ILLINOIS LIBRARY
URBANA-CHAMPAIG
r ''RAL HIST. SURV
FIELD
Botany
A Systematic Study of Flourensia
(Asteraceae, Heliantheae)
Michael O. Dillon
December 31, 1984
Pub! i
PUBLISHED BY i i OF
FIELDIANA
Botany
NEW SERIES, NO. 16
A Systematic Study of Flourensia
(Asteraceae, Heliantheae)
Michael O. Dillon
Assistant Curator
Department of Botany
Field Museum of Natural History
Chicago, Illinois 60605-2496
Accepted for publication April 18, 1984
December 31, 1984
Publication 1357
PUBLISHED BY FIELD MUSEUM OF NATURAL HISTORY
1 984 Field Museum of Natural History
Library of Congress Catalog Card Number: 84-81690
ISSN 00 15-0746
PRINTED IN THE UNITED STATES OF AMERICA
Table of Contents
ABSTRACT 1
ACKNOWLEDGMENTS 1
INTRODUCTION 1
TAXONOMIC HISTORY 3
CYTOLOGICAL STUDIES 3
MORPHOLOGY 4
GENERIC RELATIONSHIPS 5
SPECIES RELATIONSHIPS 6
TAXONOMIC TREATMENT 8
Key to Species of Flourensia 9
Doubtful and Excluded Taxa 63
LITERATURE CITED 64
INDEX OF LATIN AND COMMON NAMES . 66
List of Illustrations
1 . Distribution of the genus Flourensia . . 2
2. Species relationships among Flourensia
species 6
3. Flourensia laurifolia 11
4. Flourensia retinophylla 13
5. Distribution of Flourensia cernua 14
6. Flourensia dentata 16
7. Flourensia ilicifolia 17
8. Flourensia solitaria 18
9. Distribution of Flourensia dentata, F.
ilicifolia, F. laurifolia, F. retinophylla,
and F. solitaria 19
10. Flourensia microphylla 21
1 1 . Flourensia collodes 23
1 2. Flourensia glutinosa 24
1 3. Flourensia cernua, F. cernua x F. resi-
nosa, and F. resinosa 25
1 4. Distribution of Flourensia collodes, F.
glutinosa, and F. resinosa 26
15. Flourensia monticola 28
16. Flourensia pulcherrima 29
1 7. Flourensia pringlei 31
18. Distribution of Flourensia microphylla.
F. monticola, F. pringlei, and F. pul-
cherrima 32
19. Flourensia thurifera 33
20. Distribution of Flourensia thurifera ... 34
21. Flourensia macrophylla 36
22. Flourensia angustifolia 37
23. Flourensia peruviana 39
24. Flourensia polycephala 40
25. Flourensia heterolepis 41
26. Distribution of Flourensia angustifolia,
F. fiebrigii, F. heterolepis, F. macrophyl-
la, F. peruviana, and F. polycephala ... 42
27. Flourensia suffrutescens 43
28. Flourensia macroligulata 45
29. Flourensia tortuosa 46
30. Distribution of Flourensia blakeana, F.
hirta, F. leptopoda, F. macroligulata, F.
suffrutescens, and F. tortuosa 47
3 1 . Flourensia oolepis 49
32. Flourensia fiebrigii 50
33. Flourensia blakeana 52
34. Flourensia hirta 53
35. Flourensia niederleinii 55
36. Flourensia riparia 57
37. Flourensia campestris 58
38. Distribution of Flourensia campestris,
F. niederleinii, F. oolepis, and
F. riparia 59
39. Flourensia leptopoda 60
40. Flourensia hirtissima 61
41. Distribution of Flourensia hirtissima . 62
List of Tables
Morphological comparison of Flourensia
and Encelia 5
Distinguishing characteristics of Flouren-
sia cernua, F. resinosa, and a putative
hybrid 27
in
A Systematic Study of Flourensia
(Asteraceae, Heliantheae)
Abstract
Flourensia DC. (Asteraceae, Heliantheae) is
composed of glutinous subshrubs, shrubs, and
small trees occurring primarily in arid habitats in
the American subtropics. The genus has an am-
phitropical disjunct distribution, with 13 North
American and 1 8 South American species. Exten-
sive field studies were conducted throughout the
range of the genus. Morphological, cytological, and
phytochemical studies were utilized in determin-
ing generic and species relationships. Descrip-
tions, illustrations, distribution maps, and a key
to species are presented. [Key words: Flourensia,
Asteraceae, morphology, cytology, amphitropical
disjunct distribution, monograph.]
Acknowledgments
I am indebted to Prof. Billie L. Turner who
originally suggested the problem and under whose
direction the present study was conducted. I also
gratefully acknowledge Drs. William G. D'Arcy
and Marshall C. Johnston for providing Latin de-
scriptions for new species. I thank the following
South American botanists for their generous hos-
pitality: Drs. A. B. Andrada, Luis Ariza E., Angel
L. Cabrera, Ramon Ferreyra, Armando T. Hun-
ziker, Juan H. Hunziker, P. Legname, Ricardo Luti,
Oscar Tovar, and Frederico Vervoorst. I thank the
following people for their companionship on col-
lecting trips and/or constructive criticism of the
present study: John Bacon, Kathy Baker, Fernan-
do Chiang C., Imre Eifert, Ronald L. Hartman,
James Henrickson, Mitzi Reynolds, Alfred Rich-
ardson, Eloy Rodriquez, and Thomas Wendt. I
thank Drs. Vicki A. Funk and John L. Strother
for critically reading the manuscript during the
review process. Illustrations were prepared by Ste-
ven Chase, Felicia Bond, Jane Fulkerson, Eliza-
beth Liebman, Z. Jastrzebski, Marlene Werner,
and Yevon L. Wilson. Last, but not least, I thank
my wife, Diane, for her patience and help in proof-
reading this manuscript.
Collecting trips were supported, in part, by the
following institutions: National Science Founda-
tion (GB-37006), The Society of Sigma Xi, and
the University of Texas Graduate School.
The following herbaria have lent specimens for
this study, and their help is acknowledged: A,
ARIZ, ASU, BM, CORD, ENCB, F, GH, GOET,
HUT, LIL, LL, LP, MEXU, MICH, MO, MSC,
NY, SD, SI, TEX, UC, US, USM. The symbols
used are those of Holmgren et al. (1981) and are
used as such throughout the paper.
Introduction
As treated in this study, 1 Flourensia is com-
posed of glutinous subshrubs, shrubs, and small
trees occurring mostly in drier, elevated regions of
North and South America. The genus has an am-
phitropical distribution (fig. 1), with 13 North
American taxa, primarily Mexican (of which two,
F. cernua and F. pringlei, enter the southwestern
United States), and 18 South American taxa as-
sociated with the Andean Cordillera of Peru, Bo-
livia, Chile, and Argentina.
Since the revision of Flourensia by Blake (1921),
eight new species have been described, four from
1 Based on a doctoral dissertation submitted to the
Graduate School of the University of Texas at Austin.
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
20
10
10
20
30
40
FIG. 1 . Distribution of the genus Flourensia.
north-central Mexico, two from Argentina, and these reasons, a re-examination of the genus was
two from Peru. Many unidentified collections have desirable.
been added to herbaria over the last 60 years. For In connection with the present study, extensive
FIELDIANA: BOTANY
field collections and ecological observations were
made throughout the range of the genus in North
and South America. Approximately 1,500 her-
barium specimens were examined from the major
herbaria of North and South America. In attempt-
ing to establish species relationships, data were
used from morphological, cytological, ecological,
and phytochemical investigations.
Taxonomic History
Flourensia was erected by DeCandolle ( 1 836) to
include four species: two Mexican discoid taxa, F.
laurifolia and F. cernua, and a radiate group in
Chile composed of F. thurifera, which was origi-
nally described by Molina (1 782) as a Helianthns,
and F. corymbosa.
Bentham (1873) submerged the genus under He-
lianthus, stating that Flourensia thurifera, F. cer-
nua, and F. laurifolia do not differ significantly
from Helianthus, other than having villous ach-
enes and resinous leaves. He removed F. corym-
bosa to Viguiera due to the presence of well-de-
veloped squamellae between the pappus awns.
Gray (1873) treated Flourensia as distinct from
Helianthus and agreed with Bentham in the place-
ment of F. corymbosa in Viguiera. In 1879, Gray
described Encelia microphylla from north-central
Mexico and stated, "[It] has shrubby stems, foliage
not unlike that of Flourensia cernua, and the re-
lationship of the two is apparent." Later (1883),
Gray suggested that the discoid taxa (i.e., F. cer-
nua, F. laurifolia) were typical for Flourensia and
that the radiate F. thurifera might be best treated
as a section under Cassini's Diomedia. Gray in-
correctly attributed the authorship of Diomedia to
Bertero and Colla.
Baillon (1886) submerged Flourensia, Wyethia,
Tithonia, Diomedia, and Viguiera into Helian-
thus, thus creating a highly variable and, I pre-
sume, polyphyletic assemblage. Hoffmann (1894)
reinstated Flourensia as a distinct genus, and it
has been retained by nearly all subsequent authors.
Blake (1913) began work on the genus during a
revision of Encelia, at which time he transferred
six radiate taxa from Encelia (E. collodes, E. glu-
tinosa, E. microphylla, E. oblonga, E. resinosa,
and E. suffrutescens) to Flourensia, and also de-
scribed F. retinophylla from Coahuila, Mexico. In
1916, he described two new South American
species, F. macrophylla and F. fiebrigii. In 1918,
during a revision of Viguiera, Blake established F.
heterolepis and transferred several taxa previously
included in Flourensia (F. atacamensis, F. cor-
ymbosa var. araucana, F. c. var. lanceolata, F.
gayana, F. hispida, and F. navarri) to Viguiera.
Blake (1921) published a revision of Flourensia,
in which five new species from Argentina were
described: F. hirta, F. leptopoda, F. niederleinii,
F. oolepis, and F. polyclada. He subsequently de-
scribed three additional species: F. hirtissima from
Argentina in 1 924, F. dentata from Mexico in 1 935,
and F. solitaria from Mexico in 1950.
In 1 960, Seeligmann described F. macroligulata
from northern Argentina. The last additions to the
genus have been two species from north-central
Mexico, F. pulcherrima and F. monticola (Dillon,
1976), and three species from South America, F.
blakeana from Argentina and F. polycephala and
F. peruviana from Peru (Dillon, 1981).
Cytological Studies
Prior to the present study, only four chromo-
some counts for Flourensia were reported in the
literature. Turner & Johnston (1961) reported
meiotic counts of n = 18 pairs for the Mexican
species F. laurifolia and F. resinosa, Di Fulvio
(1977) reported a meiotic count of n = 18 pairs
for F. campestris of Argentina, and Strother (1983)
reported a meiotic count of n = 18 for the Mexican
species F. collodes. Dr. Michael Powell (pers.
comm.) found n = 27 univalents in one collection
of F. cernua from Coahuila, Mexico. In the present
study, counts were made in 28 populations rep-
resenting 14 species, 10 of which are South Amer-
ican, and four, North American (Dillon, 1976).
Vouchers are on deposit at TEX and marked with
an asterisk (*) in citations of representative species.
Field-collected bud material was fixed in mod-
ified Carney's solution (chloroform: absolute eth-
anol: glacial acetic acid, 4:3:1, v/v/v), and chro-
mosome squashes were stained in aceto-carmine.
A mitotic chromosome count of 2n = 36 for
Flourensia thurifera was determined from root tips
of laboratory-germinated achenes.
Flourensia appears to be monobasic with x =
1 8. Chromosome counts are known for only 1 7 of
the species, but all counts to date have been n =
18. This relatively high base number is character-
istic of other genera considered most closely re-
lated to Flourensia (see Generic Relationships sec-
tion).
As noted, a meiotic count of 27 univalents has
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
been reported for Flourensia cernua. However,
pollen fertility of the voucher was determined as
99% (more than 500 grains examined). Thus, it
appears that nonchiasmatic meiotic figures do not
adversely affect fertility. Because none of the other
populations of F. cernua sampled throughout its
range exhibited univalents, it is assumed that such
irregularities are relatively rare.
Morphology
Species of Flourensia are delineated through
combinations of qualitative and quantitative char-
acters. The following section explains how various
measurements (reported in the descriptions) were
made and the extent of their utility in the circum-
scription of taxa.
Leaves
All leaf measurements are for the blades only.
Petiole measurements are given separately. Leaf
size, shape, and degree of denticulation tend to be
quite uniform within most taxa. This usually al-
lows species to be recognized in the sterile con-
dition.
Leaves of various species exhibit characteristics
that presumably confer drought resistance and al-
low them to inhabit arid environments. Well-de-
veloped cuticles and resinous exudates are usually
present on leaf surfaces. Many species are drought-
deciduous, with the extent of leaf loss dependent
upon the length and severity of drought periods.
In Flourensia thurifera of central Chile, the only
species to be studied in detail, the leaves gradually
dry up as drought progresses until there are only
a few terminal leaves remaining (Mooney & Kum-
merow, 1971).
Capitulescence
In most species of Flourensia, the capitula are
arranged into determinate, secondary cymes. These
are in turn occasionally arranged into panicles or
racemes. Solitary capitula, terminating stems or
branchlets, are most common among the many-
rayed taxa, but may also be found in discoid species
(e.g., F. solitarid).
Capitula
The height of the capitula was measured from
the base of the involucre to the top of the disc
florets. The width measurements exclude the ray
florets and represent the width of the involucre
only. Capitular size is somewhat variable within
and between individuals; however, some species
with similar leaf morphologies can be distin-
guished by their capitular size.
The capitula can be grouped into two categories
based upon the presence or absence of ray florets:
( 1 ) Discoid taxa possess capitula with only tubular,
5-lobed corollas. This developmental suppression
of ray florets has occurred within six species, all
of North America. The loss of rays in usually ra-
diate genera is not uncommon among many mem-
bers of the Heliantheae. Encelia, Viguiera, En-
celiopsis, and Geraea, among others, all possess
discoid taxa, while their members are predomi-
nately radiate. Obviously such loss is not selec-
tively disadvantageous; discoid Flourensia have
been quite successful in occupying a wide range of
xeric environments (e.g., F. cernua).
(2) The radiate taxa possess capitula with typical
disc florets surrounded by ray florets with well-
developed ligules. Within this category, two ad-
ditional groups can be separated on the basis of
the number of ray florets: In one line, an actino-
morphic pattern is presented where members have
more than eight (8) rays, usually a Fibonacci num-
ber (i.e., 13, 21, etc.). In the other, a pleiomorphic
or numerate pattern is presented where members
have five (5) or eight (8) rays, but occasionally as
many as 10 or as few as four (4). Specialization in
the number of ray florets is considered to be a
response to pollinator selection, for these taxa dis-
play patterns that mimic pleiomorphic "true"
flowers (Leppik, 1970).
Phyllaries
Involucres are quite diagnostic, with phyllary
size, shape, and vestiture being uniform within
most species. The phyllaries are normally imbri-
cate in two to five series and less often equal or
subequal. In a few species, e.g., Flourensia prin-
glei, the outer phyllaries are long and overtop the
inner ones. The phyllaries of each series are usually
differentiated in size and shape. Most are herba-
ceous, or only basally indurate, and tend to be-
come reflexed at maturity. One exception is F.
solitaria, which has phyllaries that are mostly in-
durate, persistent, and remain erect at maturity.
Achenes
The achenes are usually obconical, laterally
compressed, thickened, and sericeous, at least on
FIELDIANA: BOTANY
the margins. They range from 6 to 12 mm long,
and considerable variability can be found among
members of the same population. All have a pap-
pus of two (rarely three or four) aristiform, setose
awns arising from the thickened margins. The only
exception is F. solitaria, which has nearly terete
achenes that lack a pappus and obvious pubes-
cence.
Flourensia taxa lack paleaceous squamellae such
as occur in many Viguiera and Helianthus. How-
ever, the bases of the awns can be strongly am-
pliate and deeply lacerate and often united to form
a lacerate corona between the awns (e.g., F. ilici-
folia, F. collodes, F. thurifera, F. oolepis). This
pappus condition is also exhibited by some Vi-
guieras.
Generic Relationships
While all authors since Hoffmann (1894) have
recognized Flourensia as a distinct genus, there
has been little agreement upon its subtribal place-
ment. Hoffmann (1894) placed Flourensia within
Verbesininae, between Lipochaeta and Spilanthes
(s.l.). These two genera are here considered quite
distant from Flourensia.
Blake (1913, p. 350) considered the following
genera to be related and provided a key for their
discrimination: Flourensia, Helianthus, Viguiera,
Simsia, Encelia, Enceliopsis, Geraea, Helianthel-
la, and Verbesina. In this revision of Flourensia,
Blake (1 92 1) made no mention of possible generic
relatives other than to point out the differences
between it and Helianthus and Viguiera.
Stuessy (1977) included Flourensia within He-
lianthinae, based on the following characteristics:
(1) alternate-leaved shrubs, (2) neuter ray florets
and fertile disc florets, (3) conduplicate paleae, and
(4) convex receptacles.
Robinson (1981) re-delineated the subtribes of
Heliantheae and placed Flourensia within his
"Encelia group" in Ecliptinae (a prior name for
Verbesininae). This group included Encelia, En-
celiopsis, Flourensia, Geraea, and Phoebanthus.
During my examination of the genera that had
been considered close relatives of Flourensia, the
only genus that could be considered related is En-
celia. The morphological characteristics that dis-
tinguish these two genera are summarized in Ta-
ble 1.
In addition to these morphological differences,
the two have quite different eco-geographical dis-
tributions. The center of diversity of Flourensia
TABLE 1 . Morphological comparison of Flourensia
and Encelia.
Character
Flourensia
Encelia
Habit
Subshrubs,
Scapose or
shrubs, and
small shrubs
small trees
Leaves
Usually subgla-
Usually canes-
brous and resi-
cent resin not
nous
obvious
Ray florets
Bi-denticulate
Tri-denticulate
Disc florets
Yellow
Yellow or pur-
ple
Paleae
Coriaceous or in-
Soft or scarious
durate
Achenes
Thickened to
Compressed,
plump, seri-
very flat, vil-
ceous (at least
lous on mar-
margins)
gins, faces
usually gla-
brous
Pappus
2-3(-4) aristiform
Absent, or rare-
awns
ly of 2 awns
Style branch-
Broadly to nar-
Short obtuse ap-
es
rowly acute ap-
pendages
pendages
in North America is within the Chihuahuan Desert
region of central Mexico and in South America in
the Andean Cordillera. In contrast, Encelia has its
center of diversity in arid regions of the western
United States and adjacent Baja California, Mex-
ico (chiefly the Sonoran Desert). Two species occur
in scattered coastal localities in Chile and Peru.
One species is endemic to the Galapagos Islands.
This suggests the quite different edaphic and phys-
iological requirements of these genera.
Flourensia has a probable base chromosome
number of x = 18, all counts thus far being n =
18 (see Cytological Studies section). Of the genera
considered close to Flourensia, only Encelia (n =
1 7, 1 8), Enceliopsis (n = 1 7, 1 8), and Geraea (n =
18) share this number. The last two genera are
morphologically and geographically distinct from
Flourensia.
Phytochemical data have been useful in the de-
lineation of generic groupings within certain sub-
tribes of Asteraceae (Seaman, 1982). Although a
thorough survey is lacking, present data indicate
that Flourensia elaborates a unique array of ses-
quiterpenes and triterpenes (Kingston et al., 1975;
Estrada et al., 1965; M. Aregullin, pers. comm.),
polyacetylenes (Bohlmann, pers. comm.), and fla-
vonoids (Dillon etal., 19 76; Dillon &Mabry, 1977;
Rao et al., 1970). Further analysis of taxa within
this genus and elsewhere within the tribe will be
necessary before emphasis can be placed upon these
data.
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
FIG. 2. Species relationships among Flourensia species. Key to abbreviations: ang = F. angustifolia; bla = F.
blakeana; cam = F. campestris; cer = F. cernua; col = F. collodes; den = F. dentata; fie = F. fiebrigii; glu = F. glu-
tinosa; het = F. heterolepis; hir = F. hirta; hts = F. hirtissima; ili = F. ilicifolia; lau = F. laurifolia; lep = F. leptopoda;
mic = F. microphylla; mli = F. macroligulata; mon = F. monticola; mph = F. macrophylla; nie = F. niederleinii;
ool = F. oolepis; per = F. peruviana; pol = F. polycephala; pri = F. pringlei; pul = F. pulcherrima; res = F. resinosa;
ret = F. retinophylla; rip = F. riparia; sol = F. solitaria; suf = F. suffrutescens; tor = F. tortuosa; thu = F. thurifera.
An examination of available data indicates that
Flourensia is a natural assemblage of taxa that
lacks close generic relatives, with the exception of
Encelia. While subtribal classification within He-
liantheae is being debated, the position of Flour-
ensia near the aforementioned genus is clear.
Species Relationships
Efforts to establish species relationships within
Flourensia have been made more difficult by the
parallel development of various character states
in both North and South American taxa. In this
study, species groupings have been made primarily
through the comparison of exomorphic features.
Capitular morphology, including the size and shape
of phyllaries, and the presence and number of ray
florets were considered most important in the de-
lineation of groups. Secondarily, characters such
as leaf size and shape, pubescence, capitulescence
type, ecological preferences, and geographical lo-
cality were considered. In addition, data from phy-
tochemical studies were helpful in inferring affin-
ities between various taxa. The results of the
phytochemical studies will be presented in a future
publication.
Figure 2 represents the interspecific relation-
ships within the genus as suggested by these data.
The presumed relationships within North Amer-
ican taxa will be discussed first, followed by those
of South American taxa. Finally, consideration will
be given to the possible origin of the amphitropical
distribution of the genus.
Two groups can be distinguished in North
FIELDIANA: BOTANY
America by the presence or absence of ray florets.
This character is constant within any given species.
All the radiate species occur at higher elevations,
usually in arid, montane sites. Flourensia monti-
cola, F. pulcherrima, and F. pringlei form one line
within the radiate taxa. They possess large capit-
ula, usually solitary at the tips of branchlets, and
have 1 3-2 1 ray florets. Their involucres are com-
posed of large, foliaceous phyllaries that equal or
overtop the disc.
Flourensia resinosa, F. collodes, and F. gluti-
nosa form another line, which is characterized by
possessing small capitula with 8-13(-16) ray flo-
rets and cymose capitulescences. Their involucres
are composed of small indurate phyllaries that tend
to be imbricate and not overtopping the disc.
Flourensia microphylla represents a highly re-
duced radiate type, which shares characteristics
with the discoid taxa (e.g., reduced habit and small
leaves). The relationships of this rare species are
unclear at present; however, capitular morphology
suggests ties with F. resinosa.
The six discoid species are considered to form
a monophyletic group derived from now extinct
radiate stock resembling Flourensia collodes or F.
glutinosa. All discoid taxa occur within the Chi-
huahuan Desert Region, with the exception of F.
laurifolia of the Tamaulipan thorn scrub. Flour-
ensia laurifolia, F. retinophylla, and F. cernua form
one line, which appears to be a reduction series in
response to increasing aridity in their respective
environments. Flourensia solitaria, F. ilicifolia,
and F. dentata are each rather isolated, primitive
derivatives from the F. cernua line. Flourensia
ilicifolia and F. dentata are the only North Amer-
ican taxa that lack entire leaves.
Three weakly differentiated lines can be recog-
nized among the South American taxa. Flourensia
macrophylla, F. angustifolia, F. peruviana, and F.
polycephala are all distributed within the Andes
of northern to southern Peru. They share similar
capitulescences, capitular morphologies (8-13 ray
florets), and ecological preferences. Flourensia
thurifera of central Chile is clearly related to this
line through F. macrophylla; both have similar
leaves and involucres.
Flourensia suffrutescens, F. tortuosa, F. macro-
ligulata, and F. oolepis form a line characterized
by large capitula with broad phyllaries and 1 3-2 1
ray florets. Flourensia heterolepis appears transi-
tional between this group and the last and is most
closely related to F. polycephala.
The remaining eight species are all closely re-
lated and share many characters, including similar
capitulescences and capitular morphologies. These
taxa are distributed from southern Bolivia to
southern Argentina and share similar ecological
preferences. Flourensia riparia, F. campestris, F.
leptopoda, F. niederleinii, F. hirta, F.fiebrigii, and
F. blakeana all exhibit a trend toward fewer ray
florets, with the majority of species possessing 5-
8 ray florets. Flourensia hirtissima, with solitary
capitula, most closely approaches some individ-
uals of F. fiebrigii and is probably a product from
that line. This lineage is clearly related to the pre-
vious one, but tends to occupy more arid envi-
ronments at lower elevations. Flourensia riparia
seems basal within the line and shares habit, foliar,
and capitular characteristics with F. heterolepis.
The two hemispheres contain comparable num-
bers of taxa, 1 3 North American and 1 8 South
American. No single species is disjunct between
continents. Despite their mutual cohesion, there
are parallel trends among the species on both con-
tinents, including similar growth forms, leaf shapes,
capitula, and achenes. Flourensia can be classified
as an example of a generic allodisj unction (Turner,
1972), for the taxa concerned are widely separated
spatially and appear to have been derived through
phyletic divergence from populations now extinct.
How did Flourensia attain its present amphi-
tropical distribution? There is a gap in its range
of approximately 1,500 km from Chiapas, Mexico
(ca. 16N lat.), to northern Peru (ca. 8S lat.). Geo-
morphic evidence indicates that the continuous
land bridge in Middle America is of recent origin
(Raven & Axelrod, 1975) and has probably not
acted as a corridor for widespread migrations of
xeric elements between North and South America.
The opportunity for this has been greater in recent
times than at any period in the past. The north-
ernmost distribution of Flourensia in South Amer-
ica is just south of the Huancabamba Deflection
in northern Peru. Simpson (1975) has pointed out
that this area is lower than many inter-Andean
valleys and that it has acted as a significant barrier
to north-south land migration since early times.
If Flourensia had been previously more wide-
spread within the tropics, one would expect to find
the genus represented in appropriate habitats in
deep valleys and basins in north-central Guate-
mala and central Honduras. These areas, due to
rain-shadow effects, receive relatively scant pre-
cipitation and exhibit dry tropical scrub vegeta-
tion. The genus is also absent in dry Andean val-
leys from western Venezuela to Ecuador.
Considering this absence of the genus in Middle
America and northern South America, the exis-
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
tence of a widespread, more or less continuous,
tropical progenitor seems unlikely. Rather, the ge-
nus probably reached its present distribution
through long-distance dispersal of achenes, per-
haps by birds. Cruden ( 1 966) has pointed out that,
for many groups of taxa, transport of propagules
by birds is the only likely mode of long-distance
dispersal. Carlquist (1981) stated, "External at-
tachment of seeds and fruits to birds has also played
an appreciable role in the dispersal of flora to Ha-
waii." In particular, Gillet & Kim (1970) have
shown that the large array of endemic Bidens
species in the Hawaiian Islands has evolved from
a single introduction from North America during
the past five million years. Evidence also indicates
that transport of seeds and fruits on or in birds
can account for many of the North-South Amer-
ican desert disjunctions (Carlquist, 1983; Solbrig,
1 972). Though it may seem unreasonable to evoke
long-distance dispersal to explain present-day dis-
junctions (especially in taxa that today are not
actively dispersed long distances), this hypothesis
remains the best explanation for many of these
unusual distributions. As Carlquist (1981) pointed
out, it is unfortunate that one must "use evidence
that is circumstantial, indirect, and subjective and
therefore vulnerable."
That Flourensia is a long-time occupant of both
continents may be deduced from ecological con-
siderations. Species of the genus are often the sole
dominants of the communities that they occupy.
In fact, when dominant, they occupy different kinds
of communities on the two continents. For ex-
ample, in North America, F. cernua tends to dom-
inate flats with deep soils (Muller, 1 940), while F.
tortuosa dominates dry grassy bajadas in northern
Argentina. The dominant position of Flourensia
in these totally different ecosystems must reflect
long-time physiological selection for their respec-
tive roles.
Axelrod (1970) and Williams (1975) have ar-
gued that the present extensive regions of arid en-
vironment are of Pliocene-Pleistocene origin and
were developing simultaneously in both hemi-
spheres. Given the present amount of morpho-
logical divergence within the species of each con-
tinent, and their eco-geographical distribution, it
appears that Flourensia was represented on both
continents prior to Pleistocene time. The various
taxa have almost certainly evolved independently
on each continent in response to changing con-
ditions since that time.
Flourensia possibly had its origin in North
America. This conjecture is plausible simply be-
cause there is considerably greater morphological
divergence among the North American taxa, and
North America has been postulated as the origin
for a great number of genera of Heliantheae, in-
cluding all those thought to possess some affinities
with Flourensia (Bentham, 1873; Turner, 1977).
Although there are more species of Flourensia
in South America, this is a reflection of more re-
cent events. It appears likely that many of the
South American species have radiated into geo-
graphical and ecological areas postulated to have
undergone a series of humid-arid cycles during the
Quaternary which drastically and repeatedly al-
tered vegetation patterns (Simpson, 1975). This
area undoubtedly represents a region of secondary
radiation.
Taxonomic Treatment
Flourensia DC., Prodr. 5: 592. 1836. LECTO-
TYPE (Blake, 1921): Flourensia laurifolia DC.
Subshrubs, shrubs, or small trees; trunks and
stems with well-developed bark, brown to black;
branchlets usually glandular, resinous, aromatic,
glabrate to pilose-lanate. Leaves simple, alternate,
linear-lanceolate to oval, pinnatinerved, midrib
prominent on abaxial surface, finely prominulous-
reticulate, mostly coriaceous, resinous, viscid,
vernicose, the margins entire to dentate, often
strigillose. Capitulescences solitary to cymose-pa-
niculate; peduncles to 20 cm long, often bracteate.
Capitula discoid or radiate, 6-20 mm high, 5-20
mm wide; involucres cylindrical, campanulate,
hemispheric, or turbinate; phyllaries 2-5 -seriate,
imbricate, graduate, equal, or the outer overtop-
ping the disc, linear-lanceolate to rhombic-ovate,
herbaceous to indurate, glandular, resinous, gla-
brous to hirsute; paleae usually oblanceolate, em-
bracing (and deciduous with) achenes, carinate,
scarious to coriaceous, apically attenuate to trun-
cate or cucullate, often mucronate, glandular, re-
sinous, rarely hispidulous; receptacles flat to con-
vex; ray florets 5-21 (or absent), neuter (rarely
styliferous), sterile, the ligules yellow, oval to ob-
long, 7-50 mm long, apically bifid, the tube gla-
brous to sericeous; disc florets 10-1 50, the corollas
yellow, cylindric-campanulate to salverform, 4-8
mm long, the tube (0.5-) 1-1.5 (-2) mm long,
5-lobed, the lobes lance-triangular to deltoid, glan-
dular, resinous, rarely spiculiferous; anthers ca. 4
mm long, the terminal appendages ovate, basally
FIELDIANA: BOTANY
obtuse; style branches slender, recurved, the ap- dular, resinous, often finely striate; pappus of 2
pendages broadly acute to attenuate, dorsally his- (rarely 3 or 4) awns, rarely absent, persistent or
pidulous. Achenes laterally compressed to thick- disarticulating, ciliolate, the bases ampliate, lac-
ened, rarely terete, oblong to obconical or cuneate, erate; true squamellae absent. Base chromosome
4- 1 2 mm long, glabrous to villous-sericeous, glan- number: x = 1 8.
Key to Species of Flourensia
1 . Plants of North America (Mexico, southwestern United States) 2
2. Capitula discoid 3
3. Leaves entire 4
4. Leaves 1.5-13.5 cm long, 2-6 cm wide; petioles 5-10 mm long 1. F. laurifolia
4. Leaves 1-5 cm long, 0.5-1.5 cm wide; petioles 1-4 mm long 5
5. Achenes obscurely puberulent (appearing glabrous), pappus absent; phyllaries ca.
5-seriate 6. F. solitaria
5. Achenes villous-sericeous, pappus of 2, persistent, aristiform awns; phyllaries ca.
2-seriate 6
6. Capitulescences racemose-cymes; leaves narrowly elliptic to lanceolate
2. F. retinophylla
6. Capitulescences spiciform; leaves elliptic to ovate 3. F. cernua
3. Leaves dentate or iliciform 7
7. Leaves rhombic-ovate, the margins with 3-6, stiff, mucronate teeth; corolla lobes ca. 2.5
mm long 5. F. ilicifolia
7. Leaves elliptic-ovate, the marginal teeth lacking mucros; corolla lobes ca. 1 mm long . . .
4. F. dentata
2. Capitula radiate 8
8. Mid-stem leaves not exceeding 2.5 cm long, 5-10 mm wide 7. F. microphylla
8. Mid-stem leaves 3.5-14 cm long, 2-7 cm wide 9
9. Suffruticose, stems unbranched, to 0.5 m tall; ray florets 13-21 13. F. pringlei
9. Shrub, stems much-branched, usually over 1 m tall; ray florets 7-13 (-16) 10
10. Capitulescences cymose-paniculate, 5-20-headed; ray florets 7-10 . . . 9. F. glutinosa
10. Capitulescences cymose to solitary, 1-5-headed; ray florets 10-13 (-16) 11
1 1 . Phyllaries 2-seriate, 1 8-20 mm long, the outer overtopping the disc
12. F. pulcherrima
11. Phyllaries 3-4-seriate, 4-10 mm long, imbricate to subequal 12
12. Cauline leaves 3.5-7 cm long, 8-18 mm wide; petioles 2-4 mm long; ray
florets ca. 10 10. F. resinosa
12. Cauline leaves 6-14 cm long, 2-6.5 cm wide; petioles 7-22 mm long; ray
florets ca. 1 3 13
13. Leaves ovate, basally oblique, rounded; Capitulescences cymose-pani-
culate, 4-5-headed 8. F. collodes
13. Leaves lanceolate to obovate, basally attenuate; Capitulescences solitary
1 1 . F. monticola
1. Plants of South America (Peru, Chile, Bolivia, Argentina) 14
14. Leaf margins deeply to shallowly repand-dentate to cuspidate-denticulate 15
1 5. Capitula 1-2 cm high, 14-25 mm wide; ray florets 12-16 16
16. Leaves ovate to oblong-elliptic, the margins repand-dentate with 4-10 pairs of triangular
teeth; Capitulescences cymose, 4-8-headed; peduncles 3-13 cm long . . 14. F. thurifera
16. Leaves elliptic-lanceolate to elliptic, the margins with 2-3 pairs of teeth distally; cap-
itulescences solitary or weakly cymose, 2-3-headed; peduncles 4-6 cm long
23. F. oolepis
15. Capitula 8-12 mm high, 5-15 mm wide; ray florets 5-8 17
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
17. Leaves oval to oblong or lanceolate, the margins shallowly denticulate-cuspidate; pet-
ioles 2-5 mm long; capitula 10-12 mm high, 8-15 mm wide 18
18. Leaves oval to oblong-oval, apice obtuse to subobtuse 15. F. macrophylla
18. Leaves lanceolate to narrowly-elliptic, apices acute 16. F. angustifolia
1 7. Leaves lanceolate to rhombic-ovate or ovate, the margins deeply and irregularly repand-
dentate or with slight denticulations; petioles (2-) 5-13 mm long; capitula ca. 8 mm
high, 5-7 mm wide 19
19. Capitulescences weakly cymose, 2-4-headed 30. F. leptopoda
19. Capitulescences cymose-paniculate, 5-15-headed 29. F. campestris
14. Leaf margins strictly entire 20
20. Subshrubs to 20 cm tall; largest leaves narrowly linear-lanceolate to linear-oblanceolate, 2-
4mm wide (some individuals of F. fiebrigii and F. suffrutescens have reduced habits, but
leaves 7-1 8 mm wide) 3 1 . F. hirtissima
20. Shrubs greater than 20 cm tall; leaves elliptic to lanceolate or ovate, the largest leaves 5-60
cm wide 21
2 1 . Phyllaries greater than 2 mm wide (at least the inner); ray florets (9-) 1 0-2 1 22
22. Capitulescences weakly cymose to cymose-paniculate (rarely solitary); outer phyl-
laries 7-9 mm long, 1-2 mm wide, linear-lanceolate to lanceolate 23
23. Capitulescences cymose-paniculate, 4-8-headed; peduncles mostly 3-5 cm long
18. F. polycephala
23. Capitulescences weakly cymose, 2-5 -headed (occasionally solitary); peduncles
mostly 5-8 cm long 1 9. F. heterolepis
22. Capitulescences solitary (rarely weakly cymose); outer phyllaries (5-) 10-22 mm
long, 2-7 mm wide, lanceolate-elliptic to ovate 24
24. Leaves narrowly lanceolate to oblong, 8-18 mm wide . . 20. F. suffrutescens
24. Leaves lanceolate to elliptic or oval, 1 5-60 mm wide 25
25. Phyllaries sericeous; ray florets 13-21, the ligules 25-50 mm long
21. F. macroligulata
25. Phyllaries puberulent to glabrous; ray florets ca. 10, the ligules 18-30 mm
long 22. F. tortuosa
21. Phyllaries to 2 mm wide; ray florets 5-8 (-10) 26
26. Leaves ovate-lanceolate to ovate, (1 1-) 15-50 mm wide 27
27. Leaves 6-14 cm long, 1 5-50 mm wide 28. F. riparia
27. Leaves 3.5-9 cm long, 1 1-34 mm wide 28
28. Capitulescences cymose, 2-4-headed 27. F. niederleinii
28. Capitulescences cymose-paniculate, 5-15-headed .... 29. F. campestris
26. Leaves narrowly oblong-elliptic to lanceolate or oblanceolate, (3-) 4-14 (-20) mm
wide 29
29. Leaves mostly less than 3.5 cm long, narrowly oblong-elliptic; outer phyllaries
glabrous 25. F. blakeana
29. Leaves mostly greater than 3.5 cm long, linear-lanceolate to oblanceolate; outer
phyllaries strigillose to hirsutulose, rarely glabrescent 30
30. Leaves lanceolate to linear-lanceolate, 5-10 (-12) mm wide; phyllaries 6-
10 mm long, the margins strigillose to hirsutulose; ray florets 5-8
26. F. hirta
30. Leaves lanceolate to oblanceolate, (5-) 7-14 (-20) mm wide; phyllaries
4-6 (-8) mm long; ray florets 7-10 24. F. fiebrigii
1. Flourensia laurifolia DC., Prodr. 5: 592. 1836. 800. 952: I. 4!, BM!, F!, GH!, MO!, NY!). Figures
TYPE: Mexico, Tamaulipas, between Victoria 3, 9.
("Vittoria") and Tula, "cerca Las Minces," Nov.
1 830, J. L. Berlandier 2205 (lectotype, chosen Helianthus i aU rifolius (DC.) Benth. & J. D. Hook, ex
from two isotypes, G-DC, IDC Microfiche 800. j D. Hook. & A. B. Jackson, Ind. Kew. 1: 1112.
952: I. 3!; isolectotypes, G-DC, IDC Microfiche 1893.
10 FIELDIANA: BOTANY
I cm
FIG. 3. Flourensia laurifolia (from Dillon & Reynolds 659, F). A, habit; B, capitulum; C, floret.
Arborescent shrubs or small trees to 5 m tall;
branches gray-brown; branchlets resin-encrusted.
Leaves ovate to elliptic-ovate, 5.5-13.5 cm long,
2-6 cm wide, the costae strigillose, otherwise gla-
brous, upper surface vernicose, basally cuneate,
apically acuminate to attenuate (rarely obtuse), the
margins entire; petioles 5-15 mm long, strigillose.
Capitulescences cymose-paniculate, 3-7-headed;
peduncles 1-4 cm long, bracteate. Capitula dis-
coid, 11-18 mm high, 10-15 mm wide; involucres
cylindrical to hemispheric; phyllaries 3-4-seriate,
imbricate, subherbaceous, ciliolate, the outer lin-
ear-lanceolate to lance-ovate, 5-6 mm long, 1-3
mm wide, the inner oblong-ovate to oblong-lan-
ceolate, 8-10 mm long, 2-3 mm wide, all apically
acute, indurate and reflexed in fruit; paleae oblan-
ceolate, ca. 12 mm long, apically obtuse; florets
30-50, the corollas cylindric-campanulate, 6-7 mm
long, the tube ca. 2 mm long, the lobes ca. 1.5 mm
long. Achenes obconical, 6.5-8 mm long, thick-
ened, sericeous; pappus of 2 awns, ca. 5 mm long.
Chromosome number: n = 18.
FLOWERING (AND FRUITING) PERIOD Septem-
ber-December (December-April).
DISTRIBUTION AND HABITAT (Fio. 9) Domi-
nant locally on dry, steep, limestone slopes of in-
termontane valleys in the Sierra Madre Oriental,
from southwestern Tamaulipas, western San Luis
Potosi, and northern Hidalgo, Mexico (900-1,600
m).
VERNACULAR NAME Ojancha.
REPRESENTATIVE SPECIMENS EXAMINED MEXICO.
Hidalgo: Jacala, Kenoyer839(\Riz, F, MO); dry slopes be-
yond Hilo Juanico on road to Pacula, Moore 1802 (GH).
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
11
San Luis Potosi: ca. 37 km E of Rioverde, Cronquist
1 1276 (F, GH, NY, us); ca. 15 km NW of Cardenas, along
road to Ciudad del Maiz, Cronquist & Villosenor 11743
(F, NY); W of Minas de San Rafael, Moron 10012 (ARIZ,
so, uc, us); San Luis Potosi to Tampico, Palmer 1109
(GH); Minas de San Rafael, Purpus 4789 (BM, F, GH, MO,
NY, so, us), Pozo de Acuna, Guadalcazar, Rzedowski
686 (ENCB, GH, TEX, us); ca. 5 km W of Santa Catarina,
San Nicolar Tolentino, Rzedowski 5729 (ENCB). 1 amau-
lipas: ca. 20 mi SW of Victoria, Bacon & Dillon 1713
(F); 1 3 mi S of Victoria, Carlson 2750 (p[2], GH, TEX);
Mesa de Llera, Davis s.n. (TEX); 11 mi N of Tropic of
Cancer, 20 mi S of Victoria, Dillon & Reynolds 659 (F,
MEXU, MO, NY, TEX); ca. 40 mi NE of Tula, Dillon et al.
639 (F, MEXU, MO, TEX); 16 mi S of Victoria, Graham &
Johnston 4717* (TEX); near Llera, Kenoyer & Crum 3435
(A); ca. 20 mi S of Victoria, Lowrey et al. s.n. (TEX); 13
mi WSW of Jaumave, Moran 10025 (so); vicinity of
Victoria, Palmer 32 (F, GH, MO, NY, us); Tula, Puig 3678
(ENCB); between Jaumave and Victoria, Rozynski 178 (F,
NY, uc); La Jolla Ranch, Runyon 1013 (us); valley of
Jaumave, Runyon 5453 (TEX); 20 mi S of Ciudad Vic-
toria, Smith & Barkley 17 M 165 (F, GH, MSC); Jaumave,
Viereck 851 (us); 34 mi S of Victoria, Webster & B reckon
16374 (GH). CULTIVATED UNITED STATES. Tex-
as: Houston, nursery, raised from seeds collected at
Tamazunchale, San Luis Potosi, Mexico, Lowrys.n. (us);
Brownsville, grown from seed collected S of Victoria,
Tamaulipas, Mexico, Runyon 2004 (F[2], TEX), Runyon
3544 (BM, TEX).
Flourensia laurifolia is readily distinguished by
its arborescent habit and large, discoid capitula in
cymose panicles. It has shiny, evergreen leaves and
fragrant flowers, and has been taken into culti-
vation as an ornamental in northeastern Mexico
and southern Texas.
In the Tamaulipan Thorn Scrub, this species is
locally dominant, with populations commonly
having many seedlings evident in the understory.
Its associates include Acacia, Agave, Celtis, Cor-
dia, and Opuntia.
2. Flourensia retinophylla S. F. Blake, Proc. Amer.
Acad. Arts 49: 505. 1913. TYPE: Mexico, Coa-
huila, Sierra de la Paila, Nov. 1 9 1 0, J. A. Purpus
4728 (holotype, GH!, isotypes, BM!, F!, MO!, NY!,
uc!, us!). Figures 4, 9.
Shrubs to 3 m tall; stems much-branched, resi-
nous, aromatic, the bark brown to black. Leaves
narrowly elliptic to lanceolate, 1.5-6 cm long, 4-
1 2 mm wide, upper and lower surfaces glabrous,
acute to attenuate at both ends, the margins entire,
strigillose; petioles 1-3 mm long. Capitulescences
racemose-cymose, 2-6-headed; peduncles 5-20
mm, bracteate. Capitula discoid, 10-13 mm high,
5-10 mm wide; involucres cylindrical to campan-
ulate; phyllaries 2-seriate, subequal, subherba-
ceous, the outer lanceolate to lance-oblong, api-
cally acute, the inner ovate-lanceolate, apically
acute to obtuse, 4-6 mm long, 1-2 mm wide; pale-
ae oblanceolate, ca. 10 mm long, apically acute to
obtuse; florets 10-25, the corolla cylindric-cam-
panulate, ca. 6 mm long, the tube ca. 1.5 mm long,
the lobes ca. 1 mm long. Achenes obconical to
cuneate, ca. 6 mm long, sericeous; pappus of 2 (-3)
awns, ca. 3 mm long, basally ampliate.
FLOWERING (AND FRUITING) PERIOD August-
November (November-March).
DISTRIBUTION AND HABITAT (Fio. 9) Found on
steep, limestone slopes in the mountains sur-
rounding the Cuatro Cienegas Basin and Laguna
del Key in central Coahuila, Mexico (1,200-2,100
m).
VERNACULAR NAME Yerba de la mula.
REPRESENTATIVE SPECIMENS EXAMINED MEXICO.
Coahuila: N foot of Sierra de la Madera, ca. 5 km SE of
Rancho Cerro, Chiang et al. 9370 (TEX); Sierra de Paila,
ca. 10 mi N of Sta. Marte, Dillon & Hart man 658 (BM,
F, GH, HUT, MEXU, MO, NY, TEX); ca. 23 mi NW of Las
Delicias, Sierra de Las Delicias, Henrickson 6143 (TEX);
ca. 62 mi WSW of Cuatro Cienegas, Sierra de Organos,
Henrickson 12141 (TEX); ca. 35 km NW of Cuatro Cie-
negas, Sierra de la Madera, Henrickson & Wendt 1 1848
(TEX); Puerto Colorado, Sierra de la Fragua, Johnston
8698 (GH, TEX); ca. 6 km S of Ejido La Noria, Sierra de
San Marcos, Johnston et al. 10311 (TEX); Mina La Abun-
dancia, Sierra de la Paila, Johnston et al. 10509A (TEX);
Sierra San Marcos, Johnston et al. 10923 (TEX); Mina El
Aguirreno, N side of Sierra de la Paila, Johnston et al.
11702 (TEX); 8 km W of Cuatro Cienegas, Sierra de la
Madera, Johnston et al. 72079C(TEx); 9.5 km E of Puer-
to del Gallo, Sierra de los Organos, Johnston et al. 12136D
(TEX); Sierra de San Marcos, opposite Los Fresnos, Keil
et al. 6082 (ASU); Canon de San Salvador, Sierra Mojada,
Muller 3314 (F, GH, MICH, MO, TEX, uc); 6 km SE of
Esmeralda, Sierra Mojada, Stewart 2218 (BM, F, GH, TEX);
Canon de la Barrica, Wendt & Lott 1382 (TEX); Valle de
Buenavista, Sierra Organos, Wendt & Lott 1416 (TEX);
above El Pajarito, Sierra de la Fragua, Wendt & Lott
1427 (TEX); upper reaches of Canon Corazon del Toro
at Mina La Abundancia, Wendt et al. 10 110 A (TEX).
Flourensia retinophylla is distinguished from the
other discoid taxa by its narrowly elliptic to lan-
ceolate leaves and many-headed capitulescences.
It occupies a wide altitudinal range, from just above
the desert floor up to the highest portions of many
canyons. Its associates include Acacia berlandieri,
Agave lecheguilla, Arctostaphylos, Dasylirion,
Hechtia, Pinus pinceana, Quercus intricata, Rhus
virens, and Viguiera stenoloba.
The present distribution of this species suggests
12
FIELDIANA: BOTANY
2cm
FIG. 4. Flourensia retinophylla (from Dillon & Hartman 658, F). A, habit; B, capitulum; C, floret.
that it may have been widespread at lower ele-
vations within the Cuatro Cienegas basin during
pluvial periods and became fragmented as more
arid conditions developed at lower elevations.
3. Flourensia cernua DC., Prodr. 5: 593. 1836.
TYPE: Mexico, Nuevo Leon, "ad Monterrey,"
Jan. 1828, /. L. Berlandier 1401 (lectotype, here
designated, G-DC, IDC Microfiche 800. 952: I.
5!; isotypes BM!, F!, GH!, MO!). Figures 5, 13.
Helianthus cernuus (DC.) Benth. & J. D. Hook, ex J.
D. Hook & A. B. Jackson, Ind. Kew. 1:1112. 1893.
Shrubs to 2 m tall; stems much-branched;
branchlets, resinous, aromatic, brown to black,
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
13
FIG. 5. Distribution of Flourensia cernua.
strigillose. Leaves elliptic to ovate, (10-) 17-25
(-40) mm long, 5-12 (-20) mm wide, upper and
lower surfaces strigillose, basally cuneate, apically
acute, the margins entire, strigillose, often undu-
late; petioles 1-5 mm long, strigillose. Capitules-
cences solitary, terminal and axillary, spiciform;
peduncles to 10 mm long, bracteate. Capitula dis-
coid, 5-10 mm high, 5-10 mm wide, nodding in
fruit; involucres cylindrical; phyllaries ca. 3-seri-
ate, imbricate, subherbaceous, ciliolate, lanceolate
to ovate-lanceolate, 3-5 mm long, 1-2 mm wide;
paleae lanceolate, 5-9 mm long, apically acute to
attenuate; florets 10-25 (-40), the corollas cylin-
drical, 3-4 mm long, the tube ca. 1 mm long, the
lobes ca. 0.3 mm long. Achenes obconical to cu-
neate, 4-6.5 mm long, villous; pappus of 2 awns,
2.5-3.5 mm long. Chromosome number: n = 18.
FLOWERING (AND FRUITING) PERIOD Septem-
ber-November (December-March).
DISTRIBUTION AND HABITAT (Fio. 5) Frequent
on caliche and sandy soil throughout the Chihua-
huan Desert region of north-central Mexico, in-
cluding the states of Chihuahua, Coahuila, Du-
rango, Guanajuato, Hidalgo, Nuevo Leon, San Luis
Potosi, and Zacatecas, and the southwestern United
States, including Arizona, New Mexico, and Texas
(800-2,000 m).
14
FIELDIANA: BOTANY
VERNACULAR NAMES Blackbrush, tarbush,
varnish bush; hojase, hojasen, ojasen.
REPRESENTATIVE SPECIMENS EXAMINED MEXICO.
Chihuahua: 45 mi SE of Delicias, Dillon & Hartman
645 (TEX); hills and plains near Chihuahua, Pringle 292
(A, BM, F, GOET, MICH, us). C'oahuila: 1.5 km W of Tres
Lomas, Chiang et al. 10057* (TEX); 3 mi S of Agua
Nueva, 20 mi S of Saltillo, Dillon & Hartman 654* (F,
TEX); Sierra de Paila, on road to Mina La Abundancia,
Dillon & Hartman 657* (F, HUT, MEXU, MO, NY, TEX,
us); near Saltillo, Palmer 286 (A, F, GH, MO, MSC, us); at
Parras and vicinity, Palmer 434 (BM, F, GH, MO, uc, us).
Durango: 2 mi S of Pedricena, 54 mi S of Gomez Palacio,
Dillon & Hartman 649 (F, TEX); 27 km SW of Ceballos,
Wendt et al. 9979* (TEX). Guanajuato: ca. 2 km E of
Fabrica de Melchor, SW of Municipio de San Felipe,
Rzedowski 9541 (ENCB). Hidalgo: ca. 10 mi SE of Ixmi-
quilpan, 20 mi NW of Actopan, Dillon & Reynolds 675
(TEX). Nuevo Leon: ca. 3 mi S of San Roberto Junction,
ca. 75 mi N of Matehuala, Cronquist 9833 (GH, MO, MSC,
TEX, us). San Luis Potosi: region of San Luis Potosi,
Parry & Palmer 469 (BM, F, MO, us). Zacatecas: 38.5 mi
N of Zacatecas, 1 2.5 km N of Banon, Dillon & Hartman
651* (F, MEXU, TEX). UNITED STATES. Arizona:
Cochise Co.: Portal to Paradise, Chiricahua National
Forest, Eggleston 10667 (us). New Mexico: Dona Ana
Co.: 27.7 mi E of Las Cruces, Dunn 5335 (us); Eddy
Co.: road to Carlsbad Cavern, Standley 40376 (us); Grant
Co.: Hachita, Goldman 1306 (us); Luna Co.: 12 mi E of
Deming, Dillon & Baker 723 (F, TEX); Otero Co.: Tu-
larosa, Gaul 20 (us); Sierra Co.: Las Palomas, Goldman
1792 (us). Texas: Brewster Co.: 9 mi S of Marathon,
Dillon & Baker 714* (F, TEX); Crane Co.: ca. 16 mi W
of Crane, Warnock 14638 (LL); Crocket Co.: 31.3 mi W
of Ozona, Dillon 419 (TEX); Culberson Co.: 9 mi W of
Kent, Dillon & Baker 719* (F, TEX); El Paso Co.: N end
of Franklin Mts., Correll 26528 (LL, uc); Howard Co.:
Big Springs, Bray 401 (TEX, us); Hudspeth Co.: 20 mi
W of Van Horn, Dillon & Baker 721* (F, TEX); Jeff Davis
Co.: 34 mi N of McDonald Observatory, Dillon & Baker
717 (F, TEX); Mitchell Co.: 26 mi S of Colorado City,
Cory 49345 (GH); Pecos Co.: 1 mi S of Ft. Stockton,
Dillon & Baker 711* (F, TEX); Presidio Co.: 23 mi S of
Marfa, Muller 5081 (GH, LL); Reagan Co.: between Up-
ton Co. line and Texon, Correll & Correll 27118 (TEX).
Val Verde Co.: Comstock, Palmer 11062 (A, us).
Flourensia cernua is easily distinguished by its
small, entire, ovate to oval leaves and small, nearly
sessile discoid capitula. The pungent odor of its
foliage is also quite characteristic. There is con-
siderable variation in leaf size within its range; the
smallest leaves are found in southeastern popu-
lations, the largest in the northwest (Arizona and
New Mexico).
This is the only widespread species within the
genus in North America. It is a co-dominant with
Larrea tridentata over much of its distribution in
north-central Mexico and the southwestern United
States. This type of vegetation was referred to by
Muller ( 1 940) as the Larrea- Flourensia climax as-
sociation. Gardner (1951) suggested that L. tri-
dentata outlives F. cernua in such mixed com-
munities, and Larrea eventually becomes the
postclimax dominant.
Flourensia cernua has long been used medici-
nally by native peoples and is still sold in markets
of central Mexico. It was listed by Martinez (1 969)
as an indigestion remedy. A tincture is prepared
from several grams of leaves placed in 90% ethanol
and consumed along or mixed with another bev-
erage. Maxwell (1968) stated that it was used by
curanderos of northern Mexico as a treatment of
yellow jaundice.
Flourensia cernua is poisonous to sheep and
goats in western Texas and, probably, throughout
its range. Controlled feeding experiments (Math-
ews, 1944) using ripe achenes reportedly produced
acute inflammation of the abomasum and duo-
denum of sheep, goats, and rabbits, with death
within 1 8 to 72 hours. Green leaves were not found
to be toxic. Most poisoning is likely to occur in
late fall and winter (December-March) when the
fruiting heads are formed and more desirable for-
age plants become depleted. Although the toxic
agent has not been identified, F. cernua is known
to possess several potentially toxic flavonoids and
sesquiterpenes (Dillon et al., 1976; Dillon & Ma-
bry, 1977; Kingston etal., 1971, 1975). Cattle loss-
es from F. cernua have not been reported; either
cattle do not feed heavily on this species or are
tolerant to it.
Flourensia cernua forms putative hybrids with
F. resinosa (see discussion under the latter species).
4. Flourensia dentata S. F. Blake, J. Wash. Acad.
Sci. 25: 315. 1935. TYPE: Mexico, Durango,
Terreros near Pedriceno, "campos guayuleros,
ad viam," 11 Nov. 1925, S. Juzepczuk 609
(holotype, us!; isotype, LE; isotype fragment,
TEX!). Figures 6, 9.
Rounded shrubs to 1 m tall; stems much-
branched, the bark black to brown; branchlets red-
dish brown, resinous, minutely strigillose. Leaves
oblanceolate to elliptic, 10-25 (-37) mm long, 5-
1 5 mm wide, upper and lower surfaces minutely
strigillose, basally cuneate, apically acute, the mar-
gins dentate or dentate-serrate, 1-5 pairs of un-
equal teeth, 0.5-5 mm long, acute, axillary leaves
occasionally entire; petioles 1-4 mm long, strigil-
lose. Capitulescences solitary, or weakly cymose,
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
15
1cm
5mm
FIG. 6. Flourensia dentata (from Dillon & Hartman 652, F). A, habit; B, capitulum; C, floret.
1-3-headed; peduncles 1-4 cm long, bracteate.
Capitula discoid, 9-1 1 mm high, ca. 8 mm wide;
involucres cylindrical, substended at base by 1-3
spatulate or oblanceolate leaves; phyllaries 2-3-
seriate, subequal, subherbaceous, the outer linear-
oblong to linear-lanceolate, 6-10 mm long, 1.5-
2.5 mm wide, apically acute, ciliolate, the inner
oblong to oblanceolate, 7-9 mm long, 2-4 mm
wide, apically obtuse to rounded, erose-lacerate;
paleae oblanceolate, ca. 8.5 mm long, apically
rounded, erose-lacerate, the margins scarious; flo-
rets 1 5-25, the corollas cylindrical, ca. 5 mm long,
the tube ca. 1 mm long, the lobes 0.5-0.8 mm
long. Achenes cuneate, ca. 6 mm long, sericeous;
pappus of 2 awns, 3-4 mm long, deciduous or
rarely absent.
FLOWERING (AND FRUITING) PERIOD Septem-
ber-November (November-January).
DISTRIBUTION AND HABITAT (Fio. 9) Scattered
populations occur on limestone soils from central
16
FIELDIANA: BOTANY
FIG. 7. Flourensia ilicifolia (from
Purpus 1105, F). A, habit; B, capitulum;
C, floret.
5mm
5mm
2cm
Zacatecas, north to the Rio Nazas basin in eastern
Durango (1,500-2,100 m).
SPECIMENS EXAMINED MEXICO. Durango: Menores
and vicinity in Rio Nazas Basin, Gentry 8611 (GH, MICH,
uc); Sombreretillo, Juzepczuk 550 (us); near La Puri-
sima, Shreve 9180 (ARIZ, GH, MICH, uc). Zacatecas: 38.5
mi N of Zacatecas, 12.5 mi N of Ban6n, Dillon & Hart-
man 652 (F, GH, HUT, MEXU, MO, NY, TEX, us); 17 mi NE
of Zacatecas, Hartman et al. 3848 (TEX); 11 mi N of
Sierra Hermosa, Johnston 7400 (GH, us); 14 mi S of Sta.
Maria de Ban6n, Johnston 7441 (GH, us); 11 mi N of
Sierra Hermosa, Shreve 8587 (ARIZ, us); 58.6 km N of
Fresnillo, Wendl et al. 2185 (F).
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
17
5mm
2cm
5mm
FIG. 8. Flourensia solitaria (from
Henrickson & Dillon 15602, F). A, habit;
B, capitulum; C, floret.
Flourensia dentata and F. ilicifolia are the only
Flourensias with discoid heads and toothed leaves.
Flourensia dentata is readily distinguished by its
smaller and narrower dentate leaves and corolla
lobes less than 1 mm long.
In central Zacatecas, Flourensia dentata and F.
cernua occur sympatrically in the Opuntia scrub
and intermittent grasslands. Individuals often oc-
cur within a few meters of each other. Efforts to
detect hybrids have been unsuccessful.
18
FIELDIANA: BOTANY
fa Flourensia laurifolia
Flourensia retinophylla
Flourensia dentata
Flourensia ilicifolia
A Flourensia solitaria
FIG. 9. Distribution of Flourensia dentata, F. ilicifolia, F. laurifolia, F. retinophylla, and F. solitaria.
5. Flourensia ilicifolia Brandegee, Zoe 5: 238. 1906.
TYPE: Mexico, Coahuila, Sierra de Parras, Mar.
1905, /. A. Purpus 1150 (holotype, uc!; iso-
types, BM!, F!, GH!, MO!, NY!). Figures 7, 9.
Shrubs to 1.5 m tall; stems much-branched;
branchlets grayish brown, resin-encrusted, puber-
ulent. Leaves rhombic-ovate, 1-2.5 (-5.5) cm long,
0.6-1.5 (-2.5) cm wide, puberulent to glabrescent,
basally cuneate, apically acute, the margins den-
tate with 3-6 pairs of stiff, mucronate teeth (rarely
entire); petioles 2-4 (-6) mm long, puberulent.
Capitulescences solitary or in 2-3-headed terminal
clusters; peduncles to 1 cm long, puberulent, 1-3-
bracteate, the bracts linear-spathulate, 5-7 mm
long. Capitula discoid, 10-15 mm high, 10-13 mm
wide; involucres campanulate to cylindrical; phyl-
laries 2-seriate, subequal, coriaceous, oblong to
oblong-ovate, 5-7 mm long, 1.0-2^5_ mm wide,
apically obtuse, ciliolate; paleae oblanceolate, 7-
9 mm long, apically cucullate, obtuse to rounded,
lacerate, scarious; florets 20-30, the corollas cy-
lindric-campanulate, ca. 6.5 mm long, the tube ca.
1 mm long, the lobes ca. 2.5 mm long. Achenes
cuneate, 7-9 mm long, sericeous; pappus of 2 awns,
2.5-4.5 mm long, persistent, broadly lanceolate,
basally ampliate, united by a low crown of fused
hairs, 2-3 mm long.
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
19
FLOWERING (AND FRUITING) PERIOD Septem-
ber-October (October-November).
DISTRIBUTION AND HABITAT (Fio. 9.) Endemic
to the Sierra de Parras, in south-central Coahuila,
Mexico. The population occurs predominantly in
dry canyons on calcareous gravel, but occasional
individuals occur on lower bajadas in close prox-
imity to Flourensia cernua (1,600-1,800 m).
SPECIMENS EXAMINED MEXICO. Coahuila: 1 km W
of Parras, Dillon et al. 629 (F, MEXU, TEX); Sierra de
Parras, Johnston et al. 10996 (TEX); Sierra de Parras,
Shreve & Tinkham 9878 (GH).
Flourensia ilicifolia is distinguished by its rhom-
bic-ovate, dentate leaves with mucronate-tipped
teeth and its loose involucre with large, obtuse
phyllaries. It also possesses characteristically long
corolla lobes, ca. 2.5 mm long versus ca. 1 mm
long for most congeners.
6. Flourensia solitaria S. F. Blake, J. Wash. Acad.
Sci. 40: 49. 1950. TYPE: Mexico, Coahuila,
rocky flats and slopes, top of grade at Cuesta de
Zozaya, road from Ocampo W over mountains
to Puertecito via Cuesta de Zozaya, 20 Sept.
1941, /. M. Johnston 9289 (holotype, GH!; iso-
types, TEX!, us!). Figures 8, 9.
Shrubs to 60 cm tall; stems much-branched, the
back gray to brown, fissured, aromatic, strigillose.
Leaves oblanceolate to obovate, 1.2-3.3 cm long,
0.3-1 cm wide, upper and lower surfaces minutely
strigillose, basally cuneate, sessile to subsessile,
apically acute, the margins entire, undulate, strigil-
lose. Capitulescences solitary, terminal; peduncles
1 3-20 cm long, strigillose, reddish brown, multi-
bracteate. Capitula discoid, ca. 12 mm high, 8-13
mm wide; involucres campunulate; phyllaries 5-
seriate, imbricate, the outer lanceolate, 3.5-5 mm
long, 1-1.5 mm wide, the inner oblong-obovate
to rhombic, 4.5-6 mm long, 1.5-2.5 mm wide, all
basally indurate, stramineous, apically herba-
ceous, acute, strigillose; paleae rhombic-obovate
to narrowly cuneate-spatulate, 10- 12 mm long, 1-
3 mm wide, apically acute, scarious, strigillose.
Achenes cylindrical to oblong-lanceolate, 4.8-5.5
mm long, ca. 2.2 mm wide, 5-6-ribbed, obscurely
puberulent; epappose. Chromosome number: n =
18.
FLOWERING (AND FRUITING) PERIOD Septem-
ber-November (December-January).
DISTRIBUTION AND HABITAT (Fio. 9) This rare
species is known only from the type locality and
one additional site, both in central Coahuila, Mex-
ico. Although limited in distribution, it is quite
dominant locally in small areas of rocky, coarse
soils on flat hillside terraces (400-1,000 m).
SPECIMENS EXAMINED MEXICO. Coahuila: 18 mi
WSW of Villa Ocampo at Cuesta Zozaya, limestone E-W
pass, on road to Laguna del Rey, Henrickson & Dillon
15602 (F, MEXU, TEX); Cuesta de Zozaya, 23 mi W of
Ocampo, 12.5 mi E of Puertecitos, Wendt & Lott 1438
(TEX), 1873* (TEX); Puerto del Guarache, in Sierra de
Zacatosa, about 2.5 mi SW of Arocha, Wendt & Lott
1425 (TEX).
Flourensia solitaria is unique within the genus
in possessing solitary, discoid capitula borne on
long peduncles and achenes lacking the usual se-
riceous or villous pubescence.
This species occurs in very xeric and windblown
habitats just above the Flourensia cernua-Larrea
tridentata formation. Its associates include Agave
falcata, A. lecheguilla, Dasylirion, Hechtia, Koe-
berlinia, and Opuntia.
7. Flourensia microphylla (A. Gray) S. F. Blake,
Proc. Amer. Acad. Arts 49: 374. 1913. Figures
10, 18.
Encelia microphylla A. Gray, Proc. Amer. Acad. Arts
15: 37. 1879. TYPE: Mexico, Coahuila, gravelly
hills near Saltillo, Aug. 1878, C. C. Parry 462 (ho-
lotype, GH!).
Shrubs to 1 m; stems much-branched, the bark
grayish brown, densely hispid-pilose; branchlets
purplish brown, striate. Leaves ovate to elliptic-
ovate, 1.5-2.5 cm long, 0.5-1 cm wide, upper and
lower surfaces strigillose, acute at each end, the
margins entire, undulate, strigillose; petioles 1.5-
4 mm long, hispid-pilose. Capitulescences soli-
tary, terminal; peduncles 3-12 cm long, multi-
bracteate. Capitula radiate, 10-15 mm high, 10-
1 5 mm wide; involucres cylindrical; phyllaries 2-
3-seriate, subequal, herbaceous, hispid-pilose, the
outer narrowly lanceolate, 8-10 mm long, ca. 2
mm wide, apically acute, the inner lance-ovate to
lance-obovate, 10-15 mm long, 2-2.5 mm wide,
apically attenuate; paleae lanceolate, ca. 12-14 mm
long, apically acute, ciliolate; ray florets ca. 10,
neuter (rarely with a vestigial achene), the ligules
oval to ovate, ca. 10 mm long, 4-6 mm wide; disc
florets ca. 36, the corollas cylindric, ca. 6 mm long,
the tube 1-2 mm long, the lobes 0.5-0.8 mm long,
puberulent. Achenes oblong-obovate, 4-6 mm
20
FIELDIANA: BOTANY
2cm
5mm
5mm
1cm
FIG. 10. Flourensia microphylla (from Palmer 795, F). A, habit; B, capitulum; C, disc floret; D, ray floret.
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
21
long, densely pilose-sericeous; pappus of 2 awns,
ca. 3 mm long, caducous.
FLOWERING (AND FRUITING) PERIOD Septem-
ber (October).
DISTRIBUTION AND HABITAT (Fio. 18) Very
rare and known from only a few collections from
dry, limestone slopes of the mountains in south-
eastern Coahuila, Mexico.
SPECIMENS EXAMINED MEXICO. Coahuila: Sierra de
San Marcos, opposite Los Fresnos, Keil et al. P110B
(ASU); vicinity of Saltillo, Palmer 795 (BM, F, GH, MO,
MSC, NY, uc, us); Cameras Pass, Pringle 2392 (BM, F, GH,
MO, MSC, NY, uc, us); no exact locality, Palmer 589 (GH).
Flourensia microphylla is unique among the
North American species in possessing small ovate
to elliptic-ovate leaves and solitary, radiate heads
borne on long peduncles.
This rare species was re-discovered in 1 969 by
collectors (Keil et al. P110B, ASU) in the Sierra
de San Marcos. This marked the first collection of
this species since 1898.
Though the type collection of this species was
cited as C. C. Parry andE. Palmer 462 by A. Gray
and subsequent authors, it is likely that 462 was
solely a Parry collection. The type sheet at GH has
only Parry's name on his personal label with the
printed locality, "En route from San Luis Potosi
to San Antonio, Texas." Moreover, Parry collect-
ed alone between April and the end of July (1878),
a time when Palmer was in Mexico City. Parry
left San Luis Potosi for his home in Iowa around
the first of August, but fell ill and stayed in Saltillo
for 10 days to recuperate (McVaugh, 1956). After
Parry left, Palmer collected exclusively in the state
of San Luis Potosi for the next three months.
8. Flourensia colludes (Greenman) S. F. Blake,
Proc. Amer. Acad. Arts 49: 373. 1913. Figures
11, 14.
Encelia collodes Greenman, Proc. Amer. Acad. Arts
39: 1 10. 1903. TYPE: Mexico, Chiapas, along road
from Ocuilapa to Tuxtla, 2,100-3,000 ft, 29 Aug.
1895, E. W. Nelson 3071 (holotype, GH!; isotype,
us!).
Arborescent shrubs to 4 m tall; stems grayish
brown; branchlets striate, pilose to glabrescent.
Leaves lance-ovate to ovate, 6-14 cm long, 2.2-
6.4 cm wide, mostly falcate, upper surface sparsely
strigillose, lower surface glabrous, basally oblique,
rounded, apically acute to attenuate, the margins
entire, strigillose; petioles 7-20 mm long, strigil-
lose. Capitulescences weakly cymose, 4-5 -head-
ed; peduncles 2-8 cm long, bracteate. Capitula
radiate, ca. 1.5 cm high, ca. 2 cm wide; involucres
hemispheric; phyllaries 3-4-seriate, imbricate, in-
durate, striate, the outer lanceolate, 4-6 mm long,
1-1.5 mm wide, apically acute, subherbaceous,
ciliolate, the inner oblanceolate, 7-10 mm long,
1.5-2 mm wide, apically acute to obtuse; paleae
oblong, 12-15 mm long, apically subcucullate,
rounded, erose, ciliolate; ray florets ( 1 2-) 1 3 (- 1 6),
neuter (rarely styliferous), the ligules narrowly el-
liptic, 1 5-22 mm long, 5-8 mm wide, the tube 5-
6 mm long, glabrous; disc florets 30-100, the co-
rollas cylindric, ca. 6 mm long, the tube 1-1.5 mm
long, the lobes 0.6-1 mm long. Achenes obconical
to cuneate, 6-10 mm long, sericeous on margins,
the faces glabrate, reddish brown; pappus of 2 awns,
4-7 mm long, persistent, basally ampliate, lacer-
ate. Chromosome number: n = 18.
FLOWERING (AND FRUITING) PERIOD August-
October (November-December).
DISTRIBUTION AND HABITAT (FiG. 14) Infre-
quent on thin, rocky soils in the Tropical Decid-
uous Forest in the extreme southern portion of the
Mesa del Sur, Oaxaca, and the Central Depression
of Chiapas, Mexico (400-1,000 m).
SPECIMENS EXAMINED MEXICO. Chiapas: 5 km E
of Berriozabal on Mex Hwy 190, Breedlove 20388 (DS).
Oaxaca: 100 mi SE of Oaxaca, 54 mi NE of Tehuantepec,
Cronquist & Sousa 10453 (ENCB, GH, MICH, MCS, us); 45
mi SE of Oaxaca, Dillon & Reynolds 696 (F, HUT, MEXU,
TEX); San Pedro Oscurana, MacDougall s.n. (us); San
Pedro Istmo, MacDougall s.n. (us).
Flourensia collodes is distinguished by its large,
falcate, lance-ovate leaves and capitula with ( 1 2-)
1 3 (-1 6) ray florets. Its associates include Bursera,
Ceiba, and Heliocarpus.
Although, in Greenman's description, he cited
the type collection as Nelson 307, it is clearly
marked as 3071 on the holotype and isotype spec-
imens.
9. Flourensia glutinosa (Robinson & Greenman)
S. F. Blake, Proc. Amer. Acad. Arts 49: 374.
1913. Figures 12, 14.
Encelia glutinosa Robinson & Greenman, Amer. J.
Sci. III. 50: 1955. 1895. TYPE: Mexico, Oaxaca,
Las Hoyas Canyon, 4,500 ft, 2 Nov. 1894, C. G.
22
FIELDIANA: BOTANY
1cm
2cm
FIG. 1 1. Flour ensia col lodes (from Dillon & Reynolds 696, F). A, habit; B, capitulum.
Pringle 6024 (holotype, GH!; isotypes, A!, BM!, MO!,
MSC!, NY!, uc!, us!).
Arborescent shrubs to 5 m tall, the bark gray,
furrowed; branchlets pilose-lanate. Leaves ovate
to ovate-lanceolate, 4.5-13 cm long, 1.5-3.8 cm
wide, falcate, upper surface minutely strigillose,
lower surface glabrous, basally cuneate, apically
acuminate, the margins entire, strigillose; petioles
2-4 mm long, lanate-pilose to glabrescent. Capitu-
lescences cymose-paniculate, 5-20-headed; pe-
duncles 2-5 cm long, striate, puberulent, brac-
teate. Capitula radiate, 1-1.5 cm high, ca. 1 cm
wide; involucres hemispheric; phyllaries 3-4-se-
riate, imbricate, indurate, striate, the outer lan-
ceolate, 2-3.5 mm long, 0.6-1 mm wide, apically
acute, ciliolate, the inner oblong- lanceolate, 3-5.5
mm long, 1-1.5 mm wide, apically attenuate to
obtuse, ciliolate; paleae oblanceolate, 8-1 1 mm
long, apically truncate and crested with two scar-
ious wings, ciliolate; ray florets 7-10, the ligules
oblong-oval, 11-23 mm long, 5-7 mm wide, the
tube pilose; disc florets ca. 40, the corollas cylin-
drical, ca. 7 mm long, the tube ca. 1.5 mm long,
the lobes ca. 1.5 mm long. Achenes obconical to
narrowly cuneate, 6.5-1 1 mm long, sericeous-pi -
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
23
2cm
FIG. 12. Flourensia glutinosa (from Dillon & Reynolds 678, F). A, habit; B, capitulum; C, disc floret.
lose; pappus of 2 (rarely 4) awns, 2-5 mm long,
occasionally deciduous.
FLOWERING (AND FRUITING) PERIOD October-
November (November-December).
DISTRIBUTION AND HABITAT (Fie. 14) Infre-
quent on limestone and shale slopes in the valleys
of the Mesa del Sur of southern Puebla and western
Oaxaca (1,400-1,600 m).
SPECIMENS EXAMINED MEXICO. Oaxaca: 50 km
NNW of Teliztlahuaca, along road to Tehuacan, Cron-
quist & Fay 10923 (ENCB, F, GH, MICH, MSC, NY, TEX, us);
6 mi above Domiquillo, Nelson 1832 (GH, us). Puebla:
14 mi NW of Huajuapan de Leon, Dillon & Reynolds
678 (F, GH, HUT, MEXU, MO, NY, TEX, US).
Flourensia glutinosa is distinguished by its ar-
borescent habit and 5-20-headed, cymose-panicu-
24
FIELDIANA: BOTANY
FIG. 13. A-C, Flourensia cernua (from Cronquist 11262, MO). A, habit; B, capitulum; C, floret. D, F. cernua x
F. resinosa (from Cronquist 11263, MO). E-G, F. resinosa (from Cronquist 9626, MO). E, habit; F, capitulum; G, disc
floret.
late capitulescences. Its associates include Brahea,
Opuntia, and Tithonia.
10. Flourensia resinosa (Brandegee) S. F. Blake,
Proc. Amer. Acad. Arts 49: 375. 1913. Figures
13, 14.
Encelia resinosa Brandegee, Zoe 5: 240. 1906. TYPE:
Mexico, Hidalgo, Ixmiquilpan. mountains, Aug.
1905, C. A. Purpus 1458 (holotype, uc!; isotypes F!,
GH!, MO!, NY!).
Shrubs to 2 m tall, the bark grayish brown to
black; branchlets reddish brown, striate. Leaves
lanceolate to narrowly oblong-elliptic, 3.5-7 cm
long, 0.8-1.8 cm wide, upper and lower surfaces
sparsely strigillose, basally acute to cuneate, api-
cally acute, the margins entire, strigillose; petioles
2-4 mm long. Capitulescences weakly cymose, 2-4
(-S)-headed; peduncles 2-7 mm long, bracteate.
Capitula radiate, 11-17 mm high, 10-17 mm wide;
involucres hemispheric; phyllaries 3-seriate, sub-
equal, herbaceous, narrowly lanceolate, 5-9 mm
long, 1-2 mm wide, apically acute to acuminate;
paleae oblanceolate, 8-12 mm long, apically acute
to acuminate; ray florets ca. 10, the ligules oblong,
13-22 mm long, 5-9 mm wide, the tube puber-
ulent; disc florets 30-50, the corollas cylindric, 6-
7 mm long, the tube ca. 1 mm long, the lobes ca.
1 mm long. Achenes obconical to cuneate, ca. 8
mm long, the margins sericeous, the faces sparsely
sericeous, glabrescent; pappus to 2 awns, 3-5 mm
long, persistent. Chromosome number: n = 18.
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
25
50 100 200 mi.
4 1 * 1-
M-l-l_( 1 ,
50 150 225 km.
O
-15
O Flourensia collodes
() Flourensia glutinosa
Flourensia resinosa
FIG. 14. Distribution of Flourensia collodes, F. glutinosa, and F. resinosa.
FLOWERING (AND FRUITING) PERIOD June-No-
vember (December-January).
DISTRIBUTION AND HABITAT (FiG. 14) Domi-
nant locally on low, arid, limestone hillsides in the
vicinity of Ixmiquilpan, Hidalgo, Mexico (1,000-
1,900 m). This region is considered a southern
extension of the Chihuahuan Desert (Rzedowski,
1973).
REPRESENTATIVE SPECIMENS EXAMINED MEXICO.
Hidalgo: 1 2 km SE of Ixmiquilpan, Chiang et al. 855
(BM, F); 7 mi SE of Ixmiquilpan, Cronquist 9626 (GH,
MICH, MO, TEX, us); 10 mi SE of Ixmiquilpan, Dillon &
Reynolds 676 (F, MEXU, MO, NY, TEX); 6 mi S of Ixmi-
quilpan, Graham & Johnston 4758* (TEX); El Capulin,
between Actopan and Ixmiquilpan, Moore 1265 (BM, GH,
MICH, us); ca. 2 mi W of Villagran, Quintero 2006 (TEX);
38 mi NW of Pachuca, Waterfall & Wallis 14098 (us).
Flourensia resinosa is distinguished by its ex-
tremely resinous, lanceolate to elliptic leaves and
long- pedunculate capitula with 10 ray florets. Its
associates include Agave, Dasylirion, Hechtia,
Opuntia, Yucca, and Zaluzania.
It is sympatric with Flourensia cernua at lower
elevations within its distribution. Cronquist col-
lected what he believed to be a hybrid from an
area 15 km southeast of Ixmiquilpan (11263; F,
GH, MO, NY, TEX, us). This specimen has charac-
teristics intermediate between its supposed par-
ents. Table 2 and Figure 13 compare these taxa.
Further sampling will be necessary to assess the
extent and direction of hybridization at this lo-
cality.
Schultz Bipontinus (ca. 1 840) annotated Ehren-
berg 1564 (B), from the vicinity of Ixmiquilpan,
as Flourensia glutinosa sp. nov.\ however, he pro-
vided no description. Around 1914, Blake anno-
tated the specimen as F. schultzii, since the epithet
glutinosa was preoccupied, but also provided no
description. In his revision, Blake (1921) recog-
nized the specimen as F. resinosa, and from an
examination of a photograph of that collection, I
agree with Blake's placement.
Label data from Moore 1265 indicate possible
use of this species by local peoples as "edible ex-
udate chewed like chicle."
26
FIELDIANA: BOTANY
Although Brandegee cited Purpus 1456 as the
type in the original description, the correct number
of the collection is 1458.
1 1 . Flourensia monticola Dillon, Southw. Natu-
ralist 21: 147. 1976. TYPE: Mexico, Coahuila,
dry, limestone and shale slopes, 13.5 km E of
Los Lirios, 24 km W of La Jacinta (N.L.) very
near Nuevo Leon state line, 2,150 m, 7 Nov.
1972, F. Chiang, T. Wendt, & M. C. Johnston
10130 (holotype, TEX!; isotype, MEXU!). Figures
15, 18.
Shrubs to 2 m tall; stems much-branched from
base, ascending, the bark black. Leaves lanceo-
late to obovate, 6-1 1.5 cm long, 2-4.5 cm wide,
crowded at tips of branchlets, upper and lower
surfaces sparsely strigillose, basally acute to cu-
neate, apically acute, obtuse, or occasionally re-
tuse, the margins entire, strigillose; petioles 1.8-
2.2 cm long. Capitulescences solitary (rarely
2-headed), terminal on branchlets; peduncles 4-
11 cm long, bracteate. Capitula radiate, 1.2-1.5
cm high, 1.5-2 cm wide; involucres hemispheric;
phyllaries 3-seriate, subequal, herbaceous, the out-
er lanceolate, 9-1 3 mm long, 2-2.5 mm wide, api-
cally acute to attenuate, the inner ovate-lanceolate
to oblong, 1 1-16 mm long, 2.5-3 mm wide, api-
cally acute to acuminate; paleae oblanceolate, ca.
1 cm long, apically acute to attenuate: ray florets
(10-) 1 3 (-1 5), the ligules oblong, 20-30 mm long,
5-7 mm wide; disc florets ca. 50, the corollas cy-
lindric-campanulate, ca. 8 mm long, the tube ca.
1.5 mm long, the lobes ca. 1.5 mm long. Achenes
obconical to cuneate, 8-9 mm long, the margins
sericeous, the faces sparsely sericeous, glabrescent;
pappus of 2 awns, ca. 5 mm long, persistent. Chro-
mosome number: n = 18.
FLOWERING (AND FRUITING) PERIOD July-No-
vember (November-December).
DISTRIBUTION AND HABITAT (Fio. 18) Known
from three localities in canyons of the northern
Sierra Madre Oriental (ca. 2,150 m). This appar-
ently local species is found on dry, southwest-fac-
ing limestone and shale slopes.
SPECIMENS EXAMINED MEXICO. Coahuila: Canon
de Los Lirios, 10 mi E of Los Lirios, on road to La
Jacinta, N.L., and Cola de Caballo, Dillon & Hartman
656* (F, HUT, MEXU, MO, NY, TEX). Nuevo Leon: Can6n
del Diente, S of Monterrey, C. H. & M. T. Mueller 252
(F, GH, MEXU, TEX); near Monterrey, Smith A/275 (TEX);
Cerro de La Silla, White & Chatters 9 (MEXU, MICH).
TABLE 2. Distinguishing characteristics of Flourensia
cernua, F. resinosa. and a putative hybrid (values are
given for the entire range of the taxa).
Character
F.
cernua
Putative
hybrid
F.
resinosa
Leaf length (cm)
ca.
2.5-3.5
3.5-7
1.7-2.5
Peduncles (cm)
ca. 1
1-5
2-7
Ray florets
Absent
1-7 or
ca. 10
absent
Ligules length (cm)
Absent
<1
1.3-2.2
% Pollen stain-
>90
ca. 36
>90
ability (> 500
grains each)
Flourensia monticola is distinguished from F.
resinosa and F. pulcherrima, its nearest relatives,
by possessing wider leaves and capitula that are
intermediate in size. In the vicinity of the type
locality, it is associated with Agave, Finns, and
Quercus.
12. Flourensia pulcherrima Dillon, Southw. Nat-
uralist 21: 145. 1976. TYPE: Mexico, Durango,
steep limestone slopes, N end of Sierra de Ro-
sario, ca. 20 km SW of Mapimi and 3 km E of
Santa Librada, 2,000 m, 25 June 1973, M. C.
Johnston, F. Chiang, & T. Wendt 11469* (ho-
lotype, TEX!; isotype, MEXU!). Figures 16, 18.
Shrubs to 1.5 m tall; stems much-branched ba-
sally, the bark black. Leaves lanceolate to narrowly
elliptic, (5-) 8-12 (-15) cm long, 2-3 cm wide,
upper and lower surfaces puberulent, attenuate at
both ends, the margins entire. Capitulescences sol-
itary, terminal on branchlets, or weakly cymose,
3-5-headed; peduncles 1-6 cm long, bracteate. Ca-
pitula radiate, 1.5-2 cm high, 1.3-2 cm wide; in-
volucre broadly hemispheric; phyllaries 2-seriate,
the outer linear to lanceolate, 1 8-20 mm long, 2-
3 mm wide, the inner ovate-lanceolate, 10-12 mm
long, 2-3 mm wide, all basally indurate, all api-
cally attenuate, herbaceous, puberulent, reflexed
in fruit; paleae oblanceolate, 10-15 mm long, api-
cally acute to attenuate, ciliolate; ray florets ca. 1 3,
the ligules oblong, 22-26 mm long, 5-6 mm wide,
the tube ca. 6 mm long, sericeous; disc florets 50-
60 (-1 50), the corollas cylindric, 6-7 mm long, the
tube ca. 1 mm long, the lobes ca. 1 mm long.
Achenes obconical, 7-9 mm long, the margins se-
riceous, the faces short-sericeous, glabrescent;
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
27
FIG. 15. Flourensia monticola (from Chiang, Wendt, & Johnston 10130, TEX).
28
FIELDIANA: BOTANY
FIG. 16. Flourensia pulcherrima (from Johnston, Chiang, & Wendt 11469, TEX).
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
29
pappus of 2 awns, 3-5 (-6) mm long, persistent.
Chromosome number: n 1 8.
FLOWERING (AND FRUITING) PERIOD June-Oc-
tober (October-November).
DISTRIBUTION AND HABITAT (Fio. 18) Found
on steep, limestone slopes in the mountains as-
sociated with the Bolson de Mapimi in eastern
Chihuahua, northeastern Durango, and south-
western Coahuila, Mexico (1,500-2,100 m).
SPECIMENS EXAMINED MEXICO. Chihuahua: Sierra
de las Pampas, Chiang et al. 8836 (TEX); 20 km ENE of
Cd. Jimenez, NW of summit of Sierra de Chupaderos,
Henrickson 13754 (TEX). Coahuila: ca. 26 mi SE of Tor-
re6n, Sierra de Jimulco, Henrickson 13130 (TEX); Sierra
de Jimulco, Johnston et al. 11506 (TEX). Durango: N end
of Sierra del Rosario, ca. 20 km SW of Mapimi, Dillon
& Hartman 647 (F, MO, TEX); Sierra del Rosario, Wendt
et al. 10014 (TEX).
Flourensia pulcherrima is distinguished by its
narrowly lanceolate to elliptic leaves and long
phyllaries, often overtopping the disc. Its associ-
ates include Agave, Dasylirion, Fouquieria, and
Yucca.
1 3. Flourensia pringlei (A. Gray) S. F. Blake, Proc.
Amer. Acad. Arts 49: 375. 1913. Figures 17, 18.
Helianthella pringlei A. Gray, Proc. Amer. Acad. Arts
21: 389. 1886. TYPE: Mexico, Chihuahua, rocky
hills near Chihuahua City, 7 Sept. 1885, C. G. Prin-
gle 646 (holotype, GH!; isotypes, BM!, F!, MO!, NY!,
us!).
Encelia oblonga Robinson & Fern., Proc. Amer. Acad.
Arts 30: 118. 1894. TYPE: Mexico, Chihuahua,
plains near Casas Grandes, 10 Oct. 1891, C. V.
Hartman 812 (holotype, GH!; isotype, us!).
Suffruticose subshrubs to 1 m tall; stems erect;
usually unbranched, yellowish green. Leaves ellip-
tic to oblong-lanceolate (2-) 5-10 cm long, 1-4.3
cm wide, upper and lower surfaces strigose, basally
cuneate, apically acute to rounded, the margins
entire, strigose. Capitulescences solitary, terminal;
peduncles 5-1 1 cm long, bracteate. Capitula ra-
diate, 1-2 cm high, 1.5-2.5 cm wide; involucres
broadly hemispheric, subtended by calyculate, fo-
liaceous bracts; phyllaries ca. 2-seriate, linear from
ovate base, 10-30 mm long, 1.5-2 mm wide, api-
cally attenuate, ciliolate; paleae oblanceolate, ca.
1 1 mm long, apically acute to obtuse; ray florets
1 3-2 1 , the ligules oblong to oval, 10-16 mm long,
3-4 mm wide, the tube 5-7 mm long, sericeous;
disc florets 40-50, the corollas cylindric, ca. 6.5
mm long, the tube ca. 1 mm long, the lobes ca. 1
mm long. Achenes cuneate, ca. 12 mm long, 4-8-
ribbed, subterete, sericeous, pappus of 2 awns, ca.
4 mm long, persistent or disarticulating.
FLOWERING (AND FRUITING) PERIOD August-
October (September-October).
DISTRIBUTION AND HABITAT (Fio. 18) Known
from rocky foothills of the eastern Sierra Madre
Occidental from southwestern New Mexico,
United States, and central Chihuahua to central
Durango, Mexico (1,500-2,100 m).
SPECIMENS EXAMINED MEXICO. Chihuahua: Ran-
cho Tepehuanes, Namiquipa, Enriquez 207 (F, TEX); 4
mi S of Matamoros, Gentry & Arguelles 17927 (TEX, us);
4.6 mi NE of Buenaventura, Oliver et al. 542 (MO); hills
near Chihuahua, Pringle 1056 (F, MO, MSC, NY, uc). Du-
rango: El Oro to Guanacevi, Nelson 4730 (us); vicinity
of Santiago Papasquiaro, Palmer 425 (BM, F, GH, MO, NY,
uc, us). UNITED STATES. New Mexico: Hidalgo Co.:
along SW side of Alamo Hueco Mts., R. & M. Spellen-
berg 3861 (NY, TEX).
Flourensia pringlei is distinguished by its suf-
fruticose habit with 6-12 erect, leafy stems and
large capitula with long linear phyllaries. In south-
western New Mexico, it is found on severely ov-
ergrazed slopes that are eroded down to cobble-
stone. Its associates in this area include Fouquieria,
Jatropha macrorhiza, Juniperus, Pectis filipes, P.
prostrata, Portulaca suffrutescens, Quercus arizo-
nica, Talinum paniculatum, and T. parviflorum
(R. Spellenberg, pers. comm.).
14. Flourensia thurifera (Molina) DC., Prodr.
5: 592. 1836. Figures 19, 20.
Helianthus thurifera Molina, Sagg. Stor. Nat. Chil. 1 60.
1782. TYPE: Chile, Valparaiso, vicinity of Valpa-
raiso, Molina s.n. The holotype has not been located
at Bolo where it may have originally been deposited.
NEOTYPE: Chile, Valparaiso, sonnige Abhange, 7
Oct. 1895, Buchtien s.n. (neotype, us!, photograph,
F!; isoneotype, GH!, photograph, F!).
Diomedea thurifera (Molina) Bertero ex Colla, Mem.
Acad. Sci. Torino 38: 37. 1835.
Helianthus glutinosus Hook. & Am., Bot. Beechey Voy.
p. 32. 1830. TYPE: Chile, Valparaiso, T. Bridges
s.n. (holotype, GL, not seen).
Flourensia besseriana Meyen & Walp., Nov. Act. Aca.
Caes. Leop. Carol. 19: 270. TYPE: Chile, no exact
locality, B. Besser s.n. (holotype, B, destroyed; lec-
totype, here designated, fragment, GH!; photograph
of B specimen, F!, GH!).
Helianthus besseriana (Meyen & Walp.) Benth. & J.
D. Hook, ex J. D. Hook. & A. B. Jackson, Ind. Kew.
1: 1112. 1893.
30
FIELDIANA: BOTANY
2 cm
FIG. 17. Flourensia pringlei. A, habit (from Pringle 1056, F); B, capitulum (from Palmer 425, F).
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
31
25
20
Flourensia microphylla
Flourensia monticola
Flourensia pulcherrima
Flourensia pringlei
FIG. 18. Distribution of Flourensia microphylla, F. monticola, F. pringlei, and F. pulcherrima.
Flourensia thurifera var. lanceolata Remy in Gay, Hist.
Chil. 4: 288. 1849. TYPE: p, not seen.
Shrubs to 2 m tall; stems erect, the bark brown;
branchlets reddish brown, puberulent. Leaves ovate
to oblong-elliptic, 5.5-11.5 cm long, 1 .5-4 cm wide,
upper and lower surfaces strigillose, basally cu-
neate, apically subacuminate to obtuse, the mar-
gins shallowly repand-dentate with 4-10 pairs of
triangular, mucronate teeth (rarely subentire),
strigillose; petioles 3-9 mm long, villosulose. Ca-
pitulescences cymose, 4-8 -headed; peduncles 3-
1 3 cm long, bracteate. Capitula radiate, 10-15 mm
high, 14-25 mm wide; involucres hemispheric;
phyllaries 2-3-seriate, subequal, herbaceous,
densely to sparsely villous, lanceolate to oblong-
spatulate, 6-17 mm long, 1-3 mm wide, apically
acute to acuminate, mucronulate; paleae oblan-
ceolate 9-10 mm long, apically obtuse to rounded,
often puberulent; ray florets ca. 13, the ligules oval
to oblong-oval, 14-30 mm long, 5-10 mm wide,
the tube villosulose; disc florets ca. 50, the corollas
slender- funnelform, ca. 6.5 mm long, the tube ca.
2 mm long, the lobes ca. 0.6 mm long, puberulent.
Achenes oblong-cuneate to obconical, 7-8 mm
long, densely sericeous; pappus of 2-3 (rarely 4)
awns, 3-4 mm long, basally ampliate, persistent.
Chromosome number: 2n = 36.
32
FIELDIANA: BOTANY
I cm
FIG. 19. Flourensia thurifera (from Behn s.n., F). A, habit; B, capitulum; C, disc floret.
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
33
30
32
36
FIG. 20. Distribution of Flourensia thurifera.
FLOWERING (AND FRUITING) PERIOD August-
November (November-December).
DISTRIBUTION AND HABITAT (Fie. 20). Fre-
quent in the evergreen sclerophyllous scrub of
coastal Chile from Coquimbo, south to Santiago,
and one collection from near Concepcion (400-
1,000m).
VERNACULAR NAMES Flor del incienso, incien-
so, maravilla, maravilla del campo, maravilla del
cerro.
REPRESENTATIVE SPECIMENS EXAMINED CHILE.
Aconcagua: San Felipe, Claude-Joseph 1353 (us); Que-
mados to Zapallar, Kausel 2578 (LIL); between Calera
and San Felip, Killip & Pisano 39769 (us). Concepcion:
Tome, Vera 25 (LIL). Coquimbo: 40 km S of La Serena,
Cabrera 12582 (LP); Cuesta Los Hornos, ca. 10 km from
Illapel, Kausel 4597 (LP); Tulahuen, Geisse s.n. (GH);
Fray Jorge, Jiles 306 (si), 707 (LIL); Tongoycillo, Jiles
1519 (LP); Zorrilla, Jiles 1623 (LIL); Quebrada de La-
marones, S of La Serena, Solbrig 3043 (GH); Vicuna,
Wagenknecht 18471 (F, GH, uc, MO); Rivadavia, Wer-
dermann 90 (A, BM, F, GH, LIL, NY, si, uc). Santiago:
Cerro San Cristobal, Cabrera 11330 (LP); Santiago,
Claude-Joseph 922 (us); Tiltil, Grandjot s.n. (MO); Cerro
de Renca, Looser 2942 (TEX). Valparaiso: Valparaiso,
Bertero 954 (BM, F, GH, MO); Llay-Llay, Cabrera 12516
(LP); Marga-Marga, Jaffuel 3659 (GH); Limache, Looser
627 (GH).
Flourensia thurifera is distinguished by its large
ovate to oblong-elliptic, shallowly repand-dentate
34
FIELDIANA: BOTANY
leaves, foliaceous phyllaries, and large capitula and
rays. There is considerable variation in leaf shape
and size that is presumably environmentally in-
duced; capitular morphology is quite constant.
Carhuaz and Yungay, Ferreyra 14337 (USM). La Liber-
tad: Santiago de Chuco, Los Quengos, Ldpez 435 (LIL,
LP, USM), 970 (HUT). Lima: Huarochiri, KM 86 near
Matucana, Ferreyra 7014 (us, USM); Matucana, Mac-
bride 2929 (F), Macbride & Featherstone 247 (F, GH, us).
15. Flourensia macrophylla S. F. Blake, Bot. Jahrb.
Syst. 54: 47. 1916. TYPE: Peru, Lima, Huaro-
chiri, stony places, 2,370-2,650 m, along Lima-
Oroya Railroad, between Matucana and Tambo
de Viso, 26 Dec. 1901, A. Weberbauer 119 (ho-
lotype, B, destroyed; lectotype, here designated,
fragment, GH!; photograph of B specimen, F!,
GH!). Figures 21, 26.
Shrubs to 2 m; stems much-branched, the bark
black; branchlets reddish brown, puberulent.
Leaves oval to oblong-oval, 5-10 cm long, 2-4 cm
wide, upper and lower surfaces glabrous, basally
broadly cuneate, apically obtuse to rounded, the
margins shallowly cuspidate-denticulate, strigil-
lose, the lower third entire; petioles 2-5 mm long,
strigillose. Capitulescences cymose-paniculate, 3-
6-headed; peduncles 3-6 cm long, bracteate. Ca-
pitula radiate, 9-12 mm high, 10-11 mm wide;
involucres campanulate; phyllaries 2-3 -seriate,
subequal, herbaceous, the outer lanceolate to ob-
lanceolate, 5-8 mm long, 1.5-2.5 mm wide, api-
cally acute, ciliolate, the inner oblanceolate to nar-
rowly rhombic-obovate, apically acute, ciliolate;
paleae oblanceolate, ca. 8 mm long, apically sub-
cucullate to truncate, fimbriate; ray florets ca. 8,
the ligules oval to oblong, 14-20 mm long, ca. 5
mm wide, the tube ca. 4 mm long, villosulose; disc
florets 10-30, the corollas cylindric-funnelform,
ca. 5 mm long, the tube ca. 1 mm long, the lobes
ca. 0.6 mm long. Achenes obconical, ca. 5 mm
long, densely sericeous; pappus of 2 awns, ca. 4
mm long, persistent.
FLOWERING (AND FRUITING) PERIOD Decem-
ber-March (March-May).
DISTRIBUTION AND HABITAT (Fio. 26) Scat-
tered populations on dry, rocky slopes along the
western Cordillera of the Andes from northern to
central Peru (2,500-3,500 m).
VERNACULAR NAMES Carcarillo, sdmana, uno.
REPRESENTATIVE SPECIMENS EXAMINED PERU. An-
cash: Bolognesi, ca. Chiquian, Cerrate 103 (USM), Fer-
reyra 5668 (us, USM); Carhuaz, Infantes 1122 (LIL);
Huaraz, 4 km S of Huaraz, Rio Santa Valley, Dillon el
al. 3171 (BM, F, GH, HUT, MEXU, MO, NY, TEX, us, USM);
Huaylas, Caraz, Ferreyra 14615 (us, USM); Recuay, Mar-
ca, Richardson 2087 (BM, F, MO, TEX); Yungay, between
Flourensia macrophylla is readily distinguished
by its large oval or oblong-oval, regularly dentic-
ulate leaves and small capitula with ca. 8 ray flo-
rets. The size of the leaves and capitula vary;
smallest individuals occur in the north and larger
ones to the south.
1 6. Flourensia angustifolia (DC.) S. F. Blake, Contr.
U.S. Natl. Herb. 20: 407. 1921. Figures 22, 26.
Flourensia thurifera var. angustifolia DC, Prodr. 5:
592. 1836. TYPE: Peru, Junin, Tarma, J. Dombey
24 pro parte (lectotype, here designated, G-DC, IDC
Microfiche 800. 952: I. 1!; isotype, B, destroyed;
photograph of B specimen, F!). There appear to be
two taxa in the first frame of the microfiche. The
Dombey specimen to the right is clearly marked and
is here chosen as the lectotype. DeCandolle listed
Dombey, Haenke, and Nee in the protologue, but
the last two collectors do not have representative
material in the microfiche. Dombey's collection is
labeled "Chile" in G-DC, but the B specimen was
marked as from Tarma, unquestionably the origin
of this plant.
Shrubs to 2 (-3) m tall; branchlets resinous, red-
dish brown. Leaves lanceolate to oblong-lanceo-
late, 8-13 cm long, 1.5-2 cm wide, upper and
lower surfaces glabrous, basally and apically acute
to acuminate, the margins shallowly cuspidate with
lower '/3 entire, strigillose; petioles 2-5 mm long,
strigillose. Capitulescences cymose, 3-6-headed;
peduncles 1-6.5 cm long, bracteate. Capitula ra-
diate, 8-10 mm high, 8-15 mm wide; involucres
hemispheric to campanulate; phyllaries 2-3-seri-
ate, subequal, herbaceous, lanceolate to linear-lan-
ceolate, 4-9 mm long, 1-2 mm wide, apically acute
to attenuate, ciliolate; paleae oblanceolate, 9-12
mm long, apically acute to subcucullate; ray florets
ca. 8, the ligules oblong to oval, 13-20 mm long,
5-8 mm wide, the tube ca. 5 mm long, villosulose;
disc florets 30-40, the corollas cylindric-campan-
ulate, 6-7 mm long, the tube ca. 1.5 mm long, the
lobes 0.6 mm long. Achenes obconical, 6-8 mm
long, densely sericeous; pappus of 2 awns, 3-5 mm
long, persistent. Chromosome number: n = 18.
FLOWERING (AND FRUITING) PERIOD Decem-
ber-April (February-June).
DISTRIBUTION AND HABITAT (Fie. 26) Abun-
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
35
5mm
1cm
FIG. 21. Flourensia macrophylla (from Macbride 2929, F). A, habit; B, capitulum; C, disc floret.
36
FIELDIANA: BOTANY
1 cm
2 cm
FIG. 22. Flourensia angustifolia (from Killip & Smith 21792, F). A, habit; B, capitulum; C, disc floret.
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
37
dant on clay or serpentine soils within the inter-
montane valleys of the Cordillera Central in cen-
tral Peru (1,700-3,300 m).
VERNACULAR NAMES Aserijaeba, pfanca.
REPRESENTATIVE SPECIMENS EXAMINED PERU.
Huanuco: Huanuco, near Huanuco, Kanehira 77 (F, GH).
Junin: Tarma, Tarma, Cerro San Bartolome, Dillon &
Rodriguez 449* (F, HUT, TEX, USM), Dillon & Turner
1317 (F, MO, TEX, USM); Tarma, Macbride & Featherstone
1018 (F, GH, us); between Acobamba and Tarma, Stork
10951 (F, uc); Acobamba, Woytkowski 54 (F).
Flourensia angustifolia is distinguished by its
narrowly oblong-lanceolate leaves with shallowly
cuspidate margins and small capitula with ca. 8
ray florets. Its associates include Acacia, Opuntia,
and Prosopis.
17. Flourensia peruviana Dillon, Ann. Missouri
Dot. Gard. 68: 108. 1981. TYPE: Peru, Huan-
cavelica, Huancavelica, Checcyancu, al 4 km E
de Conaica, 3,000-3,500 m, 14 March 1971, O.
Tovar 193 (holotype, us!; isotypes, F!, LP!, USM!).
Figures 23, 26.
Shrubs to 2 m tall. Leaves lanceolate to oblong-
lanceolate, (5-) 7-10 (-12) cm long, (1-) 1.5-2 (-
3) cm wide, upper and lower surfaces glabrous,
basally broadly cuneate, apically acute to obtuse,
the margins entire, strigillose; petioles (2-) 4-8 (-
1 0) mm long. Capitulescences cymose-paniculate,
4-20-headed; peduncles 5-50 mm long, bracteate.
Capitula radiate, ca. 10 cm high, 7-10 mm wide;
involucres hemispheric; phyllaries 2-3-seriate,
imbricate, herbaceous, the outer lanceolate, 2-3
mm long, 1-1.5 mm wide, apically acute, the inner
elliptic-obovate, 3-5 mm long, ca. 1.5 mm wide,
laterally chartaceous, apically acute; paleae oblan-
ceolate, ca. 9 mm long, apically rounded, erose;
ray florets 8-10, the ligules oblong to oval, 10-18
mm long, ca. 5 mm wide, the tube ca. 5 mm long,
villosulose; disc florets 20-40, the corollas cylin-
dric-campanulate, ca. 7 mm long, the tube ca. 1.5
mm long, the lobes ca. 0.5 mm long. Achenes
obconical, ca. 10 mm long, sericeous; pappus of
2 awns, ca. 3 mm long, readily disarticulating.
FLOWERING (AND FRUITING) PERIOD Febru-
ary-April (March-May).
DISTRIBUTION AND HABITAT (Fio. 26) Known
from dry, rocky slopes in the quebradas associated
with the Rio Mantaro in south-central Peru ( 1 ,700-
3,500 m).
VERNACULAR NAMES Chilca negra, yana-chil-
ca.
SPECIMENS EXAMINED PERU. Ayacucho: Huaman-
ga, La Mejorada to Ayacucho, KM 15, Ochoa 574 (GH);
Huamanga, Chaquihuaycco, above Ayacucho, Tovar
5491 (USM); Huamanga, Chanchara, Rio Cachi, Tovar
5589 (SM), 5709 (USM). Huancavelica: Tayacaya, be-
tween Izcuchaca and Mariscal Caceres, Tovar 1378 (LP,
USM).
Flourensia peruviana differs from F. polyce-
phala in possessing much smaller phyllaries of the
same shape. Its leaves are comparable in size and
shape to those of F. angustifolia, but differ in hav-
ing strictly entire margins.
18. Flourensia polycephala Dillon, Ann. Missouri
Bot. Gard. 68: 106. 1981. TYPE: Peru, Cuzco,
Calca, Pisac, April 1943, 3,000 m, F. Marin 231
(holotype, LIL!; isotype F!). Figures 24, 26.
Shrubs to 4 m; branchlets puberulent. Leaves
lanceolate to lance-elliptic, (8-) 10-12 (-14) cm
long, 1.5-2.5 (-3) cm wide, upper and lower sur-
faces glabrous, basally cuneate, apically acute or
rarely obtuse, the margins entire, strigillose; pet-
ioles 2-5 mm long. Capitulescences cymose-pa-
niculate, 4-8-headed; peduncles (1-) 3-5 (-7) cm
long, bracteate. Capitula radiate, 1 5-20 mm high,
10-15 mm wide; involucres hemispheric; phyl-
laries 3-seriate, imbricate, herbaceous, the outer
linear-lanceolate, (5-) 7-9 mm long, ca. 1 mm
wide, apically attenuate, the inner rhombic, 8-9
mm long, 3-3.5 mm wide, laterally chartaceous,
apically attenuate, ciliolate; paleae oblanceolate,
ca. 9 mm long, apically acute to rounded, erose,
ciliolate; ray florets 10-13, the ligules oblong, ca.
30 cm long, 5-6 mm wide, the tube ca. 5 mm long;
disc florets 20-30, the corollas cylindric-campan-
ulate, ca. 7 mm long, the tube ca. 1 mm long, the
lobes ca. 0.5 mm long. Achenes obconical, 8-9
mm long, villous-sericeous; pappus of 2 awns, ca.
3 mm long, readily disarticulating.
FLOWERING (AND FRUITING) PERIOD January-
April (March-May).
DISTRIBUTION AND HABITAT (Fio. 26) Known
from dry, rocky slopes in the quebradas associated
with the Rio Apurimac and Rio Urubamba in
southeastern Peru (2,700-3,200 m).
SPECIMENS EXAMINED PERU. Apurimac: Grau, Or-
opeza Valley, Vargas 9784 (F, uc). Cuzco: Calca, Hda.
Urco, Vilcanota Valley, Vargas 683 (F, MO); Urubamba,
ESE of Cuzco, Ellenberg 1000 (us); Huasao, Herrera
3098 (us); Urubamba, Lamallva 53 (LP); Rumichaca,
Vargas 7597 (LIL); Chicon Canyon, Vargas 11053 (F,
uc).
38
FIELDIANA: BOTANY
5 mm
FIG. 23. Flourensia peruviana (from Tovar 193, F). A, habit; B, capitulum; C, disc floret.
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
39
FIG. 24. Flourensia polycephala (from Mann 231, F). A, habit; B, capitulum; C, disc floret.
Flourensia polycephala differs from the closely
related F. heterolepis (Bolivia) in having more nu-
merous capitula in cymose capitulescences with
generally shorter peduncles. It has longer phylla-
ries and more ray florets than its nearest geograph-
ical neighbor, F. peruviana.
19. Flourensia heterolepis S. F. Blake, Contr. Gray
Herb. n.s. 54: 186. 1918. nom. nov. Figures 25,
26.
Viguiera glutinosa Rusby, Mem. Torrey Bot. Club
4:211. 1895. TYPE: Bolivia, Cochabamba, Coch-
abamba, 189 1, N. H. Bang 977 (holotype, NY!, pho-
tograph F!; isotypes, BM!, GH!, MO!, us!). Non Flour-
ensia glutinosa (Robinson & Greenman) S. F. Blake,
Proc. Amer. Acad. 49: 374. 1913.
Shrubs to 1 m tall. Leaves elliptic-lanceolate to
oblong-ovate, 7.5-13 (-14.5) cm long, 1.4-2.5 cm
wide, upper and lower surfaces strigillose to gla-
brous, basally cuneate, apically acute to obtuse,
the margins entire, strigillose; petioles 6-16 mm
long. Capitulescences solitary to weakly cymose,
2-5-headed; peduncles (3-) 5-8 cm long, brac-
teate. Capitula radiate, 15-20 mm high, 10-20
mm wide; involucres hemispheric; phyllaries
40
FIELDIANA: BOTANY
5mm
I cm
FIG. 25. Flourensia heterolepis (from Brooke 6220, F). A, habit; B, capitulum; C, disc floret.
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
41
5(
10
o
o-
15
20
50 100 200
' I 1 1 1
5O IOO 200 3OO 40O
O Flourensia macrophylla
~jf F_. angustifolia
25 ^X heterolepis
A polycephala
F_. peruviana
1 F. fiebrigii
FIG. 26. Distribution of Flourensia angustifolia, F. fiebrigii, F. heterolepis, F. macrophylla, F. peruviana, and F.
polycephala.
3-seriate, imbricate, the outer lanceolate, 7-9 mm
long, 1-2 mm wide, apically acute, the inner rhom-
bic-ovate, 8-10 (-11) mm long, (2-) 3-3.5 mm
wide, laterally chartaceous, fimbriate, apically at-
tenuate; paleae oblanceolate, ca. 8 mm long, api-
cally rounded to cucullate, erose to fimbriate,
sometimes cuspidulate; ray florets ca. 13, the lig-
ules oblong, 15-25 mm long, 5-7 mm wide; the
42
FIELDIANA: BOTANY
FIG. 27. Flourensia suffrutescens (from Dillon & Rodriguez 550, F).
tube ca. 6 mm long, villosulose; disc florets 30
50, the corollas cylindric-campanulate, ca. 6 mm
long, the tube ca. 1 mm long, the lobes ca. 0.8 mm
long. Achenes obconical, ca. 8 mm long, villous-
sericeous, faces glabrescent; pappus of 2 awns, ca.
5 mm long, persistent or disarticulating.
FLOWERING (AND FRUITING) PERIOD Novem-
ber-March (February-March).
DISTRIBUTION AND HABITAT (FiG. 26) Known
from arid sites within the lower-montane, sub-
tropical, thorny steppe associated with the Cor-
dillera Real in western Bolivia (2,700-3,000 m).
SPECIMENS EXAMINED BOLIVIA. Cochabamba: Vila
Vila, Brooke 6220 (F); above Arani, Cdrdenas 2416 (us);
50.3 km E of Cochabamba, Davidson 5050 (F); 11 km
from Quillacollo, King & Bishop 7559 (F); 19 km from
Tolata, King & Bishop 7585 (F).
Flourensia heterolepis is distinguished from F.
polycephala, its closest relative, by its longer pe-
duncles and fewer capitula. Its leaf size and shape
are variable; some individuals have small leaves
that approach those ofF.fiebrigii, a species readily
distinguished by its smaller capitula, phyllaries,
and ray florets. Associates of F. heterolepis within
the thorny steppe include Acacia, Carica, Cleis-
tocactus, Dodonaea, Nicotiana glauca, Schinus,
and Solanum.
20. Flourensia suffrutescens (R. E. Fries) S. F.
Blake, Proc. Amer. Acad. Arts 49: 376. 1913.
Figures 27, 30.
Encelia suffrutescens R. E. Fries, Nov. Act. Soc. Sci.
Upsal. IV. 1: 83. 1903. TYPE: Argentina, Jujuy,
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
43
Moreno, rocky slope, 3,600 m, 16 Dec. 1901, R. E.
Fries 926 (holotype, UPSV, not seen; isotype, us!).
Subshrubs to 40 cm tall; stems decumbent-as-
cending, pilose, gray. Leaves narrowly lanceolate
to oblong, 2-8.5 cm long, 8-18 mm wide, upper
and lower surfaces pilose, basally cuneate, apically
acute to acuminate, the margins entire; petioles 1-
3 (-5) mm long, pilose. Capitulescences solitary,
terminal; peduncles 8-1 1 cm long, densely pilose,
distally canescent, bracteate. Capitula radiate, ca.
12 mm high, 12-18 mm wide; involucres hemi-
spheric; phyllaries 2-seriate, equal, the outer ob-
long-lanceolate to ovate-lanceolate, subcanescent-
pilose, apically attenuate, the inner rhombic-ob-
ovate, sparsely pilose, apically acuminate, all ca.
1 1 mm long, ca. 2.5 mm wide, herbaceous; paleae
oblanceolate, 8-10 mm long, apically obtuse to
truncate; ray florets 9-15, the ligules linear-oblong
to elliptic, 17-32 mm long, 4-10 mm wide, the
tube ca. 5 mm long, sericeous; disc florets ca. 50,
the corollas cylindric, ca. 5 mm long, the tube ca.
1 mm long, the lobes ca. 0.7 mm long, spiculifer-
ous. Achenes obconical, ca. 6 mm long, densely
sericeous; pappus of 2 awns, equal 3-4 mm long,
persistent. Chromosome number: n 18.
FLOWERING (AND FRUITING) PERIOD February
(March).
DISTRIBUTION AND HABITAT (Fio. 30) Known
from scattered populations in the altiplano of Salta
and Jujuy in northwestern Argentina (2,500-3,600
m).
SPECIMENS EXAMINED ARGENTINA. Salta: Rosa-
rio de Lerma, Quebrada de Tastil, Las Cuevas, Cabrera
9002 (F); Cachipampa, Cabrera 22040 (LP); Puerta Tas-
til, Cabrera 22398 (LP); Cachipampa, 1 5 km W of Piedra
del Molino, Dillon & Rodriguez 550* (F, MO, NY, TEX).
Flourensia suffrutescens is distinguished by its
small habit and large capitula with subcanescent-
pilose phyllaries that equal or overtop the disc. At
the Cachipampa locality, it is associated with Lar-
rea at the lower end of its range (ca. 2,500 m) and
becomes dominant at higher elevations and is often
associated with Baccharis boliviensis, Cassia, and
Senecio.
21. Flourensia macroligulata Seeligmann, Lilloa
30: 113. 1960. TYPE: Argentina, Jujuy, Volcan,
Loma de las Lagunas, 1 5 Feb. 1 924, R. Schreiter
2663 (holotype, LIL!). Figures 28, 30.
Rounded shrubs to 1.5m tall; stems decumbent
to ascending; branchlets sparsely sericeous. Leaves
elliptic to obovate-elliptic, 7-13 cm long, 2.5-6
cm wide, upper and lower surfaces sparsely seri-
ceous, basally cuneate to rounded, apically acute
to rounded, the margins entire; petioles 5-10 mm
long, the upper leaves subsessile. Capitulescences
solitary, terminal; peduncles 4-10 cm long, seri-
ceous, bracteate. Capitula radiate, 1 8-20 mm high,
ca. 25 mm wide; involucres hemispheric; phyllar-
ies 2-3-seriate, all lanceolate-elliptic, the outer
overtopping the disc, 20-22 mm long, ca. 5 mm
wide, overtopping the disc, the inner ca. 18 mm
long, ca. 4 mm wide, all apically acute to obtuse,
sericeous; paleae obovate, ca. 1 3 mm long, apically
acute to truncate, sericeous; ray florets 1 3-2 1 , the
ligules oblong-elliptic, 25-50 mm long, 4-7 mm
wide, the tube 5-9 mm long, sericeous; disc florets
50-75, the corollas campanulate, ca. 5 mm long,
the tube ca. 1 mm long, the lobes ca. 0.8 mm long,
sparsely pilose. Achenes obconical, ca. 1 1 mm long,
densely sericeous; pappus of 2 awns, ca. 3 mm
long, persistent.
FLOWERING (AND FRUITING) PERIOD January-
February (February-March).
DISTRIBUTION AND HABITAT (FiG. 30) Known
from extensive collections on the rocky, over-
grazed slopes in the vicinity of the Laguna de Vol-
can, Jujuy, and is represented by one collection
each from Tan, Tucuman, and Tilcara, Jujuy, Ar-
gentina (2,000-3,000 m).
REPRESENTATIVE SPECIMENS EXAMINED ARGEN-
TINA. Jujuy: Volcan, Cabrera 12187 (LP), Cabrera &
Frangi 20649 (LP), Cabrera & Marchionni 12945 (us),
Castillon 9519 (LIL); ca. 41 km NE of San Salvador de
Jujuy, Dillon & Rodriguez 553 (BM, F, GH, MO, NY, TEX,
USM); Tilcara, Venturi 7402 (us). Tucuman: Tan, Sierra
del Cajon, Venturi 6284 (us).
Flourensia macroligulata is distinctive with its
large leaves and large capitula with the largest lig-
ules to be found within the genus.
In the vicinity of the type locality, individuals
occur on very steep walls of the upper reaches of
arroyos. The adjacent hillsides are overgrazed and
deep erosional areas are prevalent. A local goat
herder said that the goats would browse this species
and have destroyed all but those individuals in
inaccessible locations. I estimate the population
there to be of no more than a few hundred plants.
At lower elevations, the rocky slopes are covered
with dense cushions of Bromeliaceae and low Cac-
taceae.
44
FIELDIANA: BOTANY
5mm
1cm
FIG. 28. Flourensia macroligulata (from Dillon & Rodriguez 553, F). A, habit; B, capitulum; C, disc floret.
DILLON: SYSTEMATIC STUDY OF FLOURENSIA 45
2cm
FIG. 29. Flourensia tortuosa (from Dillon & Rodriguez 511, F). A, habit; B, capitulum; C, disc floret.
46
FIELDIANA: BOTANY
-23 17'
Tropic of Capricorn
25
Flourensia tortuosa
^ Flourensia macroligulata
Q Flourensia suffrutescens
O Flourensia hirta
% Flourensia blakeana
B Flourensia leptopoda
30
32
FIG. 30.
tortuosa.
Distribution of Flourensia blakeana, F. hirta, F. leptopoda, F. macroligulata, F. suffrutescens, and F.
22. Flourensia tortuosa Griseb. Abh. Konigl. Ges.
Wiss. Gottingen 19: 184: 1874. TYPE: Argen-
tina, Catamarca, fields between Belen and Ya-
cutula, 24 Jan. 1872, P. G. Lorentz 659 (holo-
type, GOET!; isotype, CORD!, photograph, F!).
Figures 29, 30.
Shrubs to 2 m tall; stems ascending; branchlets
sparsely sericeous. Leaves lanceolate to oval, (3-)
5-9 (-14) cm long, 1.5-3.5 (-5) cm wide, upper
and lower surfaces strigillose, basally cuneate to
rounded, apically acuminate to obtuse, the mar-
gins entire, strigillose; petioles 3-17 mm long.
Capitulescences solitary or weakly cymose, 2-3-
headed; peduncles 1-4 cm long, puberulent, brac-
teate. Capitula radiate, 10-15 mm high, 10-20
mm wide; involucre hemispheric, often subtended
by calyculate bracts; phyllaries 2-3-seriate, equal
to subequal, broadly ovate to oblong-lanceolate,
(5-) 7-15 mm long, (2-) 3-7 mm wide, herba-
ceous, apically acute to attenuate, ciliolate; paleae
oblanceolate, ca. 10 mm long, apically acute to
truncate, erose-ciliolate; ray florets ca. 10, the lig-
ules broadly oblong, 18-30 mm long, 7-10 mm
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
47
wide, the tube ca. 8 mm long, glabrous; disc florets
30-50, the corollas cylindric, 4-6 mm long, the
tube ca. 1 mm long, the lobes ca. 0.7 mm long.
Achenes obconical, 5-6 mm long, the margins se-
riceous, the faces sericeous to glabrescent; pappus
of 2 awns, ca. 3.5 mm long, often bifid, persistent
or disarticulating.
FLOWERING (AND FRUITING) PERIOD January-
March (February-April).
DISTRIBUTION AND HABITAT (Fio. 30) Found
on coarse sand in arroyos of upper bajadas be-
tween the Sierras de Zapata, de Anconjuija, and
de Belen in south-central Catamarca; and scat-
tered populations in central Salta and Tucuman,
Argentina (1,200-3,100 m).
REPRESENTATIVE SPECIMENS EXAMINED ARGEN-
TINA. Catamarca: Andalgala, Cabrera 1023 (LP, us);
Cuesta de Mina Capillitas, Cabrera et al. 14140 (LP, NY);
Tinogasta, Cuesta de Zapata, Tinogasta to Helen, Ca-
brera et al. 16736 (LP); Londres, Cabrera 18116 (LP);
Punta de Balasto, Cabrera 21807 (LP); 4 km N of An-
dalgala. Cantino 670 (ARIZ); Andalgala. Cuesta de La
Chilca, Cristoba 1477 (LIL, uc); 10 km SW of Londres,
Dillon & Rodriguez 511 (F, GH, MO, NY, TEX, USM); Cerro
Duraznos, Job 1380 (LP); El Candado, Jorgensen 1273
(GH, LIL, MO, si, uc, us); Cerrillos, Sierra de Aconquija,
Peirano s.n. (GH, LIL). Salta: Cafayate, Rio Lorohausi,
Hayward2055 (LIL); Cafayate, El Alisal, Cerro del Cajon,
Rodriguez 1341 (A, LIL, si, us); Rosario de Lerma, Nev-
aro to Castillo, Venture 9271 (us). Tucuman: Valle Tan,
La Banda, Castilldn s.n. (A, LIL).
Flourensia tortuosa has variable leaves, seem-
ingly depending upon available moisture in re-
spective habitats. Its phyllaries are also variable;
individuals from Tucuman and Salta have narrow,
oblong-lanceolate phyllaries and those surround-
ing the Bolson de Pipanaco, Catamarca have wid-
er, ovate phyllaries. Its associates include Cerci-
dium, Heliotropium, Larrea, and Senecio.
23. Flourensia oolepis S. F. Blake, Contr. U.S.
Natl. Herb. 20: 403. 1921. TYPE: Argentina,
Cordoba, Cuesta de La Oyada, Sierra Achala,
22 March 1876, G. Hieronymus s.n. (holotype,
B, destroyed; lectotype, here designated, frag-
ment GH!; photograph of B specimen, F!, GH!).
Figures 31, 38.
Flourensia grindelioides S. Moore, J. Bot. 64: 192.
1926. TYPE: Argentina, San Juan, s.d., Ms. Wright
s.n. (holotype, BM!; isotype MO!, isotype fragments
GH!, us!).
Shrubs to 3 m tall, stems ascending, the bark
brown, fissured. Leaves elliptic to elliptic-lanceo-
late, 5.5-8.5 cm long, 2-3.2 cm wide, upper and
lower surfaces glabrous, basally and apically acute,
the margins entire or with 4-6 teeth apically; pet-
ioles 5-10 mm long. Capitulescences solitary or
weakly cymose, 2-3-headed; peduncles 4-6 cm
long, bracteate. Capitula radiate, 15-18 mm high,
15-25 mm wide; involucres hemispheric; phyl-
laries 3-4-seriate, imbricate, the outer broadly
ovate, the inner gradually more oblong, all 5-6
mm long, 2.5-4 mm wide, subherbaceous, apically
acute to attenuate, ciliolate; paleae oblanceolate,
ca. 7 mm long, apically subtruncate to cucullate;
ray florets 12-16, the ligules oblong, 12-28 mm
long, 3-8 mm wide, the tube 4-5 mm long, seri-
ceous; disc florets ca. 50, the corollas cylindric, 5-
6 mm long, the tube ca. 1 mm long, the lobes ca.
0.5 mm long. Achenes obconical, 5-8 mm long,
sericeous; pappus of 2 awns, 4-5 mm long, basally
strongly ampliate and deeply lacerate, frequently
united into a lacerate corona, persistent. Chro-
mosome number: n = 18.
FLOWERING (AND FRUITING) PERIOD Septem-
ber-March (January-March).
DISTRIBUTION AND HABITAT (Fio. 38) Abun-
dant in the regions west of the Sierras de Las Co-
mechingones and de Cordoba in northwestern
Cordoba and the Sierra de San Luis, northeastern
San Luis, Argentina (1,000-2,000 m).
VERNACULAR NAMES Chilca gomosa.
REPRESENTATIVE SPECIMENS EXAMINED ARGEN-
TINA. Cordoba: La Vina, Bart let t 20615 (GH, MICH, si,
TEX, us); San Javier, Bridarolli 1006 (LP); Sierra de Po-
cho, Los Tuneles, Burkart 20864 (LP); Los Cocos, Ca-
brera 7 (GH, LP); 2 km S of Charbonier, Dillon & Ariza
567* (F, MO, TEX, USM); Sierra Grandes, Chacras, Hun-
ziker 2737 (LIL, si); Los Terrenes, Ongamira, Luti 4927
(CORD, LP); Capilla del Monte, O'Donell & Rodriguez
356 (F, LIL); Arroyo Saltos Blancos, Solomon & Solomon
4115 (F, MO); La Cumbre, Sola 401 (LIL); Villa Dolores,
Varela 444 (A, LIL); Yacanto, Vattuone 17 (si); San Mar-
cos, Villafane289(iM-). San Luis: Merlos, Piedra Blanca,
Burkart 13935 (si); Nogoli, Gez 109 (si); Sierra de Los
Comechingones, 4 km E of Merlo, Conrad & Dietrich
2490 (F, MO); El Volcan to Potero de Los Funes, Nicora
4253 (si); Sololosta, Vignati 168 (LP).
Flourensia oolepis is distinguished by its short,
broadly ovate phyllaries, 12-16 ray florets, and
achenes with the pappus awns united basally to
form a corona.
24. Flourensia fiebrigii S. F. Blake, Bot. Jahrb.
Syst. 54: 47. 1916. TYPE: Bolivia, Tarija, slope,
48
FIELDIANA: BOTANY
5mm
Icm
2cm
FIG. 31. Flourensia oolepis (from Conrad 2490, F). A, habit; B, capitulum; C, disc floret.
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
49
I cm
FIG. 32. Flourensia fiebrigii (from Meyer s.n., F). A, habit; B, capitulum; C, disc floret.
50
FIELDIANA: BOTANY
summit of pass, near Paicho, W of Tarija, 3,200
m, 5 Feb. 1904, K. Fiebrig 3050 (holotype, B,
destroyed; lectotype, here designated, F!; iso-
types BM!, GH!, MO!, si!, us!). Figures 26, 32.
Shrubs to 50 cm tall; stems decumbent to as-
cending; branchlets brown to gray, puberulent.
Leaves lanceolate to oblanceolate, 3.5-5 (-8) cm
long, (5-) 7-14 (-20) mm wide, upper and lower
surfaces hispid-pilose to glabrescent, basally and
apically acute to acuminate, the margins entire,
strigillose; petioles 2-6 mm long. Capitulescences
solitary or weakly cymose, 2-3 -headed; peduncles
1-5 cm long, hispid-pilose. Capitula radiate, 8-9
mm high, 7-9 mm wide; involucres campanulate;
phyllaries 2-3-seriate, subequal, the outer linear-
lanceolate to lance-ovate, apically acute, the inner
rhombic-ovate, apically attenuate, all 4-6 (-8) mm
long, 1-2 mm wide, densely to sparsely ciliolate,
hispid to glabrescent; paleae oblanceolate, 6-7 mm
long, apically acute to truncate, lacerate, glabrous
to hirsute; ray florets 7-10, the ligules oblong-oval,
11-16 mm long, 6-8 mm wide, the tube 3-4 mm
long, sericeous; disc florets 10-15 (-25), the co-
rollas campanulate to narrowly salverform, 3-4
mm long, the tube 0.5-0.8 mm long, the lobes
0.5-0.7 mm long, spiculiferous or glabrous.
Achenes obconical, 4-6 mm long, sericeous; pap-
pus of 2 (-3) awns, 2-2.5 mm long, basally am-
pliate, lacerate, persistent.
FLOWERING (AND FRUITING) PERIOD Febru-
ary-March (March).
DISTRIBUTION AND HABITAT (Fio. 26) Known
from dry, rocky slopes and bajadas from the cen-
tral Cordillera Real in Bolivia, and south to the
Quebrada de Humahuaca in central Jujuy, Argen-
tina (2,700-3,700 m).
REPRESENTATIVE SPECIMENS EXAMINED ARGEN-
TINA. Jujuy: Maimaria, Hualchin, Budin 79(uL); Sierra
de Zenta, Budin 7446 (LIL, us); Tilcara, Quebrada del
Chorro, Cabrera 7672 (LP, us); Huacalera, Quebrada de
La Huerta, Cabrera 12051 (LP, us); Purmamarca, Que-
brada de Huachichocana, Cabrera 15022 (LP); Yavi, Abra
de Yavi, Cabrera 15337 (LP); Quebrada del Yocordite,
Cabrera 21262 (LP); Quebrada del Rio Guasamayo, Ca-
brera & Solbrig 17031 (LP); Garganta del Diablo, Ca-
brera et al. 13932 (LP); Tilcara, Cabrera et al. 13285
(LP); Yavi, 1 6 km E of La Quiaca, Dillon & Rodriguez
579 (F, MO, TEX, USM); Tilcara, Dillon & Rodriguez 587
(F, TEX); La Quiaca, Meyer s.n. (F, GH, LIL); Pena Alta,
Venturi 4910 (F, GH, LIL, si, TEX, uc, us); 5 km NE of
Humahuaca, West 6318 (MO). BOLIVIA. Potosi: Atocha
to Quechisla, West 6100 (GH, uc).
Flourensiafiebrigii is distinguished by its small,
hispid-pilose leaves and small capitula with 7-10
ray florets. Leaf size, degree of pubescence, and
growth form are quite variable. Individuals from
the type locality are robust shrubs with wide leaves
and sparse pubescence; to the southwest, individ-
uals are smaller and the leaves are quite pubescent.
With continued study, these forms may warrant
formal taxonomic recognition. Its associates in-
clude Baccharis, Cassia, Hoffmanseggia, Hyme-
noxys, Parthenium, and Trichocereus.
25. Flour ensia blakeana Dillon, Ann. Missouri Bot.
Gard. 68: 108. 1981. TYPE: Argentina, Tucu-
man, KM 95-105 on Ruta 307, between Amai-
cha del Valle and Tan del Valle, 2,900-3,000
m, 22 Feb. 1973, M. Dillon & E. Rodriguez
560* (holotype TEX!; isotypes, BM!, F!, HUT!, LP!,
MO!, NY!, USM!). Figures 30, 33.
Shrubs to 1 m tall; stems ascending, the bark
gray to black. Leaves narrowly oblong-elliptic, ( 1 5-)
20-35 (-47) mm long, (3-) 4-8 (-11) mm wide,
upper and lower surfaces sparsely strigillose, ba-
sally attenuate, apically acute, the margins entire,
strigillose; petioles 1-3 mm long. Capitulescences
cymose, 2-4-headed; peduncles 1-4 cm long,
sparsely strigillose. Capitula radiate, 6-11 mm high,
(5-) 7-1 (-1 4) mm wide; involucres campanulate;
phyllaries 2-3-seriate, subequal, the outer linear-
lanceolate, (3-) 4-6 mm long, 0.8-1 mm wide,
apically attenuate, black, strigillose, the inner nar-
rowly rhombic, 5-6 (-7) mm long, apically atten-
uate; paleae oblanceolate, 5-6 mm long, apically
obtuse; ray florets ca. 8, the ligules oblong-oval,
10-24 mm long, 5-8 mm wide, the tube 3-4 mm
long, pubescent to glabrous; disc florets ca. 25, the
corollas cylindric-campanulate, 4-5 mm long, the
tube ca. 1 mm long, the lobes 0.6-0.8 mm long.
Achenes obconical; pappus of 2 awns, 2.0-3.5 mm
long, the bases ampliate, persistent. Chromosome
number: n = 18.
FLOWERING (AND FRUITING) PERIOD January-
March (March).
DISTRIBUTION AND HABITAT (Fio. 30) Fre-
quent on sand and gravel of lower bajadas in the
arid quebradas in the Cordillera Oriental of north-
western Tucuman and adjacent eastern Catamar-
ca, Argentina (1,800-3,000 m).
VERNACULAR NAME Viscol.
SPECIMENS EXAMINED ARGENTINA. Catamarca:
Santa Maria, Torollaco, Reales 1056 (LIL); Pafaquillo,
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
51
5mm'
2cm
I cm
FIG. 33. Flourensia blakeana (from Dillon & Rodriguez 560, F). A, habit; B, capitulum; C, disc floret.
Reales 1702 (LIL). Tucuman: ca. 25 km NW of Tafi de
Valle, Bacon & Bohnstedt 77 (TEX); Cuesta del Infier-
nillo, Cabrera & Frangi 20763 (LP); Divisadero, Cafay-
ete-Tafi del Valle, Carenzo 1358 (LIL); Tafi, KM 95, Los
Cardones, camino del Infiernillo a Amaicha, Legname
& Vervoost 34 (NY); Machorastroja, Schreiter 1311 (LIL);
Amaicha to Santa Maria, Schreiter 5636 (A, LIL); Las
Areas, Schreiter 5637 (A, LIL); Quebrada del Chorro,
Venturi 4110 (LIL, us).
Flourensia blakeana is a frequent element of the
xeric formation in the Cuesta del Infiernillo. It
most closely resembles F. fiebrigii and is distin-
guished from that species by its smaller leaves and
narrower phyllaries. It is ecologically isolated from
its nearest geographic neighbor, F. riparia, which
occurs below 2,000 m in eastern Tucuman.
52
FIELDIANA: BOTANY
I cm
5mm
FIG. 34. Flourensia hirta (from Dillon & Rodriguez 471, F). A, habit; B, capitulum; C, disc floret.
DILLON: SYSTEMATIC STUDY OF FLOURENSIA
53
26. Flourensia hirta S. F. Blake, Contr. U.S. Natl.
Herb. 20: 402. 1921. TYPE: Argentina, La Rio-
ja, vicinity of Los Corrales, Sierra Famatina, 7
Feb. 1897, G. Hieronymus & G. Niederlein 635
(holotype, B, destroyed; lectotype, here desig-
nated, fragment GH!; photograph of B specimen,
F!, GH!). Figures 30, 34.
Shrubs to 1.5 m tall; stems ascending; branch-
lets dark brown, hirsutulose. Leaves 3-6.5 (-7.5)
cm long, 5-10 (-12) mm wide, upper and lower
surfaces hirsutulose-strigillose, basally and api-
cally attenuate, the margins entire, strigillose; pet-
ioles 1-5 mm long. Capitulescences cymose, 2-4-
headed; peduncles 1-6 cm long, hirsutulose. Ca-
pitula radiate, ca. 10 mm high, ca. 8 mm wide;
involucres cylindric-campanulate; phyllaries 2-se-
riate, subequal, the outer linear to lanceolate, strig-
illose to hirsutulose, the inner narrowly ovate-lan-
ceolate, all apically attenuate, (5-) 6-10 (-13) mm
long, 1-1.5 mm wide; paleae oblanceolate, ca. 6.5
mm long, apically obtuse to acute; ray florets 5-
8, the ligules oblong, 8-20 mm long, 3-8 mm wide,
the tube ca. 5 mm long, puberulent, disc florets
ca. 25, the corollas cylindric-campanulate, ca. 4
mm long, the tube ca. 0.5 mm long, the lobes ca.
0.5 mm long. Achenes obconical, 4-5 mm long,
the margins sericeous, the faces glabrescent; pap-
pus of 2 awns, 3-4 mm long, persistent. Chro-
mosome number: n = 18.
FLOWERING (AND FRUITING) PERIOD January-
March (February-April).
DISTRIBUTION 
