Androgyny of Individuals and Polygamy in Populations of Salix Myrsinifolia Salisb

Vol. 1/2, pp. 238–266 Perspectives © Gustav Fischer Verlag, 1998 in Plant Ecology, Evolution and Systematics

Androgyny of individuals and polygamy in populations of Salix myrsinifolia Salisb. in the south-western part of its geographical range (NE-Poland)

Janusz B. Falin´ski

Geobotanical Station of Warsaw University, 17-230 Bial/owiez˙a, Poland; email: [email protected]. bial/owiez˙a.pl

Abstract

The aims of the study were to describe the phenomenon of androgyny (a change in the sexual behaviour of individuals) in Salix myrsinifolia, and to consider the implications of androgyny for the sex structure of local populations and for the sex structure of the species across a larger geographical range. Field surveys of the sexual behaviour of individuals and populations of Salix myrsinifolia were carried out over nine years (1989–1997) in an area of 40,000 km2 of NE-Poland. More detailed studies were performed on populations in Polana Bial/owieska (the Bial/owiez˙a Clearing) in the Bial/owiez˙a Primeval Forest, in the Bial/ystok area, in the Biebrza Valley and in the experimental garden and laboratory of the Bial/owiez˙a Geobotanical Station. The bisexuality of Salix myrsinifolia is basically expressed through the development of a number of different forms of catkin that are intermediate between those that are entirely male and those that are entirely female. Flowers on bisexual catkins are fully developed, as on monosexual ones, but the male segment usually develops prior to the female one. With the exception of one form, a clear partitioning between the male and female parts of the catkin remains. This partitioning of the genders mainly takes place transversely, but in one case longitudinally. It is thus usually possible to speak of the division of a bisexual catkin into male and female sectors. In all three populations studied in detail, marked shrubs, on which bisexuality had been noted at the beginning, retained this trait throughout the 9-year observation period. However, there were changes in both the expression of bisexuality, i.e. the frequency of bisexual and monosexual catkins, and in the frequency of different patterns of bisexual catkin. Only bisexual individuals with a clear prevalence of female features retained their character. In the two larger populations studied, many originally monosexual individuals became bisexual during the study period. In the south-western part of the range of S. myrsinifolia in NE-Poland all local populations were characterized by the presence of bisexual individuals and are thus polygamous. There was a close association between the presence of S. myrsinifolia and the degree of ruderalization of habitats. The degree of polygamy in a population was also significantly correlated with ruderalization. It is concluded that androgyny and polygamy may be favoured not only by changes in environmental conditions, but also by the particular pressures to which individuals and populations of a species may be subject at the edge of its geographical range.

Key words: catkin structure, Bial/owiez˙a, bisexuality, environmental conditions, polygamy, ruderalization, sex partitioning, willows Androgyny and polygamy in Salix myrsinifolia 239

Introduction Wagner 1993). Thus the issue of polygamy can only be considered with reference either Bisexuality and polygamy in the to a particular population or to a group of pop- genus Salix ulations, or to a species as a whole. Most early reports of unstable bisexuality Although the genus Salix is characterized as in Salix are for Salix myrsinifolia Salisb. (S. dioecious, the sporadic occurrence of an- nigricans Sm.; Fig. 1) and they document a drogyny and polygamy has long been ob- wide range of morphological variation. Never- served among several lowland species of wil- theless, the number of cases involved has low (Falin´ski 1997b, 1998). Androgyny nor- been small and the phenomenon is not repre- mally refers to the presence of separate male sented abundantly in herbarium collections and female flowers on the same plant. In this (see Table 3 and Discussion). It is interesting context it refers to an unstabilized form of bi- to note how earlier researchers viewed the sexuality and is a phenomenon associated phenomena of androgyny and monoecy of with the flower, the infloresence and the indi- willows (Hegelmaier 1866; Dorn 1875; vidual. In plants, polygamy means the co-oc- Hibsch 1875; Bail 1878; Potonié 1892) and currence and function of monosexual and bi- described the biology of flowers and flower- sexual individuals in a population (Schubert & ing among willows (Hampe 1840; Hegelmaier

Fig. 1. Branches from two shrubs of S. myrsinifolia with bisexual catkins. The origi- nal plants grew beside a forest road in the Bial/owiez˙a Forest and were observed for seven years (1989– 1995). Branches were later transplanted to the experimental garden. The photo- graph was taken two years after transplanting (Photo J.B. Falin´ski). 240 J. B. Falin´ski

1879; Burkil 1898; Strasburger 1900). In gen- At the level of the species, polygamy in eral, androgyny was treated as a freak of na- Salix may reflect one of the following morpho- ture (lusus naturae), as an anomaly, or as a logical types (Fig. 2): teratological form (see titles of work from: 1. The individual is bisexual because some Turpin 1833; Henry & Marquart 1841; Leefe or nearly all flowers in the catkin develop 1841; Magnin 1878; von Seemen 1887). As into bisexual flowers. In some cases, the recently as 1979 Chmelar & Meusel referred pistil and stamen are fully developed and to “freaks of nature” among willows. Indeed, function properly, but in others one struc- even more recent floras and specialist identi- ture may remain relatively undeveloped. fication keys do not mention the occurrence On different shrubs or trees only some of of androgyny and polygamy in the genus (see the catkins develop in such a way while Neumann 1981; Lautenschlager 1983; the rest remain monosexual. In a local Meikle 1984; Martini & Paiero 1988). How- population, the proportion of individuals ever, Stace (1997: 230) wrote: “Bisexual with bisexual flowers is limited. catkins are not rare, especially in hybrids, in- 2. The individual is bisexual because there cluding some of those noted as female only”. has been a functional division of catkins The sporadic bisexuality of flowers, inflores- into a part with male flowers and a part cences and individuals, and hence the with female flowers. polygamy of some species of willow, was 3. The individual is bisexual because flowers thus by earlier researchers foremostly treated of both sexes appear mixed together as a departure from the monosexuality of within a catkin, but they are always mono- flowers, inflorescences or individuals, and sexual, fully-developed and properly func- from the dioecy which characterizes the tional (Fig. 1). genus as a whole. General descriptions of the development Linné (1753) advocated a “taxonomic ap- and variability of bisexual flowers (i.e. type 1) proach” to exceptional phenomena. For ex- have been given by Rainio (1927), and later ample, some 20 years after the publication of by Maljutina (1972, 1973a, 1973b, 1974) and “Systema Plantarum” in 1733 he described Maljutina & Maljutin (1972) mainly for Salix Salix hermaphrodita (as a form of S. pentan- myrsinifolia and S. cinerea and their hybrids. dra). Following this lead, during the 19th and In contrast, there appears to be no literature early 20th centuries different departures from referring to the development of different kinds dioecy had been described as separate of catkins (types 2 and 3), and the presence of forms, variants and subspecies of what were bisexual and polygamous individuals in such fundamentally dioecious species. Several ex- populations apart from occasional reports of amples of this approach can be found in the “aberrant taxonomic” forms and “anomalies” work of Rainio (1927). (see above). The study by Elmqvist et al. In the present study dioecy is treated as (1988) devoted to the reproductive biology of one of eleven biological features which char- S. myrsinifolia did not address the issues of acterize woody pioneer species (Falin´ski bisexuality and polygamy in this species. 1980a, 1980b, 1991, 1996, 1997a, 1997b), Based on long-term observations of thus augmenting the list established by other marked willows and examination of herbarium authors, notably Iversen (1973). Dioecy is a materials, I have come to the conclusion that feature of all species of Salix and hence of polygamy as a result of the development of one of the largest genera of woody plants, one of various forms of bisexuality in individual with some 300 species according to Rehder willows has recently become much more fre- (1940), Skvorcov (1968) and Chmelar & quent in Poland. It is sometimes even com- Meusel (1979), or 500 according to Rechin- mon and has persisted for many years (Fa- ger (1958) and Krüssmann (1978). The lin´ski 1996, 1997b). This conclusion that poly- genus also exhibits entomogamy and gamy is increasing in some populations of wil- anemochory, both features are regarded as lows relates to the spread of bisexuality of the characteristic of pioneer plants (Falin´ski second and third types in S. myrsinifolia. In 1980a, 1996). In comparison, Populus, also a this monograph I describe the phenomenon member of the Salicaceae, has only 40 chiefly in relation to the population structure species. These are also dioecious, though and geographical range of this species, and anemogamic and anemochoric, and bisexu- the environmental conditions where it occurs. I ality occurs rather rarely. have also observed the same form of bisexu- Androgyny and polygamy in Salix myrsinifolia 241

Fig. 2. Patterns in the partitioning of the sexes on bisexual catkins of S. myrsinifolia (twelve types) distinguished at the beginning of the study and used in de- scribing the bisexuality of shrubs in the field (cf. Fig. 4 and Tables A, B in Ap- pendix).

ality (i.e. catkin bisexuality) in the study area north-eastern part of its geographical range in other related species (i.e. S. cinerea, S. also includes NE-Poland, from the Warmia caprea and S. aurita), but much more rarely. Lowland and Olsztyn Lakeland through to the north-west, and via the North Mazowsze (Ma- Salix myrsinifolia as a study subject zovian) Lowland, the North Podlasie Lowland and the valley of the Upper Bug to the south- Salix myrsinifolia is a Euro-Siberian willow east (Fig. 7). species. In Europe’s flora, it represents the Salix myrsinifolia (S. nigricans) (Section boreal-montane (or as appropriate the bo- Caprisalix; Rechinger 1958; Lautenschlager real) type of distribution. The more extensive, 1983) is a tall shrub or small tree (it grows to 242 J. B. Falin´ski over 7 m in England; Meikle 1984). The 2. The frequency of occurrence of bisexual species has a girth of 20–35 cm at ground and monosexual catkins on individual level and lives for up to 45 years. In NE- shrubs. Poland, it flowers in May and June, before the 3. The permanence of the sexual character- leaves have developed. However, protandry istics of bisexual individuals over periods is not as marked as it is in S. caprea, S. aurita of many years. and S. cinerea. Salix myrsinifolia is among 4. The sex structure of local populations and the most variable willow species (Enander their variability as measured by an index of 1910; Hörandl 1992). The number of chromo- polygamy. somes is 2n = 38, 6n = 110 (Dreschler in Neu- Local and regional variability in popula- mann 1981). Hybrids are formed with 20 tions of S. myrsinifolia: in addition to field other species of willow (Neumann 1981), but studies an attempt was made to investigate most often with S. caprea, S. cinerea and S. the duration and rate of spread of androgyny aurita. There is a marked sexual dimorphism and polygamy by examining herbarium spec- in the foliage of shrubs: the part of branches imens for the presence of bisexual vouchers where male catkins were present previously (Table 3; Falin´ski 1997c, 1997d). In all these remain without leaves even in early summer. aspects of the research, an important ques- The habit of shrubs and branches is strongly tion was the extent to which environmental affected by browsing and debarking by large factors are responsible for the present in- herbivores (Cervidae). In addition, larger crease in androgyny and polygamy in the branches are often debarked and the bases species. of shrubs chewed away by beavers (Castor fiber). Bisexual individuals in a population can often be distinguished by their vigorous Material and methods growth, as well as by the abundance of bisexual catkins which are often larger than other Field research on individuals and populations catkins. of Salix myrsinifolia was performed over nine In NE-Poland, S. myrsinifolia only occurs years (1989–1997) in an area of some in habitats modified by man: in exploited fens 40,000 km2 of NE-Poland. Work was concen- where the peat undergoes oxidative de- trated in Polana Bialowieska (the Bial/owiez˙a composition, beside abandoned drainage Clearing) in Bial/owiez˙a Primaeval Forest, in ditches, and especially in excavations and the Bial/ystok area, in the Biebrza Valley, and depressions in which household rubbish, in the experimental garden and laboratory of chemicals (including pesticides) and used Bial/owiez˙a Geobotanical Station. The loca- equipment (like televisions, fridges, etc.) has tion of the study sites, and the reference been dumped. The species often occurs numbers given to them can be taken from abundantly with S. cinerea and S. pentandra, Figs. 5, 6 and 7; reference numbers are given but it avoids habitats that are permanently in italics in the text. waterlogged. The main study was preceded by a pilot project to establish the relative frequency of Aims bisexual individuals in different populations within selected areas of the NE-Polish range The aims of this study were to describe the of the species. At the same time the first bi- phenomenon of androgyny in Salix myrsinifo- sexual individuals (that is plants with male, lia as a change in the sexual behaviour of in- female and bisexual catkins) to be found dividuals, considering the implications for the were marked in order to study the perma- sex structure of local populations and for the nence of this feature in individual plants. species as a whole across part of its geo- More than 3300 individuals of S. myrsinifolia, graphical range. including c. 600 bisexual ones, were investi- The following information was used to gated. characterize androgyny and polygamy in S. The research programme involved the fol- myrsinifolia: lowing observations and experiments: 1. The patterns of variability and diversity 1. The variety of patterns in the spatial parti- among catkins in terms of the positioning tioning of genders on bisexual catkins of flowers of both sexes (bisexuality of the were recorded in terms of twelve catkin inflorescence and the individual). types (Fig. 2) on selected shrubs or trees. Androgyny and polygamy in Salix myrsinifolia 243

The relative frequency of the different the following factors, each recorded on a types at different positions on 100 shoots five-point scale: distance from the edge was recorded for 873 catkins in a popula- of a settlement, habitat transformation, tion at Jaginty (639; Fig. 7). dumping of chemical wastes, and pro- 2. The frequency and persistence of androg- portion of ruderal plants (maximal score yny in three local populations in the neigh- (= 4 × 5) = 20; cf. Fig. 8). bourhood of Bial/owiez˙a (168; 169; 184ab; In all cases, the sex structure of a local Fig. 5) was investigated by long-term ob- population was described with the aid of servations of 100 shrubs in each popula- the author’s own index of polygamy ex- tion. The plants chosen were vigorous and pressing the proportion of bisexual individ- sufficiently far apart to exclude possible uals in relation to the total number of indi- linkage by roots. In cases of doubt, ac- viduals whose gender could be scored. count was taken of morphological and de- 3. The incidence of polygamy in 42 local velopmental features of neighbouring populations across the whole range of shrubs (shape, colour and degree of de- S. myrsinifolia in NE-Poland (601–640) velopment of leaves and catkins, pattern was surveyed. With the aid of maps, the of branching, colour of branches, reaction work was organized on a grid with inter- to browsing, etc.). In the observation pe- vals representing every 20’ of latitude and riod, all individuals were given numbered every 1 degree of longitude. The largest tags and their branches were paint- possible population of the species at or marked in relation to the sex of the catkins: near the designated point was then lo- yellow for males, red for females and yel- cated (Fig. 7). Where there were no popu- low + red for bisexual ones. Individuals not lations in the immediate vicinity of the grid yet in flower at the time of observation point, the species was sought further were marked white, with the appropriate afield. In no case was the distance from a change being made following the initiation planned grid intersection greater than 1–2 of flowering. Annual measurements were km, and only at the limits of the range did it made of the height and breadth of each become impossible to obtain samples shrub, and the number of catkins was (three populations). The populations se- estimated (according to the classes lected occurred in more or less homoge- <10, 10–100, 100–1000, 1000–10,000, neous habitats. Where a population was >10,000). The proportions of catkins on very small, all individuals were recorded. each shrub that were male, female and bi- For larger populations, between 50 and sexual were also analyzed each year (to 100 individuals were sampled. the nearest 10%). The survey work was Observations and descriptions of indi- done in the spring of nine successive years viduals in all 42 designated populations (1989–1997) when the plants were in full (as above) were made in spring 1995. At flower, and particular attention was paid to this time, notes were made of the environ- possible changes of gender (from bisexual mental conditions where S. myrsinifolia to monosexual and vice versa), as well as and associated woody species (including to changes in sex ratios and in patterns of all remaining species of willow) occurred. spatial partitioning of genders. Material was collected from all of the bi- Repeated observations (in 1995 and sexual individuals in each population stud- 1997) were also made using the same ied, and from selected monosexual ones. methods for two very large populations of 4. The following garden and laboratory stud- Salix myrsinifolia in the Bial/ystok suburbs ies were made: (a) Selected bisexual (Fig. 6; 650; 400 shrubs) and the Biebrza shrubs observed previously in natural con- Basin (660; 500 shrubs). In addition, all 29 ditions were transplanted from population local populations at Polana Bialowieska 183 in Bial/owiez˙a Forest to the experi- (57–74, 77–80, 92, 96, 168, 169, 183, mental garden; (b) 15 branches from each 184a, 184b) were investigated on one oc- of ten bisexual shrubs from population 65 casion, but with more precise definition of in Polana Bialowieska were collected and the environmental conditions. For this pur- planted in a plot in the experimental gar- pose an index of ruderalization (i.e. an- den; (c) germination tests of seeds from thropogenic transformation) of habitats female and bisexual catkins were per- was developed. This index took account of formed; (d) specimens of bisexual catkins 244 J. B. Falin´ski

in different phases of development were occurred at the apex. The remaining parts collected, preserved and sent to plant em- had male flowers (Fig. 2: type 3–7). The re- bryologists to investigate the phenomenon verse location of flowers, i.e. male in the of secondary bisexuality in more detail. upper part of the catkin and female in the The material collected is preserved in the lower part, was very rare (type 10). In most collections of Warsaw University’s Bia- cases flowers of one of the sexes dominated. /lowiez˙a Geobotanical Station in Bial/o- Occasionally, catkins were found devoid of wiez˙a. flowers or with under-developed flowers in 5. Specimens of S. myrsinifolia in several extreme positions, e.g. at the bases of female herbaria of Poland and Sweden were ex- catkins or at the apex of some male ones amined for bisexual specimens. (type 2 and 8). The rare cases of catkins with a longitudinal division by gender, i.e. with stamens concentrated on one side and pistils on Results the other, exhibited a characteristically arched catkin in which the male flowers were Forms of bisexual catkins on the inner (ventral) side. This form (type 11) was still rarer than the form on which prop- The bisexuality of Salix myrsinifolia catkins in erly-developed flowers of both genders were the study sites was expressed by various mixed together (type 12). types intermediate between entirely male and Bisexual catkins were usually larger than entirely female. With the exception of one monosexual ones – a feature that was partic- type, both sexes were spatially separated. ularly marked at the end of fruit maturation. The partitioning of the genders within a catkin Particularly large bisexual catkins up to 15 mainly took place transversely, but in one cm long were characteristic of S. myrsinifolia case a longitudinal separation was observed. shrubs in the population from Bial/ystok (650). It is thus usually possible to speak of the divi- In most cases flowers on bisexual catkins sion of a bisexual catkin into male and female were as fully developed as on monosexual sectors (cf. Fig. 1). Most frequently, the fe- ones, but the male segment usually devel- male flowers occupied the upper 2/3 to 1/3 of oped before the female one. By the time of a catkin, while in an extreme case they only pistil ripening and pollination, stamens have

Fig. 3. Germination of S. myrsinifolia seeds from female and bisexual catkins. A: seeds from a female shrub, B: seeds from bisexual catkins on a bisexual shrub, C: seeds from female catkins from the same bisexual shrub. In each case 400 seeds were used, taken from 20 capsules from each of 20 catkins. There were no significant differences in germination rates between the seed types (Kruskal-Wallis test, P > 0.05). Androgyny and polygamy in Salix myrsinifolia 245

Fig. 4. The distribution on selected S. myrsinifolia shrubs of different forms of bisexual and monosexual catkins. A sample of 100 branches (from one shrub) with a total of 873 catkins were studied, with each as- signed to one of eleven types (cf. Fig. 2); 1–18, successive locations of catkins beginning from the apex of the branches. Individual 90 (height 4.8 m, crown diameter 3.0 m) from the Jaginty population 639 in the valley of the upper Biebrza. 246 J. B. Falin´ski already dried-out and have empty anthers. tions of different forms of bisexual catkin Seed germinability of seeds derived from fe- (Table 1). Only bisexual individuals with a male or bisexual catkins did not differ signifi- clear prevalence of female features retained cantly (Fig. 3; Kruskal-Wallis test, P > 0.05). their character. The stability of bisexuality on individual The frequency and distribution of shrubs was clearly confirmed in the two different forms of bisexual catkin largest populations: in the Biebrza valley (660; 500 individuals) and near Bial/ystok A systematic study of c. 600 bisexual individ- (650; 400 individuals). All the bisexual speci- uals of S. myrsinifolia revealed that catkins mens in the Biebrza Valley which survived with a transverse gender division were the the 3-year observation period (76 out of 80) most common and the female sector chiefly retained this feature, as did all 82 bisexual occurred in the upper part of a catkin (Fig. 2: shrubs in the Bial/ystok population. The types 3–5). growth of shrubs in terms of height and Usually one type of bisexual catkin domi- breadth usually led to a relative and absolute nated on a given shrub, and catkins of one or increase in the proportion of bisexual catkins, the other sex occurred alongside them. In the as well as to a larger variety of catkin forms. presence of female catkins, bisexual neigh- However, it proved impossible to rank shrubs bours were dominated by the female seg- according to the frequency of male, female ment. Equally, where male catkins co-oc- and bisexual catkins because of the variabil- curred, male flowers often prevailed in the ity of the data (cf. Tables A, B in Appendix). neighbouring bisexual catkins. However, this In each of the two selected populations feature was not constant for a given shrub, more than 5% of individuals were monosex- and sometimes changed from year to year ual when marked but had become bisexual (Tables A, B in Appendix). Larger shrubs with by the time the two-year period had elapsed. a well-developed crown may simultaneously Such changes affected eight male and 16 fe- support all forms of bisexual catkin and also male shrubs in the Biebrza River population catkins of the two sexes separately. (660) and ten male and eleven female shrubs Bisexuality of an individual shrub did not at Bial/ystok (650). Equally, in each population appear to limit the number of catkins, and the there was one case of the reverse change, possibility that it actually favours an increase i.e. from bisexuality to monosexuality (see in- in numbers cannot be excluded. The devel- dividual 2 in Table A and individual 429 in opment of foliage occurred later on shrubs Table B). with strongly expressed bisexuality than on female shrubs. The stability of bisexuality in the A consistent pattern was evident in the dis- experimental garden tribution of different forms of catkin on bisexual shrubs (Fig. 4). Beginning at the apex of Features of bisexuality were also retained by an unbranched shoot (locations 1 and 2), fe- individuals of S. myrsinifolia transferred from male and bisexual catkins were most com- the wild state to an experimental garden. The mon; the latter typically had only a small male apical 20–25 cm of shoots from bisexual indi- segment at the base. At lower levels (posi- viduals were cut in the early spring when in- tions 3 and 4), bisexual catkins with a larger florescence buds were still closed, and trans- male segment prevailed, in the lowest posi- ferred to the experimental garden. The tions (beginning from locations 11 and 12), shoots rooted only poorly: of the 150 col- there were only male catkins were found. lected (15 from each of 10 shrubs) only 18 produced roots, of which eleven flowered in The stability of sexual forms under the next year. Bisexual catkins appeared in natural conditions abundance on five of them (up to 26 on the branch), along with female and male catkins. In all three populations, marked shrubs which In cases of death of the upper part of shoots were bisexual at the beginning of the study (a frequent side-effect of transplanting), bi- retained this trait throughout the 9-year ob- sexual catkins appeared on the offshoots, in- servation period. However, there were cluding those very near to the ground, similar changes in both the frequency of bisexual to the shrubs transplanted with their roots. and monosexual catkins and in the propor- The remaining six samples rooted poorly, Androgyny and polygamy in Salix myrsinifolia 247 –––––––––––––– 4.5 3.1 → → N catkins –––––––––––––– 3.03.0 3.0 2.9 → → N catkins in the period 1989–1997. Data from population with Salix myrsinifolia –––––––––––––– 5.74.0 1.3 1.9 → → N catkins ˙a Clearing (in 1991 no observations were made; **, catkins produced; +, damage by frost. –––––––––––––– 3.12.4 3.8 2.5 owiez → → / N catkins , in the Bial 168 –––––––––––––– 9.0 1.9 6.5 1.8 → → Identification number 44Changes in shrub dimensions (1989–1997) N 23 68 40 19 catkins Percentages of different catkin types on selected hermaphroditic individuals of Percentages of different Height (m) 4.5 Diameter (m) 4.3 ear No. (%) No. (%) No. (%) No. (%)(%) No. able 1. marked individuals on permanent plot X- T 198919901992 >10001993 . >10001994 10 40 >10,0001995 30 20 60 >10,0001996 20 70 10 >100 50 >10,0001997 20 . >100 . 70 . >10,000 >100 . 50 60 . >10,000 >100 80 50 40 10 40 . 30 20 >10,000 >1000 50 60 >10 10 70 90 >1000 60 40 50 . >100 10 >1000 10 70 40 . >10 40 30 5 90 >1000 40 . 100 >10 >10 25 90 10 . 20 . >100 50 10 80 >1000 >100 . . 20 90 20 10 >1000 90 . 30 80 10 95 50 <100 >100 10 40 . <1000 5 10 <10 + 10 90 ** >100 > 100 . + 90 . >100 . 90 10 . ** . . + 10 100 >100 ** 100 . 60 100 >1000 >1000 10 . . ** . 40 >100 100 >100 . 90 100 + 70 10 . . ** <1000 . 50 30 10 ** 40 ** ** Y 248 J. B. Falin´ski with female catkins appearing on a few poor growth. In the next year (1998), the fe- branches. The presence of single female male branches of the previous year re- catkins, and the absence of bisexual ones mained, but bisexual catkins also appeared may simply have been the consequence of on the branches flowering for the first time.

Fig. 5. The frequency of polygamy in 29 local populations of S. myrsinifolia in Bial/owiez˙a Clearing (Bial/owiez˙a Forest, NE-Poland). Androgyny and polygamy in Salix myrsinifolia 249

The sex structure of local populations in younger populations (e.g. 57, 64, 71) to of S. myrsinifolia 1:1.2 or 1:1.3 in older populations (e.g. 169, 77, 73, 184a, 185b, 168, 65). A proportion of Polana Bia/lowieska the individuals were bisexual in all but seven small populations (2–11 shrubs) at the edge In the interior of the forest complex of of Polana. A reliable index of polygamy could Puszcza Bialowieska, S. myrsinifolia was only be calculated for the larger populations widely distributed but occurred sparsely, com- (> 15 individuals) and ranged between 5% monly in groups of 10–20 shrubs. These and 35% (population 65, cf. Table 2). groups usually grew in wooded valleys, in Both the overall number of individuals and clearings and along ditches, and mostly in the index of polygamy were influenced by the settled clearings, especially in the villages of proximity of the population to built-up areas, Masiewo and Bial/owiez˙a. In all sites, bisexual refuse dumps or road systems. The highest individuals occurred alongside monosexuals. indices were found for population 65 at the At Bial/owiez˙a Clearing, the species is rep- edge of the villages of Krzyz˙e and Zastawa; resented by at least 29 local populations with population 73 near Podolany where the rail- 2–70 individuals (see Fig. 5). All or most indi- way embankments bifurcate, population 168 viduals set flowers, and in all populations (Voniaca Voda), and population 184b in the there was a clear prevalence of either male or Narewka Valley at Borek. All of these sites female individuals. The sex ratio, in terms of were characterized by marked habitat trans- males to females ranged from 1:0.4 to 1:0.6 formation by deposition of earth, drying-out of

Fig. 6. The extent of polygamy in a large population (500 shrubs) of S. myrsinifolia in Biebrza River Valley (650, NE-Poland). For analysis of the population structure the population has been divided into five sub- populations, each representing 640 m segment of causeway. 250 J. B. Falin´ski peat, and dumping of household chemicals The density of willows increased over a and pesticides (Fig. 6). length of 3200 m from the edge of the Biebrza Valley (the road on the Tsar’s Embankment) in the direction of the river. This increased ag- Biebrza Valley and in Bial/ystok gregation was associated with differences in Both populations were very dense, with indi- both the age structure and the sex structure viduals grouped linearly. In the Biebrza Val- of the population, and thus in the percent- ley, S. myrsinifolia (c. 500 plants) occurred ages of the two sexes and the index of with other species of willow along the polygamy. These differences were revealed Hon´czarowska Causeway, while at the sub- by an analysis of the whole population that urbs of Bial/ystok (400 plants) it was present was divided into five sub-populations related in ditches between abandoned fields. These to subsequent 640-m stretches of the em- populations included large shrubs, some of bankment inhabited by S. myrsinifolia (Fig. them >7 m tall; all but a few flowered. Both 6). As the density of willows increased on populations had a preponderance of females successive sections of the embankment (Table 2), but each showed an increase in the (from 25 to 250 individuals per 640-m numbers of bisexual individuals during the stretch), there was a clear change in the sex observation period (Tables A and B). The sex ratio from a prevalence of males at the far ratio did not change significantly as a result of end of the embankment via a balanced ratio this transition, but the index of polygamy in in the central section to a clear preponder- these populations changed from 16.6–21.6% ence of females along the final sections 4 at the Biebrza site to 23.8–29.6% in Bial/ystok and 5. between 1995 and 1997 (Table 2).

Table 2. Temporal changes in the sex structure in three polygamous populations of Salix myrsinifolia.

Number of sample 660 650 65 Locality River Biebrza Bial/ystok Bial/owiez˙a on Honczarowska abandoned farmland Clearing dump- causeway near railroad ing ground near –––––––––––––––––– –––––––––––––––––– village Krzyz˙e Year 1995 1997 1995 1997 1995

Total number 500 488 401 375 100 of individual shrubs

Number of individuals 168 158 121 104 21 243 224 180 153 43 726102 82 104 94 108 34

Percentage of flowering 98.6 99.6 98.5 97.3 98.0 individuals

Sex ratio : 1:1.4 1:1.4 1:1.5 1:1.5 1:2.1 Index of ––––––– · 100% 16.6 21.6 23.8 29.6 34.7 polygamy ∑

Number of bisexual individuals : 82 = 100% 104 = 100% 94 = 100% 108 = 100% 34 = 100% –with predominance 24 = 29.3% 48 = 46.1% 43 = 45.7% 47 = 43.5% 4 = 11.8% of catkins –with predominance 12 = 14.6% 27 = 26.0% 29 = 30.9% 28 = 25.9% 12 = 35.3% of catkins –with predominance 46 = 56.1% 29 = 27.9% 22 = 23.4% 33 = 30.6% 18 = 52.9% of catkins

Individual sex not manifested. Androgyny and polygamy in Salix myrsinifolia 251

Fig. 7. The extent of polygamy in S. myrsinifolia populations in NE-Poland. Distribution and sex and size structure in local populations. (see Material and methods – p. 242). 252 J. B. Falin´ski

The population found on the outskirts of Bial/ystok (a city of 280,000 inhabitants) was divided into four sub-populations of some 100 individuals. These also showed spatial differ- entiation. Females dominated in all four sub- populations (with male:female sex ratios between 1:1.2 and 1:1.8), but the index of polygamy was 16–33%. The sub-population with the highest percentage of bisexual individuals occurred at an extreme location in a habitat highly-modified by the movements of earth and the dumping of refuse. Intra-popu- lational differences increased as a result of the changeover in some individuals from monosexuality to bisexuality during the study period. While the sex ratio remained constant in both the four sub-populations and the population as a whole, there was an overall increase in the index of polygamy (cf. Table 2).

Regional variation in the proportion of bisexual individuals in NE-Poland The south-western part of the range of S. myrsinifolia coincides with NE-Poland (Fig. 7); 42 local populations in this area were studied using a regular grid of mapped lines separated by one degree of longitude and 20’ of latitude. Irrespective of size, all populations included bisexual individuals and were thus Fig. 8. The relationship between the indices of polygamous. habitat ruderalization and polygamy (cf. Table 2) in While there was always a clear prevalence local populations (> 50 individuals only) of S. myr- of males over females (especially in the sinifolia from Polana Bialowieska and NE-Poland (Spearman rank correlation, r = 0.61, P < 0.01). largest and oldest populations), the index of s polygamy ranged widely (1–35%). In spatial terms, this variability was continuous in nature. The highest indices of polygamy oc- alized. Populations isolated from major anthro- curred in the large populations in the central pogenic influence (e.g. 626 Zelwa, 638 Gaw- part of the geographical range of S. myrsini- rychruda, in Puszcza Augustowska, as well as folia in NE-Poland. The locations of highly 603 /Le˛gi, 610 Bytyn´ and 609 Dubienka in the polygamous populations extend north as far Bug Valley), have markedly lower proportions as the central part of the Mazurian Lakeland of bisexual individuals (Fig. 7). A significant (the Miko/lajki area), then along the Biebrza positive correlation (P < 0.05) was found be- Valley and the North Podlasie Lowland as far tween the index of polygamy and the index of as Bial/ystok in the south-east. ruderalization (degree of transformation of Once again the highest levels of polygamy habitat and environmental conditions; Fig. 8). are associated with highly modified habitats (for example dried-out peatlands in the peripheral parts of the Biebrza Valley, e.g. population Discussion 627 Sucholaski, 639 Jaginty, and 660 Hon´- czarowska Embankment; or in depressions The evidence presented here suggests that filled with refuse (633 Borowskie, 634 Ol- the formerly rare phenomena of bisexuality szewo, 65 Bial/owiez˙a). Small populations (e.g. and polygamy have become much more 601 Treblinka, 605 Sokóle, 611 Hanna, 614 abundant in the dioecious species S. myrsini- Zare˛by) occupied sites that were highly ruder- folia in recent years. What are the reasons for Androgyny and polygamy in Salix myrsinifolia 253 this change? – In discussing this question we division of catkins into uneven male and fe- must consider the nature and causes of an- male segments) may be defined as either androgyny in S. myrsinifolia and the possible dromonoecy or gynomonoecy. Both denote a mechanisms responsible for the changeover condition in which individuals produce both bi- of an individual from monosexuality to bisexual flowers and other male (andromo- sexuality. The role of bisexual individuals in noecy) or female flowers (gynomonoecy; com- the structure of local populations and the pare the definitions in botanical dictionaries of scale of the phenomenon of polygamy in a Sugden 1984; Schubert & Wagner 1993; large part of the species’ geographical range Szweykowska & Szweykowski 1993, as well are also matters of interest. In this discussion as the handbooks of Silvertown & Lovett Doust I consider the following issues: (1) the nature 1993; Pannell 1997b). Such cases occur in S. of bisexuality as seen in the genus Salix; (2) myrsinifolia, but the terms do not adequately the dating of the appearance of this phe- describe the range of variability in the phenomenon at a large scale; (3) possible nomenon of bisexuality. For example individu- causes the changeover from monosexuality als in a population may have different propor- to bisexuality in individuals of S. myrsinifolia; tions of bisexual inflorescences together with and (4) the functional consequences of the both male and female ones. However, even spread of bisexuality for the populations. where bisexuality and polygamy are most in- tense, the majority of individuals in local popu- The nature of bisexuality in Salix lations are either male or female. To date, only a few small shrubs with few catkins have been It is clear that bisexuality in willows is not found to bear exclusively bisexual catkins. equivalent to hermaphroditism in other flow- The phenomenon of polygamy in popula- ering plants. The permanent functional link- tions of S. myrsinifolia – and to a lesser de- age in one flower of both sexual organs is gree in those of other willows – is similar to morphologically and physiologically estab- that in populations of Acer (A. platanoides, A. lished in typically hermaphroditic individuals pseudoplatanus, etc.) and Fraxinus excelsior, and further manifested in common perianths, in that it reflects the co-occurrence of mono- nectaries, etc. Further, secondary differentia- sexual and bisexual individuals which may tion of the model structure of the flower (e.g. function, according to circumstance, as males heterostyly) is also maintained genetically or females (Val’cova 1953; De Jong 1976; and can be understood in functional terms. Falin´ski & Pawlaczyk 1995). However, the In contrast, the highly varied bisexuality ob- significance of this phenomenon in the genus served in individual willows is best defined in Salix is not yet as universal as in Acer or Frax- terms of the concept of androgyny. In the old inus, in which almost all species are polyga- literature, “androgyny” was not only applied in mous, albeit with larger or smaller proportions the description of bisexuality as a case in of bisexual specimens in their populations. Bi- which both stamens and pistils are present on sexuality in willows is rather secondary in na- the same flower, but also in the case in which ture, though it may well develop further. both male and female flowers occur on the same inflorescence. First and foremost, the The spread of bisexuality in concept of androgyny includes bisexuality as S. myrsinifolia an undecided, unstable phenomenon with various departures in the directions of either true The widespread occurrence of bisexuality in hermaphroditism or monosexuality, and also S. myrsinifolia is an impressive finding which as a phenomenon involving a change of sex in- appears to be new, at least as far as the scale duced or enhanced by the action of external of the phenomenon is concerned. Evidence factors such as disease (see for example from early writings strongly suggests that it Szweykowska & Szweykowski 1993). This was formerly rare and exceptional, and this was how the concept was understood by the conclusion is supported by the small numbers earliest researchers who observed the phe- of bisexual specimens of S. myrsinifolia that nomenon of bisexuality in willows (e.g. Hegel- can be found in old herbarium collections maier 1866; Dorn 1875; Bail 1878). As an ex- (Table 3). One of the richest and oldest of Eu- tension of this concept, the frequent domi- rope’s herbaria is that of the University of Upp- nance of one sex on bisexual shrubs (a higher sala, Sweden, which has assembled over fraction of male or female catkins, or a spatial nearly two centuries an exceptionally rich 254 J. B. Falin´ski collection of this species from the centre of its low proportion of bisexual specimens in her- geographical range. Nevertheless, of 1245 baria may be an over-representation, since sheets, only 15 display bisexual specimens. many collectors paid particular attention to the Other herbaria have even lower proportions of description and documentation of curiosities. such individuals. In the case of systematic collections oriented towards Salix species (e.g. Factors determining bisexuality in the BSG herbarium in Bial/owiez˙a since 1960), S. myrsinifolia all the bisexual specimens derive from the years 1989–1997. The recent increase of the Rainio (1927) suggested several factors as phenomenon is documented to a lesser de- possible causes for the appearance of bisex- gree in other Polish herbaria. Indeed, even the ual flowers in S. myrsinifolia including ex-

Table 3. Documentation of Salix myrsinifolia SALISB. bisexual individuals in some herbaria.

Herbarium, City, Range of Time of Number of specimens Bisexual Oldest Country Salix collections ––––––––––––––––––––––– individuals bisexual collections total (%) specimen in herbarium

Uppsala University Sweden, 1809–1972 708 100 474 123 11 1.6 1844, without FYTOTEKET, Norway, locality; Uppsala, Sweden Finland lg. M. Lindland Salix myrsinifolia 1863, Ångml., Säbrå, Sweden; lg. H.W. Arnell Salix myrsinifolia as above as above 537 51 428 54 4 0.7 1907, Dovre, × Salix sp. div. Drivdalen, Norway; lg. E. Ekman Uppsala University Sweden 1887–1940 38 8 20 10 0 – – Dept. of Ecol. Botany, Uppsala, Sweden Vilnius University, Lithuania 1925–1933 36 2 6 28 0 – – Vilnius, Lithuania W. Szafer Institute of NE-Poland, 1874–1973 189 31 77 76 5 4.4 1914, Melenki, Botany, Polish Acad. SE-Poland, Vladimirskaja of Sciences, Kraków, Lithuania, Gub., Russia*; Poland [KRAM] Beylorussia, lg. M. Nazarov Ukraine, Austria, Italy, 1930, Lviv envi- Finland, rons, Ukraine; Germany lg. S. Batko Natural Forest Depart. NE-Poland 1963–1973 216 7 28 180 1 2.8 1967, Z˙ytkiejmy, Forest Research Suwal/ki woj, Institute, NE-Poland; Bial/owiez˙a, Poland lg. A.W. Soko- [BIL] /lowski

Bial/owiez˙a Geobota- Bial/owiez˙a 1960–1997 163** 20 84 37 22 17.6 1989, Bial/o- nical Station of Forest and wiez˙a, Warsaw University, environs NE-Poland; Bial/ywiez˙a, lg. J.B. Falin´ski Poland [BSG]

* Pl. Exsicc. from Petersburg; ** +2000 specimens, incl. 600 bisexuals from NE- and E-Poland (1989–1997); individual sex not manifested. Androgyny and polygamy in Salix myrsinifolia 255 treme temperatures, habitat properties and The close linkage between the presence attack by insects. He also drew attention to of androgyny in S. myrsinifolia and ruderal- the frequent appearance of bisexual flowers ization of habitats suggests that two sets of on individuals of hybrid origin. Rainio (1927) factors may be at work in such habitats. On proposed a very complicated classification of the one hand, some aspect of these habitats the different forms of the phenomenon based clearly favour the spread of this species. On on the dominance of one of the sexes during the other hand, habitat conditions affect their development of a bisexual flower. This classi- sexual behaviour through the partial replace- fication was never adopted and now has only ment of monosexuality by bisexuality at the historical significance. The role of similar en- level of the individual, and in consequence of vironmental factors was also considered by dioecy by polygamy at the level of the popula- Maljutina (1972, 1973a) and Maljutina & Mal- tion. It seems probable that the change in re- jutin (1972). The work of the present author productive behaviour of some species of wil- suggests that bisexuality in individuals of the low has occurred in response to anthro- species is not strictly linked with hybrid origin. pogenic influences in the environment that Even the very large polygamous populations are hard to identify at present. To understand of the Biebrza Valley and Bial/ystok show no the evolutionary implications, we need to increase in the frequency of bisexual individ- consider how bisexuality affects dynamics of uals amongst plants of hybrid origin. willow populations. In seeking a direct environmental factor responsible for the recent growth of poly- Implications for population dynamics gamy in S. myrsinifolia in Poland, we should and evolutionary processes not ignore the most dramatic environmental event occurring in the period immediately It is interesting to speculate about the implica- prior to the first observations is this study, tions of bisexuality for the population dynam- namely the radioactive contamination result- ics of the species and the genetic structure ing from the disaster at the Chernobyl nuclear and functioning of populations. These ques- power station in 1986. Equally, the contami- tions are extremely complex, and little infor- nation of the local environment with house- mation is so far available. However, relevant hold chemicals and pesticides must be con- findings from this study include: (a) the sidered. Evidence that the phenomenon is in demonstration of different repeatable patterns fact related to local pollution is the tendency for the partitioning of genders on infloresences for S. myrsinifolia to occur in all excavations and individuals; (b) the full functioning of flow- filled with the packagings of household chem- ers and inflorescences and the vitality of icals, and more generally in habitats which seeds from bisexual individuals; (c) the reten- have been very highly modified by human action of the features of bisexuality on the same tivity (see the characterization of the species individuals over several successive years, in- in the Introduction). Of all Europe’s Salix cluding on individuals transferred whole to an species S. myrsinifolia seems to show the experimental garden or set from branches; (d) strongest association with ruderalized habi- the changeover of further individuals from tats, being almost entirely absent from pris- monosexuality to bisexuality; (e) the large and tine forests and well-preserved peatlands. increasing proportions of bisexual individuals As yet, we have no evidence about the in local populations (from 1 in 6 to 1 in 3, with a physiological basis for androgyny in willows. male:female ratio changing with the age of the The explanation for the changeover of indi- population from 1:0.4 to 1:1.5; this is thus a viduals from monosexuality to bisexuality trend in the ratio comparable to that noted for may lie in a rise in the concentrations of aux- Salix pentandra (Falin´ski 1980b); and (f) the ins and gibberellins in the environment or, exceptional vigour of bisexual plants; and (g) more likely, disturbances of their production bisexual plants are capable of self pollination, in particular branches in this willow. The roles and their seeds are fertile. of auxins in masculinization and gibberellins As we have seen, bisexual plants are often in feminization are known for other species, particularly vigorous. This higher than aver- and the substances are frequently used in age vigour (growth, abundant flowering) could horticulture. Equally, the similar action of be an effect of the polyploidy often present in other chemical substances in farm wastes or S. myrsinifolia. However, high numbers of pesticides cannot be ruled out. chromosomes (>100) occur in at least 20 256 J. B. Falin´ski

Salix species (A. Jankun, pers. corr.), and in necessary to characterize polygamous popu- S. glauca the number may even reach 2n = lations of S. myrsinifolia in a large peripheral 190 or 224 (Wilkinson 1944; Hakansson part of its range. A not yet fully explained bio- 1955; Argus 1973; Büchler 1985). Other pos- logical observation, studied only with the aid sible consequences for population dynamics of ecological methods, has turned out to be arise from the disturbances to the normal an interesting phytogeographical pheno- phenology of flowering, pollination and fruiting menon as well. It may also prove to be an ex- that were noted by Elmqvist et al. (1988) in ample of rapid biological change in reponse local dioecious populations of S. myrsinifolia. to anthropogenic environmental factors. It is The changeover of some monosexual in- necessary to continue the observations on dividuals to bisexuality (and vice versa ) also marked individuals and to perform experi- has implications for the genetic structure of mental studies of the factors affecting sex de- populations; the further fate of such individu- termination. als has been discussed in other genera, e.g. by Lloyd & Webb (1977), Charlesworth & Charlesworth (1978), Charnov (1982), Silver- Acknowledgements town & Lovett Doust (1993) and Pannell (1997a, 1997b). The work was done in the first years as part of statutory research and later under the grant of the Accepting that the bisexuality of individuals Polish Committee for Scientific Research (Grant 6 of S. myrsinifolia is of secondary nature, that it P204 022 07). It is the author’s pleasant duty to may occur in both inititally male and initially thank his co-workers in the field research, in the female individuals, and that it is induced by experimental garden and in the laboratory. My some environmental factor, the issue of niche thanks go to R. Wol/kowycki, W. Szpakowicz, R. partitioning between the two sexes becomes Kozak, I. Wol/kowycka, A. Wiktoruk and W.Ma- complicated. Niche separation between the ciejewska. The figures and maps were prepared by sexes has been addressed for a number of I. Wol/kowycka, while H. Kos´cielecka worked tire- dioecious species (e.g. Freeman et al. 1976; lessly on the typing-up of the text and tables. The supporting herbarium material was preserved by Falin´ski 1980a, 1980b; Cox 1981; Ågren Dr. W. Adamowski and his student A. Masalska. I 1987; Crawford & Balfour 1990, among oth- am also grateful to the following herbarium custodi- ers). However, polygamous populations of ans for making their collections available to me: Dr. Salix effectively involve three “genders” of in- R. Moberg (University of Uppsala), Prof. Z. Mirek dividuals. Similarly, the sexual dimorphism of (Institute of Botany, Polish Academy of Sciences, individuals, and its consequences in, for ex- Kraków) and Prof. A.W. Sokol/owski (Department of ample, the biomass production and its alloca- Natural Forests, Forest Research Institute, Bia- tion (see e.g. Falin´ska 1982; Ramp & Ste- /lowiez˙a). During the course of the study very help- phenson 1987) take on new significance. ful with their remarks were Profs. J. Szweykowski (Poznan´), J. Zielin´ski (Kórnik), L. Mejnartowicz Future work should consider the possibility (Kórnik) and M. Giertych (Kórnik). I am also much that the spread of androgyny and polygamy indebted to Profs. A. Jankun and K. Zarzycki in S. myrsinifolia may be not simply a physio- (Kraków) and K. Falin´ska (Bial/owiez˙a) for their logical response to changes in habitat/envi- valuable remarks and critical appraisal of the text. ronmental conditions, but may be favoured Finally, further special thanks go to Prof. A. Jankun by the particular pressures to which individu- for pointing out many valuable references, for als and populations of the given species at drawing up lists of chromosome numbers in the the edge of its geographical range are sub- genus Salix and for his interesting suggestions re- ject. garding the interpretation of sexual behaviour in willows. The studies within the Biebrza National In conclusion, the presence in the same Park (requiring the establishment of a transect and local populations of S. myrsinifolia of bisexual the marking of individuals) were only possible individuals alongside monosexual ones rep- thanks to the kindness of the Park Directorate, resents a change in the sex structure of the while similar thanks go to the owner of the land population from dioecious to polygamous. studied in Bial/ystok, Mr. M. Kotyn´ski. The necessary identification of the mechanisms behind the changeover of individuals from monosexuality to bisexuality lies beyond References the direct aim of the present research. How- Ågren, J. (1987) Sexual dimorphism and reproduction ever, a presentation of the nature and scale in the dioecious perennial herb Rubus chamae- of the phenomenon of androgyny and was morus. Sveriges Lantbruksuniversitet, Umea. Androgyny and polygamy in Salix myrsinifolia 257

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(1983) Atlas der Schweizer Wei- structure of the populations of pioneer dioecious den (Gattung Salix L.). Schwabe Verlag, Basel. woody plants. Vegetatio, 43, 23–38. Leefe, J.E. (1841) Observations on some curious Falin´ski, J.B. (1991) Procesy ekologiczne w zbiorowis- metamorphosis of the pistil in Salix caprea. Trans- kach lesńych. – Ecological processes in the forest actions and Proceedings of the Botanical Society of communities. Phytocoenosis (N.S.) Seminarium Edinburgh, 1, 113. Geobotanicum, 1, 17–41. Linné, C. (1753) Species Plantarum. Holmiae. Falin´ski, J.B. (1996) Les espèces pionnières ligneuses /L loyd, D.G. & Webb, C.J. (1977) Secondary sex et leur rôle dans régénération et dans la succession characters in plant. The Botanical Review, 43, secondaire. Colloques Phytosociologiques, 24, 177–216. 47–76. Magnin, A. (1878) Sur les monstruosités florales des Falin´ski, J.B. (1997a) Declines in populations of Salix saules et en particulier du Salix cinerea. Annales caprea L. during forest regeneration after strong de la Societé Botanique de Lyon, 5, 183–186. herbivore pressure. Acta Societatis Botanicorum Maljutina, E.T. (1972) O morfologicˇeskoj prirode cˇastej Poloniae, 66, 87–109. cvetka nekotorych vidov roda Salix L. i vozmonye Falin´ski, J.B. (1997b) Pionierskie gatunki drzewiaste i puti ich evolucii. Botanical Z˙urnal, 57, 524–531. ich rola w regeneracji i sukcesji wtórnej. Dynamika i Maljutina, E.T. (1973a) Nekotorye dopolnitel’nye ochrona ros´linnosći Pomorza. (eds. W. Fal/tynow- svedenija ob androginii u iv. Zˇurnal Biological Nauk, icz, M. Latal/owa & J. Szmeja), pp. 33–54. – Pioneer 6. woody species and their role in the regeneration Maljutina, E.T. (1973b) O geomafroditizme u iv sekcii and secondary succession. Dynamics and conser- Vetrix. Lesnoj Zˇurnal, 1, 5–8. vation of the Pomeranian vegetation (eds. W. Maljutina, E.T. (1974) Morfologija plodov i semjan Fal/tynowicz, M. Latal/owa & J. Szmeja), pp. 33–54. 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Revised version accepted 18 September 1998 Androgyny and polygamy in Salix myrsinifolia 259 in mix –––––––– ..+. ..+. ..+. ..+. ..+. ..+. ..++ ..+. ..+. ––––––––––––––––––––––––––––– +. ++. +++++ + + + +++++ +. +++ +. ++. ++. ++ + +. +++ + ++. ++ ++. +. + ++. ++ + +++++ 10 40 60 40 50 60 30 20 60 10 80 .+ + .+ + ...... , diameter; +, present; ·, not present). ∅ 90 20 10 70 60 40 60 50 50 10 40 40 30 10 60 70 80 40 90 50 10 40 10 50 40 10 60 30 20 10 10 80 ––––––––––––––––– 100 100 r mbe <100 <100 <100 <100 <100 <1000 <1000 <1000 <1000 <1000 <1000 10,000 nu –––––––––––––––––––––––––– –––––––––––––––––––––––––––––––––––––––––––––––––––– dead cut <10,000 < <10,000 <10,000 <10,000 . in mix . . . . + . . + . . . . .+ .+ .+ .+ .+ .+ .+ ..+ ..+ ++. ..+ ..++ <10 ..+. ..+ ++. ..+. <10 ..+. <10 ; May 5, 1995 and 8, 1997 (H, height; + + + +. ++. + + + + ++++. +. +++ ++ +++++ <10 ++ ++ + + ++ + ++++. ++ ++ ++ ystok. Temporal changes in sexual characteristics of 116 bisexual individuals (1995–1997). Data changes in sexual characteristics of 116 Temporal ystok. / X-650 5 10 20 20 20 20 20 30 30 40 40 40 40 .+ ...... + . + . . + + population near Bial 95 50 10 40 90 80 80 80 80 80 70 70 70 10 20 7070 10 10 20 20 70 10 20 60 60 10 30 60 60 10 30 60 60 60 10 30 100 ––––––––––––––––– ber otal % Total % T num Catkin number–––––––––––––––––––––––––– ––––––––––––––––––––––––––––– Catkin pattern Catkin number Catkin pattern Salix myrsinifolia ∅ 2.16.6 1.9 5.8 <10,000 <100 –––––––––––––––H –––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– 2.8 2.7 <100 3.8 3.4 <1000 3.8 2.3 <100 1.4 1.0 <100 5.75.7 2.2 6.5 >100 <1000 2.2 1.9 <100 4.86.1 4.0 6.0 <1000 <5000 2.4 2.0 <10 1.85.9 2.4 3.2 >100 <5000 4.3 2.0 <1000 4.2 2.7 <1000 5.6 3.4 <5000 1.3 0.6 >10 3.2 2.3 <100 5.8 5.9 <100 8.0 8.0 <5000 1.9 2.9 <100 Polygamy in a 9 able A. 66 able A (continued) 12 74 11 94 61 Appendix I. Individuals observed as bisexual in 1995 and 1997 117 287 T from 400 shrubs with marked individuals on permanent plot Numberof indi- Dimensions 1995viduals of shrub (m) Catkins 1997 Catkins 125 306 T 133 250 292 278 112 350 398 153 377 124 378 260 J. B. Falin´ski in mix –––––––– ++. +. .+.+. +. . +...... ++. +. +++++ .+.+. ++. +. ++. ++ .+..+ ++. +. ++. +. .+.+. ++. +. ++. +. .+.+. ++. +. ++. +. +. . +. ++. +. ++. +. .+.+. ++. +. ++. +. ++. +. .+.+. ––––––––––––––––––––––––––––– 50 +.+.+. +.+..+ 70 +.+.+. 40 60 ..+... +.+.+. . .. 90 10 + 90 10 70 30 . 40 60 60 40 100 100 100 + 100 100 5050 40 10 .9010 . . . 10 80 10 30 .9010 . 60 10 10 80 10 5040 40 .9010 10 50 40 .7030 10. 10 80 . 20 10.9010 10 70 20 7010 20.4060 20 10 60 80 ––––––––––––––––– ber <10 <100 <100 <100 <100<100 . <100 <100 <100 <1000 <1000 + <1000 <1000 <1000 <1000 <1000<1000 + <1000 <1000 <1000 <1000 <1000 + <1000<1000 + <1000 <1000 num –––––––––––––––––––––––––– –––––––––––––––––––––––––––––––––––––––––––––––––––– <10,000 <10,000 . + + + + in mix +. ++ ++ ++ +. +. +. ++ ++ +. ++ +. ++ ++ +. ++ +. +. +. +. +. +. ++ .+ .. .+ .+ ++. ++++. <10 .+ ++. ++ . .+ .+ ++. ++. .+ +++ +++ ++. .+.+ ++. +++ +++ ++. ++. ++. +++ ++. ++. +++ +++ ++++++++ ++. ++. <10 +++ +++ ++. 90 10 90 10 90 10 80 20 60 40 70 30 70 30 80 20 60 40 80 20 80 20 0.5 80 19.5 30 30 40 30 30 40 50 10 40 50 20 30 10 70 20 10 70 20 5040 3040 3040 20 30 30 40 30 20 1010 80 80 10 10 4030 4020 4020 20 4510 30 5010 35 6010 30 60 30 60 30 30 ––––––––––––––––– ber otal % Total % T num Catkin number–––––––––––––––––––––––––– ––––––––––––––––––––––––––––– Catkin pattern Catkin number Catkin pattern ∅ 3.5 2.3 <100 2.3 2.5 <100 + 2.2 0.5 <10 5.4 7.8 <1000 . 2.8 2.1 <100 . 1.8 1.2 <100 5.9 5.2 <1000 3.1 4.6 <1000 5.8 3.8 <5000 2.6 2.0 <1000 . 2.82.3 2.15.1 1.75.9 2.7 3.2 <100 <10 <100 <1000 1.6 1.2 <100 . 3.5 2.0 <10 + 3.3 1.5 >100 . 4.34.3 4.33.9 3.6 3.0 <1000 <1000 <1000 2.5 2.6 <1000 + 1.83.1 2.03.6 3.25.8 2.43.1 3.22.2 2.33.9 <10 <1000 0.95.3 <1000 1.8 <1000 3.1 <100 <10 <100 <1000 + 3.3 2.1 <1000 + 2.1 1.3 <10 + –––––––––––––––H –––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– (continued). 3 2* able A. 51 77 17 391 372*** 375 115 384 109 313 351 221 120 334 400 338 136 182 301 302 379 297 288 342 352 383 159 167 360 T Numberof indi- Dimensions (m)viduals 1995 of shrub Catkins 1997 Catkins Androgyny and polygamy in Salix myrsinifolia 261 . . . . + + + + ...... ++. ++ +++++ ++. +. .+.+. ...+. .+.+. .+.+. +++++ .+.+. +. . +. +++++ ++++. +. . +. .+.+. + ++ ++ + .+.+. +++++ ++. +. +++++ ++. ++ +++++ ++. ++ ...++ ++. ++ ++. +. ++. +. .+.+. +. . +. ++. +. ++. +. .+.+. ++. +. .+.+. ++. +. 80 40 30 100 100 80 20 1020 90 80 + .. .. 90 10 30 70 60 40 70 30 + 70 30 30 70 40 60 + 30 10 60 1050 30 10 60 40 7020 .20 10 30 70 10 60 30 90 . 10 30 30 40 . 20 . 80 40 . 60 50 10 40 40 10 50 30 10 60 20 20 60 30 10 60 10 60 30 60 10 20 70 70 50 . 50 6030 10 10 30 60 10 80 10 20 10 70 <10 <10 <10 <10 . <10 . <10 . <100 <100 . <100 <100 <100 . <100 <100 <100 <100 <100 <100 <100 <100 <1000 <1000 <1000 <1000 <1000 <1000 . <1000 . . <1000 <1000 <1000 <1000 . dead dead dead <10,000<10,000 + <10,000 . <10,000 . + . . + + ...... + + . . + + ++ + ++ ++ + +++ .+ .+ .+ .+ . .+ .+ .+ ++. . . . .+ .+ ++. ++. .+ ++. .+ .+ ..+ .+ .+ .+ .+ ++. .+ .+ .. ++ ++ +++++ . .+.+. <10. <10. ++ ++ +. . + +++++ <10 .+ +. . +.+ ++ . +. +. +. ++ ++ ++ ++ +. . +. ++ ++. +. .+ ++ ++ ++ ++ ++ .+.++ +. +. ++ ++ ++ ++ ++ ++ +++. . ++. +. +. . +. ++ 80 80 70 50 50 60 60 100 + + 10 90 + 30 70 . + 40 60 30 70 50+ 50 + 50 50 20 1010 10 10 80 80 20 10 5 85 30 . 70 50 . 50 3030 .30 . . 70 70 70 30 20 10 70 4040 1030 10 50 20 50 50 50 50 3030 10 10 60 60 20 10 70 20 10 70 20 30 50 40 20 40 4040 . . 60 60 30 30 40 2020 20 20 60 60 2010 30 40 50 50 40 40 . 60 40 10 40 50 7.26.1 4.82.4 3.9 2.0 >1000 <1000 <100 5.7 3.93.81.3 >1000 2.5 0.9 <1000 <10 . 1.1 0.6 >10 1.7 0.7 <10 2.93.6 3.05.3 2.1 5.5 >100 <100 <1000 3.25.8 1.9 3.8 >100 >1000 3.8 2.2 >100 . 2.54.5 3.16.8 4.1 6.3 <10 >1000 <5000 6.4 4.4 <100 3.72.5 3.6 1.1 >1000 <100 6.1 5.0 >1000 1.5 2.6 <100 1.4 1.1 <100 5.7 4.7 <2000 1.55.9 2.5 4.4 <100 <1000 2.9 1.3 <100 2.3 2.1 <100 + . 3.45.7 3.2 2.1 <100 <100 3.6 2.6 >100 . 2.1 2.8 <1000 + 4.12.6 3.4 1.5 <1000 <100 2.41.4 1.0 1.61.4 1.6 <10 <100 . <100 3.7 2.8 <1000 5.21.7 1.9 0.7 <1000 <10 + *** 1.9 1.3 >10 50 84 34 60 able A (continued) 54 96 36 28 57 261 238 235 210 376 363 150 158 161 300a 228 137 291 318 T 290 399 262 316 321 114 122 393 205 315 143 200 368 396 367 146 162 370 262 J. B. Falin´ski in mix –––––––– ++++. .+.+. .+.+. .+.+. ++. +. +++++ ++. +. ++. +. ++. ++ ++. ++ +. +++ +. . ++ +. +++ +. . +. ...+. +. . +. +. . +. +. +. . +. . +. ...+. ––––––––––––––––––––––––––––– +.+.+. +.+.+. 100 100 30 70 40 60 70 30 90 10 100 100 30 10 60 10 70 20 1010 40 50 50 40 10 10 80 20 10 70 80 .6030 . 20 30 . . 40 70 70 80 .80 . 20 20 90 . 10 90 . 10 ––––––––––––––––– ber <10 . <10 <10 . . <10 <100 . <100 . <100 . <100 + <100 <100 <100 <100 <1000 <1000 . <1000 <1000 <1000 <1000 <1000 num –––––––––––––––––––––––––– –––––––––––––––––––––––––––––––––––––––––––––––––––– . . . . <10,000 . . . <10,000 . . . in mix ...... ...... +. +. +. +. +. +. +. +. +. +. +. +. . . +. +. +. +. +. +. ...... +...... +...... .. +...... 100 100 100 100 100 100 100 100 100 100 100 100 .100100 . . 100 .100 . . 100 100 100 100 100 ––––––––––––––––– ber otal % Total % T num Catkin number–––––––––––––––––––––––––– ––––––––––––––––––––––––––––– Catkin pattern Catkin number Catkin pattern ∅ 2.8 3.0 <10 . 6.4 4.2 >1000 . 1.8 1.5 <100 . 3.6 1.0 <10 . 2.8 2.5 >100 . 5.4 2.7 <1000 . 5.7 2.2 >100 . 1.03.3 1.0 2.3 <10 <2000 . . 5.6 4.3 >1000 . 1.7 1.5 <1000 . 2.9 2.05.83.1 6.03.4 2.01.3 >100 1.3 1.6 <2000 >100 <100 >100 1.5 1.24.8 3.4 <10 >100 4.6 2.6 <1000 4.5 5.0 <5000 2.7 1.6 >10 3.3 1.7 ...... <10 . . –––––––––––––––H –––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– (continued). able A. 79 24 49 42 27 241 144 389 296 227 229 260 180 361 135 253 169 108 308 303 *Bisexual catkins not observed in 1997; ** 1995; ***catkins 1997. II. Individuals observed as monosexual in 1995 and bisexual 1997 118 254** T Numberof indi- Dimensions (m)viduals 1995 of shrub Catkins 1997 Catkins Androgyny and polygamy in Salix myrsinifolia 263 in mix –––––––– ..+...... +. ..+. ..++ ..+. +++. ..+. ++++ ––––––––––––––––––––––––––––– + .+.+. + + ++. ++ + ++. +. ++. ++ + ++++. .+.+. ++. +. . ++. +. ++. +. +++++ ++. +. ++. +. ++. +. + . .+.++ ++. ++ ++. +. ++. +. , diameter; +, present; ·, not present). ∅ 10 . .. + 90 10 90 10 10 90 70 30 20 80 80 20 20 80 90 40 . 60 60 . 40 60 10 30 80 . 20 30 10 60 60 10 30 80 . 20 40 20 40 20 10 70 20 40 40 10 30 60 60 10 30 40 10 50 80 . 20 30 30 40 10 50 40 10 20 70 ––––––––––––––––– 100 ber >100 >100 >100 >100 >100 >100 >100 >100 . >100 . >100 >1000 >1000 . >1000 >1000 >1000 . >1000 >1000 + >1000 + >1000 >1000 >1000 >1000 . >1000 >1000 num –––––––––––––––––––––––––– –––––––––––––––––––––––––––––––––––––––––––––––––––– . in mix . . +. +. +. +. +. +. +. +. +. +. +. +. +. +. +. +. +. +. ++ ; May 20, 1995 and 13, 1997 (H, height; ++ X-660 ..+ ..+ + ++. ++. + +. ++. ++. ++. ++++. ++. ++. ++. ++. +.++. >10 ++. ++. +. >10 ++. +++++ ++. ++. ++. ++. ++. ++. ++. ++. 10 . population in the valley of River Biebrza. Temporal changes in sexual characteristics of 108 bisexual individuals (1995– Temporal population in the valley of River Biebrza. 90 70 10 20 10 60 30 60 . 40 60 . 40 60 10 30 60 10 30 60 10 30 6050 20 10 20 40 50 20 30 50 20 30 5030 30 40 20 30 20 50 30 20 50 30 10 50 40 20 50 30 10 50 40 10 50 40 10 50 40 10 60 30 10 60 30 10 60 30 10 60 30 10 60 30 ––––––––––––––––– ber tal % Total % To num Catkin number–––––––––––––––––––––––––– ––––––––––––––––––––––––––––– Catkin pattern Catkin number Catkin pattern Salix myrsinifolia ∅ 3.2 2.8 <10 3.4 3.4 >100 H ––––––––––––––– –––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– 3.2 1.8 >100 3.1 2.3 >100 4.5 4.2 >100 5.1 3.6 >100 3.2 2.3 <100 1.9 3.5 >100 2.42.5 1.6 1.7 <100 >10 4.6 5.0 >100 1.5 1.8 <10 2.36.4 2.0 5.7 <10 >100 3.2 1.6 >10 2.9 1.5 >10 4.5 3.4 >1000 3.6 3.5 >1000 3.2 2.7 >100 3.6 4.9 >100 6.4 7.0 >100 5.1 5.7 >1000 5.0 3.2 >100 5.0 3.3 >100 3.8 3.1 >100 4.2 3.8 >1000 Polygamy in a 5 able B. 85 able B (continued) 36 77 68 14 19 78 I. Individuals observed as bisexual in 1995 and 1997 429* T 1997). Data from 500 shrubs with marked individuals on permanent plot Numberof indi- Dimensions 1995viduals of shrub (m) Catkins 1997 Catkins 472 T 229 457 230 467 212 499 112 412 318 237 334 475 469 419 140 247 264 J. B. Falin´ski in mix –––––––– ..+. ++. +. .+.+. ++. +. ++. +. ++. +. ++. +. .+.++ .+.+. ++. +. ++. +. .+.+. .+.+. .+.+. .+.+. ++. +. ++. ++ ++. +. +++++ ++. +. +++++ ++. +. ++. +. ++++. .+.+. ––––––––––––––––––––––––––––– ++. +. + ++. +. ++. +. .+.+. 10 90 10 60 40 80 20 80 20 30 70 90 10 80 20 70 30 + 80 20 60 40 10 40 50 10 40 50 20 40 40 10 30 60 10 40 50 10 50 40 10 40 50 30 20 50 1010 4030 40 50 20 50 50 10 80 10 10 20 70 90 20 30 50 20 10 70 10 20 70 90 . 10 30 20 50 ––––––––––––––––– ber >10 . >10 >100 >100 . >100 >100 . >100 >100 >100 <100 <100 . >100 >100 >100 >1000 >1000 >1000 >1000 . >1000 . >1000 >1000 >1000 . >1000 >1000 >1000 >1000 >1000 + dead –––––––––––––––––––––––––– –––––––––––––––––––––––––––––––––––––––––––––––––––– num ...... >10,000 ...... in mix . . + . .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+ .+.+. .+ ++ ++. +. ++ ++++. ++++. ++ ++ ++ ++++. ++ ++ ++ ++ ++. + ++ ++ ++++. >10. ++ 70 30 80 20 80 20 80 20 80 20 80 20 80 20 90 10 90 10 90 10 90 10 90 10 70 30 10 80 10 10 80 10 1010 7010 70 20 70 20 20 10 70 20 10 70 20 10 70 20 10 70 20 10 70 20 10 70 20 10 70 20 10 70 20 10 70 20 20 70 10 10 60 30 10 60 30 ––––––––––––––––– tal % Total % Catkin number–––––––––––––––––––––––––– ––––––––––––––––––––––––––––– Catkin pattern Catkin number Catkin pattern To number ∅ 2.5 1.8 >10 . 2.0 1.4 <100 . 3.8 3.1 >10 . 2.3 1.3 >10 . 4.2 3.1 >100 . 2.4 1.8 >10 . 2.8 4.5 >100 . 5.7 4.7 >1000 . 5.8 3.6 >100 . 4.3 3.9 <10 . 1.3 2.0 >100 . 2.8 2.3 >10 . 3.64.9 2.8 3.3 >100 >100 + 4.8 3.3 >100 4.54.8 2.32.5 3.9 1.6 >100 >100 >10 5.4 4.9 >100 5.6 3.6 >1000 5.1 3.7 >1000 3.7 3.0 >100 2.5 2.9 >100 2.6 2.0 >10 –––––––––––––––H –––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– 2.5 1.9 >10 1.3 4.3 >100 2.7 2.4 >100 4.3 2.1 >100 1.2 1.7 >100 2.8 2.8 >100 (continued). le B. 40 57 280 438 312 300 185 164 113 174 304 303 294 338 363 268 180 196 291 154 151 359 452 494 Tab Numberof indi- Dimensions 1995viduals of shrub (m) Catkins 1997 Catkins 493 484 489 400 476 480 Androgyny and polygamy in Salix myrsinifolia 265 ...... +. ..+. ..+. ..+. ..+. ..+. ..++ ..+. ..+. ..+. ..+. ..++ ..+. ..+...... +. ..++ ++. +. ++. +. .+.+. + ++. +. + ++. ++ .+.+. + + + + + + + + + ++. ++ + ++. +. + +. +++ ++. +. + ++. +. ++. +. ++. ++ + ++. +. ++. +. + ++. +. ++. +. .+.+. + 80 20 20 20 40 40 40 60 60 70 20 90 10 40 + 60 40 30 70 ...... + . .. + . 70 30 . 30 10 60 20 10 30 60 90 . 10 70 20 10 60 . 40 80 90 . 10 80 60 80 . 20 40 . 60 60 50 20 30 60 30 10 60 40 40 40 10 50 30 80 40 10 50 10 20 70 10 10 30 60 10 40 50 90 30 10 60 70 10 20 60 100 . . 100 >100 >100 . >100 >100 >100 >100 >100 >100 >100 >100 >100 >100 >100 >100 . >1000 >1000 . >1000 >1000 80 . >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 <1000 >1000 >1000 >10,000

...... +. +. +. +. +. +. +. +. ++ ++ +. +. +. +. +. .+ ++ ++ .+ .+ ...... >10 ...... >10 ... ++. ++. .+ .+.+. 1 ....+ >10 + ++. + ++. ++. + ++. + ++. ++. + ++. + ++. + ++. + ++. ++. ++. +. >10 ++. ++. ++++. ++++. +. +. .+ .+ ...+. 60 80 100 100 6060 40 40 40 60 . . 40 60 10 90 ...... + ...... + .. 30 20 50 30 10 60 40 20 40 30 10 60 30 10 60 30 10 60 20 40 40 20 10 70 20 20 60 20 30 50 20 10 70 20 10 70 10 40 50 10 20 70 10 30 60 10 30 60 10 30 60 40 20 100 100 100 100 100 100 100 100 100 100 4.3 3.2 >100 4.3 2.6 >100 1.2 1.7 >10 . 3.8 2.9 >1000 . 2.6 1.4 >10 . . 4.4 2.2 >10 4.2 7.4 >1000 5.8 5.0 >1000 2.3 1.7 >100 3.4 2.2 >100 2.7 3.4 >100 3.2 2.4 >100 4.7 4.8 >100 3.0 3.2 >100 1.5 0.9 <10 4.9 1.7 >10 4.2 3.6 >100 3.6 2.6 >10 4.8 3.9 >100 3.7 3.6 >100 3.7 3.6 >100 1.8 2.2 >100 2.7 2.0 <10 2.4 2.2 >10 2.1 2.4 >10 5.8 3.7 >100 2.5 1.6 >10 3.7 2.7 >100 4.2 3.7 >100 4.5 4.3 >100 3.6 3.9 >100 + 1.5 1.8 >100 3.6 2.5 >10 3.8 3.7 >10 . 1.96.2 1.8 4.0 >100 <10 . . . 6* able B (continued) 35 37 66 74* 333 314 279 176 149 224 II. Individuals observed as monosexual in 1995 and bisexual 1997 440 248 T 441 434 458 342 439 253 306 288 256 275 221 449 309 463 431 462 141 143 460 455 447 413 199 266 J. B. Falin´ski in mix –––––––– .+.+. .+.++ .+.++ .+.+. ++. ++ ++. +. ++. +. ++. +. ++. +. ++. +. ++. +. ++. ++ ++. +. .+.+. ++. +. ++. +. ––––––––––––––––––––––––––––– 30 70 60 40 90 10 90 10 80 20 50 50 5905 10 20 70 10 30 60 10 40 50 10 40 50 10 60 30 10 50 40 10 60 30 3020 10 30 60 50 ––––––––––––––––– ber >10 >10 >100 . >100 >100 >100 >1000 . >1000 . >1000 >1000 >1000 >1000 >1000 –––––––––––––––––––––––––– –––––––––––––––––––––––––––––––––––––––––––––––––––– num <10,000 . >10,000 +

in mix ...... +. +. +. +. +. +. +. +. +. +. +. +. +. ...... +. ..+. .. 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 ––––––––––––––––– tal % Total % Catkin number–––––––––––––––––––––––––– ––––––––––––––––––––––––––––– Catkin pattern Catkin number Catkin pattern To number ∅ 5.9 6.7 >100 . 6.1 3.4 <10 . 2.9 3.1 >100 . 2.6 3.2 >100 . 8.0 6.5 >1000 . 3.7 3.9 >100 . 3.9 2.9 >100 . 4.1 4.5 >10 . 4.2 2.3 >10 . 4.1 2.8 >100 . 5.4 3.6 >100 . 3.7 3.1 >100 . 1.02.8 1.2 2.2 <10 >100 . . 4.1 3.0 >100 . 2.0 1.8 0 ...... >10 . –––––––––––––––H –––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– (continued). > le B. Bisexual catkins not observed in 1997; ** catkins not observed in 1995. 67 33 92 48 81 72 20 97 225 170 401 184 * 235 213 292 498** Tab Numberof indi- Dimensions 1995viduals of shrub (m) Catkins 1997 Catkins