-2 elliplic, 5.5x3.5 cm al maximum, on average 3x2 cm. Fnlils ovale lO FnlilS round Ol' oval, drooping, lhick bloom. Tasle acid. Pedicels glabrous, Number 9 15 lenglh 6-8 mm,diameler 1 .0- I .4mm./l/sililia fealures: lreedimensions, Lenglh 21.7(20.4-23.4) 24.7(23.3-26.0) fruils. Sp il/osa fealures: fo liage, Slones. Thickness 19.9( 18.7-2 1 .2) 19.3( 1 7.9-20.6) Breadlh 20.6( 1 9.4-22.0) 19.8( 18.6-20.9) ROB-92- I: Robert, Dordogne, France, 1992 Slones Thickels over c. 30 meler, heighl c. 3 m. Leaves oval, 3-4.5x2-3 cm. Number 21 25 Fruils drooping, almOSl round, wilh Ol' wilhoul bloom. Tasle sweel. Lenglh 14.0( 12.9- 1 5.0) 15.2( 13.3- 16.5) Pedicels pubescenl, lenglh 4- 10 mm, diameler 1.0- 1.7 mm. II/sililia Thickness 9.8(8.9- 10.5) 8.6(7.7-9. 1 ) fe alures: size and lasle of fru ils, slones. Sp il/osa fealures: leaves, Breadlh 6.4(5.8-7.2) 5.6(5. 1-6.5) growlh properties. Gemlinalion rale c. 30%. Seedlings display hClerogeneous growlh.

GR.ST-92-2: Groningen 'Sladspark', lhe Nelherlands, 26lh AuguSl 1992 Slurdy lree wilh few spines, uprighl-spreading wilh few roolsuckers, heighl c. 4 m. Summer ShOOlS pubescenl. Leaves oval, 3.5-5x2.5-3.5 cm. Fnlils drooping, slighlly necked, oval, asymmelric, in oulline resembling prunes. Tasle acid. Pedicels pubescenl, lenglh 5- 16 mm, diameler 1.2-1.5 mm. II/sililia fe alures: size and shape of fnl ils, Slones. Sp il/osa fe alures: leaves. Anolher specimen wilh similar slones grows in lhe park. 01/ the origin af pItlIllS 561

ST. ROM-95-2

ST. BONNET- 92-1

LE PECH-92- 1

CHAL-95-1

ROB -'92 - 1

GR.ST - 92-2

o 2cm I I 562 H. WOLDRING

AMPN-96- 1: Ampney Saint Mary, Cotswold Hilis, Gloueestershire, AMPN-96- 1 PEI .'W-92- 1 Great Britain, 9th September 1996 Fruits Productive shrubs bordering a path over ten metres, height up to 2.5 Number 19 IS m. Summer shoots pubescent. Leaves obovate, smaller ones elliptic Length 20. 1 ( 1 7.9-22.3) 18.3(17.1-19.7) to oval, 3.S-6.Sx2.S-S cm. Fru its oval, drooping, sweet but not tasty. Thickness 17.1(15.6- 18.7) 16.3(1 5.0- 17.8) Pedicels smooth, also in pairs, length 7- 13 mm, diameterO.7- 1.0 mm. Breadth 17.0( 1 5.3- 18.6) 16.9( I 5.4- 18.9) Mostly il/sititia fe atures with stones much resembling those of the Stones loeal English damson. The fruits ofthis specimen are smallerthan any Number 25 23 ofthe collected English damsons. The eombination ofsmall (but full­ Length 13.6( 12.2- 1 5.5) 12.2( 11.0- 13.4) grownl) shrubs and small damson-type stones suggests a crossing Thickness 8.7(7.8-9.4) 7.8(7. 1-8.4) between dam son and sloe. A type with similarstones was found at the edge ofa small orchard in Sapperton, west ofthe town ofCirencester, Breadth 6.4(5.8-7.6) 5.1 (4.5-5.6) Gloucestershire. This type has somewhat larger stones, necked and wry fruits and spil/osa-type leaves. TU-90- IS Fruits PE I.'W -92- I: Peizerwold, provinee of Groningen, the Netherlands, Number 21 st August 1992 Length Small-sized tree, alongside a sloe specimen in hedgerow between Thiekness meadows, height 4 m. Summer shoots smooth. Leaves 6.Sx3 cm. Breadth Fruits obovate, taste wIY. Pedicels pubescent, length 7-1 1 mm, Stones diameter 0.9- 1.4 mm. ll/sititia fe atures: habitus, leaves, drooping Number 20 fruits, shape of stones. Sp il/osa fe atures: taste of fruits, size of stones. Length 15.7(1 4.9- 16.5) Thickness 13.2(12.1-14.5) TU-90- 1 S: Tuoro, loeality Monticehio, ltaly, 10th May 1990. Breadth 7.6(6.9-8.0) Stones from under tree with few rootsuekers in vineyard. Summer shoots thickly pubescent. Leaves erenate, oval to obovate, 7x4 em. Leaves of lateral spurs variable, 2.S-6.Sx 1.5-4 cm. Leave margins serrate to erenate. Fruits oval, immature (therefore not measured). Pedicels thickly pubescent, length I S mm.

AMPN -96-1

PEI.'W- 92-1

TU-90 - 15

o 2cm I I