CRATAEGUS SERIES PARVIFOLIAE AND ITS PUTATIVE HYBRIDS IN THE SOUTHEASTERN UNITED STATES

2006·14.2 MB·English

by  J B Phipps

AND
CRATAEGUS
PARVIFOLIAE PUTATIVE
SERIES
ITS
HYBRIDS THE SOUTHEASTERN UNITED
IN STATES
Phipps and Dvorsky
J.B.
K.
m
Deport en of Biology
t
The University of Western Ontario
154 Richmond North London
St.,
1
N6A CANADA
Ontario
5B7,
ABSTRACT
This paper deals with Crataegus series Parvi/oIitU'CRosaceae, subfamily Pyroideae) in the main part
C
of its range, the southeastern United States. Two species, unijlora and C. brittonii, are recognized
C
together with one putative interserial hybrid, Xvailiae. A number of other obscure entities are
also discussed. The series and constituent species are provided with detailed descriptions, syn-
full
onymy, keys to taxa and are typified so far as possible. Line illustrations and county level distribu-
tion maps, the latter derived from a database of over 1200 records, are also given for each species
treated.
Keywof^ds; Crataegus, series Parvijoliae, Rosaceae, taxonomic revision, interserial hybrids, southeast-
ern United States
RESUMEN
Este articulo trata de Crataegus serie Parvijoliae (Rosaceae, subfamilia Pyroideae) en la parte princi-
C
pal de su area, el sureste de los Estados Unidos. Se reconocen dos especies, i.mi//ora y C. briKonii,
junto con un hibrido putative interserial, C._vaHiae. Se discuten tambien un numero de entidadcs
como
poco claras. Tanto de la serie de las especies constituyentes se ofrecen descripciones detalladas,
sinonimia completa, claves de los taxa, y se tipifican en lo posible. Para cada especie tratada se dan
ilustraciones y mapas de distribucion a nivel de condado derivados de una base de datos de mas de
1200
reeistros.
INTRODUCTION
The was
first author asked to prepare the Crataegus treatment for the Vascular
Flora the Southeastern United States only (Cronquist 1980) of which,
of vol.
1
was
however, completed. In spite of the soon defunct status of this flora JBP
now
which
continued with this Crataegus project being issued as a set of
is
accounts usually deahng with individual or a few series, Phipps (1988, 1998).
e.g.
The third of these presented here and deals with Crataegus series Parvijoliae.
is
This series extends well beyond the borders of the flora area, to Texas and Mexico
New New
westwards and and
York northeastwards; however,
Jersey best
it is
represented in the southeastern United States. Here, there one widespread
is
C C
and abundant which somewhat
species, unijlora, variable, plus the local
is
hrittonii (perhaps the same as rhodella of western North Carolina). Several
C.
C
names have been synonymised with
of the that unijlora nevertheless repre-
SIDA 423-445. 2006
22(1):
424 BR1T.ORG/SIDA
22(1)
comment
nodes and
sent distinct of variation these will receive explicit here.
C
Forms such as Xvailiae and related types, however, appear to represent
C
hybrids with calpodendron Macracanthae) but
interserial (series are treated
here convenience.
for
The primary function of this paper to provide a taxonomic revision that
is
illustrates the variation within series Parvifoliae and putative interserial
its
manner
hybrids in a synoptic Crataegus unijlora has often been illustrated
C
but more variant forms have not, as with hrittonh, and both are illustrated
its
C
x None
hybrid
here as well as the putative interserial vailiae. of the taxa rec-
C
maps
ognized in this paper, even uniflora, have ever received detailed range
maps
While raw
so far as can be determined. the information to create dot did
exist in our database, the scale of work necessary to provide each specimen with
mapping coordinates precluded such an ideal approach and instead, county
its
An
maps, refined so as to indicate record frequency were made. appendix lists
A
one representative specimen per county. key taxa recognized here
to all is
The and synonyms
also provided. taxa recognized their are typified so far as
Ashe names
possible. However, lack of lectotypifiable material for the involved
has caused familiar difficulties for the typification of his names. In the cases
was
encountered here, resolution through neotypification not, however, adopted
making would
because of the arbitrary aspect of type choices that correctly
match The with rhoddla
critically defective protologues. situation (discussed
C.
on 433) perfectly exmplifies Fortunately, although Ashe names consti-
this.
p.
tute the majority in series Parvifoliae, the variation encountered in the
exsiccatae and material seen could be accommodated within the names
iield all
of other authors. The synonymy provided based on names encountered in
is
commence
Palmer (1925). The paper will with a description of the series, fol-
low with and on
descriptions of the constituent taxa close the putative interserial
hybrids.
made
This work has been possible by loans of over 1200 specimens from
43 herbaria and the first author has endeavored to see and collect representa-
exemplars 20
tive in the field of all the taxa treated in the course of over field
trips to the southeastern United States. However, the rarer forms, which appar-
ently have always been rare, were never encountered in fieldwork, and possibly
UWO.
no longer exist. The database of specimens held at The taxonomic de-
is
made
cisions have been by the author and the second author (K.D.)
first
(J.B.P.)
has been responsible creating the distribution maps.
for
The and
ultimate resolution of variation in series Parvifoliae putative
its
interserial hybrids invites a further generation of work in which extensive popu-
supported by chromosome morphometric
lation studies are counts,
critical
The
analysis as well as molecular studies. revisionary treatment presented here
thus erects the platform for such work.
PHIPPS AND DVORSKY, CRATAEGUS SERIES PARVIFOLIAE AND PUTATIVE HYBRIDS
ITS 425
TAXONOMIC TREATMENT
series Parvifoliae (Loudon) Rehder, Man. Cult. Trees Shrubs, 2nd ed.l940.
Sect.
Parvijoliae Loudon, Arbor, ct Frutic. Brit. 2. 1838. Group without rank Uniflorae Beadle, nom.
nud. Biltmore Bot. Stud. 1:117. 1902. Type SPECIES: C. uniflora Muenchh.
±
Small, xeromorphic shrubs with fine straight thorns. Leaves deciduous; usu-
ally nearly epetiolate, petioles glandular or eglandular; blades small, longer than
and
broad, entire, often with conspicuous black glands on the tips of the teeth;
unlobed shallowly margins ±
to lobed; crenate or crenate-serrate; pubescent,
coriaceous. Inflorescences 1-few flowered, bracteolate, the bracteoles small, ca-
membranous
ducous, linear, gland-margined, to thinly herbaceous. Flowers 10-
mm
hypanthium
18 diam.; externally dense-tomentose; calyx-lobes
foliaceous,
us. glandular-serrate, often deeply so, as long as to somew^hat longer than the
±
petals; petals circular, white; stamens 20, anthers us. ivory to cream; styles us.
mm
up ±
Fruit to 12 diam., orbicular, quite hairy yellowish ruddy;
5. us. to ca-
lyx-lobes conspicuous, patent, glandular-serrate, often deeply nutlets 4-5,
so;
dorsally grooved, sides plane.
This is a small series confined to North America. consists mostly of one
It
C
somewhat common
variable species, uniflora, widespread and often in the
coastal plain from Texas to Long Island (N.Y.) with outliers further inland and
much
in Tamaulipas, Mexico. There is also a second, rarer species, C. hrittonii,
from North and
Carolina adjacent In addition there are three dubiously
states.
C
placed croomiana, and
entities, C. C.grossiserrata choriophylla that will re-
ceive brief discussion. Of the 15 names assigned by Palmer (1925) to series
may
group
Parvifoliae (as natural Uniflorae), one, choriophylla, not belong
C.
and
is therefore only treated briefly here. This is a very rare and probably ex-
Florida endemic with
tinct tree distinctly petiolate, thin, strongly toothed, of-
ten slightly lobed leaves, 3-5 flowered inflorescences, cream anthers and or-
C
ange-red Sargent doubted
fruit. (1922) that choriophylla really belongs in
am
doubt which which
series Parvifoliae, a endorsing, in case a rare local
I it is
species or hybrid. Crataegus Xvailiae, a putative interserial hybrid with series
Macracanthae, is treated here for convenience, on account of its foliaceous ca-
lyx-lobes.
Small rather glandular small ± unlobed
stature, plants, often
leaves,
±
unif lorous inflorescences, rather small flowers, foliaceous calyx-lobes as long
as or longer than the petals and normally non-anthocyanic anthers, are fea-
may
Anther
tures that characterize this series. color in practice be described as
white, ivory or cream, representing both degree of precision in observation and
some
natural
variation.
perhaps most and
Series Parvifoliae is closely related to series Triflorae, at
some
least in specimens, shares the characteristic that flowering shoots are leafy
shoots of the season and not permanent woody short shoots. However, the plant
BRlT.ORG/SiDA
22(1)
426
C
much
parts are so smaller than those of irijlora. that even casual confusion
members Lacrimatae
not actually with smaller of series that
possible.
is It is
Members medium-sized
confusion most frequent. of both series are small to
is
xeromorphs that are rather glandular, often hairy and often have yellowish fruit.
may
Lacri matae, however, be immediately distinguished by their zigzag
Series
much
and and
non-foliaceous calyx-lobes shorter than petals fewer styles
twigs,
nutlets.
KEY TO
SPECIES
m
±
Plants often only 1-2 leaf-blades elliptic. 1.6:1 or narrower, unlobed; an-
tall;
1.
___^^
l.C.uniflora
white cream
thers to
m
3-4 broad-ovate broad-obovate, or
ants at maturity; leaf-blades or 1.3:1
tall
though sometimes only shallowly, lobed;
broader, larger leaves usually distinctly,
anthers anthocyanic or not.
smooth
margins 2.C. brittonii
Lobes of leaves obtuse; crenate; sides of nutlets
2.
Lobes of leaves sharper; margins with sharp, distinct teeth; sides of nutlets
2.
Xvailiae
eroded C.
C
Du
non umjlora
Muenchh., Der Hausvater
Crataegus uniflora 5:147. 1770;
1.
Der Harbkesche Baumzucht,
Roi, ed. 1:184. 1771. (Figs. 1, 2, 3, 4, 7). tvph:
SW
U.S.A. GnoRGiA. Crawford Co.: ca. 2 mi of Roberta, 13 Apr 2006 J.R Ph ipps 9060 (nf.OTYPE
UWO.
designated here: iSONrOTYPES: A, BRIT, GA, MO, NCU, US). Mucnchhausens original
material would be at LINN according to TL-2 but none could be located of this species.
Kew iomentosaUim'
Crataegus parvijolia Alton, Hort. 2:169. 1789. Tvpi:: Specimen labeled 'C
with 'iomcntosa crossed out; no further information except a 'type" label (lectotype desig-
nated here: Banksian Herb., BM).
Loudon herbarium
Crataegus parvijolia var./lDritia Loudon, Arbor. Frut. Brit. 2:842 (no exists
and this variety has not been ncotypified; see discussion).
Loudon
Crataegus pafvifoliavdr. grossulanacjolla Loudon, Arbor. Frut. Bnt, 2:842 (this variety
has also not been neotypilied; see discussion).
Crataegus hisulcata Ashe, Bull. North Carolina Exp. Stn. 175:112. 1900.
?
Crataegus carla Ashe, Bull. North Carolina Exp. Stn. 175:112. 1900.
Crataegus grossiserrata Ashe. Bull. North Carolina Exp. Stn. 175:112. 1900.
Crataegus raJcighcnsis Ashe, Bull, North Carolina Exp. Stn. 175:112. 1900.
Alabama. Marsludl
Crataegus arnienlahs Beadle, Biltmore Bot. Stud. 1:117. 1902. TYPE: U.S.A. Co.:
near Albertville, no date, TO. Harbison 3281, fruiting specimen (lectotype designated here:
US).
North Carolina. Buncombe
Crataegusgrcgalis Beadle, Bilrmore Bot. Stud. 18. 1902. Type: U.S.A.
1:1
(lectotype
Co.: flats of French Broad River, 18 Sep 1900, Biltmore Herb. 1270b, in parr desig-
US
nated here: 969361).
Crataegus penlaneura AsheJ. Elislia Mitchell Sci. Soc. 19:12. 1903.
&
Lownes
CrcUtu-gu^s^Hi/ZiiiSarg., Trees Shrubs 2:67. 1903. Type: U.S.A. Pennsylvania. Delaware Co.:
Run, Springfield, 21 May 1902, B.K Smith 201 (lectotype designated here: A).
&
Shannon
Shrubs MiSSOURL near
Crataegus [rituitJiophoraSarg., Trees 1.1907. Type: U.S.A. Co.;
2:1
Grandin, (lectotype to be designated by Phipps et in press).
al.,
USA
Crataegus croomiana Sarg.J. Arnold Arbor. 3:202. 1922, Type: Florida. Leon Co.: near
?
Tallahassee, 15 Apr 1920, T.G. Harbison 5710 (holotype: A).
PHIPPS AND DVORSKY, CRATAEGUS SERIES PARVIFOLIAE AND ITS PUTATIVE HYBRIDS 427
Fig. 1. Typical leaf form in Crataegus uniflora. Fruiting specimen, fruit details and leaf magnifications from Smith 1350
=
(MO, UWO); flowering shoot and flower details from Sherman 214 (TENN). S. Laurie-Bourque del.; scale bars T cm.
428
BRIT.ORG/SIDA
22(1)
Fig. 2. Young shoots of Crataegus uniflora clearly illustrating developing thorns, which possess bract-like appendages;
=
Chapman
from s.n. (US). S. Laurie-Bourque del.; scale bars 1 cm.
PHIPPS AND DVORSKY, CRATAEGUS SERIES PARVIFOLIAE AND ITS PUTATIVE HYBRIDS 429
Fig. 3. Parvifolia- or trianthophora-Wke form of C. unifJora showing several-flowered inflorescence form with pointed
=
leaves; from Mu/r/V/Z (MO). S. Laurie-Bourque del.; scale bars 1 cm.
m m
commonly
Shrubs, us. under 2 tall at maturity, less to 3 and occasionally
reaching 5 m; extending shoots densely appressed-pubescent; one-year old twigs
cm
±
brown, older grayish; thorns 3-5(-8) long, usually plentiful, straight,
young commencing
needle-like, occasionally absent, black at yr old; thorns
1
as rapidly growing, needle-pointed-shoots with small linear bracts, often
soft,
curved at first and then straightening out (Fig. 2). Leaves deciduous; petioles
cm
very short to lacking, glandular or not; blades (l-)L5-3(-6) long, narrow-
narrowly
obtrullate, spatulate, oblanceolate or rhomb-elliptic,
elliptic, elliptic,
occasionally suborbiculate; cuneate at the base, obtuse to broadly acute at the
margins crenate dentate, with variably caducous black gland-
tip; entire; to
tipped teeth though sometimes eglandular even young; venation semi-
— — — —
430 BR1T.ORG/SI0A
22(1)
Fig. 4. Various morphotypes of Crataegus uniflora sens, fat., showing variation in thorns and leaf-shape as well as lobed
leaves with veins to sinuses on extension shoots. From left: somewhat broad-leaved form Phipps 7677 (UWO); pos-
C C
sible arenkola form Shinners 12651 (GA); croomiana form MurrHlin FLAS 34624; grossiserrata form with two
=
extension shoot leaves top right Bozeman 7188 (NCU). S. Laurie-Bourque del.; scale bars 1 cm.
PHIPPS AND DVORSKY, CRATAEGUS SERIES PARVIFOLIAE AND PUTATIVE HYBRIDS
ITS 431
camptodromous, ±
lateral veins 3-4(-5) per impressed; densely scabrous-
side,
when
±
pubescent above especially young, below densely pubescent on
the
veins, thinly to moderately pubescent on the surface; often somewhat glossy
±
above maturity
at coriaceous. Inflorescences l-3(~5) flowered; pedicels pu-
bescent, bearing one or two small, caducous, membranous herba-
us. linear, to
mm
ceous, gland-margined Flowers 10-15 hypanthium
bracteoles. diam.;
strongly tomentose externally sometimes bearing membranous herbaceous,
a to
linear, caducous, gland-margined bracteole; calyx-lobes us. longer than the pet-
mm
2-4 ± ±
wide, foliaceous, narrowly triangular, deeply glandular-ser-
als,
rate except in rare aberrant forms, thinly pubescent on both ±
sides; petals cir-
cular, white; stamens 20, anthers white to cream, except in rare, possible
mm
±
interserial hybids; styles Fruit 8-10(~12) orbicular, tomentose, yel-
5. tall,
low-green, yellow, or yellow orange to ruddy; flesh firm, dry or mealy; calyx-
mm
lobes to ca. 7 long, persistent, conspicuous, patent; nutlets 4-5, dorsally
furrowed, smooth.
laterally
Common
name.—
One-flowered hawthorn.
Distribution—This widespread
species in the southeastern part of the
is
United States (Fig. 7) from Long Island (New York) to eastern Texas with an
Tamaulipas Oklahoma,
outlier in (Mexico). Inland reaches the line Missouri,
it
southern Ohio, West There remarkable
Virginia. a disjunction in the Missis-
is
embayment
between and
sippi trans-Mississippian cis-Mississipian populations
that mirrors a similar pattern in C. spathulata (Phipps 1998). Crataegus unijlora
usually found in sand barrens and open scrubby woodland.
is
Crataegus unijlora should be easy to identify on account of small
its size,
unusually
large sepals (relative to the petals), unif lorous or few-flowered inflo-
rescences and yellowish to ruddy However, has sometimes been con-
fruit.
it
fused with some members of series Lacrimatae which include similar sized
xeromorphs,
also of sand-plains of the southeastern United States as ampli-
is
fied under the series discussion. Sterile plants can most easily be distinguished
&
C
from
small, sterile plants of berberifolia Torrey A. Gray, a superficially
member
number
similar of series Crus-galli, by the smaller of lateral veins on
An
the leaves. interesting feature of this species the occasional deep lobing of
is
extension-shoot leaves, even narrow ones, with veins to sinuses. The United
Champion
National from
States of unijlora in 1998, Gainesville, Florida,
C.
measured an unusually
18 ft tall in 1992, great stature for this species,
common
somewhat
Crataegus unijlora variable as befits a species, in
is
plant size, precise leaf shape (when strikingly obtrullate with acute tip or when
number
suborbiculate presenting an
a quite different facies), of flowers to in-
and
florescence (usually one), anther color (usually ivory to cream). Hov/ever,
names
under which
15 specific listed series Parvijoliac (Palmer 1925), 11 of are
may
accounted and some
for in this paper, attest to this variation in cases repre-
we
sent perhaps apomictic, microspecies perhaps
valid, or, as shall see, interserial
BR1T.ORG/5IDA
432 22(1)
hybrids. Crataegus unijlora had never hitherto been typified perhaps partly
because the protologue unusually diagnostic for one of the period on
is
C
Crataegus. The protologue clearly represents unijlora as construed here. have
I
common
and small
thus neotypified on regard as the v^idespread form: a
v^^hat
I
numer-
± obovate usually
shrub, with coriaceous, spatulate to narrovv^ leaves,
ous fine straight thorns, 1-2 flowered inflorescences, glandular-pectinate se-
Among
anthers white to cream and yellows-green to yellow-orange fruit.
pals,
C
group are some particularly dw^arf forms of unijlora from laterites in
this
when
Georgia have been observed with over one hundred flowers less than
that
m
0.3
tall.
There are two main kinds of deviation from the above norm, firstly, a group
where multi (3-6)Tlowered inflorescences occur and second, odd forms very
We
like the putatively typical group but with often small and unlobed sepals.
will deal with the multiflow^ered types The most striking of those that
first.
C C
can confidently be included unijlora parvijolia Alton, lectotypified
in
is
A
type wTth 2-6 flowered inflorescences. similar form
above, C.
is
its
Faxon
irianthophora, nicely illustrated by in Sargent's protologue, scattered
C
through the range of the species and being the main form of unjlora in Mis-
Multif low^ered forms such as parvjolia and ria nthophora represent one
souri.
t
extreme of variation in the u n ijlora complex but the existence of two- and three-
on some makes any recogntion dubi-
flowered inflorescences plants varietal
ous Generally forms with multif lowered inflorescences have larger
at this point.
C
with
and broader leaves than unijlora but this not the case the
relatively
is
complex. Multiflowered specimens with broad and slightly lobed
parvijolia
C
leaves and unpitted nutlets are however, assigned to hrittomi.
C
The other main kind of variation exemplified by croomiana (Figs.
is 4,
whose type comes from Tallahassee, Florida, and wdiich has the distinction
9),
Out
of pink anthers and entire to merely glandular-serrate calyx-lobes. of the
UWO
complex
approximately 1200 specimens of the unijlo ra that in the data-
have ± calyx-lobes and come from the northern Florida coun-
base, ten entire
Alachua, Gadsden, Leon and Liberty The foliage and non-geniculate
of
ties
C
may
These specimens be
twigs nevertheless, quite typical for unijlora.
are,
part of the variation that MurriU (1942) noticed. Further investigation is re-
quired whether croomiana, plus perhaps some other names, should be
to see C.
members
upheld, possibly as sporadic interserial hybrids wath of series
Lacri matae. Crataegus bisulcata from North Carolina has similar calices though
C
from
'rounder leaves while the striking grossiserrata (Fig. 4) wnth a type
Tlorida' (no location) also has similar calyx-lobes, though often orbicular (un-
m
and and sharp
usual extension shoot leaves particularly strong
this series)
A
tendency deep
leaf-teeth. feature of these broad, extension-shoot leaves is a to
sometimes with populations such forms could be
lobing, veins to sinuses. of
If