Folia Geobotanica 33: 429~t39, 1998

A HIGH POLYPLOID ELEOCHAR/S UN/GLUM/S S.L. (CYPERACEAE) FROM CENTRAL AND SOUTHEASTERN EUROPE

Petr Bure~

Department of Systematic Botany and Geobotany, Faculty of Science, Masaryk University, Kotld~sl~ 2, CZ-611 37, Brno, Czech Republic; fax +420 5 4121 1214, E-mail bures@sci.muni.cz

Keywords: Chromosome numbers, Eleocharis palustris agg., Eleocharis uniglumis subsp, sterneri

Abstract: Chromosome counts and morphological measurements were carried out on Eleocharis uniglumis s. 1. samples from nine populations in Slovakia, Hungary, Austria and Croatia. A high polyploid Eleocharis uniglumis s.l. (2n=71-88) was found on halophilous sites: in western Slovakia (Sv~itojursk~ gtir near Bratislava; 2n=71-78), on the Hungarian and Austrian shores of Lake Neusiedlersee (Hungary: Hidegsrg; Austria: Tadten, St. Andra am Zicksee; 2n=71-82), and on the Croatian island of Krk, (shores of Lake Jezero and Lake Ponikve; 2n=80-88). These high polyploid populations have the same ploidy level as E. uniglumis subsp, sterneri, described as endemic to the islands of Oland and Gotland. Morphological similarities between the high polyploids and subsp, sterneri were found both in quantitative features correlated with ploidy level (stomatal length, anther length and fertile glume length) and in other characters (number of perianth bristles, broad sterile glume margins). Differences were detected in the receptacle density and in the length of perianth bristles compared to the length of the acbene. Intermediate somatic chromosome numbers 2n=60-70, corresponding to Scandinavian hybrids between E. uniglumis subsp, uniglumis and E. uniglumis subsp, sterneri, were found near Neusiedlersee (Austria: Apetlon, Tadten; Hungary: Hidegsrg, Hegyk6). These (karyologically intermediate) plants have intermediate stomatal lengths. In other features they are similar to the Central European high polyploids. Eleocharis uniglumis subsp, uniglumis (2n=46) was found here as well (Hungary: Fertrr,'ikos).

INTRODUCTION

Eleocharis palustris agg. (= Eleocharis R.BR. subser. Eleocharis) is represented by four different ploidy levels in Europe (STRANDHEDE 1965, 1966):

1. 2n=16

2. 2n=38,39

3. 2n=46

4. 2n=74-82

E. palustris (L.) ROEM. et SCHULT. subsp, palustris E. mamillata H. LINDB. subsp, mamillata E. mamillata subsp, austriaca (HAYEK) STRANDH.

E. palustris subsp, vulgaris WALTERS

E. uniglumis (LINK) SCHULT. subsp, uniglumis

E. uniglumis subsp, sterneri STRANDH.

Most of the above taxa have relatively extensive distributions which extend across the European continent and beyond (E. mamillata subsp, mamillata, E. uniglumis subsp, uniglumis - both Holarctic, E. mamillata subsp, austriaca - Euro-Asian). The distribution of E. palustris is subcosmopoli tan (WALTERS 1980, EGOROVA 1981). Eleocharis palustris subsp, vulgaris has a somewhat smaller sub-Atlantic distribution (STRANDHEDE & DAHLGREN 1968, WALTERS

430 P. Buret,

1.c.). A stenochoric taxon, E. uniglumis subsp, sterneri was described by STRANDHEDE (1961) from the islands of Oland and Gotland in the Baltic Sea as distinct from subsp, uniglumis on the basis of the following more or less quantitative features (according to STRANDHEDE & DAHLGREN 1968):

stomatal length (~tm) hyaline margin of basal

spikelet glume colour of this margin anther length (mm) pollen length (~tm)

pol len width (~tm) perianth bristles

chromosome number

subsp, uniglumis

(40-)50-63(-76)

+- narrow or lacking somewhat yellowish 2.0-2.7 (36-)39-53(-58) (26-)31--40(-45) 0-4(-8) variable in length 2n=46

subsp, sterneri

(52-)63-78(-85)

markedly broad silvery hyaline 2.0-3.5 (43-)47-62(70) (33-)35-38(--45) 4 longer than half of the achenes 2n=74-82

In addition to morphological and cytological differences, these taxa differ ecologically. Subsp. sterneri is known only from small, shallow, +- ephemeral waters called "v~itar" and calcareous fens and has never been reported from seashores, where subsp, uniglumis, on the other hand, sometimes occurs (STRANDHEDE & DAHLGREN 1968).

Chromosome numbers of E. uniglumis have been investigated in Northern, Western and Central Europe by many authors (H,~KANSSON 1928, PIECH 1927, 1928a,b, WALTERS 1949, BATI~AGLIA 1954, HARTSHORNE in DARLINGTON & WYLIE 1955, LOVE & LOVE 1956, SAWN'rE 1958, STRANDHEDE 1958, 1965, 1966, SORSA 1962, THIt~BAUD 1970, POGAN 1972, POGAN in POGAN et al. 1980, AROHONKA 1982). Very detailed analyses were made by STRANDHEDE (1958, 1961, 1965, 1966). He analyzed many populations of E. palustris agg., about 3500 plants in total from 1100 localities (!) primarily from Sweden, Finland and Norway, but also from other parts of Northern, Western and Central Europe. Of these, more than a quarter (ca. 280) of localities appeared to include E. uniglumis. He synthesized his results with the results of earlier authors to create a convenient model of individual cytotype distributions (cf. STRANDHEDE 1961). For cytotype 2n=46- subsp, uniglumis, he found a widespread distribution throughout many European countries: Sweden, Norway, Finland, Denmark, Iceland, Great Britain, France, Poland, USSR, Germany (this cytotype was first described by H,8,KANSSON 1928; for a detailed list of citations see STRANDHEDE 1965, 1966). During investigations from 1991-1997, the same somatic number was verified in the Czech Republic, Slovakia, Austria and Hungary (BUREL unpubl.). From extra-European territories, 2n=46 for E. uniglumis s.1. was reported from the eastern Asian peninsula, Chukchi (Chukotka), as E. uniglumis (LINK) SCHULT. by YURTSEV & ZHUKOVA (1978); from Virginia, USA, as E. ambigens FERNAL9 by STRANDHEDE (1967); from New Jersey, USA, as E. ambigens FERNALD by SCHUYLER (1977); and from Manitoba, Canada, as E. uniglumis (LINK) SCHULT. by LOVE & LOVE in LOVE (1981 ).

A regular somatic number of 2n---46 was present in ca. two-thirds of examined samples studied by STRANDHEDE (1965), The remaining somatic chromosome numbers, roughly one-third, vary between 2n=42 and 50, with a few counts slightly exceeding 50 chromosomes. These irregularities in chromosome number are caused by fusion or fragmentation due to the holocentric character of Eleocharis chromosomes. These irregular somatic chromosome

A high polyploid Eleocharis uniglumis 431

numbers were observed in Sweden, Norway, Finland, Denmark, Faeroes, Belgium, Great Britain, Switzerland, Germany, Romania, Portugal (STRANDHEDE 1965, 1966, THI]~BAUD 1970), Poland (POGAN in POGAN et al. 1980), the Czech Republic, Austria and Italy (BUREg unpubl.).

In contrast to this widespread ploidy level (2n=ca. 46), STRANDHEDE found a different chromosome number, with 2n varying between 72 and 84, relatively common only in calcareous fens on the islands of 01and and Gotland. This contrast between the distributions of the two cytotypes led STRANDHEDE to the conclusion that the high polyploid represents an individual taxon- Eleocharis uniglumis subsp, sterneri, which he considered to be an endemic of these islands (STRANDHEDE 1965, 1966, STRANDHEDE 8z DAHLGREN 1968). This opinion was largely accepted in basic European Floras (e.g. SCHULTZE-MOTEL 1966, WALTERS 1980, CASPER & KRAUSCH 1980).

On the basis of the chromosome number investigations presented in his paper, STRANDHEDE (1966) hypothesized that the high polyploid of E. uniglumis occurs outside Oland and Gotland only to a very restricted degree in isolated localities in Western Europe - (see Discussion). From Central Europe, he cited a herbarium specimen of E. uniglumis "Schur bei St. Georgen [Sv~tojursk2~ ~tir or Stir near Bratislava, Slovakia], ANONYMOUS 1908 W", which was found to have morphological characteristics typical for E. uniglumis subsp, sterneri. During the revision of Czech and Slovak herbarium specimens of E. palustris agg., another specimen with similar features was found from the locality "Bratislava - Vajnory, wet meadows at the southeastern margin of the flood plain forest Stir, 0.5 km north of the village of Cierna Voda, ca. 150 m above sea level (1988 B. TRAVNf~EK OL)".

For these reasons, the locality Sv~itojursk2~ Stir - (~ierna Voda was visited in 1997. The expectation that the high polyploid (2n > 70) E. uniglumis s.1. would be found at the location Sv/~tojursk~ Stir - (~ierna Voda was confirmed. Completely unexpected, however, was the discovery that samples from similar localities near Neusiedlersee (Hungary, Austria) and those from the central part of the island of Krk, in the Rijeka Bay (Adriatic Sea, Croatia) had the same, or an intermediate ploidy level.

MATERIAL AND METHODS

Material used in the present study includes twenty eight samples of Eleocharis uniglumis s.1. from natural populations transferred to cultivation in the Botanical Garden of Masaryk University, Brno.

List of population localities

Apetlon: Austria, Neusiedlersee, Apetlon: salt meadow along the road, 2 km E of village, 20.VI.1997 (2 samples).

Fert6"rfikos: NW Hungary, Fert6 t6i Nemzeti Park, Fert6rfikos: brackish pools in littoral zone of Lake Fert6 (=Neusiedlersee), 1.5 km SSE of village, 17.VII. 1~997 (2 samples).

Hegykii: NW Hungary, Fert6 t6i Nemzeti Park, Hegyk6: margins of brackish pools in salt meadow, N of village, 17.VII.1997 (3 samples).

Hidegs~g: NW Hungary, Fert6 t6i Nemzeti Park, Hidegs6g: margin of brackish pools, 0.5 km N of village, 17.VII.1997 (4 samples).

Jezero: Croatia, island of Krk: subsaline meadow on shores of Lake Jezero, 13.VIII.1997 (3 samples).

432 P. Bure.~

Ponikve: Croatia, island of Krk: subsaline meadow on shores of Lake Ponikve, 13.VIII.1997 (4 samples).

St. Andrii: Austria, Neusiedlersee, St. Andr~,i am Zicksee: salt meadow near Lake Gansellacke, 17.VII.1997 (1 samples).

Stlr: W Slovakia, Cierna Voda: salt meadow at the southeastern margin of the flood plain forest, Stir, 0.5 km north of from the village, 20.VI.1997 (3 samples).

Tadten: Austria, Neusiedlersee, Tadten: northern littoral zone of Lake Schochstolacke, 17.VII.1997 (6 samples).

Eteocharis uniglumis has a typical clonal character with a dense network of long rhizomes, usually forming a homogeneous monotypical stand, a few dm to a few m in diameter. Samples were collected from these suspected clones isolated from each other by the surrounding halophilous vegetation (approximately 10 x 10 cm of belowground material from the densest part of the sod). Individual samples were collected 10-300 m apart.

Somatic chromosome counts were carried out on root mitoses. The rapid squash method was employed (pretreatment: p-dichlorbenzene - 2 h; fixation: mixture of ethanol and glacial acetic acid (3:1); maceration: mixture of ethanol and hydrochloric acid (1:1) - f o r two rain at room temperature; washing in water for one min; staining with lacto-propionic orcein).

Preliminary morphological measurements were done on seven herbarium samples from the clones Stir 1, St. Andr~i, Apetlon 2, Hidegs6g 2, Hegyk6 2, Ponikve 3 and Jezero 1 (numbers refer to codes from Tab. 1); only anther length was measured on corresponding fresh ramets in culture. Altogether 33 morphological characters were observed or measured. They were selected on the basis of their diagnostic importance in the E. palustris group. Characters which differentiate E. uniglumis from other members of this taxonomically critical group, as well as characters which differentiate E. uniglumis subsp, uniglumis from E. uniglum& subsp, sterneri, were especially preferred. Characters observed and measured, are listed in the Results section and in Tab. 2. Voucher specimens for morphological studies are kept in the herbarium BRNU; individual clones are kept in culture in the Botanical Garden of the Masaryk University Brno, Czech Republic.

RESULTS

Chromosomes

94 somatic metaphases from 28 samples were counted. Somatic chromosome number variability was detected either between or within populations or individual samples - see Tab. 1. On the basis of this variability, the following four groups of chromosome numbers or ploidy levels were recognized:

(1) Two samples from the locality Fert6rLkos appeared to be E. uniglumis subsp, uniglumis, somatic chromosome number 2n=46.

(2) Six samples from Neusiedlersee have an intermediate chromosome number (2n=60-70) ("intermediate ploidy level").

(3) 13 samples from Slovakian Stir and from the Hungarian and Austrian shores of Lake Neusiedlersee have the same ploidy level as E. uniglumis subsp, sterneri viz. 2n=71-82. ("Central European high polyploid").

(4) The highest chromosome numbers were detected in localities from the Croatian island of Krk - 2n=80-88 ("SE European high polyploid").

A high polyploid Eleocharis uniglumis 433

Table 1. Somatic chromosome number variability of investigated subpopulations and samples of Eleocharis uniglumis s.l. (number of metaphases studied in brackets).

Ploidy level Sample E. uniglumis subsp. Intermediate Central European high SE European high No. uniglumis 2n=46 2n=60-70 2n=71-82 2n=80-88

Country Hungary Hungary, Hungary, Austria, Croatia Austria Slovakia

Fert6rhkos 1 46 (3) FertSr~kos 2 46 (5) Hegyk6 1 Hegyk6 3 Hidegs6g 2 Hegyk6 2 Tadten 2 Apetlon 1 Apetlon 2 Tadten 1/5 Hidegs6g 3 Hidegs6g 4 Hidegs6g 1 Stir 4 Stir 1 Sfr 2 St. Andr~i

60, 63 (6) 63, 64 (5) 66, 68 68 (3) 66, 67, 69 (3) 62, 68, 70

74, ca. 75 (2), 76 (2), 77 ca. 75 ca. 75 71 74 71, 73, 74 ca. 75 (2), 75, 78 77 73 (2), 74 (3), ca. 75, 75 (2), 78 (2)

Tadten 1/4 76 Tadten 1/1 78 (2), 82 Tadten 1/2 79 (2) Tadten 1/6 78, 80 (2), 79+2F Ponikve 3 80, 81 (2), 82, 86,

87 (2) Ponikve 4 ca. 80 Jezero 3 82, 85 (2), 88 Jezero 1 84, 85 Jezero 4 84 (2), 85 (2) Ponikve 5 86 (3) Ponikve 6 86

Morphology The most important results of a morphological comparison between investigated populations

and STRANDHEDE'S characteristics of Eleocharis uniglumis subsp, uniglumis and subsp. sterneri are presented in Tab. 2. The characters not presented in Tab. 2 include:

(1) Those which show large plasticity between individual samples and populations, similar to the mode of variability in E. uniglumis s.1. (incl. subsp, uniglumis and subsp, sterneri) presented by STRANDHEDE: stem - length, width, length/width ratio and colour; vascular bundles - number and density; upper sheath - length and colour; spikelet - length, width and length/width ratio; fertile glumes - colour; achene - shape, colour and length/width ratio; stylopodium - shape.

(2) Those which were homogeneous in all cases: presence of single conical silica bodies on the stem (none); upper sheath lustre (lustrous in all cases); constriction below the spikelet (none); basal glume - number (1 in all cases) and presence of green midrib (none); achene

- reticulate sculpture (present in all cases).

434 P. Buret,

(a) (b) o 4 al , •

~ e

o e • e eD~ Q

' ° = %~ '0

Ic, i t

I 0 l.tm

£ ~JOoo •

(d) e, e s - O 5 qe . • , S ~ o

ee~ t g b o~ • d w- •

o~ • f o db ~ ° ° •

drF =o

Fig. 1. Somatic metaphases of Eleocharis uniglumis s.1. (a) Eleocharis uniglumis subsp, uniglumis - 2n=46, Fert6r~kos - sample 2, Neusiedlersee, Hungary (del. author and O. Rotreklov~i); (b) Intermediate ploidy level (between high polyploid and subsp, uniglumis) - 2n=63, Hegyk6 - sample 1, Neusiedlersee, Hungary (del. author and O. Rotreklov~); (c) High polyploid E. uniglumis s.l. - 2n=74, St. Andr~i, Neusiedlersee, Austria; chromosomes are connected to the structure commonly called "matrix" (del. author and O. Rotreklov~i); (d) High polyploid E. uniglumis s.1. - 2n=86, Ponikve - sample 5, island of Krk, Croatia (del. author).

Measurements of the taxonomically most important characters (differentiating between E. uniglumis subsp, uniglumis and subsp, sterneri) showed the following:

(1) Similarities between the high polyploids and subsp, sterneri were found both in quantitative morphological features correlated with ploidy level (stomatal length, anther length and width, fertile glume length and margin) and in other characters (number of perianth bristles, broad silvery hyaline margin of basal sterile glume). The different basal glume margin colour of the Croatian plants is probably caused by the fact that these plants were collected in very late phenophase (mid August). Extremely long anthers from the Apetlon 2 clone are caused by the low number of anther measurements (10) in relation to the variability of this character (anthers were measured in spring 1998 on spikelets of plants from cultivation, only a few of which were fertile) - see also the evaluation of this character in the Introduction from STRANDHEDE & DAHLGREN (1968).

Tab

le 2

. Pre

lim

inar

y m

orph

olog

ical

com

pari

son

of th

e pr

esen

ted

Cen

tral

Eur

opea

n an

d So

uthe

aste

rn E

urop

ean

popu

lati

ons

of h

igh

poly

ploi

d E

leoc

hari

s un

iglu

mis

wit

h S

tran

dhed

e's

(STR

AN

DH

EDE

1965

and

STR

AN

DH

EDE &

DA

HLG

REE

N 19

68)

char

acte

rist

ics

of s

ubsp

, uni

glum

is a

nd s

ubsp

, ste

rner

i.

Tax

on

n E

. un

iglu

mis

s.

l. E

uni

glum

is s

.1.

E u

nigl

umis

s.l.

E

uni

glum

is

E u

nigl

umis

Pl

oidy

leve

l C

entr

al E

urop

ean

high

pol

yplo

id

inte

rmed

iate

plo

idy

leve

l SE

Eur

opea

n hi

gh p

olyp

loid

su

bsp,

uni

glum

is

subs

p, s

tern

eri

Som

atic

chr

omos

ome

num

ber

(71-

82)

(60-

70)

(80-

88)

(44-

)46(

-50)

74

-82

Cou

ntry

Sl

ovak

ia

Aus

tria

A

ustr

ia

Loc

alit

y, s

ampl

e St

ir 1

St

. A

ndr~

i A

petl

on 2

Stom

atal

leng

th (

ktm

) 30

73

.9-8

8.5

72.4

-80.

0 71

.2-8

2.6

Bas

al g

lum

e m

argi

n 1)

5

0,93

-1.3

5 0.

66-1

.34

0.62

-1.2

6 B

asal

glu

me

wid

th (

mm

)

Bas

al g

lum

e co

lour

si

lver

y si

lver

y si

lver

y hy

alin

e hy

alin

e hy

alin

e -

slig

htly

ye

llow

ish

Fert

ile

glum

es,

leng

th (

mm

) 2)

10

4.87

-5.2

9 4.

54-4

.94

4.45

-5.3

1

Fert

ile

glum

es,

mar

gin

2)

5 0.

14-0

.22

0.18

-0.4

2 0.

23-0

.45

Fert

ile

glum

es,

wid

th (

ram

)

Rec

epta

cle

dens

ity

3)

5 19

.1-2

0.9

16.2

-19.

8 13

.1-1

8.1

Bri

stle

num

ber

4)

5 4(

4),

5(1)

, 4(

3),

5(2)

4(

3),

5(2)

Bri

stle

leng

th

5 lo

nger

sh

orte

r lo

nger

(c

ompa

red

to t

he a

chen

e or

equ

al

wit

hout

sty

lopo

dium

) 5)

(1.1

-1.2

) (0

.6-1

.0)

(1.2

-1.3

)

Ach

ene

leng

th (

mm

) 10

1.

55-1

.77

1.80

2.10

1.

74-1

.88

Ach

ene

wid

th (

mm

) 10

1.

09-1

.27

1.32

-1.4

2 1.

10-1

.20

The

ca le

ngth

(m

m)

10

2.80

-2.9

0 3.

20-3

.50

n =

num

ber

of m

easu

rem

ents

fro

m o

ne s

ampl

e nu

mbe

rs w

itho

ut b

rack

ets

are

J? +

s.e

. (e

.g,

73.9

-88.

5 im

plie

s th

at £

=81

.2 a

nd

s.e.

=7.3

)

I) G

lum

e m

argi

ns w

ere

mea

sure

d at

the

top

of

the

glum

e.

2) F

erti

le g

lum

es w

ere

mea

sure

d in

the

mid

dle

part

of

the

spik

elet

. 3)

Rec

epta

cle

dens

ity

= nu

mbe

r of

flo

wer

or

frui

t rec

epta

cles

per

cm

of

the

spik

elet

rac

his.

Hun

gary

H

unga

ry

Cro

atia

C

roat

ia

Swed

en, F

inla

nd

Swed

en

Hid

esdg

2

Heg

ykO

2

Poni

kve

3 Je

zero

1

Scan

dina

via

Ola

nd, G

otla

nd

59.6

-68.

6 63

.9-7

5.3

71.3

-79.

1 89

.1-9

3.7

50.1

-63.

3 63

.3-7

7.6

0.73

-1.0

7 0.

8.-1

.24

0.55

-0,8

1 0.

47-0

.77

narr

ow o

r m

arke

dly

lack

ing

broa

d

silv

ery

silv

ery

beig

e be

ige

ofte

n si

lver

y hy

alin

e hy

alin

e hy

alin

e hy

alin

e so

mew

hat

hyal

ine

- sl

ight

ly

- sl

ight

ly

hyal

ine

mst

y-re

d m

sty-

red

yell

owis

h

4.40

-4.8

2 4.

59-4

.91

4.87

-5.3

7 4.

86-5

.08

(3.5

-4)

3.5

<. ~

= 4

0.21

-0.3

1 0.

29-0

.39

0.23

-0.3

7 0.

34-0

.42

narr

ow o

r co

nspi

cuou

sly

lack

ing

broa

d

19.6

-23.

4 18

.2-2

3.4

14.5

-15.

9 11

.0-1

1.52

24

.3-3

5.7

24.5

-28.

9

4(3)

, 5(

2)

4(4)

, 5(

1)

4(5)

_<

4 4(

-6)

long

er

long

er

long

er

long

er

vari

able

, sh

orte

r re

duce

d (0

.5 _

<)

(1.2

-1 5

) (1

.2-1

.3)

(1.2

) (1

.1-1

.2)

or la

ckin

g

1.50

-1.6

4 1.

52-1

.68

1.48

-1.7

0 1.

47-1

.65

1.40

-1.7

6 1.

38-1

.66

1.04

-1.1

8 1.

13-1

.31

1.07

-1.1

7 1.

07-1

.17

1.12

-1.3

8 1.

15-1

.33

2.68

-2.9

0 2.

14-2

.56

2.38

-2.8

9

4) N

umbe

r of

cas

es i

n br

acke

ts.

5) M

inim

um a

nd m

axim

um in

bra

cket

s.

tQ

21"

0.9_

,<

"O

O.

Q. .q-

~O

O1

436 P. Bure~

(2) Differences between the high polyploids and subsp, sterneri were detected in receptacle density and in perianth bristle length compared to achene length. It is interesting that plants from Croatia (localities Ponikve and Jezero) have very low receptacle density.

Plants with intermediate somatic chromosome numbers, 2n=60-70, have intermediate stomatal length; in the other features they are similar to the high polyploid.

DISCUSSION

STRANDHEDE (1961, 1965, 1966) predicted a widespread distribution of cytotype 2n=46 (Eleocharis uniglumis subsp, uniglumis) and a stenoendemic character of high polyploid 2n=72-84 (E. uniglumis subsp, sterneri) on the basis of investigations in Northern, Western and Central Europe. Almost no chromosome counting has been done on Panonian and East-Submediterranean E. uniglumis populations. Together with one old report from Romania (TARNAVSCHI 1948) which lists 2n--50 for E. uniglumis, the above analyses form the first karyological reports from this area. It is interesting to note that the vast majority of these cases suggest a high polyploid populations similar to subsp, sterneri.

High polyploids cytologically similar to subsp, sterneri were reported by STRANDHEDE (1965, 1966) from Great Britain: Cambs, Wicken Fen (2n--88) and France: P6rign6, Deux-SEvres (2n=80,85). Wicken Fen plants were regarded as a "tetraploid" of subsp. uniglumis by WALTERS (1950; cit. sec. STRANDHEDE 1.C.). STRANDHEDE (1965)considered the Pdrign6 plants to also be of different origin than subsp, sterneri. The largest somatic chromosome number for E. uniglumis, 2n=92 (which corresponds to a simple doubling of the diploid chromosome number of subsp, uniglumis), is reported from England also by HARTSHORNE in DARLINGTON & WYLIE (1955). On the basis of herbarium revisions, STRANDHEDE (1965, 1966) predicted the existence of small populations of a similar high polyploid in Central Europe, e.g. in Slovakia (see Introduction). STRANDHEDE & DAHLGREN (1968) also considered that high polyploids might possibly occur in Switzerland and Austria, despite no concrete evidence.

The wide fluctuation in somatic chromosome numbers (2n--71-88) of the high polyploid in the present paper corresponds with similarly variable numbers reported by STRANDHEDE (1961, 1965, 1966) in Scandinavian populations of E. uniglumis subsp, sterneri (2n=74-82). Similar irregularities in somatic chromosome numbers (within small ranges, however) are quoted by STRANDHEDE (1965) for all species of E. palustris agg. He reported aneuploidy due to non-disjunctions, which he studied in detail in all species of E. palustris agg., to be one of the causes of these fluctuations. The present author found different chromosome numbers in the same rhizome. The same mixoploidy was detected by STRANDHEDE (1958, 1965) in E. palustris subsp, palustris, E. palustris subsp, vulgaris and E. uniglumis subsp. uniglumis. Mixoploid plants of E. palustris subsp, vulgaris and E. uniglumis subsp, uniglumis were also reported by POGAN (1972) from Poland. Similar intraclonal chromosome variability was detected by OTZEN (1962) in four species and three hybrids of the related genus Schoenoplectus (RCHB.) PALLA.

Intermediate chromosome numbers varying between 2n=62 and 69 (found in the localities Hegyk6, Hid6gs6g, Apetlon and Tadten) are similar to those of plants from Oland and Gotland considered by STRANDHEDE (1965, 1966) to be hybrids between the sympatric E. uniglumis subsp, uniglumis and E. unigtumis subsp, sterneri. Similarly, the Neusiedlersee area, where all 4 localities of intermediate chromosome numbers were found, is near populations of the high polyploid as well as of subsp, uniglumis (from the nearby Fert6r~ikos locality). Outside

A high polyploid Eleocharis unigtumis 437

Oland and Gotland, STRANDHEDE (1965, 1966) reports intermediate numbers from: Norway - Stj6rdal, Nord-Tr6ndelag (2n=68); Sweden - Hov in Sk~ine, Gr~th6garna (2n=64); Great Britain - Berks, Oxford, Hagley Pool (2n--68). He considered these to be cases either of an "autotriploid" of the subsp, uniglumis (a combination of reduced and unreduced gametes) or of a hybrid between E. palustris subsp, vulgaris and E. uniglumis subsp, uniglumis. Subsequently, it is necessary to point out that the area surrounding Neusiedtersee is very probably not within the distribution range of the subatlantic E. palustris subsp, vulgaris.

Ecological similarities probably include the salinity of the habitats of the presented high polyploid and E. uniglumis subsp, sterneri (STRANDHEDE, pers. comm.). All the presented localities are situated inland, as is the case with subsp, sterneri in Oland and Gotland (STRANDHEDE 1965). In saline coastal vegetation types approximately analogous to those in which subsp, uniglurnis is present on Oland and Gotland, no E. uniglumis was found in any the place in Croatia where it was searched for (Istrian Peninsula, islands of Krk and Pag, shores in the vicinity of Zadar). Relatedly, it is interesting that chromosome numbers of high polyploids from the island of Krk, (2n--80-88) are somewhat higher than the ones from the Panonian part of Austria, Hungary and Slovakia (2n--71-82) and STRANDHEDE'S results from Oland and Gotland (2n=74-82). These differences may be the result of hybridization between sympatric populations of high polyploids and the subsp, uniglumis (both in Oland and Gotland as well as in Neusiedlersee and St~r). In this case, these results may mean that on the island of Krk, or perhaps an even larger part of Southern or Southeastern Europe, the type subspecies is absent.

The high polyploid is very similar to E. uniglumis subsp, sterneri in most of the important morphological characters. The large plasticity of most morphological features in E. palustris agg. (STRANDHEDE 1965) should be taken into consideration when evaluating the identity of Scandinavian, Central European and Southeastern European populations of high polyploid E. uniglumis, and definitive conclusions should be made only on the basis of comparative morphological analysis of uniformly cultivated plants.

If populations of the high polyploid and E. uniglurnis subsp, sterneri are identical, it will imply that subsp, sterneri occurs in Southeastern Europe, with the northern limit of its continuous distribution stretching to the Panonian region of Austria, Hungary and Slovakia (where it is probably sympatric with the type subspecies) and with an absolute limit of distribution reaching an exclave restricted to C)land and Gotland in the Baltic Sea. Analogous populations of Southeastern European plant species occurring in additional isolated exclaves on (3land and Gotland are reported by STERNER (1938). From this phytogeographical point of view, a group of species with Pontic or Submediterranean distribution (e.g. Ranunculus ittyricus L., Adonis vernalis L., Viola elatior FR., Vincetoxicum hirundinaria MEDIK., Anthericurn ramosum L., Helianthemum canum (L.) BAUMG., Fumana procumbens (DUNAL) GREN. et GODR., Coronilla emerus L., etc.) is most interesting. The hypothetical distribution of the high polyploid Eleocharis uniglumis ecologically and geographically coincides very well with the distribution of Plantago tenuiflora WALDST. et KIT., a halophilous species, which reaches the northern extreme of its continuous Pontic-Panonian distribution on saline locations in the Ukraine, Austria, Hungary and Southern Slovakia, from which its exclave on Oland is isolated by almost t000 km. Such north-south disjunctions are common in plants which can be spread by birds, including species of the genus Eleocharis (cf. RIDLEY 1930: 492--493). In the genus Eleocharis, large north-south disjunctions are reported e.g. for E. cylindrica BUCKLEY by GUAGLIANONE 8~ UENO (1990) and for E. montevidensis KUNTH

438 P. Bure~

by SVENSON (1939) from the New World. In Eurasia e.g. E, mamillata subsp, austriaca and E. ovata (ROTH) ROEM. et SCHULT. have a polydisjunctive distribution.

If Eleocharis palustris subsp, vulgaris WALTERS is accepted by ,/~. LOVE & D. LOVE (1975) at the species level - E. vulgaris (WALTERS) A. LOVE & D. LOVE - the same taxonomic level should be accepted for E. uniglumis subsp, sterneri STRANDrt. The specific binomial is in this case also dependent upon the relationship between European high polyploid populations (incl. subsp, sterneri) and Eastern European-Asian E. klingei (MEINSH.) B. FEDTSCH. (Syn.: E. scythica ZINSERL., E. korshinskiana ZINSERL.) -- cf. STRANDHEDE (1966) and EGOROVA (1981). For the present, it seems better to accept the subspecific level with regard to the probably common existence of karyological intermediates, which are commented upon above.

Questions for continuing study (1) What is the geographical distribution of high polyploid Eleocharis uniglumis, especially

in the Panonian region, Southeastern and Southern Europe? (2) Are types 2n=46 and 2n=72-86 sympatric or allopatric? (3) Are the karyological intermediates between E. uniglumis subsp, uniglumis and the high

polyploid as common as it seems from the above research? (4) Are high level polyploids from 131and and Gotland the same as or different from Central

European and Southern European ones? (5) Are they of the same origin? (6) Does Eastern European-Asian E. klingei (Syn.: E. scythica, E. korshinskiana) have the

same ploidy level as E. uniglumis subsp, sterneri, as seems possible on the basis of STRANDHEDE'S (1966) morphological comparisons between the type specimen of E. scythica and the characters of E. uniglumis subsp, sterneri?

Acknowledgments: I wish to thank Olga Rotreklovfi for her help in chromosome preparing and counting. My thanks are due to Sven-Olov Strandhede and Karol Marhold for reading and commenting on the manuscript. I am also grateful to Sierra Dawn Stoneberg for her help in language correction. This work was made possible in part by Grant no. 206/95/0508, supported by the Grant Agency of the Czech Republic (project leader: J. Kirschner).

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Received 19 January 1998, revision received 3 November 1998, accepted 6 November 1998