Taxonomy of Xylopia barbata (Annonaceae) and related species from the Amazon/Orinoco region

8 Pages·1999·6 MB·English

by  K J Bagstad

Contr. Univ. Michigan Herb. 21-28.
22: 1999.
TAXONOMY
OF XYLOPIA BARB ATA (ANNONACEAE)
AND RELATED FROM THE
SPECIES
AMAZON/ORINOCO
REGION
Kenneth Bagstad and David M. Johnson
J.
Department Botany-Microbiology
of
Ohio Wesleyan
University
Delaware, Ohio 43015
Annonaceae
Xylopia, a pantropical genus of characterized by axillary inflo-
rescences, long narrow petals, and dehiscent fruits, well-represented in the Neo-
is
tropics, where about 50 species are known to occur (Fries 1959). One of the more
named
distinctive Neotropical species X. barbata Hoffmanns, ex Martius, for
is
brown
the shaggy or brownish yellow hairs that clothe the twigs and lower surfaces
of the leaves; also has especially long and narrow flowers. Fries (1931), in
it
describing X, conjungens, noted the similarity of leaf and flower pubescence,
its
floral structure, and leaf venation to those of X. barbata, but observed that the
X
Many
leaf shape was similar to that of frutescens Aublet. recent specimens with
this combination of distinctive pubescence and elongate flowers are either inter-
mediate between X, barbata and X, conjungens in leaf shape or in neither
fit
taxon.
As a result of a herbarium study, we place X, conjungens in synonymy under
X, barbata, and recognize two new species, X. rigidiflora and X. orinocensis. The
long hairs and narrow petals of these three species are a unique combination of
among
character states Neotropical xylopias, suggesting that these species form a
common
The
natural group. pollen tetrads are of a type Xylopia (Kathleen
in
Peterson, pers. comm.), and the seeds bear the bilobed that characterizes the
aril
largely Neotropical Section Xylopia. All three species are restricted to sandy
perhaps group was
habitats, indicating that the ancestor of this a habitat specialist.
Fries (1959) did not indicate the relationship of X. barbata or X. conjungens to
them means
other species, choosing instead to group by of a key, with
artificially,
narrow and
species that share petals, free sepals, elliptic to oblong-elliptic leaf
blades. Intrageneric relationships of the Xylopia barbata group remain unclear.
Key Group
to the of the Xylopia barbata
Species
cm
Leaves 2.3-3.8 wide, concolored or only slightly darker adaxially than abaxially; leaf venation
1.
with loops outside the closed arches of the secondary veins ("festooned-brochidodromous'');
mm
outer petals 2.7-3.2 wide midpoint, fleshy and somewhat woody. X.
at rigidiflora
cm
Leaves 0.8-2.3 wide, discolored, distinctly darker adaxially than abaxially; leaf venation
1.
mm
L3-L9
without regular loops adorning the secondary vein arches; outer petals wide
at
midpomt,
coriaceous
to fleshy.
Lamina
base cuneate to attenuate and minutely decurrent on petiole; corolla orange,
2.
pubescence not brown. X. orinocensis
2. Lamina base cuneate to broadly cuneate but not decurrent on petiole; corolla yellow, with
brown
pubescence. X, barbata
21
— —
VOLUME
HERBARIUM
CONTR. UNIVERSITY OF MICHIGAN
22 22
Xylopia barbata Hoffmannsegg ex Martius, Fl. bras. 13(1): 40. 1841. Xylopicnim
barbatiun (Hoffmannsegg ex Martius) Kuntze, Revis. gen. 1891.
pi. 8.
1;
Type: Brazil. [Para:] "In ripa fluvii Tocantins, locis sabulosis virgultosis,
MO!
M,
ad Camcta," Sieber [J5J] (leclotype, here designated: photos: F!
NY!; BR).
isolectotype:
Xylopia conjungens Acta Horti Berg. 1931. Type: Peru. Loreto:
Fries, 10: 333.
Feb-Mar
Mishuyacu, 100 m, near Iquitos, 1930, Khig 970 (holotype: B;
NY!). IF-H.
isotypes: F! Fig.
DBH
m m
Shrub 2.5 to medium-sized tree 25 6-41 cm; bark pale red,
tall tall,
mm
wrinkled (ex Benko-Tseppon). Leaf-bearing twigs 0.4-2.5 diameter, tomen-
in
mm-long
tose-velutinous to glabrate, the hairs golden to straw-colored, dotted
1
brown Lamina cm
with light circular Icnticels. of larger leaves 3.2-7.3 long, 1-2.3
cm
wide, subcoriaceous, elliptic or oblong, paler abaxially, cuneatc to broadly
cuneate and not decurrent on petiole at the base, acuminate, acute, obtuse, or
mm
acumen,
retuse at the apex, the present, 1.5-14 long, glabrous adaxially,
if
sparsely pubescent to puberulent abaxially, midrib tomentose abaxially, margins
puberulent to tomentose; midrib impressed to plane adaxially, raised and semiter-
ete abaxially; secondary veins 6-12 per side, departing at 45-75*^ from midrib,
mm
indistinctly brochidodromous, anastomosing (1.2-) 1.6-3.9 from margin; sec-
ondary and
higher-order veins indistinct, raised adaxially, slightly raised abaxially.
mm mm
Petiole 0.6-2.5 long, 0.4-1.4 wide, tomentose-velutinous puber-
terete, to
ulent. Inflorescences Lflowered, occasionally 2-3-flowcrcd from a very short pedun-
mm mm
cle, axillary; pedicels 1.4-3.5 long, 0.5-1.4 thick, bracts 2-3, occasionally
mm
Buds
1.9-3.8 long, ovate, clasping, tomentose-velutinous to glabrate. linear-
4,
mm mm
lanceolate, acute. Calyx 3.2-5.8 long, 3.8-7.4 diameter, cup-shaped,
in
mm mm
coriaceous, sparsely tomentose-velutinous; lobes 1.8-3.5 long, 1.8-3.7
wide, apiculate apex. Corolla yellow, brown- or maroon-pubescent, coriaceous
at
tomentose
to fleshy, to thickly velutinous; outer petals spreading slightly anthe-
at
mm mm
cm
1.4-2.2 long, 2.2-3.1 wide at base, 1.3-2.2 wide at midpoint, linear,
sis,
acute at apex, expanded and concave at base, glabrous adaxially, finely appressed
mm
cm
pubescent abaxially; inner petals 1.3-1.9 long, 1.8-2.6 wide base, 0.6-0.8
at
mm
wide at midpoint, linear-filiform, acute at apex, expanded and concave at
mm
rhomboidal Stamens
base, in cross section, puberulent. 50-80, 1-1.2 long,
mm
narrowly oblong, glabrous; anthers septate at anthesis; apex of connective 0.2
mm
long, truncate or slightly hemispheric; filament 0.3-0.4 long; innermost
sta-
mens
staminodial, appressed to the stigma bases. Carpels 4-5, seated in the con-
mm
cavity of the torus with only stigmas emergent; ovaries Ll-1.2 long, long-
mm
2-3
sericeous; ovules attached laterally; stigmas 4.2-5.6 long, coherent,
(-6),
mm
filiform, pubescent. Torus 1.8-2.5 in diameter, conical, deeply concave in
mm
center, glabrous. Fruit of 2-4 monocarps borne on pedicel 4.9-5.9 long, 1.4-
a
mm
tomentose
1.7 thick, to glabrate, with sepals persistent; torus o\ fruit 3.2-4.2
mm
monocarps
in diameter; dehiscent, yellow or green with a red interior, 2.2-4
mm
cm
long, 4.6-7.5 wide, oblong, falcate to semi-torulose, surface verrucose and
somewhat
with the venation of the pericarp raised, puberulent to glabrate; stipe
mm mm
mucro
4-5.5 long, 1.8-2 wide midpoint; apex acute, with an oblique
at
mm mm
mono-
1.2-3 long; pericarp ca. 1 thick. Seeds 3-6, at 75"" to long axis of
mm mm mm
carp, 9.8 long, 4.2 wide, 3.7 thick, ellipsoid, elliptic in cross section,
mm
black or dark brown, smooth and somewhat shining; white, bilobed, 2
aril
mm
long, 3.8 wide.
—
BAGSTAD AND
JOHNSON: XYLOPIA
1999
23
FIG. Xylopia barbata, X. rigidiflora, and X. orinoceiisls. A-B, X. orinocensis. A. Habit, xl. B.
1.
Close-up of pedicel, calyx, and petal bases, x5. C-E, X. rigidiflora. C. Stamen, x20. D. Staminode,
F-H,
x20. E. Habit, xl. X. barbata. F. Habit, xl. G. Leaf of Peruvian specimen, xl, H. Seed, lateral
view, x2.5. Based on: A-B, Yanez 172 (US); C-E, Silva 221 (INPA, NY); F, Benko-Iseppon 373
(OWU); &
G, Vdsqiiez Jaramillo 15259 (MO); H, Prance al 5433 (US).
et
Additional Specimens Examined. Brazil. Amazonas: Rio Urutii [Urubu?-sec note below], Froes
margem
25487 (NY); Manaus, do Ig. dos Franceses, Mello 3177 (U); Enseada Grande, Ponta Negra,
margem do rio, Rodrigiies & Lima 2205 (F); Manaos, Rio Negro, Ule 5428 (K). Para: Mpio. de
Santarem, Vila de Alter do Chao, 2^31'S, 55°00'W, Albernaz 148 (K, NY, U); Mpio. Alter do Chao,
km em
69 a sul de Santarem, 'ilha" do Rio Tapajos, cerca de 200 ni distante da principal rua do
(OWU,
Mpio. Alter do Chao, Benko^Iseppon 373 SPF, U); Mpio. de Santarem, Vila de Alter do
—
VOLUME
HERBARIUM
CONTR. UNIVERSITY OF MICHIGAN
22
24
Kuhhmmn
Chao, 2''3rS, 55°()0'W, Ferreira 054 (K, NY, U); Santarem, 1736 (NY, U); Sla. Terezinha,
&
margcm dircita do Rio Tapajos, Maciel Cordelro 137 (NY, U); in siccis arenosis tempori pluviali
Nov NY,
inundalis Sanlarcm, Riedel 1566 (NY, US); vicinibus Santarem, 1849, Spruce 388 (K,
in
G K
B
fragments ex and at F; only the sheet from Herb. Benlh. at bears date and collection number);
Dec
Le)\ver Amazons, campos near Santarem, Trail! 8 (K-2 sheets, one dated 21 1873, the other 25
Dec 1873); Santarem, Bellerra, as proximidades do igarape Iru(janga, entre Pindobal e Porto Novo,
MO,
NY,
Vilhena ul 162 (NY, U). Rondonia: vicinity of Mutumparana, Prance al 5433 (K, U,
et et
(OWU).
US); margin of Mutumparana Prance 8851 Peru, Loketo: Maynas, Mishana,
airstrip. et
al.
3°55'S, 73^35'W, Vasquez et al. 4048 (MO); Iquilos, Allpahuayo, Estacion Experimental del Instiluto
&
de Investigaciones de Amazonia Peruana, 4°10'S, 73°30'W, Vasquez Jaramillo 15259 (MO),
la
(MO,
15268
U).
Flowering specimens have been from October through March, and one
collected
Peruvian specimen was collected with buds in May. Fruits have been collected in July
known
and November. Xylopia barbata from Loreto Department Peru, and from
in
is
Amazonas, and Rondonia
the Brazilian states of Para, (Fig. occurring at elevations
2),
The
of 100-180 meters. usual habitats of X. barbata are praia arenosa, restinga, and
savanna forest, sandy open habitats along rivers, which are widely distributed
i.e.,
&
Amazon
and numerous endemic Prance
within the basin contain species (Pires
f985).
The type oi X, conjungens, as well as subsequent collections from Loreto, Peru,
X
differ from most material of barbata in having distinctly acuminate leaf apices and
golden spreading pubescence on the twigs and abaxial midribs of leaves. These speci-
X
m
mens were collected from trees 20-25 In contrast, plants of barbata from
all tall.
m
the vicinity of Santarem are typically shrubs or small trees 2.5-10 with acute to
tall,
obtuse or even retuse leaf apices and brown or brownish yellow pubescence. These
characters seem vary independently, however: the two Prance specimens from
to
Rondonia have golden hairs, but the leaves are acute to obtuse, and the trees were
m
Amazonas
10-11 the Froes specimen from has acute leaf apices and from a
tall; is
m We
tree 12 but hairs are not conspicuously golden. have therefore conclud-
tall, its
ed that arc best treated as a single species for which there seems to be clinal
all
variation in size, shape of the leaf apex, and color of the pubescence.
The Amazo-
specimen collected by Froes from the ''Rio Urutu'' in the stale of
Amazon
nas in fact, probably from the Rio Urubii, a river that enters the just
is,
downstream from Manaus: Froes number 25355 from Urubu on
collected the
his
September
22 1949, just 13 days earher.
Martius based Xylopia barbata on specimens collected by Sieber the
(1841) in
Cameta and by Riedel Santarem, and used Hoffmannsegg's unpub-
vicinity of at
hshed binomial. Hoffmannscgg was also the source of the Sieber collections seen
by Martius (Lasegue 1845), and the Sieber syntype accordingly chosen as lecto-
is
number BR;
type. Fries (1930) cited a Sieber specimen without collection at the
Museum
specimen in the photograph distributed by the Field attributed to the
is
Munich Herbarium and shows number ''353."
a collection tag bearing the
M
B Amazo-
Type:
frazil.
nas: Mpio. Barcelos, Rio Jauari, 00^42'N, 63°22'W, abaixo do entronca-
mento com INPA!;
igarape Pretinho, 2 Jul 1985 Silva 221 (holotype:
(fl),
IC-E.
isotypes:NY!
U!). Fig.
ambabus
Species X, barbatae X. orinocensi ab laminis foliorum
et similis,
mm
concoloribus vel leviter discoloribus 2.3-3.8 arcubus adjectis praeter
latis,
venarum medio
arcus secundariarum, exterioribus carnoso-lignosis 2.7-
et petalis
mm
3.2 latis differt.
BAGSTAD AND
JOHNSON; XYLOPIA
1999
25
TROPICAL AMERICA
map
Flora Neotropica base no
1
C 979 by thB Univarsity o( Utrsc^it Published by the Slale Univeriily of UtracKI, the Netherlands Deportment of Systomaljc Botany
1
FIG. 2. Distribution oi Xylopia barbcifa, X. rigidiflora, and X, orinocensis in South America.
m mm
Shrub 2-4
Leaf-bearing twigs 0.6-2.1 diameter, tomentose-
in
tall.
mm
velutinous or puberulent to glabrate, with grayish hairs ca. 1 long persistent
on younger twigs, marked with occasional circular cream-colored lenticels. Lami-
cm cm
na
of larger leaves 5.3-9.1 long, 2.3-3.8 wide, subcoriaceous coriaceous,
to
elliptic or occasionally oblong, concolored or slightly darker adaxially than abaxi-
ally, cuneate but not decurrent on petiole at base, cuspidate to short-acuminate at
mm
apex, the acumen 5-15 long, glabrous adaxially, puberulent with a tomentose
midrib abaxially, margins puberulent to sparsely pubescent; midrib impressed to
plane adaxially, raised and semiterete abaxially; secondary veins 9-12 per side,
departing 55-80° from midrib, festooned-brochidodromous, anastomosing 2.5-
at
mm
8.9 from margin; secondary and higher-order veins indistinct, raised adaxially,
mm mm
tomen-
sHghtly raised abaxially. Petiole 1.2-2.0 long, 0.6-1.5 wide, terete,
mm
tose or puberulent. Inflorescences 1-flowered, axillary; pedicel 2.4-3.0 long,
mm mm
0.8 thick, tomentose; bracts 2-3, 3-3.5 long, clasping, ovate, tomentose.
mm mm
Buds
Hnear-lanceolate, obtuse. Calyx 4.3-6.5 long, 5.6-8.3 in diameter,
mm
cup-shaped, tomentose
coriaceous, to puberulent; lobes 2.6-4.1 long, 2.7-3.6
mm
wide, apiculate at apex. Corolla yellow, fleshy and somewhat woody; outer
mm
cm
spreading wide
petals slightly at anthesis, 1.5-2.1 long,, 3.9-4.6 at base,
mm mm
2.7-3.2 wide and 1.1 thick at midpoint, linear-lanceolate, acute and slightly
trigonous apex, expanded and concave puberulent
at slightly at base, adaxially.
—
HERBARIUM VOLUME
CON UNIVERSITY OF MICHIGAN
26 TR. 22
mm
cm
sericeous and keeled abaxially; inner petals 1.8-1.9 long, 2.8-3
slightly
mm
wide at base, 1.6-1.8 wide at midpoint, linear, acute at apex, expanded and
concave rhomboidal puberulent on pubcr-
base, cross section, keel adaxially,
at in
mm
ulent abaxially. Stamens 1-1.2 long, narrowly oblong, glabrous; anthers sep-
mm
tate at anthesis; apex of connective 0.15-0.3 long, truncate or sHghtly hemi-
mm
spheric, papillate; filament 0.2-0.3 long; innermost stamens staminodial, appressed
to stigma bases, flattened, oblong or quadrate. Carpels seated in the concavity
9,
mm
of the torus with stigmas and upper half of ovaries emergent; ovaries 2 long,
Torus
lanceolate, long-sericeous; ovules stigmas coherent, filiform, pubescent.
3;
mm
mm
diameter, tomentose around circumference, center portion
3.6 in 1.9 in
mm
diameter, 0.9 high, conical, deeply concave. Fruits and seeds unknown.
kms
Additional Specimens Examined. Brazil. Roraima: Mpio. Sao Luiz do Aiiaua, cnlrc 350 e
Aug
355 da Estrada Manaus-Caracarai (BR-174), proximo ao Equador, O^UO', 6()°45'W, 21 1987, Cid
Fcnciya9064 (OV^V.V).
Both collections are of flowering material, one from July and the other from
August. Both were collected from lowland campina habitat on sandy northern
soil in
Brazil near the frontier with Venezuela (Fig. This area inhabited by a num-
2). is
endemic woody Pagamea
ber of other species: aracaensis (Rul^iaceae), Coiiepia
amamlae and Licania nelsonli (Chrysobalanaceae), Pithecellobium prancei (Mimos-
aceae), Ternstroemia canipinicola (Ternstroemiaceae), and Caraipa longisepala
&
(Clusiaceae) (Prance Johnson
1992).
The and
petals of X. rigidiflora are, as specific epithet suggests, thicker
its
stiffer than those of the other tw^o species treated here; the outer petals are also
The
wider. leaf markedly wider, with formation of strong loops outside the
is
arches of the secondary veins; in the type specimen the leaves are strongly cuspi-
The
date. leaves are concolored or only slightly darker adaxially than abaxially,
whereas two
the leaves of the other species are distinctly discolored.
&
Xylopia orinocensis K. Bagstad D. M. Johnson, nov. Type: Venezuela.
sp.
km
SE
Amazonas: Dpto. Atabapo, Alto Rio Orinoco, 25 de Esmeralda,
la
Aynmrd &
3"03'N, 65^25"W, 80 m, f7 Feb 990 Delgado 7921 (holo-
f f (fl),
MO!; NY!
lA-B.
type: isotypes Ul). Tig.
Species X. barbatae valde affinis, a qua imprimis laminis foliorum angustiori-
bus basi attenuatis et minute decurrentibus, staminibus carpelliscjue leviter brevior-
ibus, el floribus aurantiacis differt.
m DBH
Tree 10-21 talk up to 25 cm; bark light gray. Leaf-bearing twigs 0.4-
mm
1.9 in diameter, flexuous, thickly velutinous, the dense golden patent hairs 1-
mm
marked brown Lamina
1.5 long, persistent, with circular light lenticels. of
cm cm
larger leaves 3.5-6.3 long, 0.8-1.5 wide, subcoriaceous, oblong to lan-
ceolate, occasionally paler abaxially, cuneate to attenuate and minutely
elliptic,
acumen
decurrent on petiole at base, acuminate to cuspidate at apex, the 3.5-10
mm
long, glabrous adaxially, sparsely pubescent to tomentose with midrib tomen-
tose-w^ooUy to puberulent abaxially, margins puberulent to tomentose; midrib im-
pressed to plane adaxially, raised and semitercte abaxially; secondary veins 7-11
per departing 40-70° from midrib, brochidodromous, anasto-
side, at indistinctly
mm
mosing 1.6-3 from margin; secondary and higher-order veins indistinct, raised
mm mm
adaxially, shghtly raised abaxially. Petiole 0.5-1.7 long, 0.4-0.7 wide,
BAGSTAD AND
JOHNSON: XYLOPIA
1999
27
tomentose
tomentose-woolly.
terete, to Inflorescences 1-2-flowered,
axillary;
mm mm
pedicel 1.6-4.2 long, 0.6-0.8 thick, tomentose to tomentose-woolly; bracts
mm
Buds
2-3, 1.9-4 long, ovate, clasping, pubescent. linear-lanceolate, acute.
mm mm
Calyx 2.6-4 long, 3.5-4.5 in diameter, cup-shaped, coriaceous, tomentose-
mm mm
woolly tomentose;
to lobes 1.1-2.2 long, 1.8-2.4 wide, apiculate apex.
at
Corolla orange, coriaceous outer spreading
to fleshy; petals shghtly anthesis,
at
mm mm
cm
1.7-2.4 long, 1,4-3 wide base and 1.3-1.5 wide midpoint,
at at linear-
lanceolate, acute at apex, cuneate at base, glabrous adaxially, appressed-pubes-
mm mm
cm
cent abaxially; inner petals 1.8-2.0 long, 1.3-1.6 wide at base, 0.5-0.6
wide at midpoint, linear-filiform, acute at apex, expanded and concave base,
at
rhomboidal
in cross section, glabrous adaxially, sparsely pubescent abaxially. Sta-
mm
mens
ca. 60, 0.8-1 long, narrowly oblong, glabrous; anthers septate anthe-
at
inner stamens staminodial. Carpels 4-5, seated concavity of the ova-
sis; in torus;
mm mm
ries 0.7 long, long-sericeous; ovules stigmas 3.5 long, coherent, fihform,
2;
mm
Torus
pubescent. 1.6 in diameter, conical, deeply concave, pubescent around
circumference. Fruits and seeds unknown.
Additional Specimens ExAiMiNED. Venezuela, Amazonas: Prov. Alto Orinoco, Cano Surimoni
ca. 30 mill, downstream by boat (40 PS) from La Esmeralda, right tributary of Rfo Orinoco, 3°12'N,
Nov km
eS'^SS'W, 26 1995, Rainer 282 (U); Rfo Caname, a 36 de confluencia con Rio Atabapo,
la el
Nov
3"37'N, 67"07'W, 1989, Yanez 172 (US).
Plants were collected from forests in the upper Orinoco River drainage of
southern Venezuela (Fig. quartzite outcrops were noted in one locality. All
2);
three specimens bear flowers two were November and one
only; collected
in in
February. Xylopia orinocensis has distinctly long, narrow leaves with a more
at-
tenuate lamina base than either X. rigidiflora or X. barbata, and the lamina
is
minutely decurrent on the petiole. The dimensions of the flower parts are similar
to those of X. barbata. This species not included in the recently pubhshed Flora
is
Guayana
of the Venezuelan (Steyermark but the combination of spreading
1995),
cm
golden pubescence, small leaves, and narrow petals over long should
1,7 dis-
tinguish from any other species oi Xylopia in the Flora area.
it
ACKNOWLEDGMENTS
Funding for study of these species was provided by the Ohio Wcsleyan University Howard
Hughes Program funded by a grant from the Howard Hughes Medical Institute Undergraduate
We
Biological Sciences Education Program. thank Nancy A. Murray comments and help with
for for
the Froes locality. Kathleen Peterson provided us with unpubUshed pollen data. The following her-
OWU,
baria made specimens available for study: F, INPA, K, MO, NY, SPF, U, US.
LITERATURE
CITED
Fries, R. E. 1930. Revision der Arten einiger Anonaceen-Gattungen-I. Acta Horti Berg. 1-128.
10(1):
1931. Revision der Arten einiger Anonaceen-Gattungen-IT. Acta Horti Berg. 129-341.
10(2):
.
1959. Annonaceae. In Die nalurUchen Pflanzenfamilien, ed. H. Melchior, 2d ed., ]7all: 1-170.
.
&
Duncker Humblot.
Berlin:
Lasegue, A. 1845. Musee botanique de M. Benjamin Delessert. Paris: Librairie de Fortin, Masson et Cie.
Martins, C. F. P. de. 1841. Anonaceae, In Flora brasiliensis, ed. C. Martius, 13(1): 1-64. Munich, Leipzig;
F. Fleischer.
Pires, M., and G. T. Prance. 1985. The vegetation types of the Brazilian Amazon, In Key environ-
J.
ments: Amazonia^ ed. G. T. Prance and T. E. Lovejoy. Oxford: Pergamon Press.
VOLUME
MICHIGAN HERBARIUM
CONTR. UNIVERSITY OF
22
28
Prance, G. and D. M. Johnson. 1992. Plant collections from the plateau of Serra do Araca
T.,
Kew
(Aniazonas, Brazil) and their phytogeographic affinities. Bull. 47: 1-24.
&
Steyermark, A. 1995. Xylopia. In Flora of the Venezuelan Cuayana, vol 2: PteridopJiytes Spcr-
J.
matophytes (Acanthaceae-Araceae). ed. P. E. Berry, B, K. Hoist, and K. Yatskievych. Portland,
Oregon: Timber
Press.