NOTES ON ERIOCHLOA WEBERBAUERI (POACEAE: PANICEAE)

5 Pages·1994·3 MB·English

by  Robert D Webster

ON
NOTES
ERIOCHLOA WEBERBAUERI
(POACEAE: PANICEAE)
ROBERT WEBSTER
D.
United Department
States Agriculture
of
&
Systematic Botany Mycology Laboratory
Bldg Rm. BARC-West
003, 253,
MD
USA
20705,
Beltsville,
PAUL PETERSON
M.
Department Botany
of
Museum
National Natural
History
of
Smithsonian
Institution
DC
USA
Washington, 20360,
SHAW
ROBERT
B.
CO USA
80326,
Fort
Collins,
Ermh
Recent collections -om Ecuador have uncovered the presetice of a species, loa
fi
weherbaueri]Vfez,forwhi,ch comparative taxonomic informati Previou
little ion available. sly
is
umque
reported on ly from Pert this species characterized by features within the gen
is
1,
morpholog ical description is presented and based 3n studies of all availalble
.
specimens. ps with other species are discussed and based on the presence of
shared taxoiaomically nportant characters. Diagnostic features of£. weberbauen mcYud
ir
muticQus arid smooth u]pper floret, perennial habit, paired spikelets,spikelets 3.1-3.9 nim
long, and absence o fa glume.
rl.e first
Recolecc,.nesrecient en Ecuador han descubierto presenci adeunaespecie,£..-Aba
:es la
muy
Mez, de ue hay disponible poca informacion
la q
Citadapreviiamente solo de Peru, esta expecie presenta unas caract eristicas unicas dentro del
c
.
genero.Sej descripcion morfologica completa en ba a estudios de todos
Lse los
disponible: Se discuten las relaciones con otras especies en base a la presen.cia
i 5.
de caractere compartid( taxonomicamente importantes. Los •acteresdiagnosricosdef.
OS cat
s
weberbauen incluyen una flor superior mutica y habito pere:nne, espiguillas paread
lisa, as.
j
u-3.9™.
gk
espiguilks de largas ausencia de primera ..a.
y la la
: ,
INTRODUCTION
The
Pa niceae tribe of grasses characterized by a paniculate
is a inflore
.
cence, spi kelets wit h two florets, the lower floret ste rile, the upper flor
mem-
fertile and coarser in texture than the lower floret. Erwchloa Kunth, a
ber of this tribe, consists of about 30 species and occurs throughout the
warm
subtropical, and temperate regions of the world. Presence of
tropical,
from
a cup-like callus at the spikelet base differentiates Eriochloa the other
105 genera of the Paniceae. Additional significant characters used to differen-
tiate Eriochloa within the tribe include an indurate upper floret, disarticula-
tion at the spikelet base, inflorescence with racemose primary branches, and
&
the absence of a bristle (Webster Valdez 1988, Webster et 1989).
al.
Significant characters used to differentiate the species o^ Eriochloa include
awn
spikelet shape, presence of an on the upper spikelet length,
floret,
presence of hairs in the inflorescence, spikelet arrangement, longevity, and
&
the relative length of the (Webster 1987, Shaw Webster 1987).
florets
Recent collections by Peterson and others in Ecuador have revealed the
presence of specimens which do not match the morphological characteristics
commonly The
of taxa associated with that area. characteristics of this taxon
DELTA
were recorded in format (Dallwitz 1980, Dallwitz 1993) and
et
al.
compared
against other recognized species of Eriochloa. This analysis
all
know
indicated these specimens could not be differentiated from a poorly
Peruvian species, E. weberbaueri Mez. Hitchcock (1927) states that this
known
species was only from the type specimen. Tovar (1993) only two
list
specimens, the type and Anderson 740, which was collected in the same area
A
Herbarium
of Peru. survey of collections the U.S. National revealed the
at
Camp
presence of three specimens {Anderson 740, Sanchez Vega 1031, E-2346)
which
possess the diagnostic characteristics of £. weberbaueri. In addition, G.
MO
&
Davidse has identified two collections {Sanchez 3367 Smith 6190)
etal.
same
of the species.
Diagnostic features of Eriochloa weberbaueri include a muticous upper
a smooth upper paired spikelets on the primary inflorescence
floret, floret,
mm
glume
branches, perennial habit, spikelet length (3.1-3-9 long),
first
absent, and the absence of elongate rhizomes Eriochloa distachya, E. michauxii,
.
E. polystacyha, E. sericea, and E. weberbaueri are the only species with a
Of
muticous upper and perennial subgroup, and
floret habit. this E. distachya
E. weberbaueri are the only species with long hairs associated with the pedicel.
and
Eriochloa michauxii, E. polystacyha, E. weberbaueri share the presence of
paired spikelets. Therefore, the presence of hairs the pedicel apex and
at
paired spikelets distinguishes E. weberbaueri within this subgroup of mor-
most
phologically related species. Perhaps the diagnostic characteristic of
£,
weberbaueri the smooth and relatively shiny upper This characteris-
is floret.
tic appears to be unique for E. iveberbaueri within the genus. This species
appears to be associated with drier environments at elevations between
and
1,500 3,000 meters.
fragments
at US!).
Plants perennial; stoloniferous; rhizomatous. Rhizomes with compacted
dm
nodes; with glabrous Flowering culms 3-8
not
scales. caespitose;
tall;
from
erect the base; not rooting the lower nodes; with hard knotty
at a base;
terminated by a solitary inflorescence; branched from the base; 2-5-noded.
Nodes
not swollen; pubescent. Internodes hollow; glabrous; smooth; neither
viscid nor glaucous. Leaves cauline or basal; green; without Sheaths
auricles.
cm
6-1
3 long; overlapping or not overlapping; not inflated; smooth; glabrous;
mm
rounded; not keeled; not ciliate; closed. Ligule a fringe of hairs; 0.5-1.2
cm
7-20
long. Collar not differentiated; pubescent. Leaf blades long; 1.5-
mm
wide;
5 linear; flat, involute, or convolute; flexuous; spreading; lax;
smooth on the lower and upper surfaces; glabrous on the lower surface;
glabrous or hairy (minutely pubescent) on the upper surface; with a truncate
base; with margins; with margins not thickened; with scabrous margins;
flat
with glabrous margins; with midrib
the not obviously
differentiated;
lacking obvious transverse veins; acuminate. Prophyllum with scabrous
mm
nerves; with pronounced Peduncle 160-300
keels. long; glabrous.
mm
10-35
Panicle wide; fully exserted maturity; oblong. Lowermost
at
mm
node Main 60-150
inflorescence not differentiated; hairy. axis present;
long; straight; stout; hairy; pubescent; with hairy with quaquaversal
axils;
mm mm
primary branches. Primary branches 10-30 long; 0.3-0.5 wide;
main
appressed to the axis or spreading; with appressed secondary branches;
with secund spikelets; not whorled; 8-13 on the main axis; straight; not
winged; smooth;
hairy; setose; with loosely arranged
ciliate; spikelets.
mm
Rachis terminating
in a spikelet. Pedicels present; 0.2-0.5 long;
straight; scabrous; hairy; setose; with hairy apices; discoid the apex;
at
perpendicular with the spikelet base; concave. Disarticulation at the spike-
let base. Callus differentiated; not prolonged into a stipe; not flared to form
a discoid receptacle; not oblique; rounded; smooth; glabrous. Cleistoga-
mous
inflorescence absent.
mm
mm
Spikelets 3.1-3.9 long; 0.9-1.1 wide; paired; densely overlap-
ping; evenly distributed on the rachis; not divergent from the homo-
axis;
morphic; adaxial; green; dorsiventrally compressed; glume
lanceolate. First
absent. Rachilla pronounced below the second glume; not pronounced
mm
between the florets. Second glume 3.0-3.7 long; times spikelet
1
length; times the length of the lower membranous;
lanceolate;
1 floret;
rounded on smooth;
the back; 5-nerved; hairy; pubescent; acute to acumi-
nate; muticous. Fertile florets 1. Sterile florets 1. Lower floret lacking

mm
Lemmaof
stamens. lower 2.8-3.7 membranous;
floret long; lanceolate;
smooth; with equal internerve spacing; 3-nerved; the nerves pronounced but
not swollen; the nerves smooth; not keeled; with glabrous margins; lacking
lemma
Lower
a central longitudinal groove; acute; muticous; hairy. hairs not
forming a distinct horizontal line; shorter than the upper pubescent;
floret;
smooth and without
terete; apical modifications; white. Palea of lower floret
Lemma
Upper
absent. 0.9 times the length of the lower of upper
floret floret.
mm
2.3-2.8
floret long; lanceolate to ovate; cartilaginous; slightly convex;
smooth; yellow; shiny; with involute margins; with margins of the same
texture the body; glabrous; 3-nerved; the nerves not pronounced; with
as
smooth
without
nerves; basal modifications; not differentiated the apex;
at
entire; acute; muticous. Germination flap conspicuous. Palea of upper floret
well-developed; enclosed the apex; cartilaginous; smooth; the base neither
at
swollen nor protruding; the nerves pronounced but not winged. Lodicules
mm
about 0.1 long; the nerves not pronounced. Stamens Anthers L5-1.7
5 3.
mm
&
long; yellow. Stigmas yellow to orange. South America: Ecuador Peru.
SOUTH
AMERICA.
Specimens Ex Ecuador. ProviriciadeAzuay:10.2km]
amineci:
H
ofOnaonthePa wy
n American the bridge crossing the Rio Leon, 1880 m, 24 Aj
at elev.
Anm
;3kmSofCuencaonroa
1990, P.M. C.R. tbleandM.-E.PostonS9in^^':)\^
Pe^etson,
May
CO Loja, crossing of Rio Leon,. 1800 m, 30 1990, P./W..Peterson and Judziewi.
;lev. E.J.
9378 (US!); vail..yofthenoPa ute, between Paute and Cuenca, 2 6 Apr 1945, Camp E-2 34
(US!). Peru. Sarua Cruz, Sa.«f^.z V.i« 03 (US!); 11 Apr 1948, Anderson 740 (US!).
/. / i
ma
Gratitude extended Dr. Gerrit Davidse king valuable sugges
to for
IS
i i
mg
)nomy
tions concern the taxc of this group.
ripcions.Taxon 29:41-46.
DELTA
de to the system:
CSIRO
Division
ed.
ol
1
The
A.S. 1927.
,
HAW, R.B. and R.D. Webster. 1987. The genus Eriochloa (Poaceae: Panic
Central America. Sida 12:165-207.
qvar, O. 1993. Eriochloa in las gramineas (Poaceae) del Peru. Ruizia 1:
Webster, R.D. 1987. The Australian Paniceae (Poaceae). Cramer, Ber
J.
and Valdes Reyna. 1988. Genera of Mesoamerican P
J.
New
Woi
J.H. Kirkbride and Valdes Reyna. 1989.
J.
,