Chromosome numbers of some eastern North American species of Carex and Eleocharis (Cyperaceae)

15 Pages·1999·11.2 MB·English

by  R F C Naczi

Contr. Univ. Michigan Herb. 105-119.
22: 1999.
CHROMOSOME
NUMBERS OF SOME EASTERN NORTH
AMERICAN CAREX AND
OF ELEOCHARIS
SPECIES
(CYPERACEAE)
Robert
Naczi
F. C.
Department
of Biological Sciences
Northern Kentucky
University
Highland Kentucky 41099-0400
Heights,
INTRODUCTION
In the sedges (Cyperaceae), chromosome numbers are best known from spe-
cosmopolitan Carex and Within
cies of the large, Eleocharis, these genera, varia-
chromosome number Chromosome numbers
tion in quite extensive. often differ
is
among Harms
species within a genus (Wahl 1940; Strandhede 1967; 1968, 1972;
Hoshino (Wahl
Schuyler 1977; 1981; Standley 1985), populations within a species
Harms
Strandhede Hoshino Whitkus
Standley
1940; 1967; 1968, 1972; 1981; 1985;
& &
Okamura
Hoshino Hoshino Hoshino Onimatsu Water-
1991; 1992; 1994; 1994;
way
1996), and individuals within a population (Strandhede 1967; Hoshino 1981;
& &
Okamura
Luceno Whitkus Hoshino
Standley Castroviejo
1985; 1991; 1991;
&
Hoshino Onimatsu
1994; 1994).
The chromosome number
reason for the extreme variability of in sedges
is
The most
incompletely understood. hkely explanation the possession of holoki-
is
chromosomes
netic by sedges (Strandhede 1965; Faulkner 1972; Wrensch, Kethley
&
Norton Holokinetic chromosomes have centromere they
1994). diffuse activity;
&
act as the spindle attachment not localized (Wrensch, Kethley Norton
if is
chromosomes
1994). If holokinetic fragment, the fragments are retained in succes-
—
sive nuclear and divisions. Also, the opposite can happen chromosomes can
cell
comment
fuse. Especially pertinent for sedges Wrensch, Kethley, and Norton's
is
(1994, 326), "As a labile system for karyotype evolution, holokinetic chromo-
p.
somes appear superior monocentric chromosomes..."
to
Knowledge chromosome number
of variation useful for several reasons.
is
chromosome numbers
can be morphologi-
First, different useful in distinguishing
Harms Man-
cally similar species and infraspecific taxa (Strandhede 1967; 1972;
may
chromosome number
hart 1986a). Second, variation correlate with geogra-
phy and ecology, suggesting that particular combinations of alleles may be adap-
& &
Okamoto
environments (Hoshino Cayouette Morisset
tive in certain 1979;
& &
1986; Luceiio Castroviejo 1991; Hoshino 1992; Hoshino Waterway 1994).
chromosome number
Third, since can correlate with phylogeny, evaluating chro-
mosome
number
variation in light of phylogenetic hypotheses can increase under-
standing of sedge speciation (Crins 1990; Naczi 1997).
chromosome
arrangement
Variation in valuable, too, especially in the detec-
is
tion of hybridization and polyploidy. During meiosis, Carex and Eleocham hybrids
many
have nonbivalent associations, particularly univalents and trivalents, and
the associations vary from to within the same individual (Strandhede
cell cell
&
1965; Cayouette Catling 1992). Carex polyploids, which appear to be quite rare
105
CONTR. UNIVERSITY OF MICHIGAN HERBARIUM VOLUME
106 22
number
in the genus, also exhibit a relatively large of nonbivalent associations
&
during mciosis (Faulkner 1972; Cayouette Catling 1992; Luceno 1994).
Because chromosome numbers and arrangements Carex and
are so variable
in
Eleocharis, the extent of variation must be documented prior to using numbers and
Chromosome
arrangements in taxonomic, ecologic, and evolutionary studies. num-
bers and arrangements are unknown or incompletely known for most species
still
To
in the Cyperaceae. increase knowledge and improve understanding of sedge
chromosomes, paper report chromosome numbers and arrangements
in this for
I
My
various species of Carex and Elcocharis native to eastern North America.
specific
goals are to provide counts for previously unstudied taxa, provide counts
first
new
from populations of previously studied and review and vouch-
taxa, literature
ers for previously studied taxa. The groups of sedges whose chromosomes have
I
investigated are those subject to ongoing systematics research by co-workers and me.
MATERIALS AND METHODS
more
Since meiotic figures are informative and easier to interpret than mitotic
ones (Faulkner 1972), studied the number and arrangement of chromosomes
I
mother
during mciosis of pollen ceUs. Plants of selected taxa of Carex and Eleo-
charis for these studies originated in various locations in eastern Canada and
eastern U.S.A. (Appendices 1-7). transplanted most of these plants from the
T
field to greenhouses at the University of Michigan Matthaei Botanical Gardens
(Ann
Arbor, Michigan) Northern Kentucky Department
or University of Biologi-
cal Sciences (Highland Heights, Kentucky), Growing sedges greenhouses mini-
in
mizes difficulties associated with collecting meiotic material from them (rapid
mciosis that usually synchronized within spikes and occurs mostly the morn-
is in
ing and, for Carex, often before the spikes emerge from subtending bract and leaf
The chromosome
sheaths). few preparations of Carex obtained from material not
grown in a greenhouse originated from spikes collected and fixed in the field or
from plants transplanted from the field to the gardens of Anton A. Reznicek
(Ann
Arbor, Michigan) or Robert Naczi (Independence, Kentucky).
To
chromosomes, immature
detect the collected spikes containing develop-
I
ing anthers from plants that appeared to be within a few days of shedding pollen.
fixed the spikes in a solution of three parts (by volume) absolute ethanol and
I
room Any
one part glacial acetic acid at temperature for 6-12 hours. material not
70%
studied within 12 hours of fixation transferred to ethanol for storage 2°C.
I at
45%
Next, dissected several anthers from a spike into a drop of acetic acid and
I
them
then placed drop Snow's (Snow 5-15
into a of stain 1963) for minutes.
I
placed the stained anthers in a drop of a solution of equal parts (by volume)
medium 45%
Hoyer^s mounting (Becks 1955) and acetic acid on a microscope
shde, split each anther to release the pollen mother and covered the drop
cells,
with a cover slip. I squashed the pollen mother cells by covering the slide with a
much
piece of blotting paper and applying as pressure as possible on the cover
my
slip with thumb. For the determination of chromosome number, sketched
I
metaphase chromosome complement
the I of at least 5 cells per individual plant
and counted the sketched chromosomes. To make the sketches, used drawing
a
I
tube and phase lOOOx
contrast optics magnification.
at
chromosome
In the appendices, report numbers with arrangements
their
T at
metaphase where = = = IV =
and
I univalent, II bivalent, III trivalent, quadrivalent.
I,
vouchered whose chromosomes
plants studied, except the plant of Carex
I all
I
CHROMOSOME NUMBERS CAREX AND
OF ELEOCHARIS
NACZI:
1999
107
from Mackinac
crawei County, Michigan, which died shortly after collection of
staminate spikes from and before produced mature infructescences
for
it it
Voucher new MICH,
vouchering. specimens for counts are deposited with
at
KNK
dupHcates of most [herbarium abbreviations follow Holmgren al
at et (1990)].
new
For the taxa with counts, attempted to locate and examine the vouchers for
I
Wahl
previously published counts. Counts reported by Whitkus
(1940), (1981),
and Manhart (1987) are from pollen mother meioses and those of Love and
cell
Love (1981) are mitotic, apparently from root tips. Only Wahl (1940) includes
chromosome
arrangements with the counts.
AND
RESULTS
DISCUSSION
new chromosome
In this paper, I report 46 counts for 26 taxa of Cyperaceae.
Apparently, these are the counts for 10 of these taxa. In addition, located
first I
and examined vouchers 26 previously reported counts from 14
for taxa.
Carex Careyanae Tuckerman Kukenthal
Section ex (Appendix
1)
Members
endemic North America
of section of eight species are to eastern
this
and mesic deciduous Most Mackenzie
usually inhabit recent authors
forests.
(e.g.,
&
1935; Fernald 1950; Bryson 1980; Manhart 1986b; Gleason Cronquist 1991) include
this section in Carex sect. Laxiflorae\ however, phylogenetic analyses reveal that sect.
Careyanae and Laxiflorae are not each other's groups and thus are best
sect. sister
s.s.
treated as separate sections (Naczi 1989, 1992). In addition, molecular evidence sup-
Careyanae and
ports the separation of sect. sect. Laxiflorae (Starr et 1997).
al.
My
Carex abscondita Mackenzie. count of 24 appears to be the report
II first
chromosome number
which swamps,
of a for this species, inhabits floodplains,
wooded
and moist, slopes. ranges throughout the southeastern U.S.A. and north
It
to eastern Massachusetts along the Atlantic coast.
Carex austrocaroliniana L. H. Bailey. This species has a small range in the
mesic forests of the southern Appalachian Mountains in northeastern Alabama,
northern Georgia, eastern Tennessee, western South Carolina, western North Caro-
and southeastern Kentucky. variable chromosome number, with hap-
lina, It is in
loid numbers of 28 29 and 30 Chromosome number appears to form a
II, II, [II].
chromosome number
cline in this species, with an increase in southward (Fig.
1).
Carex careyana Torrey Dewey. The count obtained from an eastern Ten-
in
I
Wahl
from
nessee plant (34 II) agrees with the count (1940) reports a southern
New
York plant. Carex careyana widespread in interior eastern North America
is
mesic deciduous
in calcareous, nutrient-rich, forests.
Carex digitalis Willdenow. Three varieties constitute the very wide-ranging,
C
forest-dwelling digitalis (Fernald 1950; Bryson 1980): var. asymmetrica Fernald,
and macropoda The chromosome number asym-
var. digitalis, var. Fernald. of var.
metrica unknown. The count report for var. digitalis from northern Kentucky
is I
My
same Wahl
(24 II) the as (1940) reports from central Pennsylvania. count of
is
24 macropoda, apparently same
II for var. the for this variety, the as that
first is
known
for var.
digitalis.
CONTR. UNIVERSITY OF MICHIGAN HERBARIUM VOLUME
108 22
FIG. 1. Cytogeography of Carex aitstrocaroliniana. Each symbol represents a locality for a plant
with a particular chromosome number. Shading depicts the range of the species (modified from
Bryson,
1980).
Carex Amer-
laxiciilmis Schweinitz. This species, widespread eastern North
in
ican mesic deciduous forests, includes var. copulata (L. H, Bailey) Fernald and
The
tcixonomy Mackenzie
var. laxiciilmis. of var. copulata controversial. (1935)
is
C
treated as a species, copulata (L. H. Bailey) Mackenzie. Fernald (1906)
it first
C
considered a variety. Later, he treated as a hybrid between C. digitalis and
it it
(Fernald
laxiciilmis 1942, 1950).
C
My
Each
of the varieties of laxiciilmis cytologically variable. counts for
is
var. copulata are 23 from a southeastern Michigan plant, 24 from a southern
II II
Ohio and 24 from southern West These
plant, II a Virginia plant. counts are
WahKs
apparently the first for this variety, (1940) report of a count from C.
C
copulata notwithstanding (his voucher laxiciilmis var. laxiciilmis). Previous counts
is
New
for var. laxiciilmis are 22 from southern York and 23 from central
II II
Pennsylvania (Wahl 1940). add 25 from central North Carolina. Chromosome
I II
C
number
apparently with higher chromosonie
clinal in laxiciilmis (Fig.
is 2),
C
numbers
southward. Interestingly, both varieties of laxiciilmis follow this pattern.
C
Chromosome
numbers
support the treatment of laxiculmis var. copulata as
numbers However,
a variety, since overlap those of var. laxiculmis. overlapping
its
—
CHROMOSOME NUMBERS CAREX AND
OF ELEOCHARIS
NACZI:
1999 109
C
FIG. Cytogeography of Carex laxiculmis. Each symbol represents a locality for a plant of
2.
C
chromosome
laxiculmis var. laxiculmis or laxiculmis var. copulata with a particular number. Shad-
&
ing depicts the range of the species (Bryson 1980; Naczi Bryson 1990), including the disjunction in
northern Florida (Mitchell 1963).
chromosome numbers do not negate species status for var. copulata^ since differ-
sometimes have same chromosome number
ent (but closely related) species the
C C
One
abscondita and hypothesis that can be falsified by the
(e.g., digitalis).
C
cytologic data the origin of laxiculmis var. copulata through hybridization,
is
since three individuals studied have regular pairing during metaphase
all I.
much
Carex platyphylla Carey. This species ranges through of the northeast-
ern United States and adjacent southeastern Canada, usually in mesic deciduous
known
and Carex
deciduous-coniferous forests. Cytologically, the best of sect.
it is
Wahl
Careyanae, with a total of eight counts reported by (1940) and me.
It is
variable in both chromosome number and arrangement. In fact, C. platyphylla
is
member known
the only of the section from which nonbivalent associations are
both and The from southeastern Michi-
trivalents quadrivalents. plant studied
I
same number and arrangement chromosomes
gan, with 35 has the of as a plant
II,
Wahl studied from Pennsylvania. Wahl reports counts from two plants
(1940)
whose vouchers could not locate {Wahl 3418 and Wahl 3435), but these reports
I
whose
are identical to others vouchers did find.
I
CONTR. UNIVERSITY OF MICHIGAN HERBARIUM VOLUME
10 22
1
Mackenzie) Mackenzie
(Appiindix
2)
Six or seven species belong to Carex sect. Deweyanae, a section of primarily
woodland sedges of most of North America and eastern Asia.
Carex bromoides Willdenow. Carex bromoides two
includes subspecies, subsp.
bromoides and montana Both
subsp. Naczi. subspecies inhabit diversity of wet
a
open
habitats, usually in forests (occasionally in sites). Carex bromoides subsp.
bromoides widespread through eastern North America and subsp. montana
is
is
narrowly endemic to southwestern Virginia, western North CaroUna, and western
C
South Both
Carolina. subspecies are cytologically variable. In bromoides subsp.
bromoides, known chromosome numbers and arrangements +
are 32 31 IV,
II, IT
1
33 and 34 IL The most frequent and geographically widespread configuration
II,
Though Wahl
appears to be 33 (1940) detected a quadrivalent the one plant
II. in
C
he studied, observed only bivalents in the five studied. In bromoides subsp.
I I
montana, chromosome numbers and arrangements are 30 and 31 the
II II, first
C
chromosome
counts for the subspecies. In bromoides, the non-overlapping
numbers two
for the subspecies support the recognition of the recently described
C
subsp. montana (Naczi The wide span chromosome numbers
1990). of for
bromoides makes one more known
of the cytologically variable species for
it
eastern North America.
Carex deweyana Schweinitz deweyana. This widespread
var. variety north-
in
is
ern North American forests and forest openings, ranging from Newfoundland
to
Alaska south to the northern United States and further south in the Rocky Moun-
much
Despite wider range, appears be chromosomally
tains. its to less variable
it
C
My
than bromoides. counts of 27 from northern Michigan and northern
II
Pennsylvania are identical with those reported from northern Pennsylvania (Wahl
&
1940) and (as 2n = 54) from southern Manitoba (Love Love 1981). Additionally,
C
Packer and Whitkus deweyana
(1982) report 27 for (without variety identi-
[II]
fied) from eastern British Columbia, whose voucher could not The only
locate.
I
count reported for C. deweyana that differs from these others one count of 28
is
&
from Columbia
eastern British (Packer Whitkus Since Packer and
[II] 1982).
Whitkus
did not identify the variety and have not seen the voucher, possible
I it is
count from taxon other than deweyana deweyana.
this a C. var.
is
Carex Section Granulares Lang) Mackenzie
(O. (Appendix
3)
Carex sect. Granulares contains six species of North and Central American
meadows, and
prairies, forests.
Carex Dewey,
crawei This species ranges through most of northern North
America
(and south in scattered localities to Alabama, Arkansas, and Utah)
in
wet, calcareous prairies, meadows, and lake shores. The counts obtained from
I
northern Michigan (30 II) and southeastern Wisconsin (28 II + III) are nearly
1
identical but quite different from the one previous report of 2n = 38 from Mani-
& C
toba (Love Love 1981), whose voucher could not locate. More plants of
I
crawei from throughout range should be studied before reaching conclusion
a
its
chromosome
about the range of numbers of this species.
' t
'm
CHROMOSOME NUMBERS CAREX AND ELEOCHARIS
OF
NACZI: 111
1999
Muhlenbere Willdenow
ex
Wy
a diverse array of habitats, such as meadows, wooded floodplains, roadside ditches,
amount morphologic
and seepy openings upland and exhibits a large of
in forests,
Some Mackenzie some morphologic
variation. authors 1935) believe of this
(e.g.,
C
variation can be partitioned among segregate taxa: haleana Olney [C granu-
C
(C
and Mackenzie granulans
lans haleana (Olney) Porter] rectior var.
var.
C
recta Dewey); however, preliminary results of taxonomic investigation of gran-
Among
show morphologic variation to be continuous. the plants studied
ularis
its
cytologically are variants encompassed by the segregate taxa.
C
and morphologic
of
Correlated with the geographic, ecologic, variability
chromo-
Carex both
granularis great cytologic variability. granularis varies in
is
Wahl
some numbers and arrangements. The chromosome number obtained by
(1940) from a central Pennsylvania plant (16 II 1 IV) is lower than, but close to,
-f-
M
Mississippi
IV two northeastern Texas + IV), and southernmost
1 in individuals), (18 II 1
+ The count 2n = 42 reported from southern Manitoba
Ontario 2 IV). of
(17
II
&
(Love Love 1981), whose voucher could not locate, matches the count I
I
obtained from Ontario. Especially noteworthy the very high proportion of plants
is
of granularis with quadrivalents during metaphase L All but one plant studied
C.
by
during meiosis possessed at least one quadrivalent, including the plant studied
When
Wahl number quadrivalents per varied from one
present, the of cell
(1940).
more
The presence of quadrivalents unusual, but the presence of than
to three.
is
one per particularly rare in Carex species.
cell
is
chromosome numbers and
arrange-
Underscoring of
the striking plasticity
C
between geography and
ments granularis the apparent lack of correlation
in
is
chromosome number arrangement. As did not detect any correla-
or well,
either
I
C
between morphologic variation and cytologic variation in granularis. Thus,
tion
C
found no cytologic support for recognition of the segregate taxa of granularis.
I
&
Carex microdonta Torrey Hooker. This species inhabits prairies in the
The
southern United from northern Florida west to southeastern Arizona.
States,
same
counts obtained, apparently the for this species, are the for a plant
first
I
from southwestern Arkansas and another from eastern Mississippi: 32 Carex
11.
C
The
few counts available
microdonta morphologically very similar to crawei.
is
chromo-
numbers two Obviously, the
characterize the species.
indicate different
C
somes of more plants of both species should be studied, especially of crawei
chromosome number
from southern United before concluding that
the States,
C
microdonta and
crawei.
distinguishes C.
Kunth
Carex Laxiflorae (Appendix
Section
4)
North America, Central America,
This section contains about 23 species of
Most mesic
and Eurasia (Naczi of the species of the section inhabit forests.
1989).
mesic
Carex albursina Sheldon. This species inhabits calcareous, nutrient-rich,
My
much North America. count 22 from Ohio
deciduous forests of eastern of II
in
Wahl
one reported from Pennsylvania.
identical with the (1940)
is
CONTR. UNIVERSITY OF MICHIGAN HERBARIUM VOLUME
112 22
Carex blanda Dewey. Carex blanda very common, widespread, and mor-
a
is
phologically variable sedge of eastern North American mcsic and
forests forest
My
openings. counts of 15 and 16 from Mississippi are lower than the 18
II II [II]
New
and 15 IV reported from Jersey and Pennsylvania, respectively (Wahl
II 1
-f-
C
1940; Whitkus 1981). Love and Love (1981) reported 2n = 38 for blanda from
Manitoba, an area from which blanda unknown. The morphologically
C. similar
is
C. leptonervla (Fernald) Fernald occurs in the area from which the counted plant
and
originated likely the basis for the Loves' report (B. A. Ford, pers. comm.).
is
C
The voucher for one of WahFs (1940) counts of blanda {Wahl 125135.
C
NCU!, PAC!)
actually gracUescens. Vouchers for two counts that Wahl
is re-
C
ports blanda from Pennsylvania {Wahl NCU!, PAC! and Wahl
for central 2536,
NCU!, PAC!)
4175, are hybrids. Characteristic of hybrids, both have aborted
achenes and anthers included (rather than exserted from) subtending
in their
C C
morphology
scales. Their indicates that both of these hybrids are likely blanda x
Lam. Wahl
laxiflora var. laxiflora. reported only approximate counts for them ("ca,
38/2" and "ca. 40/2, "" respectively), because they had many nonbivalent associa-
Wahl
tions in each cell and, in 2536, an inconstant chromosome number from
cell
Both number
to the high of nonbivalent arrangements and
cell. variability in
number
within an individual are diagnostic of hybrids. Though he noted the chro-
mosomal
Wahl
similarity of these plants to hybrids, (1940: 464) stated, ''Number
C
2536 considered by the writer to be typical blanda, but 4175 has wider leaves
is
C
and suggests trend toward
a slight
laxiflora..,'"
A
Carex
gracilescens Steudel. widespread and morphologically variable inhabit-
C
North American
ant of eastern mesic forests, gracilescens variable both
in
is
My
chromosome number
and arrangement. count + from Michigan
of 15
II 1 Til is
New
lower than any of the numbers observed by Wahl from York
(1940) (20
II)
and IV
Pennsylvania (15 II + 2 and 20 II) plants. was unable to locate a voucher
I
C
for one of the plants of gracilescens studied by Wahl {Wahl whose
2516),
chromosome
configuration he reports as identical to those from two other plants
he
studied
(20
II).
Carex Gaddy.
radfordii This recently described, narrow endemic of northeast-
ern Georgia, western North Carolina, and western South Carolina grows mesic
in
C
(Gaddy
Carex and Mack-
forests 1995). radfordii sister species, piirpurifera
its
among
unique North American members
enzie, are of section Laxiflorae pos-
in
synapomorphy
sessing the of overwintered leaf blades densely papillate on the
C
The
abaxial surfaces. count of 23 II for radfordii (the first for this species)
Mack
era
if
(M
have been more chromosome
plants studied, counts are necessary for both species
before one can conclude they have non-overlapping numbers.
Carex Michaux.
striatula This species of mesic and dry-mesic occurs
forests in
the southeastern United Stales and, along the Atlantic coast, north to Connecticut.
ifi
in,
Man
hart
C
counts of 18 II and 20 II, the first for striatula, indicate cytologic overlap with
CHROMOSOME
NACZI: NUMBERS OF CAREX AND ELEOCHARIS
1999
113
C
C
Wahl New
laxiflora, (1940) reported counts of 20 for lax flora from both a
II
I
York plant {Wahl 24208, PAC!) and a Pennsylvania plant {Wahl 34146, PAC!). Thus,
C
chromosome numbers
taxonomic
to clarify the status of
fail striatula.
Don
Carex
Section Paniceae G. (Appendix
5)
Eleven species belong to Carex Paniceae, an especially wide-ranging
sect.
section (North America, Central America, South America, and Eurasia) of
prai-
meadows, and
ries, fens, forests.
Carex meadii Dewey. This species grows in prairies, meadows, and forest
much The
edges over of eastern North America. count of 28 from Wisconsin
II
agrees with the report of 2n = 56 by Love and Love from Manitoba, whose
(1981)
voucher could not
locate.
I
New
Carex woodii Dewey. This woodland species ranges from York
w^est to
C
My
Minnesota and south to northern Georgia. count of 22 for woodii from
II
New
Michigan WahPs from York WahPs
with count
identical (1940) a plant.
is
C
other count of 26 (from a Pennsylvania plant) indicates woodii cytologically
II
is
C
variable. Though Love and Love (1981) report a count of 2n = 44 for woodii
C
from Manitoba (whose voucher could not locate), woodii unknown there
I
is
(B. A. Ford, pers. comm.; A. A. Reznicek, pers. comm.). This report probably
C
applies to tetanica Schkuhr, a species morphologically similar to C. woodii and
known
from the area of Manitoba from which the counted plant originated (B. A.
Ford, comm.).
pers.
Carex
Section Phyllostachys Carey) H. Bailey (Appendix
L.
(J. 6)
Carex endemic North American and
Phyllostachys
sect. to forests forest
is
much
and been
openings, contains eight species. This section has the focus of
recent taxonomic, genetic, and phylogenetic research (Crins 1990; Catling et
al.
&
1993; Starr et 1997; Ford et 1998a, 1998b, 1998c; Naczi Ford 1998; Naczi
al. al.
et 1998).
al.
Carex jamesii Schweinitz. Carex jamesii inhabits calcareous, mesic deciduous
much
forests of of eastern North America. Not surprisingly for a widespread and
&
morphologically variable species (Naczi Ford the count reported here
1998),
Wahl
from Kentucky from the one previous report by from
(33 II) differs (1940)
Pennsylvania
(35
II).
Carex latebracteata Waterfall. This narrow endemic inhabits mesic and dry-
mesic deciduous forests of the Ouachita Mountains of western Arkansas and
member
Oklahoma. and
eastern the of Phyllostachys has the
tallest sect.
It is
member As member
widest leaves of any of the section. well, the only of sect.
it is
Phyllostachys that has strongly glaucous leaves. Furthermore, does not produce
it
members As
lateral spikes, unlike other of the section. with morphology,
all its
chromosome number members
from
is divergent the rest of the of its section. Its
chromosome number much
of 49 the reported for the species, higher
II, first is
numbers members
than the reported for of the other of the section, which
all
range from 31 II to 39 II (Crins 1990; reports in this paper).
HERBARIUM VOLUME
CONTR. UNIVERSITY OF MICHIGAN
22
114
Carex willdenowii Willdenow. This species grows calcium-poor, dry-
in acidic,
mesic deciduous forests throughout much of the northeastern U.S.A. and immedi-
adjacent Canada. The newly reported chromosome count of 39 from two
ately
II
plants from the same population in Kentucky quite different from the previous
is
report of 31 from one population in Pennsylvania (Wahl 1940). The rather high
II
C
degree of genetic and morphologic variability possessed by willdenowii (Ford
may chromosome
1998a; Naczi 1998) account for wide span of
et al. et al. its
numbers.
Eleocharis (Appendix
7)
Eleocharis brittonii Svenson and E. microcarpa Torrey. Both of these spike-
rushes inhabit sunny, wet, acidic habitats in eastern North America. Because they
taxonomic
are morphologically very similar, the merit of the later-described E.
has been controversial. Small Fernald and Svenson
brittonii (1933), (1950), (1957)
recognize E. brittonii as a species distinct from E. microcarpa; however, most
all
& &
Wooten
recent authors combine them (Radford, Ahles Bell 1968; Godfrey
&
The
1979; Gleason Cronquist 1991). intermediate position of treating E, brittonii as
microcarpa (Svenson) Svenson was advocated by Svenson
E. var. brittonii (1937).
Unfortunately, chromosomes do not clarify the taxonomy of E. brittonii, since
it
and microcarpa have the same number and arrangement Apparently, these
E.
(5 II).
chromosome
counts are the reported for both E, brittonii and E. microcarpa.
first
ACKNOWLEDGMENTS
For cultivating, fixing staminate spikes from, and vouchering three of the plants from which
I
obtained chromosomes, thank Anton A. Re/nicek. Charles T. Bryson, Allison W. Cusick, and
I
me
Michael Penskar collected and sent living plants for this project. Charles Bryson, Robert Krai,
Anton A. Re/.nicek, and Edward G. Voss showed me localities for some species. Florence Wagner
S.
shared her knowledge of cytology with me and graciously allowed me use her microscope make
to to
many of the counts reported paper. Robert Dirig (BH), Bruce A. Ford (WIN), Tim Hogan
in this
(COLO), Patricia Holmgren (NY), Carl Keener (PAC), Jimmy Massey (NCU), and Michael O.
S.
Moore (GA) looked for vouchers of previously reported counts for me. Field work and cultivation of
plants at the Matthaei Botanical Gardens were supported by National Science Foundation grant
BSR-9001260 to the University of Michigan and by grants from the University of Michigan.
LITERATURE
CITED
Beeks, R. M. 1935. Improvements in the squash technique for plant chromosomes. Aliso 3: 131-134.
A
Bryson, C. T. 1980. revision of the North American Carex section Laxiflorac (Cyperaceae). Ph.D.
Dissertation, Mississippi Stale: Mississippi State University.
W. new
Catling, P. M., A. A. Rcznicek, and Crins. 1993. Carex juniperonun (Cyperaceae), a species
J.
from northeastern North America, with a key to Carex sect. Phylloslachys, Syst. Bot. 18: 496-501.
Cayouette, J., and P. M. Catling. 1992. Hybridization in the genus Carex with special reference to
North America. Rev. 351-438.
Bot.
58:
Chromosome
Cayouette, and P. Morissct. 1986. studies on the Carex salina complex (Cyperaceae,
J.,
section Cryptocarpae) in northeastern North America. Cytologia 51: 817-856.
W.
Crins, 1990. Phyltigenclic considerations below the sectional level in Carex. Canad. Bot. 68:
J. J.
1433-1440.
Chromosome
Faulkner, 1972. studies on Carex section Aeiifae north-west Europe. Linn.
J. S. in J.
Soc, 271-301.
Bot.
65:
Fernald, M. L. 1906. Some new or little known Cyperaceae of eastern North America. Rhodora 8:
126-130, 161-167, 181-184,200-202.
The Rhodora 416-
1942. seventh century of additions to the flora of Virginia. 44: 341-405,
,
452,457-478.