CHANGES TO POTENTILLA RUBRICAULIS S.L., P. HOOKERIANA (ROSACEAE), AND ERSTWHILE SYNONYMS IN FLORA OF NORTH AMERICA NORTH OF MEXICO

2013·2.3 MB·

by  Barbara Ertter

CHANGES TO POTENTILLA RUBRICAULIS R HOOKERIANA (ROSACEAE),
S.L.,
AND
ERSTWHILE SYNONYMS
IN
FLORA OF NORTH AMERICA NORTH OF MEXICO
Barbara Reidar Elven
Ertter
University ofCalifornia University ofOslo
Berkeley, California 94720-2465, USA. P.O. Box 1172
NORWAY
Snake River Plains Herbarium Blindern, NO-03 18 Oslo,
Boise State University
Idaho 83725-1 51
Boise, U.S.A.
5,
David Murray
F.
Museum
ofAlaska of the North
University
907 Yukon
Drive
USA
Alaska 99775-6960,
Fairbanks,
Keywords: Potemilk nomenclature, Flora North America North Mexico
Potentilla rubricaulis, Potentate hookeriana, of of
COMPLEX
NOMENCLATURAL BACKGROUND OF THE POTENTILLA RUBRICAULIS
Preparation of the continent-wide treatment of Potentilla (Rosaceae) for North America since that of Ryd-
first
among
berg (1908) required a full-scale revisionary effort to synthesize differing taxonomic concepts regional
was
justify the changes was well beyond the scope of a synoptic flora. This particularly true for the P.
resultant
rubricaulis complex, which accordingly published here instead.
is
L
R«-
Inst Teas 703-711.2013
7(2):
in the century Polunin 1940; Porsild 1957; Hulten 1968; Po:
last (e.g.,
>
&
Wittman 1996; Holmgren 1997) have generally used the na
:ber
Lehm manner, with some palmate
rubricaulis licting for plants at least t<
mm)
and
temate) leaves and short styles (less than 1.5 that are usually thickened glai r-papil-
(vs. strictly
some ambiguous
late basally. Alternatives have included the segregation of elements as the P. quinquefolia
&
Dorn inP
Rydb. Hitchcock Cronquist 1961; Boivin 1967; 1977) or the inclusion of P. rubricaulis pulchel-
(e.g.,
name
la R. Br. (Scoggan 1978). As further confusion, Sojak (1986, 1994) added P. hookeriana Lehm., a previous-
synonymy
ly used for a widespread species in the P. nivea L. complex, to the of P. rubricaulis s.l.
&
Although some of our early annotations and treatments Elven Aiken 2007) also reflect an inclu-
(e.g.,
sive Potentilla rubricaulis, we now conclude that several reasonably distinct species can be parsed, based on our
combined studies of a broad range of material from the Arctic to the southern Rocky Mountains, increased
at-
and and new some
tention to vestiture inflorescence architecture, analyses of types, including lectotypifica-
tions (Ertter 2008; Sojak 1986). Most of these species collectively comprise Potentilla sect. Rubricaules (Rydb.)
originated as intersectional hybrids between members of temate-leaved sect. Niveae (Rydb.) A. Nelson and
pinnate- to subpalmate-leaved sect. Pensylvanicae Poeverl. Sojak (1986) considered at least 30 species, mostly
Eurasian, to be such intersectional hybrids. Jurtzev (1984) and Sojak (1986) have treated the Eurasian varia-
tion in this group in detail; Sojak’s work also dealt with Greenland and North American species. He initially
erican species in the complex, but later (1994) reverted to an inclu-
P
members
sive rubricaulis for non-arctic of the section.
Listed below are the species comprising sect. Rubricaules in the pending volume 9 of Flora North Amer-
of
(FNANM),
ica North of Mexico plus additional taxa that have been included in with
Potentilla rubricaulis
s.l
,
and
full discussion type paragraphs. Descriptions, keys, and distributions can be found in the pending FN-
ANM
treatment. Interpretations of probable parentage, mostly by Sojak, are provided only and sub-
for arctic
FNANM
arctic species. Problematic or minor elements not given treatment
full in are also addressed, as are
P
synonyms
other erstwhile of rubricaulis Additional information and discussion on
s.l. arctic species avail-
is
able at the Panarctic Flora website (http://nhm2.uio.no/paf/).
AND
SUBARCTIC TEMPERATE FNANM
SPECIES
IN
Outside of the Arctic, seven species previously included in
Potentilla rubricaulis are being treated as distinct
s.l.
FNANM.
species in These are only the best-defined elements
morphologically and
geographically, occurring
Rocky
primarily in the Mountains and subarctic regions of Alaska and western Canada. Further
investigation
needed numerous
is to resolve poorly understood variants and
transition zones, especially in western Canada.
For example, plants from the northern prairies of Saskatchewan, and Montana
Alberta, an
evidently represent
undescribed taxon, and from some
collections other areas Hoback
Canyon, Wyoming;
(e.g„ Ne-
Schell Peak,
vada) are also under investigation as possible
novelties.
narrow
circumscription
of Potentilla rubricaulis
is restricted to
reli rely large plants with open
inflores-
occurring mainly
ces in glaciated parts of subarctic northwesten
lanada and
southern
Alaska. Sojak
P
P
J6) initially interpreted rubricaulis (including
furcata A.E. Poi
i) as the hybrid species originating
iP
P
arenosa
(Turcz.) Juz. (sect. Niveae) x bimundorum
Sojak
(sect, f nicae), but later (1994) c
Pensylvanicae
parent
t. for a broadly defined The
P. rubricaulis.
P
distincuon between and P
rubricaulis large forms of
arenosa with
supernumerary
leaflets problematic,
is
though the lends have more
latter to spreading
stiffly and
petiole hairs
prominently
peliolulate central
leaflets.
705
md
with bimundorum mar-
ihared P. petiole hairs, sparse glands, strongly revolute leaf
;ins, and raised, partly reticulate vein: epicalyx bractlets and sepals. The range of P. rubricaulis is largely
rithin the glaciated area of overlap bet' arenosa and bimundorum, but the species nearly absent from
1 P. P. is
he unglaciated Beringian parts of Alas
“Vanamo"
2:25. 1947 [1949].
1
The name Potentilla hookeriana, or its infraspecific equivalent under P. nivea, has traditionally been applied to
a widespread primarily ternate-leaved member of sect. Niveae. As noted by Sojak (1986), however, the type has
at least some 5-foliate leaves, as do most other populations outside of the Arctic. As a result, the ternate-leaved
known now
arctic and subarctic material that was previously as hookeriana has taken arenosa (Turcz.) Juz.
P. P.
when was
as the next available name. This occurred after a brief period it called P. nivea s.s. (e.g., Sojak 1989;
Cody 1996) until that name was conserved with a conserved type (Eriksen 1999), thereby maintaining
et. al.
nivea in traditional sense for a separate species.
P. its
from the Rocky Mountains and eastern Great Basin. In addition to encompassing most of traditional hooker-
P.
P
many
new
iana from this area, our circumscription also includes 5-foliate collections previously identified as
Mus. Canada
Potentilla furcata A.E. Porsild, Bull. Natl. 121:224. 1951. Potentilla hookeriana Lehm. var. furcata (A.E.
Although included within Potentilla rubricaulis by Sojak (1986, 1994), in our interpretation P. furcata differs in
member
several characters that suggest a hybrid origin from P. arenosa and a glandular of the P. pensylvanica L.
and Yukon
complex. a characteristic species of the steppe bluffs of interior south-central Alaska, Territory,
It is
and northern Columbia, mainly within the unglaciated Beringian region largely allopatric to
British (i.e., P.
&
Potentilla modesta Rydb., N. Amer. FI. 22:331. 1908. Potentilla concinna Richardson var. modesta (Rydb.) S.L. Welsh B.C.
Potentilla modesta is the dominant component of P. rubricaulis s.l. in the Intermountain Region (e.g., Holmgren
1997, including Plants generally have more consistently 5-foliate leaves and more congested inflo-
illustration).
P
synonym
rescences than hookeriana. Sojak (1994) and Holmgren (1997) considered modesta to be a of P.
P.
P synonymy
rubricaulis while Hulten (1945) included modesta in the of his primarily arctic concept of P.
s.l.,
Welsh where
nivea subsp. subquinata (Lange) Hulten. The epithet modesta is misapplied in et al. (1993), the
&
Welsh used
combination concinna Richardson var. modesta (Rydb.) S.L. B.C. Johnst. is for long-styled
P.
plants placed by us in concinna var. divisa Rydb. (sect. Concinnae (Rydb.) A. Nelson).
P.
Mem. Columbia
Potentilla pseudosericea Dept. Bot. Coll. 2:98. 1898.
Rydb., 1
Texas GH; GH.JEPS, UC).
2:204. 2008: isolectotypes:
As endemic
discussed elsewhere (Ertter 2008), the traditional use of Potentilla pseudosericea for plants to the
White Mountains on the border of California and Nevada was at odds with Rydberg’s (1908) citation of “Rocky
Mountains” as type This citation resulted from the fact that two of the three syntypes were from the
locality.
Rocky Mountains, both now identified as bipinnatifida Douglas ex Hook, in sect. Pensylvanicae. The tradi-
P.
tional application has been preserved by lectotypification on the third syntype, purportedly from Nevada but
actually from California (Ertter 2008). Whether the species occurs in Nevada remains to be determined. Sojak
si
(1994) included pseudosericea within rubricaulis
P. P.
FL
mer. 22:3
U.S.A. Utah: La Sal Mts., Purpus 251 (holotwe: US;
p.p. isc
Potentilla paucijuga, treated by us as endemic to the La Sal Mountains of Utah, was included in the synonymy
of P. rubricaulis si by Sojak (1994) and Holmgren (1997). Plants have subpalmate leaves, with somewhat larger
&
flowers and longer styles than sympatric members of sect. Rubricaules. In Colorado Weber Wittman
(e.g.,
&
P
1996), the combination pensylvanica var. paucijuga (Rydb.) S.L. Welsh B.C. Johnston has been misapplied
P
what by us
to is treated as jepsonii Ertter (sect. Pensylvanicae).
(Rydb.) Th. Wolf,
&
Although
often included in Potentilla rubricaulis Holmgren Weber Wittm
s.1. (e.g., 1997;
tana differs in having subpinnate leaves and smooth columnar
styles. It is accordingly placed by us in sect.
Subjugae (Rydb.) A. Nelson rather than with many
sect. Rubricaules, collections being
transitional to subjuga
P.
The
Rydb. species is restricted to high elevations in the mountains of Colorado, Montana, Utah, and Wyoming.
Lectotypification of P. saximontana provided above, is required only because a specific institution was not
in-
,
GH
dicated in the protologue. Otherwise the specimen could be accepted known
as holotype, as the only du-
name
annotated with by
plicate this Rydberg.
The
lectotype of Watson
Potentilla nivea var. dissecta has been P
S. tentatively included saximontana
in
(Ertter 2008), but saximontana not otherwise known from
P. is the Canadian The name P
Rockies.
pseudoseri-
cea var. grandiflora Th. Wolf, misapplied byJepson what now
(1936) to is called probably
P. morefieldii Ertter,
represents the same and same Drummond
entity, possibly the
collection.
Although
references to Hooker’s herbarium in the protologue might
suggest
th
pseudosericea Kew, Wolf
var. grandiflora
is at (1908) is clearly referring to the specimen in his own herbari
now “NW
DR, which name
annotated with and
at is this Amerika/(ex
herb. Hooker)/Lag mit
echter
diversi-
P.
Lehm. zusammen”. The
folia corresponding sheet in Hooker’s herbarium
has a only a single specimen match-
DR
ing the specimen of P. pseudosericea var. grandiflora (K000762566), mounted
with two
large plants of
P.
P
Lehm.
glaucophylla (formerly
Lehm.). This
diversifolia sheet provides
the
additional
collecting information of
J
”
“Rocky Mt/Druir A specimen Bentham
in the herbarium (K000762567)
probably
is a duplicate, in spite
Hooker
of being the only pers
tithe
label.
ARCTIC FNANM
SPECIES IN
Treatment
of
arctic variation in sect. Rubricaules even more
is problematic than
in temperate and
subarctic
ar-
complicated by
eas, the challenge of applying the plethora of names based on
primarily
Eurasian
types in a
region with limited access and complex
a
post-glacial biogeography. At we
present, find only two compo-
arctic
nents of
sect. Rubricaules sufficiently uniform and
widespread
in North America
to merit full treatment in
FNANM:
Potentilla pedersenii (Rydb.) Rydb. and a species which we
to
provisionally apply name P
the uschak-
These two
ovii Jurtzev. species constitute the major
portion what
of has been
called
P. rubricaulis in arctic
Canada and Greenland
&
Porsild Hulten &
(e.g., 1957; 1968; Bocher
et al. 1978; Porsild Cody 1980- Hulrtn
Fnes The
1986). diagnostic morphological
characters can be
variable and
overlapping,
but two
the
species are
nevertheless
treated separately in part because of
differences in
putative
parental combinations
707
&
Zhum. (Moscow
Potentilla uschakovii Jurtzev, Bot. Leningrad) 73:1613. 1988. tvpe: RUSSIA: Wrangel island, “ad
Potentilla uschakovii was described by Jurtzev (1988) as endemic to Wrangel Island, the only place in Asia
and sym-
where the putative parents subvahliana Jurtzev Niveae] pulchella Pensylvanicae]) are
(P. [sect. P. [sect.
The major from Canadian and Greenland
original description deviates in features the arctic plants to
patric.
we Our name
which apply this name, not least in regularly temate leaves. expanded use of the is based solely
on the interpretation of the same hybrid parentage, since subvahliana and pulchella are the only represent-
P. P.
FNANM.
we Morpho-
atives of their groups within the American range of plants that treat as P. uschakovii in
more
logic features of North American uschakovii that are suggestive of pulchella as one parent include
P. P.
than three deeply dissected leaflets and leaflet teeth with soft well-developed apical hair tufts. Other features
point toward subvahliana as the second parent: caudex branches with persistent whole leaves, smooth petiole
P.
hairs, and one- or few-flowered inflorescences with large flowers. There is much variation among the North
may own
American plants, such that each island or population have its features. It is therefore probable that the
species has arisen from numerous hybridization events.
and
Sojak have arisen from crosses between arenosa subsp. arenosa
(1986) interpreted Potentilla pedersenii to P.
P. pulchella. Features of pedersenii that indicate P. arenosa as the sect. Niveae parent include no marcescent
P.
whole and with more and mostly smaller flowers than uschak-
verrucose inflorescences
leaves, petiole hairs, P.
Like polymorphic and probably the result of multiple hybridizations. has,
ovii. P. uschakovii, the species is It
from
however, North American, including Greenland. Reports of pedersenii north-
a coherent range in arctic P.
&
eastern European Russia may perhaps involve arenosa subsp. chamissonis (Hulten) Elven D.F. Murray
P.
rather than subsp. arenosa as one hybrid parent.
Jurtzev and Sojak Jurtzev 1984) described Potentilla tolmatchevii from northern Asia as a hybrid spe-
(in
cies from P arenosa subsp. arenosa x pulchella. Material annotated byJurtzev as P. tolmatchevii and numerous
P.
The two
collections from Ellesmere Island the American concept of P. pedersenii. species are therefore
fit
merged
by us under name.
the priority
name
Since was introduced by Rydberg (1908) as a “sp. nov.,” the is often treated as a
Potentilla pedersenii
P
newly However, Rydberg’s inclusion of subquinata var. pedersenii in syn-
described species Sojak 1986).
(e.g.,
P new
onymy making combination Gandhi,
name basionym, pedersenii a (K. pers.
establishes the varietal as a
comm.
2011).
FNANM
TREATMENT
TAXA NOT GIVEN FULL IN
FNANM,
In addition to the preceding species being treated in there are numerous local or scattered popula-
from Niveae and Pensylvanicae, or that have
tions of combine characters sect. sect.
Potentilla in the Arctic that
may
otherwise been included in a broadly defined P. rubricaulis. Some of these prove worthy of full taxonomic
propagate independently of their putative parents (probably
recognition they
as species of hybrid origin, as
mainly by agamospermy; Eriksen 1996). Others are too different from place to place to deserve full species
cf.
named
widespread. The following such entities— and
treatment, or sufficiently
they are not fully stabilized
i.e.,
adequately species—have been reported from arctic parts of North America and Greenland, but
described
as
FNANM.
the
evidence treatment in
is insufficient for full
1
Journal of the Botanical Research Institute of Texas
7(2)
Sojdk (1985) interpreted Potentilla borealis as the hybrid of anachoretica Sojak Pensylvanicae x areno-
P. (sect. P.
)
&
sa subsp. arenosa. Reports by B.A. Jurtzev (in Elven Aiken 2007) of this species from the Seward Peninsula
(western Alaska) and Ogilvie Mountains (Yukon Territory) refer to plants with subpalmate to subpinnate
many
leaves, very slender and silky hairy leaflet lobes, and glands on the epicalyx bractlets and sepals. The
last
feature is not in accordance with the presumed parentage, so the identity of these North American plants as
P.
SSSR
Arktichesk. 1984.
:ev, Fl. 9(1):318. Type: RUSSIA: East Chukotka: “F
tiae sinistrae fl. Czegitun),” 20Jul 1972,.Jurtzev s.n. (holotypi
&
?Potentilla murrayi Zhum. (Moscow
Jurtzev, Bot. Leningrad) 78(11):80. 1993.
Type: U.S.A.
Jurtzev (1993) interpreted Potentilla murrayi as a hybrid species from P. anachoretica and P. subvahliana. It is a
distinct local entity, forming significant and morphologically consistent populations in a small part of the
Brooks Range. The hybrid assumption partly supported by morphology: and
is leaf dissection vestiture resem-
whereas
ble P. anachoretica, the influence from P. subvahliana is very evident in its columnar tussocks, leaves,
and
flowers. Reports of P. murrayi from outside the central Brooks Range are based on rather different plants,
not forming a morphologically consistent entity. It is debatable whether P. murrayi is distinct from P dezhnevii
of the Russian Far East, since Sojak (2004) suggested that both have the same parentage.
dezhnevii
If so,
P.
would
be name.
the priority
Potentilla petrovskyi
Sojak, Cas. Nar. Mus., Odd. Pdr.
153(2):102. 1984.
Type: RUSSIA: South Chukotka: “Anadyr,
r-n.
Potentilla tschaunensisjuz. ex
Jurtzev, Arktichesk. SSSR9(1):317.
Fl.
Both
of these species, described from the Russian Far were
East, interpreted by Sojak
(2004) as Potentilla
P
anachoretica x nivea si; he accordingly synonymized
tschauensis under
P. P. petrovskyi. Plants conforming to
Jurtzev’s description are present on the Seward
Peninsula, western
Alaska. However, in our evaluation these
do
collections not constitute a coherent taxon, but rather a gathering
of scattered hybrid biotypes. Other
re-
from
ports northwest North America are based on plants included by
Sojak in
P. psychrophila.
Potentilla psychrophila
Sojak, Thaiszia 2007
16:94.
[2006],
Type: U.S.A. Aiaska: ne Brooks Range Lake Coke
Peters area
Creek
drainage, 69°21'N 144°57W, 29 Jun 1973, Batten 250 (holotype: ALA).
The
major portions of what had been
annotated as Potentilla and P
rubricaulis petrovskyi in Alaska and Yukon
were
Territory transferred by Sojak new
(2007) to his species
P. psychrophila which he assumed be hybrid
to a
,
species fromP.IitomlisandP.nivea. The
material annotatedby
Sojak polymorphic and may
is
contain the prod-
ucts of several hybridizations, perhaps among
different species. At one
least part morphologically
is consistent
known
and
is to represent fairly large populations in central and northern Alaska and Yukon
in the
Territory,
but whether an
this is acceptable hybrid species remains
in
question.
&
&
Potentilla safronoviae Jurtzev SojaMot.
Zhurn. (Moscow
Leningrad)
73:1615.
1988.
RUSSIA.
Type: Siberia:
&
PotentiMalyngei
Jurtzev Sojak subsp. spissa
Sojak. Feddes
Repert.
117:496. 2006. Greenland:
Type
Wollaston
r'Yenttlla subsp. spissa based on
plants
previously
identified by Danish
botanists
as either P. ntkncuuhs or P. ptdchella. This plant has a
significant range and
consistent morphology
in northeast
Greenland. accordingly
It is a candidate for recognition as an
independent
taxon, but our
in understanding not
We
as a subspec.es of
P. lyngei. agree with Sojak
treatment
s of
P. lyngei subsp.
lyngei (sect. PensylvumcueJ as a
isunct taxon in north European
Russia, with one
close
relative in the Russian
Far
East (P
wrangelii V.V. Petro-
709
vsky, Wrangel Island). However, in our interpretation, plants annotated by Sojak as subsp. (oran
lyngei spissa
P.
unpublished combination as a subspecies of insularis are probably hybrids between and P
P. pulchella
P.
)
P
Malte Aureae As
hyparctica (sect. (Rydb.) Juz.). such, lyngei subsp. spissa is a synonym of P. safronoviae, de-
from
scribed Siberia.
Potentilla insularis Sojak, Bot. Jahrb. 106:203. 1986. NORWAY:
Syst. Aug
TVre: Svalbard, Spitsbergen, Hyperithatten, 28
Potentilla insularis, described from Svalbard and east Greenland, was interpreted by Sojak (1986) as P arenosa
P
x
subsp. chamissonis P. lyngei s.l. Sojak believed lyngei subsp. lyngei to be the sect. Pensylvanicae parent of the
Svalbard plants, but subsp. spissa (= P. safronoviae) to be the corresponding parent of the Greenland plants. The
P
hybrid origin of insularis has been contested for morphological and molecular reasons (Hansen
2000;
et
al.
Hamre The P P
2000). Svalbard however, has proved very Greenland
insularis, close to pedersenii in gross
P RAPD
morphology and
to arenosa subsp. chamissonis in multilocus phenotypes (Hansen
et 2000).
al.
&
Potentilla arctoalaskensis Zhum. (Moscow
Jurtzev, Bot. Leningrad) 78(11):79. 1993. u a
Type: s Alaska:
SW
Seward
Peninsula, 18.5 miles of Deering near Utica Creek, 65°53'N 163°5'W, 23 Jun 1978, Wright 42 (holotype: ALA).
p.p.
known
Potentilla arctoalaskensis is evidently only from the type, whichJurtzev (1993) interpreted as P arenosa
x P. litoralis. The type sheet is a mixed collection with an unnamed variant of P that the common
litoralis is
P
form
in Alaska. Typical barely enters Alaska from the southeast.
litoralis
name
pentaphylla “Lehm.” and substitute quinquefolia Rydb. Sojak (1986), for example, included both
its P.
names in his synonymy of P hookeriana and designated a lectotype at PR, based on a specimen from the Hook-
er herbarium from “America septentr.” This interpretation results from the traditional attribution of P nivea
var. pentaphylla to Lehmann (Del. Sem. Hort. Hamburg. 1850:12. 1850), sometimes with reference to an earlier
publication (Lehmann The
in Bor-Amer. (Hooker) 1:195. 1832). earlier publication includes a description
Fl.
but
lacks the actual combination, and by the time of the later publication the combination had already been
validly published by Turczaninow. Lehmann’s putative combination is therefore at best an isonym of nivea
P.
var. pentaphylla Turcz., as accepted by Wolf (1908). By current taxonomy (e.g., Juzepczuk 1941; Sojak, pers.
comm., P Bunge, endemic name P
2011), Turczaninow’s type a variant of altaica to central Asia. Neither the
is
nivea var. pentaphylla nor P quinquefolia therefore has any application in North America. As an alternative in-
terpretation, Porsild (1951) called quinquefolia a nomen confusum to be discarded.
P.
P
Another commonly used name, Potentilla nivea var. subquinata Lange (= subquinata (Lange) Rydb.), has
names
generally been considered a heterotypic synonym of the preceding (e.g., Rydberg 1908, Hulten 1945).
However, we designated by Sojak (1986) as the casual hybrid of nivea and arenosa
interpret the lectotype P. P.
that common which
is throughout the sympatric ranges of these species, for P. prostrata Rottb. is the priority
name. mem-
Since both of the putative parents are in sect. Niveae, the epithet subquinata is not applicable to any
ber
of sect. Rubricaules. Normally trifoliolate species in sect. Niveae will occasionally produce supernumerary
&
Nylehn
leaflets, especially under favorable conditions (Eriksen 1999).
ACKNOWLEDGMENTS
We
FNANM
gratefully take opportunity dedicate this article and the pending treatment of Potentilla in
this to
whose was
to the late Boris A. Yurtzev/Jurtzev (1932-2004; LE) andJin Sojak (1936-2012; PR), joint expertise
synthesizing the previously independent taxonomic traditions in American and Eurasian Potentilla.
critical to
Without
the
resi
collaboratively treatment would be seriously deficient. This has been particularly true for
\
and
ixtensively revised as a result of recent trans-Beringian trans-Atlantic
analyses.
We
are likewise indebted to Bente Eriksen, Mats Topel, and Christoph Dobes for sharing both their
A
friendship and their latest research on the molecular phylogeny of Potentilla. comparable debt for assistance
in resolving nomenclatural quandaries owed to Kanchi Gandhi, James L. Reveal, John McNeill, and Dick
is
We
Brummitt. are most grateful to Arnold Tiehm (RENO) and an anonymous reviewer for detailed reviews and
Support to the senior author from the Lawrence R. Heckard Endowment Fund of the Jepson Herbarium
is
gratefully acknowledged, as is the University of California Botanical Garden for the maintenance of living col-
The and
lections. University Jepson Herbaria at the University of California at Berkeley, the Natural History
Museums Museum
of the University of Oslo, the University of Alaska of the North, the Snake River Plains
Herbarium Museum
at Boise State University, the Missouri Botanical Garden, and the National in Prague Her-
barium are to be thanked for use of facilities and staff support, as are ALTA, ARIZ, BRY, CAN, COLO, DAO, DR,
WTU
MONTU,
GH, K, NY, OSC, RM, US, UTC, and for providing loans used in this research.
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