Table Of ContentREINSTATEMENT OF VIBURNUM OZARKENSE
AN
ENDEMIC TAXON OF THE
(CAPRIFOLIACEAE):
HIGHLANDS OF
INTERIOR
AND OKLAHOMA
ARKANSAS,
MISSOURI
Weckman
Timothy
J.
Department
of Biological Sciences
Richmond, KY 40475, USA.
ed field work and morphological analysis of herbariu
nstated as a distinct species. Recognition of the occurre
I
synonymy
n compromised by reduction under
its to Vi
V
racterization of ozarkense and molle, a key to speci
V.
INTRODUCTION
mum
Vi hu ozarkense was described from material W. W. Ashe collected in Stone
County, Arkansas with the type locality providing the only distributional ref-
erence (Ashe 1928). Ashe was a prolific collector, amassing some 30,000 speci-
mens by his death (Massey 2001). Ashe also published 510 species and varietal
names from but many have been reduced synonymy (Coker
these collections, to
Viburnum molle was described by Michaux from material he coL
1932).
et
al.
lected in Kentucky in the late 1700s (Michaux 1803). Ashe was aware of V. molle
V
Michx., and provided characteristics to separate ozarkense from molle in
V.
his species description. Original material from both of these collections has not
American Michaux
been readily accessible to botanists: the collection of molle
V.
was deposited in the Paris herbarium (P)(acronyms after Holmgren et 1990),
al.
m
and most of Ashe's collections were inaccessible his private herbaria at the
time death (Coker
of his 1932),
et
al.
The name was an Arkansas
ozarkense retained in early checklist for
V.
(Moore 1941) and in a generic treatment of Viburnum by McAtee (1956). How-
was reduced synonymy under molk Michx. by Steyermark
ever, to (1963)
it V.
and placement has been followed by current treatments (Tucker Smith
this 1976;
NRCS
USDA,
1988; 2002). Neither taxon currently monitored by heritage
is
programs Arkansas, Missouri Oklahoma. Based on morphological analy-
in or
Vihurnum and
sis of ozarkense V. molk, recognize these taxa as distinct, pro-
I
map
vide a key to differentiate them, and the current distribution of both taxa
and Oklahoma.
Arkansas, Missouri
in
AND
METHODS
MATERIALS
Loans were requested from herbaria with Ashe collections: A, GH, ILL, LCU,
L,
MO, NCU, POM, and US, and certain herbaria having Arkansas, Missouri and
Oklahoma Vihurnum materiak APCR, BRIT, NA, NYBG, OKL, SMS, UAM,
UARK, UMO.
and Additional specimens were during work
collected field in
and Oklahoma
Arkansas, Missouri 1999-2001,
in
Measurements were recorded for 14 quantitative characteristics; leaf size,
on and
toothing, venation, length of leaf petiole length vegetative
tip, fertile
number
peduncle width and
shoots, length, of rays, inflorescence height, co-
stamen and and
rolla width, length fruit length width. Qualitative characteris-
and
tics including leaf shape, leaf petiole pubescence, the presence, placement
and pubescence on and and
stipules inflorescence bracts, flowering times shoot
pubescence and color were noted. Mensural and qualitative data were used
to
prepare a diagnostic key for the species.
Habitat and associate information was gleaned from vouchers and from
A map known V
field work. distribution of populations of ozarkense and
all
V.
molle occurring in Arkansas, Missouri and Oklahoma was prepared from an-
new
and
notated loans
collections.
AND
RESULTS DISCUSSION
An
Loans resulted in 236 vouchers for study. additional 119 collections were
produced from work during 1999-2001 Arkansas, Missouri and Okla-
field in
homa. Of these, 193 were referable to Viburnum ozarkense and 162 to molk.
V.
They specimens examined
are all listed in the section for each taxon.
Mensural
results
Mensural most
analysis indicates that the useful features for differentiating
Vihurnum from number
ozarkense
molle are leaf width, of teeth per half
V. leaf,
number
of veins per half leaf, leaf tip length, petiole length below an inflores-
cence or at the apex of a vegetative shoot, corolla width and fruit length. The
means
of these characters were all statistically significantly different (Table
1).
Measured
features not significantly different between the species were leaf
length, peduncle length, inflorescence width and height, stamen length and
my
Based on measurements Viburnum
leaves in ozarkense averaged
7.2
cm
wide, with 5.3 veins and 13.9 teeth per half leaf, and had an acuminate apex
mm
cm
averaging 7.7 long. Leaves of molle were wider, averaging 8.2 broad,
V.
with veins; more toothed, averaging 25.6 teeth per half and with an acute
6.1 leaf;
mm
apex averaging 2.9 long. Vihurnum ozarkense petioles on both flowering
and The
sterile shoots are shorter than those of molle. petioles below an
V. first
m
cm cm
inflorescence averaged ozarkense and on
2.4 for molle. Petioles
1.1 V. V.
ends on
the distal of vegetative shoots are similarly shorter ozarkense shoots
V.
cm)
(x= 2.1 than V. molle shoots (x= 3.4 cm). Corollas were significantly wider
mm)
mm),
in ozarkense flowers (x= 6.6 than in molle flowers (x= 4.4 but
V. V.
these data were derived from small sample (n= Mature were
a 40). fruits signifi-
cm)
cantly longer in ozarkense ix= than in molle (x= 0.9 cm), but again,
V. 1.1 V.
sample size was small (n= 41). Vegetative specimens of these taxa are differenti-
on number
ated based the of teeth per half This characteristic overlaps in
leaf.
only a few individuals with distinct peaks well separated
(Fig.
1).
Qualitative characteristics
Qualitative features such as leaf shape, leaf and petiole pubescence, color of
and
year shoots bark features also provided useful characteristics to
It
Vihurnum
separate the species (Table In outline, molle leaves are broadly
1).
ovate or orbicular; those of ozarkense are narrower and appear ovate in out-
V.
daxial leaf surfaces of ozarkense are uniformly hirsute, with short hairs
V.
mm
long) across the surface. In contrast, adaxial surfaces of molle
^5 V.
may
are glabrous or have a few scattered red, glandular hairs. Similarly,
ozarkense pubescent, covered with moderate dense
petioles of are to strigose
V.
and glandular hairs and an open furrow. Petioles of molle are essentially gla-
V.
brous and any observed pubescence typically manifested as a few glandular
is
hairs at the distal end of the petiole or as a few villous hairs along the margin of
the closed petiole furrow. Stipules are present in both species; in molle these
V.
occur in single pairs, while in ozarkanse two pairs of stipules per leaf stalk
V.
are often observed. In cross section, ozarkense petioles appear oval while
V. V.
molle petioles appear terete. The color of current year shoots at mid-season also
way
provides a useful to differentiate these taxa. For ozarkense they are red-
V.
dish-brown, in contrast to the yellow-tan shoots of molle. The most obvious
V.
viburnums
field character separating these the presence of exfoliating bark
is
persistent on stems after the second year of growth on molle shoots verses
V^
bark throughout branching Although
the tight the of V. ozarkense. this is a
prominent on herbarium
field character, not consistently present sheets, as
it is
many
do show enough branch
collections not to capture
it.
DIAGNOSTIC KEY
.
width (cm)
af
*length of P' petiole below 82 05-2.2(1.1+0.37) 68 1-4.2 (2.4±0,52)
inflorescence (cm)
length of P' petiole 109 0.9-3.4(2.1+0.56) 90 1.8-4,9 (3.4±0.72)
vegetative shoot (cm)
petiole pubescence 190 str,gosea^nd glandular 158 glabrous to sparse glandular
(mm)
*leaftip length 184 160 1-7(2.9±1.1)
4-9(6.6+1.5)
length (cm) 16 25 0.7-1.1 (0.9+0.11)
*fruit
throughout on >2
bark tight exfoliating year old
current season shoot color reddish-brown yellow-tan
tive shoots oval in cross-section moderately to dense lystrigose and glandular, fur-
rows open; stipules often 2 pair per leaf stalk; shoot: of currer season reddish-
It
I
brown; twigs and stems with tight bark throughout
adaxially glabrous, 7 to 44 (mlode 24) marginal
1
x=24cm, =
teeth per half petioles of pair leaves below nflorescen ce x
leaf; finSt
i
cm
3.3 at tips of vegetative shoot s,terete in cross secti(.n,glabroL.sorsparselyglan-
dular, furrow closed; stipules ins ingle pairs only; shoe
Phenology
Flowering material (about 5% each of Viburnum mol/(? and yozflrhense vouch-
Oklahoma
ers) for the plants that occurred in Arkansas, Missouri and indicated
that ozarkense flowers earlier than molle. Based on the material exam-
V: V.
I
May
ined, ozarkense flowered between 6 and June with a peak flowering
V. 7,
time May Vihurnum molle flowered between May and May with
of 19. 15 29, a
May
peak on 27-29
(Fig.
2).
Information gleaned from herbarium labels and field experience indicated that
Vihurnum ozarkense and molle occupied similar habitats and had similar
a
V.
Most associate data were compiled from field notes of the author.
X
1 [^
•
hulll
i
11
FiG.l Number of marginal teeth per half leaf for l///)urnum W6or/}ommo//e specimens collected in
m
Populations of Viburnum ozarkense Arkansas are most often encountered
and wooded
on rocky limestone slopes in rich
north-facing hillsides
ridges,
m
on and rocky woods above and along creeks
woods. also occurs ledges (ex.
It
Alum Cap Red River and Stepp
Fork, Bard Springs, Buffalo River, Fork, Little
m
Arkansas Acer saccharum,
Creek). Associates of ozarkense include:
V.
Carya
Arundinaria Berchemia scandens, Carpinus caroliniana,
gigantea,
cordiformis,ChionanthusvirginicusXornusflorida,Diospyrosvirginiana,Dirca
Hamamelis Hydrangea Magnolia acuminata,
arhorescens,
palustris, vernalis,
Philadelphuspuhescens,Quercusmuhlenhergii,Q.stellata,Rhamnuscaroliniana,
Rhusaromatica,Sideroxylonlanuginosum,Staphyleatrifolia,Tiliaamericana,
ufidu
mum
hu ozarkense has been collected from north and north-
In Missouri, Vi
from
facing limestone ledges and bluffs above the Eleven Point River, lime-
east
stone slopes along Myatt Creek, and north facing limestone slopes along the
with
South Fork of the Spring River. These are often mid-slope locations fil-
Acer saccharum,
tered Associates of ozarkense in Missouri included:
light. V.
Cornus Fraxinus
Berchemia scandens, Carpinus caroliniana, florida,
Quercus
quadrangulata, Lindera benzoin, Ostrya virginiana, alba,
Q.
muhlenbergii, rubra, Sideroxylon lanuginosum, and Viburnum rujidulum.
Q.
Oklahoma, Viburnum ozarkense has been collected from a rocky north
In
wooded
facing chert slope above Caney Creek in Adair County, and oak-pine
m
Oklahoma
McCurtain County Associates of ozarkense in at the
hillsides V.
™
Fi.w«H.s Vlb.r.y ^^^r&««.« ..d V!b..««.
ii«,*. S. 6n©ll«i p^sr^te
1
1
,
II
Adair County included: Acer saccharum, ruhrum, Asimina
site A. triloba, Cercis
canadensis, Corylusamericana, Hydrangea
Lindera Nyssa
arhorescens, benzoin,
Quercus
sylvatica, alba, Sassafras albidum, Staphylea americana
Tilia
trifolia,
and Viburnum
rufidulum.
Viburnum
molle
Viburnum
molle occurs Arkansas on
in chert slopes at the base of north facing
War A
bluffs along Eagle Creek in Madison County. single collection by
EJ.
V
Palmer documented molle Boone County from
in "rocky ledges, Harrison."
m
War
Associates of molle Arkansas the Eagle Creek Acer
V. at included:
site
saccharum, Asimina Hydrangea
triloba. arborescens,Juglans nigra, Lindera ben-
Magnolia
zoin. acuminata, Quercus muhlenbergii,
rubra, Staphylea
Q. trifolia,
and
americana.
Tilia
Habitats in Missouri which support Viburnum molle include north
facing
and
slopes, bluffs limestone ledges along creeks and rivers (ex. Castor River,
Camp
Cole Creek, Gasconade River, Jacks Fork of Current River, James River,
Jonca Creek, Lost Creek, Meramec River, Piney Creek, River Aux Vases, Stinson
Swan
Creek, Creek, West Fork Cuivre Along and
River). these creeks
rivers,
V.
molle plants typically occur understory elements
as receiving filtered or part
day sunlight, at the mid-slope point, neither in the floodplain nor the more
at
Carpinus
triloba, caroliniana, Cornusflorida, Dirca Juniperus
palustris,
imana,Qm
ircusmuhhn. Xanugmosv
SxdtroxyXon
hzrgx-
i,
Vihurnum
rufidulum.
m
Viburnum moUe isnot\enow n occur Oklahoma.
to
and
Distribution rarity
Distribution of Vihurnum ozarkense was compiled from annotated herbarium
new Vihurnum
vouchers and produced study
collections for this (Fig.
3).
ozarkense confined the Ouachita and Boston Mountains and Ozark pla-
to
is
teau, and documented from 4 counties in Arkansas, Howell and Oregon coun-
is f
and and McCurtain Oklahoma. While some
Adair counties
ties in Missouri, in
populations have been sampled repeatedly over the past 75 years, (ex. type popu-
documented by Based
lation in Stone Co., Arkansas), others are single collections.
50% known
on herbarium material, of the populations of ozarkense have not
V.
more and some sampled
been sampled than 30 populations not as
for years, for
Some
long 80 Arkansas populations have conservation protection in
as years.
the Ozark National Forest, and along the Buffalo National River
hurnum some
Vi ozarkense populations in Missouri are afforded protection
A
along the Eleven Point River in the Mark Twain National Forest. popu-
at sites
m
County
lation examined 2000, at the western edge of the range in Adair
known
Oklahoma, was composed about mdividuals and not have
of 15 to
is
The and McCurtain
conservation protection. size conservation status of the
County, Oklahoma population unknown; this population has not been
is
known
With
sampled since 1966. a distribution of 18 counties in three states, V.
under 26 county upper southeastern
ozarkense clearly the limit for rare
falls
hurnum
endemics established by Estill and Cruzan (2001). Vi ozarkense should
be considered for state listing in states where occurs and attempts should be
it
made
to locate additional populations.
commonness been
The or rarity of molle throughout range has not
V. its
Madison and Boone
critically reviewed. In Arkansas, molle restricted to
V. is
was
counties The Madison County population of molle, discovered
(Fig. V.
3).
Com-
by Shepherd 1987 while working the Arkansas Natural Heritage
in for
Weckman
mission. This population was re-visited in 2001 by and Shepherd
and is estimated to consist of 35-50 individuals. It is on private land with no
An
Boone
current conservation protection. attempt by the author to relocate the
was The
County population collected by Palmer in 1914 not successful in 2000.
terse label information, "rocky ledges, Harrison" gave few clues as to its loca-
V
may
This population no longer be extant. This research indicates molle
tion.
Vihurnum
Arkansas.
the rarest species in
is
A
Vihurnum population observed
molle occurs in 16 counties in Missouri.
m
Oregon County in 2001 was estimated to consist of about 12 individuals. La-
bels typically lack information about numbers of plants in a population; thus
unknown. study herbarium
sizes of other populations are In the three state area,
(•)and Viburnum molleMkhx.l
vouchers examined 50%
of molle reveal that of the counties were
V. last col-
lected in or before the 1950s. Conservation status of the Missouri populations
unknown may
some
of V. molle are but be afforded protection in the various
units of the Mark Twain National Forest and along the Eleven Point River
Overlap of morphology and geographic range
For mensural
the characters used in this study, ranges of the measurements
however
overlap, 8 of 14 characters were statistically significantly different
at
taxonomy
p= <0.05. If single character is desired in the field, the sine qua non
Viburnum
for molle is the presence of exfoliating bark and conversely the ab-
V
sence of exfoliating bark defines ozarkense. This an Viburnum
inviolate
is
m
Michaux
molle character, used by his type description, and observed by the
author in the field for plants in Kentucky, Ohio, Missouri, and Arkansas, and on
V
herbarium specimens of molle through range in Tennessee, Indiana,
its
Illi-
and
nois, Iowa. For determination of herbarium material collected without older
abundantly
stems, the suite of toothed leaf margins, short apex, and glabrous,
terete petioles on yellow-tan twigs would lead one to Vi burnum molle. Conversely
a specimen with moderately toothed and
leaves, longer, acute glandular-
tips,
related species.
Vihurnum ozarkense and molle co-occur in Madison County, Arkansas
V.
and Oregon County, Missouri, the southwest edge of the range of molle
at V.
m
Arkansas populations about 30 miles while Mis^
(Fig. In the are air apart,
3).
No
souri the populations are about 12 river miles apart. sympatric populations
Vihurnum molle and ozarkense were located by the author, nor were any
of
V.
individuals appearing intermediate between these species observed in the field
voucher material examined.
or
Specimens examined: Viburnum ozarkense Ashe. ARKANSAS: Baxter Co.: Baxter Co.: 6Jun 1931, Ashe
(NCU); Jun Ashe (NCU); Jun Ashe (NCU, NY). Benton Co.. Devils Eyebrow,
s.n. 7 1931, s.n. 10 1931, s.n.
U
22 Apr 1928, Demaree 4842 (UARK). Franklin Co.: Devils Hollow, 3Jun 1978, Barber 849 (UAM, ARK).
Garland Co.: creek banks, Ouachita River, 28 Aug 1939, Demaree 20517 (MO); Walnut Creek Recre-
ation Area, 10 Aug 1931, Moore 510786 (UARK); rich woods, Charlton Recreation Area, 23 Apr 1994,
SundcU 10759 (NA, UAM). Johnson Co.: creek bank, Ozark National Forest, 14 Sep 1995,
el al
&
Kirshherger Davis 101 (UAM, UARK). Madison Co.: woods understory, S of Red Star, 18 Apr 1995,
Nov (SMU) Mul-
Kirshberger 12 (UAM); mesic woods, vicinity Boston, 17 1973, Tucker 12461 Little
berry Creek, S of Red 3 Jun 2001, Weckman 6401-6419 (EKY). Newton Co.: Stepp Creek near
Star,
Swain, 20 Jul 1979, Bonars.n. (UARK); Boxley, 22 May 1948, Moore 480226 (UARK); limestone woods
above Buffalo River, 20 May 2000, Weckman 5597A,B- -5599 (EKY); upland woods Buffalo River, near
Boxley, 20 May 2000, Weckman 5603 (EKY). Polk Co.: creek banks, Bard Springs, 4 May 1955, Demaree
May MO,
creek bank, Hector, 17 Oct 1932, Merrill 89 (A); creek bank, Nogo, 11 1933, Merrill 271 (ILL,
SW
Alum
dian Creek, of Pelsor, 10 May 1969, Tucker 7926 (APCR). Saline Co.: bluffs, Fork, Sahne
&
River, 28 May 1954, Demaree 35333 (NCU, US); the Narrows, S of Crows, 24 Sep 1995, Sundell Pagan
N
11726 (UAM); narrow ridge. Saline River, 11 Jul 1997, Walker 11079701 (UARK); lace slope above
&
Alum Fork, 6 Jul 1999, Weckman Walker 5110. 5111,5113,5131 (EKY). Searcy Co.: rocky creek bluff,
Graham
Harriet, 9 May 1970, Demaree 61712 (MO); hillside, S of Marshall, 29 Apr 1967, 343 (NCU).
Stone near Sylamore, Ashe (NCU); near Sylamore, 18 May 1924, Ashe (NCU); bottom
Co.: n.d., s.n. s.n.
May
N Sylamore Creek, Jun Ashes, (NCU); along Cap Fork Creek, 6 198L Davis 2975 (APCR);
of 7 1931,
n.
creek bottom in woods. Mountain View, 10 May 1952, Demaree 31751 (US, VDB); rocky hillsides,
May Demaree (NCU, VDB); rocky open woods, Sylamore
Blanchard Springs, 19 1952, 318.50 US, bluffs,
N
May Demaree 52296 (NCU); Barkshed Recreation Area, along Sylamore Creek, 29
Creek, 19 1965,
Apr Graham etal343 (APCR); Blanchard Springs, IBJun 1945, Moore 450600 (UARK); Sylamore,
1967,
24 Jun 1945, Moore 450629 (UARK); Sylamore Forest, 24 Jun 1945, Moore 450646 (UARK); Blanchard
Aug
Springs, Jun 1945, Moore 450721 (UARK); Blanchard Springs, 18 1'
23
N N Gun
Caney Creek, of Mt. View, 21 Jun 1951, Moore 510347 (UARK); wooded lacing slope.
above creek bed, vicinity of Blanchard Springs, 22 May 1984, Sundell 6308 (UAM); along S
&
Creek, 8 Oct 1966, Tucker Demaree 3578 (APCR); alluvial woods, Barkshed Recreation Are;
N
PCR); alluvial wooc s along Sylamore Creek, 14 Oct 1967, Tucker 6867 (APCR,
Oct Tucker 8225 (APCR); rocky
Blanchard Springs Recreation Area, 2 1969,
Aug
ard Springs, 5 Aug 972, Tucker 10418 (UARK); rocky slope, Gunner Pool, 5
\PCR); along NSyla Tiore Creek, 8 Oct 1972, Tucf^erJ0605(APCR-2x, SMU, VDB);
Weckman 5160-5168 (EKY); Blanchard Springs,
Recreation Area, 7 1999, 5151,
1
J
}
NE
Rner
even Point ol Peace Valle> 12 Aut.
near Blowing Springs 14 Api 1935
ivei Sii
Nhee
eyermark78762{UMO)
limLbtom
si
JMO)
limestone bluff. SFoil Spiin^ ^^u
I
Rner
ace dolomite blulf b Fori Spring 4 Jul 19Q0
ngSpnngs Summets (MO)
14 Sep 1994 7102
Ele
iVecl2mflfi6360-6%5 637I-6385(EKY) SFoikSprii
NfKini,slopts kdt,cs Bit,Cncblufl 2 Oct
)
JukasL3S^{NCU)
2Jullb97
Big
Apr 1909 Bush 5531 (A) rich woods Noel
2
Aug
outcrops Castor River 27 1948 SUyei
i
River May 1986 Summer 1589 (MO) Cai
1
i,
