Table Of ContentTREATMENT
A SYSTEMATIC
Jawad,^ David
Jennifer Seigler,^
T. 5,
and
John
OF ACACIA COULTERI E. Ebinger"^
(FABACEAE, MIMOSOIDEAE)
AND
SIMILAR SPECIES
IN
NEW
THE WORLD'
Abstract
Detailfd ilcscrI[)lions, lial)ital preferences, geographic ranges, and representative specimens are given for the 13 laxa
of the Acacia coullcri group from Mexico, Central America, and the southwestern United States. These species form a
distinct group within Acacia series Vulgares, lacking prickles and usually having persistent stipules. A principal com-
ponents analysis (PCA) of vegetative and floral features shows that the specimens examined fonn discrete units in plots
PCA
of the three principal components. The groups estabHshed by mostly coincide with previously described
first
species. The taxa within this group are phenetically similar, sharing many morphological features. These data also
suggest that there is occasional gene flow between species, but that hybrids are not common. About half the species
have restricted ranges {A, comparta, A. dolichostachya, A. durangemis, A. millefolia, A, russelliana, A. sericea, and A.
willardiana), but the remainder are wide-ranging, either from Oaxaca and Puebla north into central and northern Mexico
{A. acailerisis, A. coulteri, A. rnammifera, and A. salazari), or soutli into Central America centralis and usiima-
(-4. ,4.
cinleri^is).
Key words: Acacia coulteri group, Acacia series Vulgares, Fabaceae, phytogeography, principal components analysis,
species delineation, hybridization.
Acacia Miller series Vulgares Benth. (Fabaceae: numerous pairs of pinnae and Peduncles
leaflets.
Mimosoideae), consists of about 200 species dis- are solitary, or in racemose clusters, from the leaf
tributed in tropical and subtropical wet to dry hab- axils, and flowers form globose heads or cylindrical
New
ilats, in both the Old and Worlds. Series Vul- spikes. Legumes of series Vulgares are relatively
gares broadly corresponds to subgenus Aculeiferum large, strongly flattened, usually dehiscent, and
Vassal (1972), according to Pedley (1978). Later, with a single row of relatively large seeds. This se-
Pedley (1986) suggested that this subgenus should ries is often separated from two other i4cacia series,
name
be elevated to generic status under the Se- Gummiferae and Filicirme, by the presence of
More
negalia Raf. recent systematic studies suggest prickles that are scattered along the stems and
may
that Acacia series Vulgares not represent a sometimes the leaf rachises (Bentham, 1875).
&
monophyletic group (Chappill Maslin, 1995; Acacia series Vulgares can be divided into sev-
Clarke, 1995). eral informal "species groups" based on
overall
Most species oi Acacia series Vulgares are of di- similarities of habit, stipule persistence, the pres-
verse habitat, habit, morphology, and chemistry. ence or of prickles, petiolar gland shape
abi:
Most are shrubs or small trees, though some are and structure, as well as inflorescence shape. At
tree-lianas, with branches scrambling over other present, however, these informal groups within the
vegetation. Most species are armed with prickles series have not been established be monophy-
to
on the stems, leaf petioles, and rachises. Leaves are letic units. The taxa of one of these groups of phe-
compound
bipinnately with deciduous stipules, and netically similar species, "the Acacia coulteri
We BSR
acknowledge support by the National Science Foundation (NSF 82-LS274 and NSF-PCM-82-17114),
the
'
United States Department of Agriculture (OICD r>H-3I9R-0-()ll), the American Philosophical Society (DSS 1992), the
University of Illinois Resean^i Board (1994), and the Rupert Barrieby Award by the New York Botanical Garden
for
DSS We
many
in 1997. also ihank the curators of the herbaria that sent specimens, and Lourdes Rico and Mario Sousa
for making manuscripts of unpublished work available. Jennifer Jawad gratefully acknowledges su[)porl as an under-
graduate intern by the Howard Hughes Foundation. The assistance of David Clarke, Kurt Polgieter, Karin Readel,
Catherine Glass, and Claudio Gratlon with field portions of the research greatly appreciated. The comments and
is
positive criticism of Richard Sp<*llenberg and an anonynions reviewer are much appreciated.
Marine
2 Virginia Institute of Science, Gloucester Point, Virginia 23062, U.S.A.
^Department
of Plant Biology, University of Illinois, Urbana, Illinois 61801, U.S.A.; author for correspondence,
[email protected].
Emeritus Fastem
* Professor of Botany. Illinois University, Charleston, Illinois 61^20, U.S.A.
Ann. Missoljhi Bot. Gahd. 87: 528-548. 2000.
Volume Number 4 Jawad
529
87.
et
al.
2000
Acacia Group
coulteri
&
group" (Maslin Stirton, 1997), are erect shrubs with which species of the A, coulteri group are eas-
and
or small trees with persistent stipules flowers confused macilenta Rose, Often, herbarium
ily is^l.
in cylindrical spikes. Except for minor differences specimens of this last species lack prickles, and
and
in flower size occasionally pubescence, flowers those specimens that lack prickles are superficially
and some members
are quite similar, with a tubular calyx corolla, similar to of the A. coulteri group,
each 5-lobed, numerous separate stamens, and a Their separation straightforward, however, as A.
is
The
short-stalked pistil. 13 species of the A, caul- macilenta has petioles that are consistently less
mm
teri group range from Arizona, south through Mex- than 25 long, and the single petiolar gland
is
They
ico into Costa Rica. are morphologically dis- dark brown and shallowly volcano-shaped. In large-
tinct from other species of Acacia series Vulgares leaved species of the A. coulteri group with which
in that they always lack prickles, are never lianas, A. macilenta might be confused, the petioles exceed
mm
and by a number of other features. Nonetheless, 25 in length and have petiolar glands that are
taxonomic treatments have not dealt with this group light green or yellow and not volcano-shaped.
as a separate unit within the Acacia series Vulgares Concepts and identification of taxa of the ^, caul-
&
(Bentham, 1875; Standley, 1920; Britton Rose, teri group have been unclear in the past. No func-
1928) tional keys that permit accurate identification of
Many
sterile and fruiting specimens of species these taxa have been published. Surprisingly, in
of the A. coulteri group have been misidentified, most herbaria, up to half the specimens of this
adding to the taxonomic confusion. Flowering spec- group of species were misidentified. Further, a cla-
imens oiAlbizia, Lysiloma, and Piptadenia can eas- distic analysis based on molecular data from chlo-
ily be distinguished from spicate species discussed roplast restriction site analyses (Clarke, 1995), and
in this work. In contrast to the A. coulteri group; cladistic analyses by Catherine Glass and David
S.
Albizia and Lysiloma have capitate inflorescences. Seigler based on morphological data (unpublished)
Although inflorescences of Piptadenia species are suggest a more ancient origin of these taxa than
spicate, these flowers have 10 stamens with strap- other species oi Acacia series Vulgares. Otherwise,
like filaments and oblong anthers that are larger there are no comprehensive studies on the phylo-
than those of i4cacia. Stamen filaments of flowering genetic relationships of the Acacia coulteri group,
specimens of A/feizta and Ly^i/oma have stamens of The present study was undertaken to clarify the
about the number and size as those in Acacia^ taxonomic status and discreteness of the taxa in-
but the filaments are united into a distinct tube. volved, as well as to provide accurate descriptions
Capitate species are normally evident, even in fruit- of and functional keys to these species,
ing condition. Most fruiting specimens of Piptad-
enia can be recognized by stamen remnants
the
at Matkkials AND Methods
base of the strongly venose appear
fruits; its fruits
distinct from those of Acacia species, especially About 500 Acacia specimens, obtained from 27
if
comparative material available. Careful search of herbaria (A, ARIZ, ASU, BM, BR, CM, DS, EIU,
is
most Piptadenia specimens reveals the presence of F, G, GH, ILL, ISC, LL, MEXU, MIN, MO, MU,
POM,
prickles, which are completely absent from NY, RSA, SD, TEX, UC, US, VT, WIS), were
all
members
of the A. coulteri group, as well as from studied to determine the geographic ranges and
members of the genera Albizia and Lysiloma. Two morphological variation of the species in the A,
spicate species of the latter genus, L. acapulcense coulteri group. These specimens were initially sep-
mem-
and L. auritum, are sometimes confused with arated into groups based on the similarity of mor-
bers of the A, coulteri group. For these two species, phological characteristics. After removal of dupli-
the two parallel sutural ribs are fused around the cate and incomplete specimens, only 15 25
to
periphery of the pod; these ribs often separate from specimens of most groups remained available for
&
(Bameby
the valves Grimes, 1996). Vegetative subsequent analysis. Only unambiguous specimens
may
specimens of al Lysiloma species be con- were scored and are indicated in the exsiccatae by
fused with Acacia species of this group. Some Lys- an asterisk. Of the original specimen pool, 237
iloma species have cordate-auriculale stipules (at were d for 1 floral and 14 vegetative charac-
least on young branches) that are never found on ters (Table All characters were measured
for
1).
the species treated in this work. Finally, vegetative each specimen (three or more measurements) and
specimens oi Albizia usually can be differentiated plotted to confirm that gaps existed in order to per-
by the palmate/pinnate venation present in the leaf- mit the use of scored characters. The data were
&
(Bameby
lets Grimes, 1996). then analyzed by principal components analysis
The member
only other o[ Acacia series Vulgares (PCA) using NTSYS-pc version 1.70 (Rohlf, 1993)
530 Annals
the
of
Garden
Missouri Botanical
compo- components
Tahle 1. (Uiararlers scored for the princi[)al Table 2. Principal for the ()ata set for ihe
nent analysis of the 13 species of the Acacia couUeri Acacia couheri gro—up
group,
Component number
Character
= =
Bark of trunk not exfoliating, 2 exfoliating).
1, (1 number
2 3
1
= =
Petiole pubescence glabrous or nearly 2
2. so,
(1
= 0.704 0.113 0.203
puberulcnt with oppressed hairs, 3 woolly pubescent). 1
=
= 2 -0.638 -0.033 0.678
0-10 mm, 10-99 mm,
Petiole length 2 3
3.
(1
= >99 3 0.698 -0.244 0.008
mm).
4 -0.651 -0,010 0.526
4. Small purple glands on petiole, rachis, and pinnae
= = 5 0.396 0.782 0.250
rachises absent, 2 present).
(1
= ~ 6 0.352 0.810 0.435
5. Petiole gland structure (1 sessile, 2 stalked, 3
= -0.446 0.428 -0.272
7
absent).
= 8 -0.139 0.564 -0.400
6. Petiole gland apex flattened, 2 loughnut-
(1
= = 9 0.744 -0.144 0.024
shaped, 3 globose, 4 absent).
= = >20 10 0.427 -0.444 0.580
1—20 mm,
Rachis length absent, 2 3
7.
(1
-0.280 -0.189 -0.761
11
mm).
= = 12 0.356 -0.368 0.353
Number
of pinna 2 7 or more).
8. ]>airs to 6,
(1 1
= 13 0.469 0.545 -0.188
mm, >2.4 mm).
Petiolule length 2.4 2
9.
(1
=
(1=5
= 14 0.404 0.394 0.441
<|.5 mm,
10. Distance between leaflets 2 1.5
-0.773
15 0.006 0.180
mm).
=
Number <36,
11. of leaflet pairs per pinna 2
(1 Percent of variance 28.2 17.0 17.2
>36).
= =
12. Leaflet length 4-36 mm, 2 >36-65 mm).
(1
~
13. Leaflet apex obtuse to broadly acute, 2 nar-
(1
rowly acute acuminate). 63%
to
The
lively, or of total variance (Tables 1, 2).
—
=
14. Leaflet pubescence glabrous or nearly so, 2
(1
amount of variance contributed by the remaining
=
pubescent with appressed hairs beneath, 3 pubescent
components diminished slowly from the third prin-
=
with ajijiressed hairs on both surfaces, 4 long hairs
cipal component onward. The best perspective for
clustered the base of midril) beneath).
at
was
= = display of the phenetic groupings in the
15. Perianth [)ubescence glabrous or nearly so, 2 s
(1
= ordination based on the second and third principal
pubescent with appressed 3 woolly pubescent).
hairs,
components (Fig. 1). This figure presents all taxa,
clearly resolved in one view. In this plot, 13 distinct
groups, corresponding the 13 previously defined
to
Data were transformed by a square root transfor-
species can be observed, although the data clusters
&
mation (Sokal 1969). Groups were ana-
Rolilf,
some
of groups are proximal. Perianth pubescence,
lyzed separately, in various combinations^ and si-
petiolule length, and exfoliating bark (characters
multaneously.
were most
15, 9, the important characters for
1)
Because cyanogenesis has previously been found
determining component
the score for the prin-
first
many
in Acacia species, and sometimes useful
is
component
cipal axis (Table Petiolar gland apex,
& 1).
taxonomically (Seigler Ebinger, 1988, 1995;
number
petiolar gland structure, and the of pinna
Clarke 1989, specimens were
et al. 1990), all test-
pairs (characters 6, 5, 8) were most important for
compounds
ed for the presence of cyanogenic by
the second principal component axis. The most im-
&
method
the Feigl-Anger (Feigl Anger, 1966; Tan-
compo-
portant characters for the third principal
tisewie et al., Seigler et al. (1978) reported
1969J.
nent axis were leaflet pairs per pinna, petiole pu-
few herbarium specimens
a of acatlensis that re-
^4.
bescence, and the distance between
leaflets
Conn
and
leased cyanide, et al. (1989) reported
(characters 11,
2, 10).
weakly cyanide both
positive tests for A. acatlensis
The
clusters on this plot do not contain recog-
and A. couheri using fresh, air-dried leaf material.
nizable subgroups, and, except for usutnacinten-
/I.
During the present study, no material examined
and A. dolichostachya, which nearly overlap on
sLs
gave a positive-test for cyanide, even after the ad-
this plot, each of the clusters clearly separated
is
dition of emulsin.
OTUs
from
the others (Fig. In addition, the of
1).
each group are closely spaced, indicating that the
Results and Discussion
species are homogeneous.
When
the entire set of 237 specimens was ana- In addition to those herbarium specimens bor-
PCA, compo-
lyzed using the three principal rowed, the present treatment also based on ex-
first is
17%
nents accounted for 28%, 18%, and respec- tensive collections and observations of these taxa
Volume Number 4 Jawad
87, et 531
al.
2000
Acacia Group
coulteri
-1.0
0.5 0.0 0.5 1.0
I I I I
I
.
1.0-
mammifera
Q
durangensis
A.
0.5
sericea
o-
compacta
willardiana
A.
coulteri
A.
salazari
A.
0.0
millefol
A.
russelliana
dol ichostachva
A.
centralis
-0.5
acatlensis
A.
usumacintensis
A,
A
X
I
s
3
1.0-
I I I I I
. .
-1.0 AXIS -0.5 0.0 0.5 1.0
2
Figure 1. Plot of axis 2 versus 3 of a principal connxjru'nts analysis, using one floral and 14 vegetative variables
frou) 237 specimens of the Acacia coulteri group.
PCAs
in Mexico and Central America by one of the au- the are included in the Hst of representative
thors (DSS) on 15 trips during 1975—1998. Only specimens (designated by an asterisk after the her-
the most reliable, diagnostic characteristics were barium abbreviation). Synonyms and types are in-
maps
sed to distinguish the taxa. Although floral char- eluded, along with showing the geographic
were measured and each
acteristics carefully, are in- distribution of species (Figs. 2, 3).
eluded in the descriptions, flower variation and Occasionally, a few flowering specimens lack
character overlap precludes using them for distin- leaves, or have extremely small leaves, making
it
number
guishing species. Extensive lists of representative difficult to determine the of leaflets per
specimens are included, as specimens are com- pinna and the number of pinnae per Even with
leaf.
number
monly misidentified. Also, all specimens used in these specimens, the of pinnae per leaf of-
i
532 Annals
the
of
Garden
Missouri Botanical
Acacia acatlensis
Acacfa centralis
Acacia dolichostachya
Acacia
sericea
X
+
Acacia
usumacintensis
Figure 2. Distribution of Acacia acatlensis, A. centralis, A. dolichostachya, sericea, and A. iisuniaciniensis in
/t.
Mexico, Belize, and (/uaternala. The distribution of centralis in the rest of Central America not sliown.
.1. is
ten can be detcnnincd from small emerging leaves, are only lightly appressed pubescent, whereas, in
number
or by counting the of pinna scars on an old the latter, the calyx, corolla, and floral brads are
may
rachis that be present. In excess of 500 spec- densely sericeous pubescent. Two other species
were examined in this study and lew lacked have these small purple glands and occur within
5
leaves altogether. Most of these were either Acacia the same geographic range. Acacici compacta a
is
acatlensis or A, sericea. Minute purple glands on small shrub with short shoots, and A. mammifera
the young stems and peduncles of both taxa distin- a small tree with flowers that have -colored
is
them
guish from other meml)ers of this group of corollas with a purplish tinge. However, these are
species. Acacia acatlensis is then separated from only uncommonly found in flowering condition
.4,
because and
sericea the former's calyx floral bracts without leaves.
KvA Spkciks
i()
more
la. PirnuH^ mostly willi than pairs of leaflets, especially those near the middle of the rachis.
'.\U
2a. Peliolar glan<l(s) flattenetl. usually located on the lower third of tiie petiole; leaflet apex obtuse to broadly
aiule.
mm
3a. Leaflets 1.2-1.9 wide; leaves with more than 6 pairs of pitniae A, usuniacintensis
1.
mm
31). Leaflets mostly less than 1.2 wide; most leaves with 6 or fewer pairs of pinnae
- " dolichostachya
2.
.4.
21). Petiolar gland(s) saucer-shaped to cu[)-shaped. usuallv located on the upper half of the petiole, rarely
apex
absent; narrowly acute acuminate.
leaflet to
common
4a. Minute purple glands at the base of the leaflets and usually along the rachis; leaflets
lacking long hairs on the lower side at the base 3. A. acatlensis
Minute
4b. purple glantls absent; leaflets usually with long hairs on the lower side th—e base
at
-
4. A. centralis
lb. Pinna** mostly widi fewer than .36 pairs of leafl(Ms, or pinnae absent.
mm
5a. Leaves less than 30 long, some clustered on short shoots compacta
5.
.4.
mm
5b. Leaves more duiti 30 long; short shoots absent: j»iimae sometimes absent Acacia willanliana.
in
6a. Leaflets appressed to erect pubescent on both surfaces, usually densely so; minute purple f^lands
common
on the rachis and pintia raehises.
7a. Petiole aitd rachis densely pubescent with erect hairs about 0.3 nmi long; petiolules less
than 2.1 nun long; fruit pubescent 6. A. sericea
mm
7b. Petiole and rachis glabrous or with short, appressed hairs; petiolules more than 2.0
long; glabrous.
fruit
Volume Number 4 Jawad
87, 533
et
al.
2000
Acacia Group
coulteri
Acacia
compacta
Acacia coulten"
Acacia
durangensis
it Acacia mammifera
Acacia
millefolia
Acacia
russelliana
Acacia
salazari
Acacia willardiana
Figure 3. Distribution of Acacia compacta, coalleri, A. (lurangensis, A. mammifera, A. millefolia, A. riLsselUana,
/I.
and
A, salazari, A, williardiana in the U.S.A., Mexico, Belize, and Guatemala.
8a. Petiolar glands raised, the apex bulbous; most leaves with fewer than 7 pairs of
pinnae
mammifera
7. A.
^
8b. Petiolar glands sessile and widi an irregularly raised apex; most leaves with more than
10 pinnae
pairs of durangensis
R.
,4.
6b. Leaflets glabrous or lightly appressed pubescent beneath; miimte purple glands absent.
mm
9a. Leaves mostly with a single pair of pinnae (rarely 2 or many petioles more 100
3); tlian
long
uitlardiana
9. A.
mm
9b. Leaves mostly with 4 or more pairs of pinnae; petioles less than 70 long.
m
10a. Rachis gland between the upper pinna pair stalked; shrub or small Iree less than 4
10.4.
tall millefolia
10b. Raehis gland between the upper pinna pair sessile, usually saucer-shaped, cup-shaped,
m
or absent; large shrub or more than 4
tree;
tail.
11a. Bark of tmnk and larger branches exfoliating and papery; petiolar glands absent
many
on apex acuminate
petioles; leaflet 11. salazari
/I.
lib. Bark of trunk and larger branches smooth to furrowed, not exfoliating; petiolar
glands present; leaflet apex broadly acute to obtuse.
12a. Leaflets appressed pubescent beneath; rachis and pinna rachises puberulent
above; perianth pubescent
12. A. coulteri
12b. Leaflets glabrous beneath; rachis and pinna rachises as well as perianth
glabrous or nearly so 13. A. russelliana
534 Annals
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Missouri Botanical
I
B
— — —
mam-
Figure 4. Peliolar glands. A. Acacia durangcfKsls. B. A. usuni<icintcnsis. C. A. dolichastachya A.
— — — — I).
mifcra. E. A, coulleri A. centralis. G. A. wilUardiana, H. A. conipacla.
F.
X
Acacia 4—7 mm,
1. usuitLacintensis Lundell, Contr. Univ. lets, oblong, 1.2—1.9 glabrous, lateral
TYPE;
Michigan Herb, 1940. Mexico, veins obvious, with a midvein and 3 smaller
4: 8. 1 to
Tabasco: Boca Cerro on the Rio Usumacinta veins from the base, base oblique, margins
ciliate,
1—5
above Tenosique, July 1939, E. Matilda apex acute to obtuse. Inflorescence a loosely flow-
mm
3550 MICH!; 50—110
(holotype, isotypes, K!, LL!, ered cylindrical spike long, 1 to 3 from
MEXU!, MICH!, sometimes racemose
NY!). the leaf axil, or in terminal
X
7-15 mm,
peduncle 0.7-1.1 puberu-
clusters;
m
30
Tree to tall with bark dark gray, shallowly mm
lent; involucre absent; floral bracts linear, to 1
brown
furrowed; twigs to greenish brown, not flex-
long, puberulent, early deciduous. Flowers sessile,
uous, glabrous to lightly puberulent; short shoots mm
1-1
creamy-white; calyx 5-lobed, long,
1 .5
mm
.
90-200
Leaves
absent. alternate, long; stipules
densely appressed pubescent; corolla 5-lobed, 1.8—
herbaceous, light brown, narrowly triangular, to 2.2 mm
2.5 long, densely appressed pubescent; stamen
mm
X
0.5 near the base, glabrous to lightly pu- mm
4—6
filaments long; ovary glabrous to lightly
berulent, persistent; petiole adaxially shallowly
mm
Legumes
pubescent, on a stipe to 0.3 long.
mm
30—70
grooved, long, glabrous to lightly pu-
yellowish brown dark brown,
light to straight, flat-
berulent; petiolar gland solitary, usually located on
X
90-250 20-33 mm,
tened, oblong, cartilaginous,
commonly
the lower third of the petiole, sessile,
transversely glabrous, eglandular, dehis-
striate,
mm
1—6
elliptical, long, flattened, glabrous (Fig.
mm
22 apex Seeds un-
cent; stipe long; acute.
to
mm
50-140
4B); rachis adaxially grooved, long,
no
iseriate, pulp, dark reddish brown, ol)long to
glabrous to lightly puberulent, a sessile, saucer-
X mm,
8.8-10.0 7.0-9.0
oval, strongly flattened,
mm
shaped gland, 1.0—1.9 across, between the up-
mm
3-4
smooth; pleurogram U-shaped,
across.
55—
per pinna pair; pinnae 7 to 15 pairs per leal,
Flowers: April—June.
mm mm
5—12
90 between pinna
ion pairs
1
mm
petiolules 1.7-3.0 long; leaflets (33)36 to 55 Distribution, Moist tropical forests, along
mm m
pairs per pinna, opposite, 1.0— 1.6 between leaf- streams, and moist disturbed sites below 500
Volume Number 4 Jawad
535
87,
et
al.
2000 Acacia coulteh Group
elevations in Belize, Guatemala, and the states of brown to greenish brown, not flexuous, glabrous;
mm
Campeche, Chiapas, Oaxaca, Tabasco, and Vera- short shoots absent. Leaves alternate, 40—120
Mexico
cruz, (Fig. 2). long, stipules herbaceous, light brown, narrowly tri-
mm
X
Acacia usumacintensis a tree that a com- angular, 1.3 0.3 near the base, glabrous,
is tall is to
mon 30—
component lowland
of tropical rainforests in persistent; petiole adaxially shallowly grooved,
mm
No
Guatemala and southern Mexico. specimens of 80 long, glabrous; petiolar gland solitary, lo-
this species have been observed by the present au- cated on the lower half of the petiole, sessile, cir-
mm
thors farth er sou th th Guat la and Belize. cular to more commonly elliptic, 1.0—2.5 long.
Specimens
labeled A, usumacintensis from Nicara- flattened or with slightly raised margins, glabrous
mm
gua are the result of confusing this taxon with var- (Fig. 4C); rachis adaxially grooved, 20—62 long,
ious species of Lysiloma, Acacia usumacintensis lightly puberulent, a sessile, -shaped gland.
mm
L
specimens are commonly misidentified as aca- 0.6-1.5 across, between the pinnae of the up-
Thompson
pulcensis (Kunth) Benth. (1980), in a re- per 1 to 2 pinna pairs; pinnae 2 to 6(8) pairs per
mm mm
4—9
vision of Lysiloma, annotated the type of A. usu- leaf, 40-75(90) long, between pinna
L mm
macintensLs as acapulcensis. This specimen [E. pairs; petiolules 2.5-4.0 long; leaflets 36 to 65
mm
Matuda
3550)^ however, is A. usumacintensis, hav- pairs per pinna, opposite, 0.7-1.1 between leaf-
X mm,
numerous
ing separate filaments remaining the oblong, 3.5—5.5(7.5) 0.8—1.3 glabrous,
at lets,
some
base of of the fruits. lateral veins usually not obvious, only one
jt
from base, base oblique, margins apex acute
ciliate,
.i.
PCA
Representative specimens. (*uscd analysis) a a
in
j
n n> « ^ ot)tuse. Intlorescencc a ^looseli y rlowered cylm-
Ar t^>
br>Li LIlIZ'zhi-. iL-Ii L/-ayo i^- Benque • Kio Mopa.n, Con-
Uist., V lejo,
mm o
^,^". ^^^, -i 2or0.-9nr0. ilong, t to 3 fr rom tihe ileafr
treras 7089 (CAS, F, LL, MO*, NY); vicinity Georgeville, ^P^^^^ 1
racemose
Western hwy., Dwrer 72662 (MO. US*); Valentin. Cayo. axil, or rarely in terminal clusters; pe-
P:1
GUATEMALA.
6356 GH, MICH*). 3-10 X mm,
Lundell (F," Izabal: duncle 0.5-0.9 glabrous to lightly pu-
km
Puerto Barrios, ca. 20 from town on the road Ma-
to
herulent; involucre absent; floral bracts linear, to 1
&
cliac-as, Marshall, Castillo Marshall 423 (MO, NY*). „
'""^ i gli a,brous to li-igihtly pub. escent, usually not
km ^^"S'
Peten: Uacandon, about 2 Contreras 3467 (CAS,
S,
deciduous. Flowers sessile, creamy-white; calyx 5-
LL*, MO); Macanrhe, Contreras 5479 MICH*, US);
F, (F,
mm
Dos Lagnnas, 19 Apr. 1969, Contreras 8356 (F*, LL, MO); lobed, 0.5—1,0 long, lightly appressed pubes-
mm
Tikal, in ramonal on Main Plaza. Lundell 15348 (CAS*,
eent; corolla 5-lobed, 1.2-2.2 long, lightly ap-
LL, MO, NY); Tikal, around Aguada Tikal, Lundell mm
F,
3—5
pressed pubescent; stamen
filaments long;
km
15973 (F*, LL, NY); Sayaxehe, in cnrozal about 5 S
mm
MO, ^^ary glabrous, on a stipe to 0.3 long. Legumes
of village, Lundell 18071 LL, NY*); Cadenas. on
(F,
&
river hank bordering Rio Gracios, Lundell Contreras light yellowish green to light brown, straight, flat-
19033 (F*, LL, NY). MEXICO. Campeche: El lonnento 80-130 X 13-20 mm,
tened, oblong, cartilaginous,
transversely glabrous, eglandular, dehis-
W striate,
^.';^frTuV^!""^
MO*). Chiapas: Lagnna Miramar E San
side of of
mm
cent; stipe to 12 long, apex acute to acuminate.
Quinlin. Breedlove 33387 (DS*, MICH, MO); 20 km SE
al
Seeds
de la desviacion San Javier Frontera Echeverria hac-ia Kiu not seen. Flowers: April-July.
&
Laeantum, Chimal, Durdn Qnlntanilla 755 ILL,
{V^
km Common
MO*); a "> al E de Crueero Corozal, camino a Frontera Distribution, in thorn-scrub thickets,
km
Corozal, Oeosingo, Martinez 7291 (MO, NY*); a 15
al ^nd disturbed dry forests in the lowlands of the
& en j-v*^
E
de Nvo. San Juan Cliamula camino a I\ean. Martinez
^ ^ Lampech\^c, Ur\um* t^ana -Kdoo, and Yucatan
G^i'ro.n 6^^2^8n8n (f\M*Or\*^, M**Li)i\. ^Oxaxaca: rR>mco^n rB.ambia, i Of^ statcs ol f > \^ '
al
Salina Cruz, Martinez 629 (MO*). Tabasco: Mun. Hal- i^^^- 2)-
(le
ancan, por la earretera 0, por el Poblado Arroyo del Trinn- Restricted to the Yucatan Peninsula, Acacia dol-
fo, Calzada 2385 (F*, NY); La Palma, Balanean, Matuda ichostachya appears to be a relatively common
3324 (F^MICH*, WIS). Veracruz: Mino^ Minatitlan, Lo-
thom-scrub and
^ ,^^^ ^f thickets disturbed
bW W
mas de i^ Oarganla, o.K km de Uxpanapa,
al al
• rri r r
& mew, ^^^^^- The fact tihat most ileaves ihave fewer than
4127
Wendt, Villalobos Navarrete }AO/\VX).
{Y,
seven pinna pairs separates A, dolichostachya from
.1
o most Other species of this eroup. Other species with
2rt. A4caei•a d1ol1.ic1hostachya b. rT-. ir>Jila1ke, rr>roc. rB>i- oL1 ^ o r- r-
six or fewer pinna pairs differ by having pinnae
Soc. Washington 34: 43. 1921. Senegalia dol-
with fewer than 35 pairs of along with
leaflets,
& N
ichostachya Blake) Britton Rose,
(S. F.
much
«'^«"er leaflet. compacta), longer petioles
AmeTFl (/I.
237112.7928. TYPE: MexicorYu-
mammi-
willardiana)^ or pubescent leaves
[A, {A.
May
catdn: Las Bocas de Silam, 1916,
G.
/.
and
& fera A, sericea).
Gaumer 23329
Sons
(holotype, F!; isotypes,
Considering the restricted distribution of this
NY
F!, G!, K!, photo!).
species, the only other taxon that A. dolichostachya
m
Small tree to 15 tall with bark dark brown to might be confused with is A, usumacintensis. Both
dark gray, scaly in rectangular plates; twigs light taxa have more than 35 pairs of leaflets on each
536 Annals
of the
Garden
Missouri Botanical
50-
pinna, flattened petiolar glands on the lower half of berulent; short shoots absent. Leaves alternate,
mm
the petiole, and petiolules that are more than 2.5 150 long; stipules herbaceous, light brown,
mm mm
X
They
long. are easily separated as A. dolichos- narrowly linear, to 3 0.5 near the base, usu-
tachya has fewer pinna pairs per leaf (mostly six or ally glabrous, persistent; petiole adaxially shallowly
mm mm
±
15—40 com-
fewer), alter stipules (less than 1.3 long), grooved, long, glabrous, but
less distance between the leaflets on the pinna ra- monly with minute purple glands; petiolar gland
chis (less than 1.2 mm), and smaller sepals (mostly solitary, located between the lower pinna pairs or
mm
less than 1.0 long). along the upper half of the petiole, sessile, nearly
mm
0.7—2.3
circular to slightly elongated, long,
MEXICO.
Cainpeohe:
Represrn,o,ire specimens. 4
^^^^^^_ ^^ ^^p-shaped, glabrous, rarely absent; ra-
km
Amaben. Hopelcheu,
(lespues olio lacuna
rle iVlpio. n inn
. o/^
.
& ^^is adiaxi•ally groovedi, 20-110 nmi ilong, gli aibrous
Chan Ucan 1023 (UC*); a 12 km E de Constilucion,
al
W
km puberulent and usually with minute pur-
o sea a 15 al de Coiiliuas, Soiaa, Raniamoorihy, to lightly
&
12229 iiuinianaRoo: En
Ibarra, Rico Hasurto {MO*), pie glands, a sessile, cup-shaped gland, 0.4-0.9
Rancho San Felipe, a 7 km al S de la desviacion a Puerto ^^
between upper pinna pinnae
^^^^^^^ the pair;
Morelos, por la carretera Caiu'un—Tulum. Cabrera 1 1456 mm mm
25—60 3—7
30
7 to pairs per leaf, long,
km N
(MO*); a 15 al dc la <lesvia<'i6ii a Puerto Morelos,
mm
& between pinna pairs; petiolules 1.0-2.4 long;
Tulum-Cancun,
sobre carretera Cabrera Cabrera
la
3I5H (MO*); a 12 km K de Carrillo Puerto, rumbo a leaflets 36 to 60 pairs per pinna, opposite, 0.5—1.2
al
km
Vigia Cliieo, C«/>rpra Gi/>rf>ra 356/ (MO*); a 35 al ^^^ between 2.5-4.8 X 0.7-1.1
it- leaflets, linear,
NW
de Carrillo Puerto, sobre el camiuo a Vigia Cliico, j r u* u
oil ^^' gli aibrous and commonliy light greenish purpli e
^
^
Cab,rera SP: Cab;rera W.nH^On (/lMuOn**)^; en el11km 2 del cami•no «
& ^^ovc, lateral vei. ns obvious, a mi. d, ve.m andi i to 2
1
al Faro de la Punla Celaraiu, Lsla de Cosumel, Cabrera
smaller veins from the base, base oblique, margins
Cabrera 10555 (MO*); Janlfn Bolaniro Quintana Roo,
3^
&
Ditran. Olmsted Honorato 85 (MO*); mi. S of Filipe ciliate, apex narrowly acute to acuminate. Inflores-
&
Carrillo Puerto, Dwyer, Spellman. Vaughan Wunderlui ittm 40-100
^^^^^ ^ loosely flowered cylindrical spike
km irT/\
258 (MO*); 5 N de Puerto Morelos, Quero
al Grether,
, r
, 4m Irom pedtuncle 5-10
tfx rLvlores 1j-3j3-^11 (iMMiOi*\^)\; a A6 Ikm al1 IMN dJe Pi>uer^to dJe ^Mflorel1os ii^ni loneo,' 1 to the leat axil;' ^
X mm,
0.5-1.0 glabrous puberulent and
a Cancun, Sousa, Tellez & Cabrera 10959 (MO*); a 48 to lightly
km NE commonly
de Filipe Carrillo Puerto. Sousa. Cabrera, Dai- with scattered minute purple glands; in-
al
NW
& mm
12441 (MO*); enironque Che-
idse Cliaier al del
yolucre absent; floral bracts linear, to 1 long,
n
lumal— Carrillo Puerto, sobre carretera Merida \ia Corta,
F.
^ earli y dicci• ujuous. r lowers sessi-li e, creamy-whii t*e; ca-
rr.n Ap /> .,/w) ,\jti\^\ ^i^ km n J
lellez CabIrera 2012 (MO*); a 10 \ al\ b de lul\ um,
mm
& i 5-li oibedi, 1.0-1.6 long, iligihtli y appressed pu-
miez Cabrera 2032 (MO, NY*); 5 km N de Ba- ^X^
a al
1
mm
&
km 2.1-2.8
ealan Cabrera 2366 (NY*); 10 antes de bescent; corolla 5-lobed, long, lightly
Tellez la
mm
eiUrada a Buenavista, de Chetumal rumbo a Felipe Car- appressed pubescent; stamen filaments 4.5—6.5
&
Ucan 985 Yucatan: mm
Puerto, Flares (UC*). 11.2
rillo
long; ovar>' glabrous, on a stipe to 0.4 long.
km N
of D/ihilehaltimi turn on road from Merida to Pro-
Legumes
Joamdn light to dark brown, straight, flattened, ob-
Uradbum '/29j7Ma'N Y*)r4!rkm a\K
greso.
X
& 80-170 13-25 mm,
long, cartilaginous, trans-
de Sueila, sobre la carretera 'H/imin-M^rida, Cabrera
&
Cabrera 13203 (MO*); near Piste, Lundell Limdell 7344 versely glabrous, eglandular, dehiscent;
striate,
MICH*, MO, km mm
(A, F. LF, US); 7 al S de Yaxeaba, Vara, 20 iii
^^-^^^ ^^ long; apex broadly acute. Seeds
•<.
& iiii
574 (CAS, MO).
Arias F*,
Isely
i
uniseriate, no pulp, dark reddish brown, oval,
7—10 X mm,
strongly flattened, 4.5-7.2 smooth;
Acacia acallensis Bentham, London mm
3. Bot.
J. 1: pleurogram U-shaped, 1.2-2.3 across. Flowers:
513. 1842. Senegalia (Bentham)
acatleiisis
March—
lune
&
Britton Rose, N. Amer. 23: 112. 1928.
Fl.
TYPE: May
Mexico. Puebla: Acatldn, 1830, G. Distribution, Dry, deciduous, tropical forests
MICH m
396 F
Andrieux (holotype, K!, photo!, and thorn-scrub between 500 and 2100
forests
NY TEX
photo!, photo!, photo!; isotypes, G!, elevations in the states of Chiapas, Guerrero, Jal-
US!) Mexico, Michoacdn, Oaxaca, and Puebla,
isco,
Mexico
(Fig.
2).
&
submonlana
Senegalia Britton Rose, N. Amer. 23:
Fl.
Acacia very similar morphologically
acatlerisis is
TYPK:
113. 1928. Mexico. Oaxaca: Cerro San An-
2046 to A. centralis. Both are widely distributed in south-
tonio, 1800 m, 12 Oct. 1907, C. Conzatti
alt.
(liolotype, US!; isotypes, F!, MEXU!, NY!). [Britton ern Mexico, although A. centralis has been collecl-
Rose
ant! (1928) listed the type as Conzatti 25,346. ed Mexico
frequently in the very south of and,
On NY number
the isotvpe. Hritton wrote the of tins u j
i.i ^ */ •»
• *i. •
' unlike A. acallensis, occurs across the border in
or o-i^ "1 it
speennen was . . I
erroneously printed
z5.,i4().
J
Guatemala and
countries to the south (see Fig.
2).
m
Shrub or small tree to 15 tall with bark dark These two species are difficult to separate, and
it
gray, shallowly furrowed; twigs light brown to is possible that they should be considered as sub-
greenish brown, not flexuous, glabrous to lightly pu- species of a single species. The two can be sepa-
Volume Number Jawad
4 537
87, et
al.
2000 Group
Acacia
coulteri
&
rated based on the presence or absence of minute negalia centralis Britton Rose, N, Amer. FL
common TYPE:
purple glands that are at the base of the 23: 113. 1928. El Salvador. Near San
leaflets, in the grooves of the rachis and petiole, Salvador, 1923, S. Calderon 1774 (holotype,
uncommon
and not along the axis of the inflores- NY!; isotypes, BM!,
F!).
cence In A. acatlensis. Rarely these glands are
m
Tree 25 with bark dark grayish brown,
to tall
clear, lacking the purple color, but are easily ob-
rough and
vertically fissured, scaling; twigs light
served under magnification. None of these minute
brown
to greenish brown, not flexuous, mostly gla-
glands were found on specimens of A. centralis ex-
70-
brous; short shoots absent. Leaves alternate,
No
amined. other characteristics could be found
mm
180 herbaceous, brown,
long; stipules light
that consistently separate these two species, though
mm
X
narrowly linear, to 4.5 0.6 near the base,
most specimens of A. centralis have leaflets with
glabrous, persistent; petiole adaxially shallowly
long hairs at the base on the ventral surface. These
mm
18-^6
grooved, long, glabrous to lightly pu-
hairs are particularly evident on young leaflets,
berulent; petiolar gland solitary, located on the
sometimes falling off as the leaves mature.
middle
part of the petiole, sessile, usually circular,
Acacia usumacin-
acatlensis is also similar to A.
mm
1.0—2.6 across, saucer- to cup-shaped, gla-
by having narrower
tensis, differing leaflets (less
mm
40-150
brous; rachis adaxially grooved, long.
mm
than 1.1 across) and lacking the large flattened
glabrous puberulent, a saucer- dough-
to sessile, to
petiolar gland of that taxon. Acacia acatlensis
is mm
nut-shaped gland, 0.6-1.3 across, between the
sympatric with A. sericea and A. mammifera in Oa-
pinnae of the upper 1 to 2 pinna pairs (Fig. 4F);
xaca; these two taxa also have minute purple glands
mm
24 30—70
pinnae per
(7)11 to pairs leaf, long,
on the leaves. Acacia acatlensis easily separated
is mm
3—9
between pinna 0.8—1.5
pairs; petiolules
from A. mammifera, which has fewer than 33 pairs
mm
long; leaflets 40 to 60 pairs per pinna, oppo-
commonly
of leaflets per pinna, leaflets that are
mm
0.5-1.2 between
distance
site, leaflets,
mm li
more and
than 1.5 wide, a stalked petiolar
X mm,
3.0—5.5 0.6—1.1 glabrous except usually
for
The pubescence
gland. dense, erect of A, sericea
some
long hairs at the base beneath, lateral veins
and
petioles fruits usually separates this species
obvious, with a midvein and 2 smaller veins
1 to
from
A. acatlensis.
from the base, base oblique, margins apex
ciliate,
MEXICO. km
Representative specimens. Chiapas: a 4 narrowly acute acuminate. Inflorescence a loose-
to
SW &
mm
de Toliman, Sousa, Ramamoorthy, Cortes Her-
al 60—140
flowered cylindrical spike long,
ly to
1
ndndez 1824 (MO*, TEX). Guerrero: Coyuca
Tario,
1
3 from the leaf axis, or in terminal racemose clus-
A
Hinton 7755 (DS, GH, MICH, NY, US); en Puerto
Dist,
4-10 X mm,
peduncle 0.5—1.0 glabrous
km N ters; to
El Salatlo, a 7 al de Tlapa camino a Iluamuxtillan,
W
km
Martinez 1070 (MO, TEX*). Jalisco: 2 de El lightly puberulent; involucre absent; floral bracts
al
km NE mm
Mirador, 10 de El Corcobado, carretera Autlan—
al linear, to 1 long, pubescent, early deciduous.
NW
km
Guadalajara, Magallanes 2169 (MO*); a 20 de
al
0.7—
Flowers creamy-white; calyx 5-lobed,
sessile,
km NE
San Magallanes 2420 (MO*); 20 Au-
Patricio, of
mm
1.3 long, lightly appressed pubescent; corolla
MO,
McVaugh 23271 (MICH*, NY); Barranea de Los
tldn,
mm
Tanqnes, desviacioti camino San Martin de las Canas, 5-lobed, 1.8—2.5 long, lightly appressed pu-
al
mm
Mllarreal 6121 (MICH*). Mexico: Pungaraneho, Temas- bescent; stamen filaments 4.5—6.5 long; ovary
caltepec Hinlon 3747 CH*, MO, NY. US). Mi- mm
Dist., (F, Legumes
glabrous, on a stipe to 0.3 long. light
km
choacan: 3 al S de Jungapeo, Solo, Aureolea, Silva
X
100—160 16-
brown, straight, flattened, oblong,
&
km
8573 (MEXU*). Oaxaca:
Fizarras 5 sobre des-
la
mm,
28
cartilaginous, transversely glabrous,
220 striate,
viacion a Barranca de Eos Calahazos, Aguilar (NY*);
mm
km NE 20 apex
3 de Tonala, carrelera a Huajuapan, Calzada eglandular, dehiscent; stipe to long;
al
&
Campos 18320 (GAS*, MICH, MSC); cave area near broadly acute obtuse and usually apiculate.
to
Onlaz,i^r%7t;(US*^^^
Mitia near pass Diaz
to
g^^j^ uniseriate, no pulp, dark reddish brown.
N
de Yosoeuta en carretera Huajuapan-Jnxllaluiara,
al la
mm
6—9
& nearly circular, strongly flattened, across,
Magallanes, Ramos Magallanes 11 (CAS*, LL, MO); 3
mm
km smooth; pleurogram U-shaped, 1.5—3.0 across.
N\^ de Santo Dotningo Tonala, carretera a Huajua-
al
p4n, Ortiz-Bermudez 291 (MEXU*); Tomellin Canyon, Flowers: April-August, and sporadically through-
MICH,
Pringle 5885 (GH. us*, VT); cerca de Tonala,
when
^^^ ^^e year moisture available.
is
^
Rzedowski 34920 (CAS*, MO); Subida a las Ruinas del
&
928
Cerro Cuiengola, Torres, Torres, Cortez Martinez, Distribution. Lowland forests, and moist dis-
Udera
(MO*); Oriente del Cen-o GuiengoUi, Torres, Torres,
j ^^qq
-^ - Guatemala, El Sal-
^ j^ j^ 1
& MO*
Martinez 400 Puebla: Teneji de Rodn-
T^llez m-
tt /-
r.-
r oc DO on. vad,or, rlondiuras, INicaraeua, Losta Kica, ana. tihe
/^ylo*^ 2v SciLr r -
guez, relIger 8:^-38 (MU*): mi.• oi A\cat*li an on ihwy. ' ^ t> '
•>
& states of Chiapas, Jalisco, Oaxaca, and Sinaloa,
190. Seigler Maslin 12692 (EIU*, ILL).
^
Mexico
(Fig.
2).
&
A
4. Acacia centralis (Britton Rose) Lundell, tall tree, sometimes entering the canopy of
Contr. Univ. Michigan Herb. 4: 7. 1940. Se- moist lowland forests, Acacia centralis is also a
