STUDIES OF NEOTROPICAL COMPOSITAE-II. A NEW COMBINATION IN CHROMOLAENA (EUPATORIEAE)

2009·4.5 MB·English

by  John F Pruski

OF NEOTROPICAL
COMPOSITAE-II.
STUDIES
NEW
CHROMOLAENA
A COMBINATION (EUPATORIEAE)
IN
John
R
Pruski
been
Most Chromolaena DC. (Compositae: Eupatorieae: Praxelinae) have treated historically as
species of
summarized by
members Robinson Chromolaena,
Eupatorium Cylindrocephala 1918, 1919). as
oi sect.
(e.g.,
by
King and Robinson however, from Eupatorium L. glabrous setulose) style bases, distinct
(1987), differs (vs.
Chromolaena
and deciduous
carpopodia, cylindrical involucres of persistent) phyllaries.
indistinct) (vs.
(vs.
on
from remaining genera Praxelinae by subequal corolla lobes, receptacles that are usually top,
of flat
differs
&
long pappus and branches that are cylindrical and never clavate (King Robinson 1987).
style
bristles,
Robinson recognized Eupatorium
In a revision of Peruvian Eupatoriums, B.L. (1919) the distinctive
and Holmes
DC. whereas King and Robinson (1987) and Robinson (2008) in
dematitis (see Fig. list it
1),
&
was Ecuador
synonymy R.M. King H. Rob. Eupatorium dematitis not listed as occurring in
of odorata
C. (L.)
common much
by Robinson Chromolaena odorata and widespread throughout of the neotropics,
(1918). is
&
My
and known an introduced weed in the paleotropics (King Robinson 1987; Pruski 1997).
also as
is
endemic
treatment Compositae the Rio Cenepa region of northern Peru recognizes C. dematitis as to
of for
The purposes paper
Ecuador and Peru, where occurs in low foothills of the eastern Andes. of this are to
it
provide a new combination for this species and a description of it for use as an aid in identifications.
nov DC,
Chromolaena comb,
dematitis (DC.) Pruski, (Fig. 2). Basionym: Eupatorium dematitis Prodr. 5:144. 1836.
G-DC
Osmia dematitis (DC.) Sch. Bip., Jahresber. Pollichia 22-24:252. 1866. Type: "Peruvia?," 1834 [sic], Poeppig3108 (holotype:
m
Perennial herbs vining shrubs, 0.7-2 stems few-branched distally, subterete, puberulent to glabrate.
to tall;
cm
0.8-3 long, slender, puberulent; blade deltate to hastate,
Leaves simple, opposite, long-petiolate; petiole
cm cm margins
from
2-7 0.6-5.5 wide, chartaceous thinly 3-veined base, base hastate to truncate,
long, to so,
puberulent along veins glabrous,
apex long-acuminate attenuate, adaxial surface to
entire to few-serrulate, to
non-glandular trichomes very
otherwise puberulent glabrous, the
abaxial surface densely red-glandular, to
with ultimate branches umbelliform corymbi-
open, thyrsoid-paniculate to
Capitulescence terminal,
short.
mm
cm cm
15-20 23-26-flowered, 9.5-12.5 high,
2-21-headed, 15 wide. Capitula discoid,
form,
to ca.
tall,
mm
mm
9-11.5 exserted; phyllaries imbricate,
2.8-3.5 wide; involucre cylindrical, long, corollas slightly
appressed, deciduous in scarious with apex subherbaceous, generally
graduated, 5-7-seriate, tightly fruit,
3-nerved, most or the mid-series phyllaries truncate-mucronate apically, glabrous to outer series
least
at
mm mm
1-2 1-2 wide, grading
sparsely puberulent outer ones elliptic-lanceolate to ovate, long,
distally,
mm mm
but
9-11.5 1-1.5 wide; receptacle epaleate, shortly clavate
into inner ones, these lanceolate, long,
mm
cm
on and wide, glabrous; peduncle 1-2.5 long, striate, often 1- or 2-bracteolate,
top, ca. 1.6 tall
flat
cm
4.8-5.7
main white, funnelform,
6 Florets bisexual; corolla
puberulent, capitulescence stalk to long.
mm
mm
spreading; anthers included; style
long, glabrous, lobes subequal, ca. 0.5 long, erect to slightly
J.Bot.Res.lnst.Texas3{2):57
Journal of the Botanical Research Institute of Texas 3(2)
mm
3-4
from proximal each
base glabrous, branches cylindrical, greatly exserted corolla, long, the half of
with minutely append-
branch with paired ventro-marginal stigmatic lines, the distal half papillose sterile
mm
brown
with 3-3.6
age with an acute obtuse apex. Cypselae narrowly obconical, tan angles, long,
to
carpopodium pappus many, stramineous,
3-4-angled, glabrous; distinct, tan, circular; bristles elongate,
&
(MO).
17
—
known
Distribution and Chromolaena dematitis to flower from June to August at elevations between
ecology. is
1-8°
350-450 Andean Ecuador and Peru from about south
meters in the eastern foothills of latitude.
known and from
Chromolaena dematitis only from a few collections in northern Peru eastern Ecuador,
is
where the type was presumably collected. By gestalt and reddish sessile glands of the abaxial leaf surfaces,
which was synonymized by King and Robinson and
under (1987)
C. dematitis similar to C. odorata,
is it
by
Robinson and Holmes Chromolaena recognized however, leaves with hastate
(2008). dematitis is easily, its
umbelliform
and with branches long-pedunculate
truncate bases capitulescences ultimate of typically
to
somewhat
capitula. Although across broad range in both hemispheres C. odorata is variable in shape
its
and minor and while remains
and pubescence of leaves phyllaries, variation continuous, C. dematitis
its is
new
A Chromolaena
combination
Pruski, in
Photograph of the holotype (PoepPigSW8, G-DC) oiEupatoriumclematitis DC.
2.
Fig.
Journal of the Botanical Research Institute of Texas 3(2)
576
Chromolaena from odorata by basally hastate to truncate (vs. at-
consistently distinctive. clematitis differs C.
and
glandular
puberulent glabrous
tenuate subtruncate) leaves with blades glandular, otherwise to (vs.
to
with long short)-pedunculate typically
pubescent) by ultimate branches of the capitulescences (vs.
abaxially,
with
umbelliform corymbiform) capitula, and by most or at least the mid-series phyllaries truncate-
(vs.
mucronate rounded)
acute apices.
to
(vs.
ACKNOWLEDGMENTS
(MO) Spanish and helping prepare Figure
would thank Rosa Ortiz translating the abstract into for
for
like to
I
comments on manuscript,
Walter Holmes (BAYLU), Rosa Ortiz (MO), and Harold Robinson (US) for the
1,
me
and Niezgoda
Kawasaki and Anna sending an image of the holotype, Christine (F)
Lucia Balla (F) for
photograph.
permission publish
this
for to
REFERENCES
Monogr. Missouri Gard.
The genera of Eupatorieae (Asteraceae). Syst. Bot. Bot.
and
R.M. H. Robinson. (1987).
King,
22:1-581.
Venezuelan Guayana,
and of the
Steyermark, Hoist, eds. Flora
997. Asteraceae. RE. Berry, B.K.
Pruski, IF. In: J.A.
1
177-393.
Garden,
Missouri Botanical Louis. Pp.
vol. 3. St.
Keyed recensions of the Eupatoriums of Venezuela and Ecuador. Proc. Amer. Acad. Arts
B.L 1918.
Robinson,
54:331-367.
A
recensic
Robinson, 91
B.L. 9.
1
and W.C. Holmes. 2
Robinson, H.